Kịch bản BĐKH và nước biển dâng cho Việt Nam 2011

B TI NGUYN V MI TRNG

KCH BN BIN I KH HU, NC BIN DNG CHO VIT NAM

H NI, 2011

MC LC Trang MC LC .................................................................................................................... 2 LI GII THIU.......................................................................................................... 3 DANH MC CC CH VIT TT............................................................................... 4 CC THUT NG CHNH .......................................................................................... 6 DANH MC BNG .................................................................................................... 10 DANH MC HNH ..................................................................................................... 11 TM TT KCH BN BIN I KH HU, NC BIN DNG CHO VIT NAM V NHNG IM MI C BN .................................................................................... 15 1. BIU HIN CA BIN I KH HU, NC BIN DNG .................................. 17 1.1. Biu hin ca bin i kh hu, nc bin dng trn th gii ............................ 17 1.2. Biu hin ca bin i kh hu, nc bin dng Vit Nam ............................. 21 2. PHNG PHP XY DNG KCH BN BIN I KH HU, NC BIN DNG CHO VIT NAM ............................................................................................. 26 2.1. Yu cu cp nht kch bn bin i kh hu, nc bin dng cho Vit Nam ..... 26 2.2. La chn kch bn pht thi kh nh knh ........................................................... 26 2.3. La chn phng php xy dng kch bn bin i kh hu, nc bin dng cho Vit Nam.................................................................................................................... 28 2.4. Mt s lu v cc kch bn bin i kh hu, nc bin dng v bn nguy c ngp ..................................................................................................................... 38 3. KCH BN BIN I KH HU, NC BIN DNG CHO VIT NAM................. 40 3.1. Kch bn bin i kh hu i vi nhit .......................................................... 40 3.2. Kch bn bin i kh hu i vi lng ma ..................................................... 56 3.3. Kch bn bin i kh hu i vi kh p v m ............................................. 70 3.4. Kch bn nc bin dng cho Vit Nam ............................................................. 71 4. NGUY C NGP THEO CC MC NC BIN DNG .................................... 74 KT LUN V KHUYN NGH ................................................................................. 96 TI LIU THAM KHO ............................................................................................. 98 PH LC................................................................................................................. 103

Kch bn bin i kh hu, nc bin dng cho Vit Nam 2


LI GII THIUBin i kh hu ang din ra quy m ton cu, khu vc v Vit Nam do cc hot ng ca con ngi lm pht thi qu mc kh nh knh vo bu kh quyn. Bin i kh hu c nhng tc ng tiu cc i vi con ngi, kinh t - x hi v mi trng. Vn bin i kh hu , ang v s lm thay i ton din v su sc qu trnh pht trin v an ninh ton cu nh lng thc, nc, nng lng, an ton x hi, chnh tr, vn ha, kinh t, ngoi giao v thng mi. L mt trong nhng nc chu tc ng nng n nht ca bin i kh hu, Vit Nam coi ng ph vi bin i kh hu l vn c ngha sng cn. ng ph hiu qu vi bin i kh hu, nhng hiu bit v kh hu trong tng lai thng qua cc kch bn bin i kh hu l rt cn thit. Trong nm 2009, da trn c s tng hp cc nghin cu trong v ngoi nc, B Ti nguyn v Mi trng xy dng v cng b kch bn bin i kh hu, nc bin dng cho Vit Nam. Cc kch bn bin i kh hu, nc bin dng to c s cho cc B, ngnh, a phng nh gi tc ng ca bin i kh hu, xy dng v trin khai k hoch hnh ng ng ph. Thc hin ch o ca Chnh ph v vic cp nht v chi tit ha cc kch bn bin i kh hu v nc bin dng cho Vit Nam, B Ti nguyn v Mi trng giao Vin Khoa hc Kh tng Thy vn v Mi trng ch tr, phi hp vi cc c quan nghin cu v cc n v qun l nh nc, tnh ton chi tit ha mc thay i ca cc yu t kh hu, tp trung vo cc yu t chnh l nhit , ch ma, nc bin dng cho cc a phng v cc khu vc ven bin Vit Nam. Cc tnh ton c da trn kt qu phm vi ton cu ca Ban lin chnh ph v bin i kh hu v cc iu kin kh hu c th ca Vit Nam v c trnh by trong bo co "Kch bn bin i kh hu, nc bin dng cho Vit Nam". B Ti nguyn v Mi trng trn trng gii thiu Kch bn bin i kh hu, nc bin dng cho Vit Nam lm c s nh hng cho cc b, ngnh, a phng nh gi tc ng tim tng ca bin i kh hu, xy dng v trin khai k hoch ng ph hiu qu vi bin i kh hu, nc bin dng.

Nguyn Minh Quang B trng B Ti nguyn v Mi trng



DANH MC CC CH VIT TT AR4 BKH CRU DBHD DEM TDB ERA40 FAR GCM GIS IMHEN IPCC JAMSTEC JMA KNK MAGICC/ SCENGEN MOS MRI/AGCM Bo co nh gi ln th t ca IPCC v bin i kh hu (Four Assessment Report) Bin i kh hu S liu ti phn tch ton cu vi phn gii 0,5 x 0,5 kinh v (Climate Research Unit) D bo hn di M hnh s cao, M (USGS Digital Elevation Model) i tng d bo S liu ti phn tch ton cu vi phn gii 2,5 x 2,5 kinh v ca Trung tm D bo thi tit hn va, Chu u. Bo co nh gi ln th nht ca IPCC v bin i kh hu (First Assessment Report) M hnh hon lu chung (General Circulation Model) H thng thng tin a l (Geographic Information System) Vin Khoa hc Kh tng Thy vn v Mi trng (Vietnam Institute of Meteorology, Hydrology and Environment) Ban Lin Chnh ph v bin i kh hu (Intergovernmental Panel on Climate Change) Cc Cng ngh v Khoa hc Tri t i dng, Nht Bn (Japan Agency for Marine-Earth Science and Technology) Cc Kh tng Nht Bn (Japan Meteorological Administration) Kh nh knh Phn mm t hp cc kch bn pht thi kh nh knh (Model for the Assessment of Greenhouse-gas Induced Climate Change/ Regional Climate SCENario GENerator) Thng k u ra ca m hnh (Model Output Statistics) Vin Nghin cu Kh tng Nht Bn (Meteorology Research Institute)/M hnh hon lu chung kh quyn (Atmosphere General Circulation Model) Trung tm Nghin cu Kh quyn Quc gia, Hoa K (The National Center for Atmospheric Research) C quan i dng v Kh quyn Quc gia, Hoa K (National Oceanic

NCAR NOAA



and Atmospheric Administration) NTDB PCMDI PP PRECIS SD SDSM SIMCLIM Nhn t d bo Chng trnh chun on m hnh kh hu v so snh ln nhau (Program for Climate Model Diagnosis and Intercomparison) Phng php s dng s liu "phn tch li" kt hp vi s liu quan trc tng ng thit lp m hnh (Perfect Prognosis) M hnh kh hu khu vc ca Trung tm Hadley, Vng quc Anh (Providing Climate Information for Impact Study) Chi tit ha thng k (Statistical Downscaling) M hnh chi tit ha thng k (Statistical Downscaling Model) H thng m hnh tch hp nh gi tc ng v thch ng vi bin i kh hu (The Simulator of Climate Change Risks and Adaptation Initiatives) Chng trnh ci tin d bo mc nc bin dng (The Sea Level Rise Rectification Program) Bo co nh gi ln th ba ca IPCC (Third Assessment Report) Ti nguyn v Mi trng T chc Kh tng th gii (World Meteorological Organization) Xoy thun nhit i

SLRRP TAR TNMT WMO XTN



CC THUT NG CHNH Ban lin Chnh ph v bin i kh hu Intergovernmental Panel on Climate Change (IPCC): IPCC l t chc quc t hng u v nh gi BKH do T chc Kh tng Th gii (WMO) v Chng trnh Mi trng Lin Hip Quc (UNEP) thnh lp nm 1988. L t chc khoa hc Lin Chnh ph ca tt c cc nc l thnh vin ca Lin Hip Quc v T chc Kh tng Th gii. Bng quyn - Cryosphere: Cc khi bng v tuyt (trn t lin v bin) ca tri t. Bin ngy ca nhit - Daily (Diurnal) Range of Temperatures: Phm vi bin i ca nhit trong vng 24 gi. Bin i kh hu - Climate Change: S thay i ca kh hu (nh ngha ca Cng c kh hu) c quy trc tip hay gin tip l do hot ng ca con ngi lm thay i thnh phn ca kh quyn ton cu v ng gp thm vo s bin ng kh hu t nhin trong cc thi gian c th so snh c. Bin i kh hu xc nh s khc bit gia cc gi tr trung bnh di hn ca mt tham s hay thng k kh hu. Trong , trung bnh c thc hin trong mt khong thi gian xc nh, thng l vi thp k. Chun (kh hu) - Normals (Climate): Trung bnh ca thi k, tnh cho mt thi k nh nhau l 30 nm Chun sai kh hu - Climatic Anomaly: (1) lch ca gi tr mt yu t kh hu so vi gi tr trung bnh ca n; (2) S khc bit gia gi tr ca mt yu t kh hu mt ni v gi tr trung bnh ca yu t ly theo vng v tuyn i qua ni . Chu trnh cacbon - Carbon Cycle: Cc qu trnh t nhin chi phi s trao i ccbon (di dng CO2, ccbnt v cc hp cht hu c v.v...) trong kh quyn, i dng v tri t. Cng c Khung ca Lin Hip Quc v Bin i kh hu - UN Framework Convention on Climate Change (UNFCCC): Thng gi tt l Cng c kh hu, c hn 150 nc k ti Hi ngh Thng nh tri t Rio de Janeiro nm 1992. Mc tiu cui cng ca Cng c l n nh nng kh nh knh trong kh quyn mc c th ngn nga c s can thip nguy him ca con ngi vo h thng kh hu. Cng bc bc x - Radiative Forcing: S thay i trong cn cn bc x ca tri t gia bc x ti ca mt tri v bc x i ca tri t di dng bc x hng ngoi v sng ngn. Nu khng c cng bc bc x, bc x mt tri c tri t hp th s gn bng bc x hng ngoi pht ra t tri t. Vic c thm kh nh knh hp th thm mt phn bc x hng ngoi trong kh quyn, bc x tr li tri t, to ra nh hng gy nng ln ton cu. Dao ng kh hu - Climatic Fluctuation: Bin ng kh hu gm bt k dng thay i c tnh h thng no, d thng xuyn hay khng thng xuyn, tr cc xu th v bt lin tc (thay i t ngt trong mt giai on, t gi tr trung bnh ny sang gi tr trung bnh khc). c trng bng t nht hai cc i (hay cc tiu) v mt cc tiu (hay cc i), gm c hai u chui s liu. ixit cacbon hay CO2 - Carbon Dioxit: Mt cht kh trong t nhin, cng l mt sn phm ph ca vic t cc nhin liu ha thch v sinh khi, cng nh ccKch bn bin i kh hu, nc bin dng cho Vit Nam 6


qu trnh thay i s dng t v cc qu trnh cng nghip khc. l cht kh nh knh ch yu do con ngi sinh ra, nh hng n nhit tri t. N l cht kh tham chiu tnh tim nng nng ln ton cu ca cc kh nh knh khc. CO2 chim gn 0,036% kh quyn. Gin n nhit ca cc i dng - Thermal Expansion of the Oceans: Vi khi lng khng i, th tch cc i dng v mc nc bin thay i theo mt ca nc bin. Mt c quan h ngc vi nhit , do , khi cc i dng m ln, mt gim v cc i dng gin n. Thay i v mn khu vc nh cng lm thay i mt v th tch nc bin, tuy nhin tc ng ny tng i nh trn quy m ton cu. Hn - Drought: Mt hin tng t nhin xy ra khi lng ging thy di mc trung bnh nhiu nm, khin mc nc h thp v cy ci cht. Hn gy nhng tn tht cho cng ng (tn tht ma mng, thiu cung cp nc). H thng kh hu - Climate System: Ton b kh quyn, thy quyn, bng quyn, sinh quyn v thch quyn cng cc tng tc ca chng th hin cc iu kin trung bnh v cc tr ca kh quyn trong mt thi k di ti mt khu vc ca b mt tri t. Hiu ng nh knh - Greenhouse Effect: Hiu qu gi nhit tng thp ca kh quyn nh s hp th v pht x tr li bc x sng di t mt t bi my v cc kh nh hi nc, ccbon ixit, nit xit, m tan v chlorofluorocacrbon, lm gim lng nhit thot ra khng trung t h thng tri t, gi nhit mt cch t nhin, duy tr nhit tri t cao hn khong 30 oC so vi khi khng c cc cht kh . Hon lu chung ca kh quyn - General Circulation of the Atmosphere: H thng trung bnh ton cu ca gi v cc h thng thi tit km theo. S chuyn ng ca khng kh gy nn bi s t nng khc nhau trn b mt tri t v kh quyn v do tri t quay, vi cc khc bit v a hnh gy nn cc bin i a phng. Hi tip kh hu - Climate Feedbacks: S tng tc gia cc kh nh knh v nhng c ch kh hu quan trng nh lp thc vt, hi nc, lp bng, my v i dng. Cc tng tc c th lm tng, gim hoc trung ha s m ln do tng nng cc kh nh knh. Kh hu - Climate: Tng hp ca thi tit c c trng bi cc tr s thng k di hn (trung bnh, xc sut cc cc tr v.v...) ca cc yu t kh tng bin ng trong mt khu vc a l. Thi k tnh trung bnh thng l vi thp k. Theo nh ngha ca WMO: Tng hp cc iu kin thi tit mt khu vc nht nh c trng bi cc thng k di hn cc bin s ca trng thi kh quyn khu vc . Kh nh knh - Greenhouse Gases (GHGs): Cc kh nh knh (KNK) lm gim lng bc x ca tri t thot ra v tr, do lm nng tng bn di kh quyn v b mt tri t. Kh quyn - Atmotsphere: Lp kh bao quanh tri t v b gi y do lc hp dn ca tri t. Kh quyn c chia thnh nhiu tng: tng i lu (t mt t n khong 8 17 km); tng bnh lu (ln n 50 km); tng gia (50 90 km) v tng nhit to thnh vng chuyn tip ra v tr. S pha trn gia cc tng l cc chm.Kch bn bin i kh hu, nc bin dng cho Vit Nam 7


Kch bn bin i kh hu - Climate Change Scenario: L gi nh c c s khoa hc v tnh tin cy v s tin trin trong tng lai ca cc mi quan h gia kinh t - x hi, GDP, pht thi kh nh knh, bin i kh hu v mc nc bin dng. Lu rng, kch bn bin i kh hu khc vi d bo thi tit v d bo kh hu l n a ra quan im v mi rng buc gia pht trin v hnh ng. Mtan - Methane (CH4) : Mt trong su kh nh knh c kim sot bi Ngh nh th Kyoto. N c thi gian sng trong kh quyn tng i ngn: 10 2 nm. Cc ngun kh mtan ch yu l bi rc thi, m than, rung la, cc h thng kh t nhin v sc vt nui. c tnh tim nng lm nng ln ton cu (GWP) ca mtan l 21 trong vng 100 nm ti. M hnh hon lu chung- General Circulation Model (GCM): Mt cng c cn bn nghin cu tc ng ca s tng nng kh nh knh i vi kh hu. GCM c bn l mt m hnh thy ng lc ca kh quyn trn mt li im hay phn gii ph, qua cc phng trnh khi lng, nng lng v ng lng cho kh quyn v i dng c tch phn vi nhau theo thi gian, trn mt khu vc ca a cu m phng s vn ng ca h thng i dng - kh quyn thc. Nhn t kh hu - Climatic Factors: Cc iu kin vt l nht nh (khc vi yu t kh hu) iu chnh kh hu (v , cao, s phn b t, bin, a hnh, cc dng chy i dng v.v...). Nhin liu ha thch - Fossil Fuels: Than, du, xng v kh t nhin cng cc hydrocacbon khc c gi l nhin liu ha thch v chng c to ra t cc xc thc vt v ng vt giu cacbon ha thch. Cc xc c chn trong cc lp trm tch v nn qua thi k a cht, dn dn chuyn thnh nhin liu. Nhit cc tr - Extreme Temperatures: Nhit cao nht v thp nht t c trong thi gian nht nh. Nng ln ton cu - Global Warming: Ni mt cch cht ch, s nng ln v lnh i ton cu l cc xu th nng ln v lnh i t nhin m tri t tri qua trong sut lch s ca n. Tuy nhin, thut ng ny thng ch s tng dn nhit tri t do cc cht kh nh knh tch t trong kh quyn. Nc bin dng - Sea Level Rise: L s dng ln ca mc nc ca i dng trn ton cu, trong khng bao gm triu, nc dng do bo... Nc bin dng ti mt v tr no c th cao hn hoc thp hn so vi trung bnh ton cu v c s khc nhau v nhit ca i dng v cc yu t khc. xit nit - Nitrous Oxide (N2O): Mt trong su kh nh knh c kim sot bi Ngh nh th Kyoto, pht sinh t vic t cc nhin liu ha thch v ch to phn bn. N c tim nng lm nng ln ton cu (GWP) l 310 trong vng 100 nm ti. Pht thi - Emissions: (nh ngha ca Cng c kh hu). S thi cc kh nh knh v/hoc cc tin t ca chng vo kh quyn trn mt khu vc v thi gian c th. Sinh quyn - Biosphere: B phn ca tri t v kh quyn ca n, trong cc sinh vt sng. B cha chu trnh cacbon ton cu, trong cha cc sinh vt sng (thc vt v ng vt v vt cht hu c t s sng (rc v mn)). Sinh quyn tri t gm h sinh vt (thc vt v ng vt), rc v vt cht hu c trong t trn lc a v sinh quyn bin gm h sinh vt v mn i dng.Kch bn bin i kh hu, nc bin dng cho Vit Nam 8


Sol kh - Aerosols: L cc ht rt nh gy ra hin tng m. Chng phn ln l nc v cc ht cht nhim nh axit sulphua v mui bin. Sol kh trong tng i lu thng c ging thy qut i. Cc sol kh c mang ln tng bnh lu thng lu hn nhiu. Sol kh tng bnh lu ch yu l cc ht sunphat t cc v ni la phun, c th lm gim ng k bc x mt tri. Thch quyn - Lithosphere: Lp bn trn (thuc i dng v lc a) ca phn tri t rn, gm ton b v tri t v phn cng, dn ca v trn cng ca tri t. dy ca n thay i t 1 n 2 km dy sng ni gia i dng, nhng dn dn tng t 60km gn sng ni ti 120 140 km bn di v i dng c tui cao hn. Thi tit Weather: Thi tit l trng thi kh quyn ti mt a im nht nh c xc nh bng t hp cc yu t: nhit , p sut, m, tc gi, ma, Thy quyn - Hydrosphere: Phn ca tri t bao gm nc, l i dng, bin, bng, h, sng v.v... T chc Kh tng Th gii - World Meteorological Organization (WMO): Mt c quan chuyn mn ca Lin Hip Quc, hin c 160 nc v vng lnh th thnh vin. Trm kh hu - Climatological Station: Mt trm thc hin cc quan trc kh hu. Trung bnh chun kh hu - Climatolgical Standard Normals: Tr s trung bnh ca s liu kh hu tnh cho tng thi k 30 nm k tip nhau: 01 thng 01 nm 1901 n 31 thng 12 nm 1930, 01 thng 01 nm 1931 n 31 thng 12 nm 1960, 01 thng 01 nm 1961 n 31 thng 12 nm 1990. Tng tc kh quyn/i dng - Atmosphere/Ocean Interactions: Ngi ta mi ch hiu mt phn ng lc hc ca cc tng tc kh quyn - i dng v cn tnh n cc mi lin h gia cc lp trn v di ca i dng, khi cn hiu t v cc lin h ny. Tuy nhin, tng tc kh quyn - i dng t ra l nhn t quan trng i vi cc bin thin kh hu vi mi quy m thi gian, v c nhng biu hin r rng v mi lin quan ca n vi nhng bin i theo quy m thi gian vi nm. Xu th kh hu - Climatic Trend: S bin i kh hu c c trng bng vic tng hay gim n iu v trn tru ca gi tr trung bnh trong thi k chui s liu. Khng ch gii hn s thay i tuyn tnh theo thi gian, m c trng bng ch mt cc i v mt cc tiu cc u, cui chui s liu. Yu t kh hu - Climatic Element: Mt trong nhng tnh cht hay iu kin ca kh quyn (nh nhit khng kh) c trng cho trng thi vt l ca thi tit hay kh hu ti mt ni, vo mt khong thi gian nht nh.



DANH MC BNG Bng 1.1. Mc tng nhit v mc thay i lng ma trong 50 nm qua cc vng kh hu ca Vit Nam ........................................................................................23 Bng 2.1. Cc h thng m hnh c tham kho trong xy dng kch bn nc bin dng cho Vit Nam .....................................................................................................35 Bng 3.1. Mc tng nhit (oC) trung bnh nm so vi thi k 1980-1999 theo kch bn pht thi trung bnh (B2) ......................................................................................55 Bng 3.2. Mc thay i (%) lng ma nm so vi thi k 1980-1999 theo kch bn pht thi trung bnh (B2) .............................................................................................69 Bng 3.3. Mc thay i lng ma ngy ln nht (%) vo cui th k 21 so vi thi k 1980-1999..............................................................................................................70 Bng 3.4. Mc nc bin dng theo kch bn pht thi thp (cm) .............................71 Bng 3.5. Mc nc bin dng theo kch bn pht thi trung bnh (cm) ...................72 Bng 3.6. Mc nc bin dng theo kch bn pht thi cao (cm) ..............................72 Bng 4.1. Din tch c nguy c b ngp theo cc mc nc bin dng (% din tch) ....74 Bng 4.2. T l chiu di quc l c nguy c b nh hng theo cc mc nc bin dng (%) .....................................................................................................................74 Bng 4.3. T l chiu di tnh l c nguy c b nh hng theo cc mc nc bin dng (%) ..............................................................................................................................75 Bng 4.4. T l chiu di ng st c nguy c b nh hng theo cc mc nc bin dng (%) .....................................................................................................................76 Bng 4.5. T l s dn c nguy c b nh hng trc tip (so vi tng dn s vng) theo cc mc nc bin dng (%) .............................................................................76



DANH MC HNH Hnh 1.1. Din bin chun sai nhit trung bnh ton cu ...................................... 17 Hnh 1.2. Din bin nhit quy m ton cu v khu vc ..................................... 18 Hnh 1.3. Chun sai nhit ton cu thng 6 nm 2010 so vi thi k 1971 2000 .................................................................................................................................. 18 Hnh 1.4. Din bin lng ma nm cc vng khc nhau trn th gii ................. 19 Hnh 1.5. Bin ng mc nc bin trung bnh ton cu ......................................... 19 Hnh 1.6. Xu th bin ng mc nc bin trung bnh ti cc trm quan trc nc bin trn ton cu...................................................................................................... 20 Hnh 1.7. Xu th bin ng mc nc bin trung bnh ton cu t s liu v tinh ... 21 Hnh 1.8. Xu th mc nc bin trung bnh ton cu theo s liu v tinh ................ 21 Hnh 1.9. Mc tng nhit trung bnh nm (oC) trong 50 nm qua ......................... 22 Hnh 1.10. Mc thay i lng ma nm (%) trong 50 nm qua .............................. 22 Hnh 1.11. Bn tn sut XTN hot ng (a), hnh thnh Bin ng (b) v nh hng n t lin Vit Nam (c) ............................................................................... 24 Hnh 1.12. Din bin ca s cn xoy thun nhit i hot ng Bin ng, nh hng v b vo t lin Vit Nam trong 50 nm qua ......................................... 24 Hnh 1.13. Din bin mc nc bin theo s liu cc trm thc o ......................... 25 Hnh 1.14. Din bin mc nc bin theo s liu v tinh (1993-2010) ..................... 25 Hnh 1.15. So snh mc nc bin t s liu ti trm hi vn v v tinh ................. 25 Hnh 2.1. S tnh ton pht thi kh nh knh theo cc kch bn v mc tng nhit trung bnh ton cu .............................................................................................. 28 Hnh 2.2. Giao din ca phn mm SDSM ............................................................... 28 Hnh 2.3. Giao din ca phn mm SIMCLIM ........................................................... 29 Hnh 2.4. S xy dng hm chuyn theo phng php PP v MOS .................. 30 Hnh 2.5. H thng M phng tri t v kch bn BKH ca m hnh AGCM/MRI .. 31 Hnh 2.6. S tnh v min tnh ca m hnh PRECIS ........................................... 32 Hnh 2.7. Cc qu trnh vt l c xt n trong m hnh PRECIS ........................ 32 Hnh 2.8. Phng php tnh v kch bn nc bin dng ca Rahmstorf, 2007 ...... 33 Hnh 2.9. Kch bn mc nc bin dng nm 2100 quy m ton cu (NCAR) ..... 34 Hnh 2.10. Mt kch bn nc bin dng theo phng php ca Doyle ................... 34 Hnh 2.11. Phng php chi tit ha thng k cho mc nc bin dng ................. 34 Hnh 2.12. Mc nc bin dng cui th k 21 theo kch bn trung bnh ca cc m hnh s tr................................................................................................................... 36 Hnh 2.13. So snh kch bn mc nc bin dng (IPCC) v s liu o c ............ 36 Hnh 2.14. Mc nc bin dng cui th k XXI t cc nghin cu khc nhau ....... 36 Hnh 2.15. Kch bn mc nc bin ton cu theo cc kch bn pht thi ............... 36 Hnh 3.1. Mc tng nhit trung bnh ma ng (oC) vo cui th k 21 theo kch bn pht thi thp...................................................................................................... 40 Hnh 3.2. Mc tng nhit trung bnh ma ng (oC) vo gia th k 21 theo kch bn pht thi trung bnh ............................................................................................ 40 Hnh 3.3. Mc tng nhit trung bnh ma ng (oC) vo cui th k 21 theo kch bn pht thi trung bnh ............................................................................................ 41 Hnh 3.4. Mc tng nhit trung bnh ma ng (oC) vo cui th k 21 theo kch bn pht thi cao ....................................................................................................... 42 Hnh 3.5. Mc tng nhit trung bnh ma xun (oC) vo cui th k 21 theo kch bn pht thi thp...................................................................................................... 42 Hnh 3.6. Mc tng nhit trung bnh ma xun (oC) vo gia th k 21 theo kch bn pht thi trung bnh ............................................................................................ 42Kch bn bin i kh hu, nc bin dng cho Vit Nam 11


Hnh 3.7. Mc tng nhit trung bnh ma xun (oC) vo cui th k 21 theo kch bn pht thi trung bnh ............................................................................................ 43 Hnh 3.8. Mc tng nhit trung bnh ma xun (oC) vo cui th k 21 theo kch bn pht thi cao ....................................................................................................... 44 Hnh 3.9. Mc tng nhit trung bnh ma h (oC) vo cui th k 21 theo kch bn pht thi thp............................................................................................................. 44 Hnh 3.10. Mc tng nhit trung bnh ma h (oC) vo gia th k 21 theo kch bn pht thi trung bnh ............................................................................................ 44 Hnh 3.11. Mc tng nhit trung bnh ma h (oC) vo cui th k 21 theo kch bn pht thi trung bnh ............................................................................................ 45 Hnh 3.12. Mc tng nhit trung bnh ma h (oC) vo cui th k 21 theo kch bn pht thi cao ....................................................................................................... 46 Hnh 3.13. Mc tng nhit trung bnh ma thu (oC) vo cui th k 21 theo kch bn pht thi thp...................................................................................................... 46 Hnh 3.14. Mc tng nhit trung bnh ma thu ( oC) vo gia th k 21 theo kch bn pht thi trung bnh ............................................................................................ 46 Hnh 3.15. Mc tng nhit trung bnh ma thu (oC) vo cui th k 21 theo kch bn pht thi trung bnh ............................................................................................ 47 Hnh 3.16. Mc tng nhit trung bnh ma thu (oC) vo cui th k 21 theo kch bn pht thi cao ....................................................................................................... 48 Hnh 3.17. Mc tng nhit trung bnh nm (oC) vo cui th k 21 theo kch bn pht thi thp............................................................................................................. 48 Hnh 3.18. Mc tng nhit trung bnh nm (oC) vo gia th k 21 theo kch bn pht thi trung bnh ................................................................................................... 48 Hnh 3.19. Mc tng nhit trung bnh nm (oC) vo cui th k 21 theo kch bn pht thi trung bnh ................................................................................................... 49 Hnh 3.20. Mc tng nhit trung bnh nm (oC) vo cui th k 21 theo kch bn pht thi cao .............................................................................................................. 50 Hnh 3.21. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma ng vo gia th k 21 theo kch bn pht thi trung bnh .............................. 50 Hnh 3.22. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma ng vo cui th k 21 theo kch bn pht thi trung bnh............................... 51 Hnh 3.23. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma h vo gia th k 21 theo kch bn pht thi trung bnh .................................. 52 Hnh 3.24. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma h vo cui th k 21 theo kch bn pht thi trung bnh................................... 52 Hnh 3.25. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) nm vo gia th k 21 theo kch bn pht thi trung bnh ...................................................... 53 Hnh 3.26. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) nm vo cui th k 21 theo kch bn pht thi trung bnh ...................................................... 53 Hnh 3.27. Mc tng s ngy c nhit cao nht trn 35oC vo cui th k 21 theo kch bn pht thi trung bnh ..................................................................................... 54 Hnh 3.28. Mc thay i lng ma ma ng (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi thp ...................................................................................... 56 Hnh 3.29. Mc thay i lng ma ma ng (%) vo gia th k 21 theo kch bn pht thi trung bnh ................................................................................................... 57 Hnh 3.30. Mc thay i lng ma ma ng (%) vo cui th k 21 theo kch bn pht thi trung bnh ................................................................................................... 58 Hnh 3.31. Mc thay i lng ma ma ng (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi cao........................................................................................ 57Kch bn bin i kh hu, nc bin dng cho Vit Nam 12


Hnh 3.32. Mc thay i lng ma ma xun (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi thp ...................................................................................... 59 Hnh 3.33. Mc thay i lng ma ma xun (%) vo gia th k 21 theo kch bn pht thi trung bnh ................................................................................................... 59 Hnh 3.34. Mc thay i lng ma ma xun (%) vo cui th k 21 theo kch bn pht thi trung bnh ................................................................................................... 60 Hnh 3.35. Mc thay i lng ma ma xun (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi cao........................................................................................ 61 Hnh 3.36. Mc thay i lng ma ma h (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi thp ...................................................................................... 61 Hnh 3.37. Mc thay i lng ma ma h (%) vo gia th k 21 theo kch bn pht thi trung bnh ................................................................................................... 62 Hnh 3.38. Mc thay i lng ma ma h (%) vo cui th k 21 theo kch bn pht thi trung bnh ................................................................................................... 63 Hnh 3.39. Mc thay i lng ma ma h (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi cao........................................................................................ 62 Hnh 3.40. Mc thay i lng ma ma thu (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi thp ...................................................................................... 64 Hnh 3.41. Mc thay i lng ma ma thu (%) vo gia th k 21 theo kch bn pht thi trung bnh ................................................................................................... 64 Hnh 3.42. Mc thay i lng ma ma thu (%) vo cui th k 21 theo kch bn pht thi trung bnh ................................................................................................... 65 Hnh 3.43. Mc thay i lng ma ma thu (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi cao........................................................................................ 66 Hnh 3.44. Mc thay i lng ma nm (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi thp .............................................................................................. 66 Hnh 3.45. Mc thay i lng ma nm (%) vo gia th k 21 theo kch bn pht thi trung bnh ........................................................................................................... 67 Hnh 3.46. Mc thay i lng ma nm (%) vo cui th k 21 theo kch bn pht thi trung bnh ........................................................................................................... 68 Hnh 3.47. Mc thay i lng ma nm (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi cao ............................................................................................... 67 Hnh 3.48. Mc thay i lng ma ngy ln nht (%) vo gia (a) v cui th k 21 (b) theo kch bn pht thi trung bnh ........................................................................ 70 Hnh 3.49. Mc thay i kh p trung bnh b mt (a) v m tng i trung bnh b mt (b) vo cui th k 21 theo kch bn pht thi trung bnh .............................. 71 Hnh 3.50. Kch bn nc bin dng cho cc khu vc ven bin Vit Nam ............... 73 Hnh 4.1. Bn nguy c ngp khu vc ven bin Vit Nam ng vi mc nc bin dng 1m .................................................................................................................... 77 Hnh 4.2. Bn nguy c ngp khu vc ng bng sng Hng v Qung Ninh ng vi mc nc bin dng 1m ..................................................................................... 78 Hnh 4.3. Bn nguy c ngp khu vc tnh Thanh Ha ng vi mc nc bin dng 1m .................................................................................................................... 79 Hnh 4.4. Bn nguy c ngp khu vc tnh Ngh An ng vi mc nc bin dng 1m ............................................................................................................................. 80 Hnh 4.5. Bn nguy c ngp khu vc tnh H Tnh ng vi mc nc bin dng 1m ............................................................................................................................. 81 Hnh 4.6. Bn nguy c ngp khu vc tnh Qung Bnh ng vi mc nc bin dng 1m .................................................................................................................... 82Kch bn bin i kh hu, nc bin dng cho Vit Nam 13


Hnh 4.7. Bn nguy c ngp khu vc tnh Qung Tr ng vi mc nc bin dng 1m ............................................................................................................................. 83 Hnh 4.8. Bn nguy c ngp khu vc tnh Tha Thin - Hu ng vi mc nc bin dng 1m............................................................................................................. 84 Hnh 4.9. Bn nguy c ngp khu vc thnh ph Nng ng vi mc nc bin dng 1m .................................................................................................................... 85 Hnh 4.10. Bn nguy c ngp khu vc tnh Qung Nam ng vi mc nc bin dng 1m .................................................................................................................... 86 Hnh 4.11. Bn nguy c ngp khu vc tnh Qung Ngi ng vi mc nc bin dng 1m .................................................................................................................... 87 Hnh 4.12. Bn nguy c ngp khu vc tnh Bnh nh ng vi mc nc bin dng 1m .................................................................................................................... 88 Hnh 4.13. Bn nguy c ngp khu vc tnh Ph Yn ng vi mc nc bin dng 1m ............................................................................................................................. 89 Hnh 4.14. Bn nguy c ngp khu vc tnh Khnh Ha ng vi mc nc bin dng 1m .................................................................................................................... 90 Hnh 4.15. Bn nguy c ngp khu vc tnh Ninh Thun ng vi mc nc bin dng 1m .................................................................................................................... 91 Hnh 4.16. Bn nguy c ngp khu vc tnh Bnh Thun ng vi mc nc bin dng 1m .................................................................................................................... 92 Hnh 4.17. Bn nguy c ngp khu vc tnh B Ra Vng Tu ng vi mc nc bin dng 1m............................................................................................................. 93 Hnh 4.18. Bn nguy c ngp khu vc thnh ph H Ch Minh ng vi mc nc bin dng 1m............................................................................................................. 94 Hnh 4.19. Bn nguy c ngp khu vc ng bng sng Cu Long ng vi mc nc bin dng 1m ................................................................................................... 95



TM TT KCH BN BIN I KH HU, NC BIN DNG CHO VIT NAM V NHNG IM MI C BN 1. Cc phng php v ngun s liu xy dng kch bn bin i kh hu, nc bin dng cho Vit Nam c k tha t cc nghin cu trc y v c cp nht n nm 2010. Thi k 1980-1999 c chn l thi k c s trong xy dng kch bn bin i kh hu, nc bin dng cho Vit Nam n nm 2100. 2. V nhit : - Theo kch bn pht thi thp: n cui th k 21, nhit trung bnh nm tng t 1,6 n 2,2oC trn phn ln din tch pha Bc lnh th v di 1,6oC i b phn din tch pha Nam (t Nng tr vo). - Theo kch bn pht thi trung bnh: n cui th k 21, nhit trung bnh tng 2-3oC trn phn ln din tch c nc, ring khu vc t H Tnh n Qung Tr c nhit trung bnh tng nhanh hn so vi nhng ni khc. Nhit thp nht trung bnh tng t 2,2-3,0oC, nhit cao nht trung bnh tng t 2,0-3,2oC. S ngy c nhit cao nht trn 35oC tng 10-20 ngy trn phn ln din tch c nc. - Theo kch bn pht thi cao: n cui th k 21, nhit trung bnh nm c mc tng ph bin t 2,5 n trn 3,7oC trn hu ht din tch nc ta. 3. V lng ma: - Theo kch bn pht thi thp: n cui th k 21, lng ma nm tng ph bin khong trn 6%, ring khu vc Ty Nguyn c mc tng t hn, ch vo khong di 2%. - Theo kch bn pht thi trung bnh: n cui th k 21, lng ma nm tng trn hu khp lnh th. Mc tng ph bin t 2-7%, ring Ty Nguyn, Nam Trung B tng t hn, di 3%. Xu th chung l lng ma ma kh gim v lng ma ma ma tng. Lng ma ngy ln nht tng thm so vi thi k 1980-1999 Bc B, Bc Trung B v gim Nam Trung B, Ty Nguyn, Nam B. Tuy nhin cc khu vc khc nhau li c th xut hin ngy ma d thng vi lng ma gp i so vi k lc hin nay. - Theo kch bn pht thi cao: Lng ma nm vo cui th k 21 tng trn hu khp lnh th nc ta vi mc tng ph bin khong 2-10%, ring khu vc Ty Nguyn c mc tng t hn, khong 1-4%. 4. V mt s yu t kh hu khc: - Kh p tng trn phm vi ton lnh th Vit Nam, Bin ng. - m tng i gim trn hu khp c nc, nht l pha ng Bc B v Nam B. 5. V nc bin dng: - Theo kch bn pht thi thp (B1): Vo cui th k 21, mc nc bin dng cao nht khu vc t C Mau n Kin Giang trong khong t 54-72cm; thp nht khu vc Mng Ci trong khong t 42-57cm. Trung bnh ton Vit Nam, mc nc bin dng trong khong t 49-64cm. - Theo kch bn pht thi trung bnh (B2): Vo cui th k 21, nc bin dng cao nht khu vc t C Mau n Kin Giang trong khong t 62-82cm; thp nht khu vc Mng Ci trong khong t 49-64cm. Trung bnh ton Vit Nam, mc ncKch bn bin i kh hu, nc bin dng cho Vit Nam 15


bin dng trong khong t 57-73cm. - Theo kch bn pht thi cao (A1FI): Vo cui th k 21, nc bin dng cao nht khu vc t C Mau n Kin Giang trong khong t 85-105cm; thp nht khu vc Mng Ci trong khong t 66-85cm. Trung bnh ton Vit Nam, mc nc bin dng trong khong t 78-95cm. 6. Nu mc nc bin dng 1m, s c khong 39% din tch ng bng sng Cu Long, trn 10% din tch vng ng bng sng Hng, Qung Ninh, trn 2,5% din tch thuc cc tnh ven bin min Trung v trn 20% din tch Thnh ph H Ch Minh c nguy c b ngp; Gn 35% dn s thuc cc tnh vng ng bng sng Cu Long, trn 9% dn s vng ng bng sng Hng, Qung Ninh, gn 9% dn s cc tnh ven bin min Trung v khong 7% dn s Thnh ph H Ch Minh b nh hng trc tip; Trn 4% h thng ng st, trn 9% h thng quc l v khong 12% h thng tnh l ca Vit Nam s b nh hng. 7. Nhng im mi ca kch bn bin i kh hu, nc bin dng - Cc kch bn bin i kh hu, nc bin dng cho Vit Nam c xy dng trn cc c s khoa hc v s liu o c thc t. Cc kch bn c xy dng da vo cc phn tch, tnh ton bng cc m hnh kh hu, cng c thng k. Cc m hnh, cng c ny c la chn, xy dng chuyn bit cho Vit Nam v khu vc ln cn. Trong tnh ton, khai thc ti a cc ngun s liu v cc loi d liu khc nhau, c th l s dng ton b s liu kh tng, kh hu, thy vn, hi vn quan trc ti gn 200 trm kh tng, 17 trm hi vn, s liu quan trc t v tinh, s liu tnh ton t cc m hnh khc nhau, Cc kt qu phn nh c tnh c th ca cc vng kh hu cng nh cc vng bin ca Vit Nam. - Cc kch bn v nhit v lng ma c th hin chi tit cho cc khu vc nh ca Vit Nam, p ng c yu cu nh gi tc ng ca bin i kh hu i vi tng khu vc nh. Cc yu t cc tr (nhit cao nht, thp nht, ma ln) cng c tnh ton phc v cho cng tc quy hoch v thit k ca cc ngnh. Cc kch bn nc bin dng c xc nh vi mc chi tit n tng khu vc ven bin. - Theo kch bn cp nht, mc tng nhit dao ng trong phm vi ln hn so vi kch bn nm 2009. Chng hn, theo kch bn pht thi trung bnh, vo cui th k 21, mc tng nhit trung bnh nm c th ti 3,5oC cc khu vc nh thuc Bc Trung B (theo kch bn nm 2009, mc tng chung cho vng kh hu ny l 2,8oC vo nm 2100). Tng t i vi ma, lng ma ma kh c th gim n 30% vo nm 2100 mt vi ni thuc Nam B, trong khi theo phin bn nm 2009 th ch gim 18%. Cc yu t cc tr nh nhit cao nht, nhit thp nht, lng ma ngy ln nht v mt s yu t khc c tnh ton v trnh by trong bn cp nht kch bn bin i kh hu. - So vi kch bn nc bin dng nm 2009, kch bn cp nht tnh chi tit hn cho cc khu vc ven bin Vit Nam. Theo cc kch bn, n nm 2100 nc bin dng cao nht khu vc t C Mau n Kin Giang, thp nht vng Mng Ci n Hn Du. - Cng vi cc bn nguy c ngp cho khu vc ng bng sng Cu Long v Thnh ph H Ch Minh, kch bn cp nht tnh ton v trnh by cc bn nguy c ngp cho ng bng sng Hng, Qung Ninh v tng tnh thuc khu vc ven bin min Trung.Kch bn bin i kh hu, nc bin dng cho Vit Nam 16


1. BIU HIN CA BIN I KH HU, NC BIN DNG 1.1. Biu hin ca bin i kh hu, nc bin dng trn th gii S nng ln ton cu l rt r rng vi nhng biu hin ca s tng nhit khng kh v i dng, s tan bng din rng v qua l mc tng mc nc bin trung bnh ton cu. Cc quan trc cho thy rng nhit tng trn ton cu v tng nhiu hn cc v cc Bc. Trong 100 nm qua (1906-2005), nhit trung bnh ton cu tng khong 0,74oC, tc tng ca nhit trong 50 nm gn y gn gp i so vi 50 nm trc (Hnh 1.1, 1.2). Theo bo co gn y ca WMO, 2010 l nm nng nht trong lch s, vi mc tng t nh cc nm 1998 v 2005. Ngoi ra, trong mi nm qua tnh Hnh 1.1. Din bin chun sai nhit t nm 2001, nhit trung bnh ton trung bnh ton cu (Ngun: IPCC/2007) cu cao hn na so vi giai on 1961-1990, mc cao nht tng c ghi nhn i vi bt k mt giai on 10 nm no k t khi bt u quan trc kh hu bng thit b o c (Michel Jarraud, 2011). Theo s liu ca NOAA (Hoa K), thng 6 nm 2010 c ghi nhn l thng nng nht trn ton th gii k t nhng nm 1880, khi cc quan trc kh tng c thc hin mt cch tng i h thng (Hnh 1.3). Trn phm vi ton cu lng ma tng ln cc i pha Bc v 30oB thi k 1901-2005 v gim i cc v nhit i, k t gia nhng nm 1970 (Hnh 1.4). khu vc nhit i, ma gim i Nam v Ty Phi vi tr s xu th l 7,5% cho c thi k 1901-2005. i v trung bnh v v cao, lng ma tng ln r rt min Trung Bc M, ng Bc M, Bc u, Bc v Trung . Tn s ma ln tng ln trn nhiu khu vc, k c nhng ni lng ma c xu th gim i (IPCC, 2007). Trn phm vi ton cu, bin i ca xoy thun nhit i (XTN) chu s chi phi ca bin i nhit nc bin, ca hot ng ENSO v s thay i qu o ca chnh XTN. Xu th tng cng hot ng ca XTN r rt nht Bc, Ty Nam Thi Bnh Dng v n Dng (IPCC, 2010). Trong th k 20 cng vi s tng ln ca nhit mt t c s suy gim khi lng bng trn phm vi ton cu. T nm 1978 n nay, lng bng trung bnh hng nm Bc Bng Dng gim khong 2,1-3,3% mi thp k (IPCC, 2007).Kch bn bin i kh hu, nc bin dng cho Vit Nam 17

B TI NGUYN V MI TRNGChu u

Bc M Chu

Nm

Chu PhiNm

Nam M

Nm

Chu cNm

Nm Nm

D thng nhit ( C)

D thng nhit (oC)

D thng nhit (oC)

Ton cu

t

Bin

o

Nm

Nm

Nm

Hnh 1.2. Din bin nhit quy m ton cu v khu vc(Ngun: IPCC AR4 WG-I Report, 2007)

Hnh 1.3. Chun sai nhit ton cu thng 6 nm 2010 so vi thi k 1971 2000(Ngun: NOAA/2010)



Xu th ging thy nm, t 1901 n 2005

% trn th k

Hnh 1.4. Din bin lng ma nm cc vng khc nhau trn th gii(Ngun: IPCC/2007)

S nng ln ca h thng kh hu r rng c minh chng thng qua s liu quan trc ghi nhn s tng ln ca nhit khng kh v nhit nc bin trung bnh ton cu, s tan chy nhanh ca lp tuyt ph v bng, lm tng mc nc bin trung bnh ton cu (IPCC, 2007). Mc nc bin tng ph hp vi xu th nng ln do c s ng gp ca: (a) hin tng gin n nhit ca i dng; (b) tan bng Greenland, Nam Cc v cc khu vc khc; (c) thay i kh nng gi nc t lin. Trong cc nhn t ny, hin tng n v nhit ca i dng tng c xem l nhn t ch yu dn n s dng ln ca mc nc bin. Tuy nhin, s liu mi v t l tan bng Greenland v Nam Cc cho thy rng nh hng ny ln hn. Bi v cc tng bng Greenland v Nam Cc cha nc lm tng mc nc bin ln 70m. Theo cc nh khoa hc v bin i kh hu (BKH) ton cu v nc bin dng cho thy, i dng nng Hnh 1.5. Bin ng mc nc bin ln ng k t cui thp k 1950. Cc trung bnh ton cu (Ngun: IPCC/2007)Kch bn bin i kh hu, nc bin dng cho Vit Nam 19


nghin cu t s liu quan trc trn ton cu cho thy, mc nc bin trung bnh ton cu trong thi k 1961-2003 dng vi tc 1,8 0,5mm/nm, trong , ng gp do gin n nhit khong 0,42 0,12mm/nm v tan bng khong 0,70 0,50 (IPCC, 2007 - Hnh 1.5). Nghin cu cp nht nm 2009 cho rng tc mc nc bin trung bnh ton cu dng khong 1,8mm/nm (Chuch v White, 2009). Mc nc bin thay i khng ng u trn ton b i dng th gii: mt s vng tc dng c th gp mt vi ln tc dng trung bnh ton cu trong khi mc nc bin mt s vng khc li c th h thp. Xu th tng ca mc nc trung bnh xut hin hu ht ti cc trm quan trc trn ton cu, mc d, vn xut hin mt s khu vc c xu hng gim nh b bin pha ng ca Nam M v khu vc ven bin pha Nam Alaska v ng Bc Canada, vng bin Scandinavia (Hnh 1.6). Theo mt s bo co ca cc nh khoa hc, trong thp k va qua, mc nc bin dng nhanh nht vng pha Ty Thi Bnh Dng v pha ng n Dng.

Hnh 1.6. Xu th bin ng mc nc bin trung bnh ti cc trm quan trc nc bin trn ton cu (Ngun NOAA/2010) Hin nay, c hai phng php ch yu o c mc nc bin l o ti trm hi vn v bng v tinh. Cc s liu t cc trm hi vn cho bit mc thay i mc nc so vi mc cao ca trm. c th bit c thay i mc nc do th tch khi nc v cc yu t vt l bin khc, s liu trm hi vn cn phi loi b c yu t do vn ng a cht ca mt t. S c tnh nh hng vn ng a cht ni chung s khng thc hin c nu khng c v tr o c hay s liu a cht. Tuy nhin, vic la chn cn thn v tr t trm c th loi b c nh hng nhng hot ng kin to v ly trung bnh cc s liu c th thu c sai s nh trong c tnh mc nc bin ton cu. S bin i mc nc bin da vo s liuKch bn bin i kh hu, nc bin dng cho Vit Nam 20


v tinh c o vi khi tm ca Tri t, do khng b nh hng ca vn ng a cht. T nm 1992, mc nc bin trung bnh ton cu c tnh ton, cp nht theo chu k 10 ngy t v tinh TOPEX/Poseidon (T/P) v v tinh JASON t 66 Nam n 66 Bc (Nerem v Mitchum, 2001). S liu o c c tng hp v hiu chnh t cc v tinh Hnh 1.7. Xu th bin ng mc nc bin trung bnh ton cu t s liu v tinh (Topex/Poisedon, Jason - 1/2, ERS - 1/2, (Ngun: AVISO) Envisat) t thng 10/1992 n 12/2010 cho rng mc nc bin dng vi tc l 3,27mm/nm (CNES, LEGOS, CLS Hnh 1.7). Trn quy m ton cu, xu th bin i ca mc nc bin tng mnh ven b Ty Thi Bnh Dng trong khi xu th gim b ng Thi Bnh Dng (Hnh 1.8).

Hnh 1.8. Xu th mc nc bin trung bnh ton cu theo s liu v tinh(Ngun: CNES/LEGOS/CLS,2010)

1.2. Biu hin ca bin i kh hu, nc bin dng Vit Nam Vit Nam, xu th bin i ca nhit v lng ma l rt khc nhau trn cc vng trong 50 nm qua. Nhit trung bnh nm tng khong 0,5oC trn phm vi c nc v lng ma c xu hng gim pha Bc, tng pha Nam lnh th.Kch bn bin i kh hu, nc bin dng cho Vit Nam 21


Nhit thng I (thng c trng 24N Trung quc cho ma ng), nhit thng VII (thng 22N c trng cho ma h) v nhit trung bnh nm tng trn phm vi c nc trong 20N 50 nm qua. Nhit ma ng tng L nhanh hn so vi ma h v nhit 18N o vng su trong t lin tng nhanh hn Q. Hong Sa 16N nhit vng ven bin v hi o. Thi Lan Vo ma ng, nhit tng 2C nhanh hn c l Ty Bc B, ng Bc 14N 1C Cm pu chia 0.5C B, ng bng Bc B, Bc Trung B 12N 0C (khong 1,3-1,5oC/50 nm). Nam Trung -0.5C B, Ty Nguyn v Nam B c nhit 10N -1C thng I tng chm hn so vi cc vng g Sa n -2C Tr- Q. kh hu pha Bc (khong 0,6-0,9oC/50 8N nm). Tnh trung bnh cho c nc, nhit 102E 104E 106E 108E 110E 112E 114E ma ng nc ta tng ln 1,2 oC Hnh 1.9. Mc tng nhit trung bnh trong 50 nm qua. Nhit thng VII tng nm (oC) trong 50 nm qua (Ngun: IMHEN/2010) khong 0,3-0,5oC/50 nm trn tt c cc 24N vng kh hu ca nc ta. Nhit trung Trung quc bnh nm tng 0,5-0,6oC/50 nm Ty 22N Bc, ng Bc B, ng bng Bc B, Bc Trung B, Ty Nguyn v Nam B 20N L cn mc tng nhit trung bnh nm 18N o Nam Trung B thp hn, ch vo khong Q. Hong Sa 0,3oC/50 nm (Hnh 1.9 v Bng 1.1). 16N Thi Lan Xu th chung ca nhit l tng 40% trn hu ht cc khu vc trn c nc, tuy 14N 20% nhin c nhng khu vc nh thuc vng Cm pu chia ven bin Trung B v Nam B nh Tha 12N 0% Thin Hu, Qung Ngi, Tin Giang c -20% xu hng gim ca nhit . ng lu l 10N -40% a ng S nhng ni ny, lng ma tng trong Tr- Q. 8N c hai ma: ma kh v ma ma. 102E 104E 106E 108E 110E 112E 114E Mc thay i nhit cc i trn Hnh 1.10. Mc thay i lng ma ton Vit Nam nhn chung dao ng trong nm (%) trong 50 nm qua khong t -3oC n 3oC. Mc thay i (Ngun: IMHEN/2010) nhit cc tiu ch yu dao ng trong khong -5oC n 5oC. Xu th chung ca nhit cc i v cc tiu l tng, tc tng ca nhit cc tiu nhanh hn so vi nhit cc i, ph hp vi xu thKch bn bin i kh hu, nc bin dng cho Vit Nam 22


chung ca bin i kh hu ton cu. Lng ma ma kh (thng XI-IV) tng ln cht t hoc khng thay i ng k cc vng kh hu pha Bc v tng mnh m cc vng kh hu pha Nam trong 50 nm qua. Lng ma ma ma (thng V-X) gim t 5 n hn 10% trn a phn din tch pha Bc nc ta v tng khong 5 n 20% cc vng kh hu pha Nam trong 50 nm qua. Xu th din bin ca lng ma nm tng t nh lng ma ma ma, tng cc vng kh hu pha Nam v gim cc vng kh hu pha Bc. Khu vc Nam Trung B c lng ma ma kh, ma ma v lng ma nm tng mnh nht so vi cc vng khc nc ta, nhiu ni n 20% trong 50 nm qua (Hnh 1.10 v Bng 1.1). Lng ma ngy cc i tng ln hu ht cc vng kh hu, nht l trong nhng nm gn y. S ngy ma ln cng c xu th tng ln tng ng, nhiu bin ng mnh xy ra khu vc min Trung. Tn ti mi tng quan kh r gia s nng ln ton cu v nhit b mt bin khu vc ng xch o Thi Bnh dng vi xu th bin i ca s ngy ma ln trn cc vng kh hu pha Nam. Bng 1.1. Mc tng nhit v mc thay i lng ma trong 50 nm qua cc vng kh hu ca Vit Nam (Ngun: IMHEN/2010) Nhit (OC) Lng ma (%)Vng kh hu Ty Bc B ng Bc B ng bng Bc B Bc Trung B Nam Trung B Ty Nguyn Nam B Thng I Thng VII Nm Thi k XI-IV Thi k V-X Nm

1,4 1,5 1,4 1,3 0,6 0,9 0,8

0,5 0,3 0,5 0,5 0,5 0,4 0,4

0,5 0,6 0,6 0,5 0,3 0,6 0,6

6 0 0 4 20 19 27

-6 -9 -13 -5 20 9 6

-2 -7 -11 -3 20 11 9

V xoy thun nhit i, trung bnh hng nm c khong 12 cn bo v p thp nhit i hot ng trn Bin ng, trong khong 45% s cn ny sinh ngay trn Bin ng v 55% s cn t Thi Bnh Dng di chuyn vo. S cn bo v p thp nhit i nh hng n Vit Nam vo khong 7 cn mi nm v trong c 5 cn b hoc nh hng trc tip n t lin nc ta. Ni c tn sut hot ng ca bo, p thp nhit i ln nht nm phn gia ca khu vc Bc Bin ng, trung bnh mi nm c khong 3 cn i qua li 2,5 x 2,5 kinh v. Khu vc b bin min Trung t 16 n 18oN v khu vc b bin Bc B t 20oN tr ln c tn sut hot ng ca bo, p thp nhit i cao nht trong c di ven bin nc ta, c khong 2 nm li c 1 cn bo, p thp nhit i i vo khu vc 1 v b bin (Hnh 1.11). S lng xoy thun nhit i hot ng trn khu vc Bin ng c xuKch bn bin i kh hu, nc bin dng cho Vit Nam 23


hng tng nh, trong khi s cn nh hng hoc b vo t lin Vit Nam khng c xu hng bin i r rng (Hnh 1.12). a) b) c)

Hnh 1.11. Bn tn sut XTN hot ng (a), hnh thnh Bin ng (b) v nh hng n t lin Vit Nam (c) (Ngun: IMHEN/2010)

Hnh 1.12. Din bin ca s cn xoy thun nhit i hot ng Bin ng, nh hng v b vo t lin Vit Nam trong 50 nm qua (Ngun: IMHEN/2010) Khu vc b ca cc cn bo v p thp nhit i vo Vit Nam c xu hng li dn v pha Nam lnh th nc ta; s lng cc cn bo rt mnh c xu hng gia tng; ma bo c du hiu kt thc mun hn trong thi gian gn y. Tuy nhin, mc nh hng ca bo n nc ta c xu hng mnh ln. Hn hn, bao gm hn thng v hn ma c xu th tng ln nhng vi mc khng ng u gia cc vng v gia cc trm trong tng vng kh hu. Hin tng nng nng c du hiu gia tng r rt nhiu vng trong c nc, c bit l Trung B v Nam B. Vit Nam, s liu mc nc quan trc ti cc trm hi vn ven bin Vit Nam cho thy xu th bin i mc nc bin trung bnh nm khng ging nhau. Hu ht cc trm c xu hng tng, tuy nhin, mt s t trm li khng th hin r xu hng ny. Xu th bin i trung bnh ca mc nc bin dc b bin Vit Nam l khong 2,8mm/nm (Hnh 1.13).



S liu mc nc o c t v tinh t nm 1993 n 2010 cho thy, xu th tng mc nc bin trn ton bin ng l 4,7mm/nm, pha ng ca bin ng c xu th tng nhanh hn pha Ty. Ch tnh cho di ven b Vit Nam, khu vc ven bin Trung Trung B v Ty Nam B c xu hng tng mnh hn, trung bnh cho ton di ven bin Vit Nam tng khong 2,9mm/nm (Hnh 1. 14). Nh vy, xu th mc nc bin cho khu vc ven bin t s liu thc o ti trm quan trc hi vn v t v tinh l gn bng nhau. iu ny cng c kim chng khi so snh gia s liu thc o ti trm hi vn v t v tinh. Kt qu so snh cho thy c s tng ng cao v pha v bin dao ng ca mc nc trung bnh cng nh tng quan gia chng (Hnh 1.15).

Xu th mc nc bin trung bnh nm trm Bi Chy 10.0 5.0

Mc nc (cm)

0.0 -5.0 -10.0 -15.0 -20.0 1962 1966 1970 1974 1978 1982 1986 Nm 1990 1994 1998 2002 2006

Xu th mc nc bin trung bnh nm trm Hn Du20 15

Mc nc (cm)

10 5 0 -5 -10 1966 1970 1974 1978 1982 1986 Nm 1990 1994 1998 2002 2006

Xu th mc nc bin trung bnh nm trm Cn C10 8 6

Mc nc (cm)

4 2 0 -2 -4 -6 -8 -10 1991 1995 1999 Nm 2003 2007

Xu th mc nc bin trung bnh nm trm Ca Vit10 8 6Mc nc (cm)

4 2 0 -2 -4 -6 -8 -10 1977 1981 1985 1989 1993 Nm 1997 2001 2005

Xu th mc nc bin trung bnh nm trm Sn Tr10 5

Mc nc (cm)

0 -5 -10 -15 -20 1978 1982 1986 1990 1994 Nm 1998 2002 2006

Xu th mc nc bin trung bnh nm trm Quy Nhn20 15 10

Mc nc (cm)

5 0 -5 -10 -15 -20 1993 1996 1999 Nm 2002 2005 2008

Xu th mc nc bin trung bnh nm trm Ph QUhy20 15 10

Mc nc (cm)

5 0 -5 -10 -15 -20 1986 1990 1994 Nm 1998 2002 2006

Xu th mc nc bin trung bnh nm trm Vng Tu20 15 10

Mc nc (cm)

5 0 -5 -10 -15 -20 1978 1982 1986 1990 1994 Nm 1998 2002 2006

Xu th mc nc bin trung bnh nm trm Ph Quc10 8 6

Mc nc (cm)

4 2 0 -2 -4 -6 -8 -10 1986 1990 1994 1998 Nm 2002 2006

Xu th mc nc bin trung bnh nm trm Rch Gi10.0 5.0Mc nc (cm)

0.0 -5.0 -10.0 -15.0 -20.0 1978 1982 1986 1990 1994 Nm 1998 2002 2006

Hnh 1.13. Din bin mc nc bin theo s liu cc trm thc o (Ngun: IMHEN/2010)60

D thng mc nc (cm)

50 40 30 20 10 0 -10 -20 -30

Thy triu V tinh

-40 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008Tng quan gia hai chui s liu -Trm Hn Du40 30 20H s tng quan R=0.7

V tinh

10 0

-10 -20 -30 -40

-20

-15

-10

-5

0

Thy triu

5

10

15

20

25

30

70 50 30 10 -10 -30 -501993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008Thy triu V tinh

D thng mc nc (cm)

Tng quan gia hai chui s liu -Trm Sn Tr40H s tng quan R=0.91

30 20

V tinh

10 0

-10 -20 -30 -40 -30 -20 -10 0 Thy triu 10 20 30 40

60

D thng mc nc (cm)

50 40 30 20 10 0 -10 -20 -30

Thy triu V tinh

-40 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 200840 30 20 Tng quan gia hai chui s liu -Trm Quy NhnH s tng quan R=0.83

V tinh

10 0

-10 -20 -30 -30 -20 -10 0 Thy triu 10 20 30 40

D thng mc nc (cm)

50 30 10 -10 -30

Thy triu V tinh

-50 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007Tng quan gia hai chui s liu -Trm Vng Tu 40H s tng quan R=0.88

30 20

V tinh

10 0

-10 -20 -30 -40 -30 -20 -10 0 Thy triu 10 20 30 40

Hnh 1.14. Din bin mc nc bin theo s liu v tinh thi k 1993 - 2010 (Ngun: IMHEN/2010)

Hnh 1.15. So snh mc nc bin t s liu ti trm hi vn v v tinh (Ngun: IMHEN/2010)



2. PHNG PHP XY DNG KCH BN BIN I KH HU, NC BIN DNG CHO VIT NAM 2.1. Yu cu cp nht kch bn bin i kh hu, nc bin dng cho Vit Nam Nhn thc r tc ng ca bin i kh hu n Vit Nam, Chnh ph ph duyt Chng trnh mc tiu quc gia ng ph vi bin i kh hu. Mt trong nhng ni dung quan trng ca Chng trnh l xy dng v cp nht kch bn bin i kh hu. Kch bn BKH l c s cc B, ngnh, a phng nh gi tc ng ca bin i kh hu, xy dng v trin khai k hoch hnh ng ng ph. B Ti nguyn v Mi trng c Chnh ph giao: Da trn c s cc nghin cu c trong v ngoi nc, u nm 2009 hon thnh vic xy dng cc kch bn bin i kh hu Vit Nam, c bit l nc bin dng, Cui nm 2010, hon thnh vic cp nht cc kch bn bin i kh hu v n nm 2015, tip tc cp nht cc kch bn bin i kh hu, c bit l nc bin dng cho cc giai on n nm 2100. Cc kch bn BKH, nc bin dng cho Vit Nam cng b nm 2009 c xy dng ch yu da trn c s cc nghin cu trong v ngoi nc v BKH n thi im v vi mc chi tit n vng kh hu v chung cho c vng bin ca Vit Nam. Vic cp nht cc kch bn BKH cn phi c thc hin trn c s ng dng cc m hnh kh hu, phn mm thng k, phng php lun c la chn, xy dng chuyn bit cho Vit Nam v khu vc ln cn. Cc loi s liu khc nhau cng cn c khai thc ti a trong qu trnh xy dng cc kch bn BKH, nc bin dng nh s liu quan trc ti cc trm kh tng, kh hu, cc trm hi vn, d liu v tinh, s liu m phng ca m hnh, Cc kch bn BKH, nc bin dng cho Vit Nam phi c c s khoa hc v thc tin. Nhm p ng c cc yu cu nh gi tc ng ca BKH i vi cc lnh vc v cc a phng khc nhau ca Vit Nam, kch bn BKH, nc bin dng cho Vit Nam cn c chi tit ho n n v hnh chnh cp tnh v nh hn. 2.2. La chn kch bn pht thi kh nh knh Bin i kh hu hin nay cng nh trong th k 21 ph thuc ch yu vo mc pht thi kh nh knh, tc l ph thuc vo s pht trin kinh t - x hi. V vy, cc kch bn bin i kh hu c xy dng da trn cc kch bn pht trin kinh t - x hi ton cu. Con ngi pht thi qu mc kh nh knh vo kh quyn t cc hot ng khc nhau nh cng nghip, nng nghip, giao thng vn ti, ph rng, Do , c s xc nh cc kch bn pht thi kh nh knh l: (1) S pht trin kinh t quy m ton cu; (2) Dn s th gii v mc tiu dng; (3) Chun mc cuc sng vKch bn bin i kh hu, nc bin dng cho Vit Nam 26


li sng; (4) Tiu th nng lng v ti nguyn nng lng; (5) Chuyn giao cng ngh; (6) Thay i s dng t; Trong Bo co c bit v cc kch bn pht thi kh nh knh nm 2000, IPCC a ra 40 kch bn, phn nh kh a dng kh nng pht thi kh nh knh trong th k 21. Cc kch bn pht thi ny c t hp thnh 4 kch bn gc l A1, A2, B1 v B2 vi cc c im chnh sau: - Kch bn gc A1: Kinh t th gii pht trin nhanh; dn s th gii tng t nh vo nm 2050 v sau gim dn; truyn b nhanh chng v hiu qu cc cng ngh mi; th gii c s tng ng v thu nhp v cch sng, c s tng ng gia cc khu vc, giao lu mnh m v vn ho v x hi ton cu. H kch bn A1 c chia thnh cc nhm da theo mc pht trin cng ngh, nh: + A1FI: Tip tc s dng thi qu nhin liu ha thch (kch bn pht thi cao); + A1B: C s cn bng gia cc ngun nng lng (kch bn pht thi trung bnh); + A1T: Ch trng n vic s dng cc ngun nng lng phi ho thch (kch bn pht thi thp). - Kch bn gc A2: Th gii khng ng nht, cc quc gia hot ng c lp, t cung t cp; dn s tip tc tng trong th k 21; kinh t pht trin theo nh hng khu vc; thay i v cng ngh v tc tng trng kinh t tnh theo u ngi chm (kch bn pht thi cao, tng t nh A1FI). - Kch bn gc B1: Kinh t pht trin nhanh ging nh A1 nhng c s thay i nhanh chng theo hng kinh t dch v v thng tin; dn s tng t nh vo nm 2050 v sau gim dn; gim cng tiu hao nguyn vt liu, cc cng ngh sch v s dng hiu qu ti nguyn c pht trin; ch trng n cc gii php ton cu v n nh kinh t, x hi v mi trng (kch bn pht thi thp, tng t nh A1T). - Kch bn gc B2: Dn s tng lin tc nhng vi tc thp hn A2; ch trng n cc gii php a phng thay v ton cu v n nh kinh t, x hi v mi trng; mc pht trin kinh t trung bnh; thay i cng ngh chm hn v manh mn hn so vi B1 v A1 (kch bn pht thi trung bnh, c xp cng nhm vi A1B). Nh vy, IPCC khuyn co s dng cc kch bn pht thi c sp xp t thp n cao l B1, A1T (kch bn thp), B2, A1B (kch bn trung bnh), A2, A1FI (kch bn cao) vi cc mc pht thi kh nh knh trong th k 21 v d tnh mc tng nhit trung bnh ton cu c th hin trn Hnh 2.1. Tuy nhin, ty thuc vo nhu cu thc tin v kh nng tnh ton ca tng nc, IPCC cng khuyn co la chn cc kch bn pht thi ph hp xy dng kch bn bin i kh hu.Kch bn bin i kh hu, nc bin dng cho Vit Nam 27


Cc kch bn bin i kh hu, nc bin dng cho Vit Nam c xy dng v cng b nm 2009 theo cc kch bn pht thi kh nh knh mc thp (B1), trung bnh (B2) v cao (A2, A1FI), trong kch bn trung bnh B2 c khuyn ngh cho cc B, ngnh v a phng lm nh hng ban u nh gi tc ng ca bin i kh hu, nc bin dng v xy dng k hoch hnh ng ng ph vi bin i kh hu. K tha cc nghin cu c v trn c s cc kt qu tnh ton ca cc m hnh kh hu Vit Nam, cc kch bn pht thi kh nh knh c chn nhm cp nht kch bn BKH, nc bin dng cho Vit Nam trong bo co ny bao gm: B1 (kch bn thp) , B2, A1B (kch bn trung bnh), A2 v A1FI (kch bn cao).

Hnh 2.1. S tnh ton pht thi kh nh knh theo cc kch bn v mc tng nhit trung bnh ton cu (Ngun: IPCC) 2.3. La chn phng php xy dng kch bn bin i kh hu, nc bin dng cho Vit Nam 2.3.1. Cc phng php xy dng kch bn bin i kh hu Nhiu phng php c s dng xy dng kch bn BKH cho Vit Nam nh: ng dng cc phn mm SDSM, SIMCLIM, ng dng phng php chi tit ho thng k, khai thc sn phm ca cc m hnh ng lc ton cu v khu vc, Cc phng php tnh cng nh cc sn phm minh ho ca cc phng php c gii thiu Hnh 2.2. Giao din ca phn mm s lc sau y: SDSM ng dng phn mm SDSM Phn mm SDSM l mt cng c h tr, nh gi s thay i kh hu quy m a phng bng cch s dng k thut chi tit ha thng k (Hnh 2.2). Cu trc hot ng ca SDSM nh sau:Kch bn bin i kh hu, nc bin dng cho Vit Nam 28


- Kim sot cht lng v chuyn i d liu thng k; - Kim tra cc nhn t d bo; - Hiu chnh m hnh; - T hp cc d liu hin ti bng cc nhn t trong quan trc; - a kt qu ca m hnh ln cng c ha; - T hp cc d tnh kh hu tng lai (kch bn BKH). ng dng phn mm SIMCLIM Phn mm SIMCLIM c 2 chc nng chnh l tnh ton xy dng cc kch bn (Scenarios Generation) v nh gi tc ng theo cc kch bn (Impact model). Chc nng xy dng kch bn: Da trn sn phm ca cc m hnh ton cu (GCM) theo tng kch bn v chui s liu ca cc yu t kh hu, mc nc bin dng cc a phng, phn mm SIMCLIM c th tnh ton cc kch bn v cc yu t kh hu v mc nc bin dng cho cc a phng . Phng php chnh c s dng l thng k kt hp vi cc cng c ha. Cc yu t kh hu bao gm: lng ma, nhit (trung bnh, cc tr) v cc yu t khc nh m, gi, Sn phm ca hn 20 m hnh hon lu chung kh quyn c tch hp trong SIMCLIM v c sn trong c s d liu ca t chc PCMDI (http://wwwpcmdi.llnl.gov/). Chc nng nh gi tc ng bao gm: - nh gi tc ng ln ti nguyn nc: c th hin thng qua cc tnh ton cn bng nc. Phn mm tnh ton s khc nhau gia lng ma v bc hi tim nng. u vo ca m hnh l nhit trung bnh, lng ma v bc x mt tri, v u ra l gi tr cn bng nc.

Hnh 2.3. Giao din ca phn mm SIMCLIM - nh gi tc ng ln nng nghip: S dng cc tnh ton nhit ngy (degree - day) nh gi tc ng ca bin i kh hu ln nng nghip.Kch bn bin i kh hu, nc bin dng cho Vit Nam 29


- nh gi tc ng xi l ng b v cn bng nc. Phng php chi tit ha thng k Phng php chi tit ha thng k (Statistical Downscaling) s dng nhng thng tin kh hu v BKH t m hnh kh hu ton cu (GCMs) c phn gii tng i th tnh ton chi tit v c phn gii cao hn cho mt khu vc. Mc d GCM ngy cng c hon thin trn phm vi khng gian v thi gian, tuy nhin kt qu ca cc m hnh vn cha chi tit nh gi tc ng ca BKH cho mt khu vc nh v cc iu kin nh a hnh, mt m c nh hng ln n kh hu a phng nhng cha c th hin trong GCM. M hnh chi tit ha thng k xy dng mi quan h nh lng gia cc bin kh quyn quy m ln, ng vai tr l cc nhn t d bo (NTDB) v cc bin lp b mt ca a phng - i tng d bo (TDB). Cc m hnh chi tit ha thng k pht trin kh mnh trong d bo ni chung, d bo hn di (DBHD) ni ring. ng dng phng php chi tit ha thng k xy dng kch bn v BKH l trng hp c bit trong d bo hn di. C 3 phng php c p dng trong chi tit ha thng k: Cc m hnh hi quy (Regression models); Cc s phn loi thi tit (Weather Classification schemes hoc Weather Typing); Cc "my" to thi tit (Weather Generators). Trong cc nghin cu xy dng m hnh d bo v xy dng kch bn BKH, hai phng php thng c dng l phng php thng k u ra ca m hnh (MOS) v phng php s dng s liu "phn tch li" kt hp vi ngun s liu quan trc tng ng thit lp m hnh (PP), nh c trnh by trong Hnh 2.4.Phng php PP/MOS

Xc nh hm chuyn

S liu phn tch li theo li / S liu m phng ca m hnh trong qu kh

S liu quan trc ti a phng

La chn hm chuyn

Kch bn BKH t cc m hnh kh hu ton cu

Kch bn BKH cho khu vc nh

Hnh 2.4. S xy dng hm chuyn theo phng php PP v MOS - Phng php "Thng k t u ra ca m hnh" (Model Output Statistics MOS). Phng php ny s dng kt qu u ra ca m hnh trong qu kh, ktKch bn bin i kh hu, nc bin dng cho Vit Nam 30


hp vi s liu quan trc tng ng ti cc trm xy dng m hnh hi quy, chuyn cc kch bn c c t cc m hnh ny cho tng lai v cc khu vc nghin cu. - Phng php s dng s liu "phn tch li" kt hp vi ngun s liu quan trc tng ng thit lp m hnh (Perfect Prognosis - PP). Do ngun s liu ti phn tch c coi l ngun s liu gn thc t, tng t nh s liu quan trc nn mi quan h to ra gia chng c coi l gn vi quan h thc. Vic nh gi mc tin cy v tiu ch la chn c thc hin khi xy dng v la chn hm chuyn. Cc phng php dng xy dng v kim chng m hnh c la chn cho ph hp vi di v c im ca cc chui s liu. ng dng kt qu ca m hnh AGCM/MRI (Nht Bn) M hnh AGCM/MRI do Vin Nghin cu Kh tng Nht Bn v Cc Kh tng Nht Bn (JMA) xy dng, kt hp gia m hnh d bo thi tit thi on ngn vi m hnh kh hu th h mi m phng kh hu thi gian di. M hnh phn gii 20 km v 60 km, chy bng h thng m phng tri t (Earth Simulator) ti Cc Cng ngh v khoa hc Tri t - i dng, Nht Bn. AGCM/MRI dng s liu 25 nm t nm 1979 - 2003 m phng kh hu qu kh nhm tnh ton cc c trng kh hu cho thi k c s. Tng lai gn c m t t 2015 n 2039 (25 nm) v tng lai xa c m phng t 2075 n 2099 (25 nm). Sn phm ca m hnh gm khong 70 yu t kh hu theo kch bn pht thi trung bnh A1B.

Hnh 2.5. H thng M phng tri t v kch bn BKH ca m hnh AGCM/MRI ng dng m hnh PRECIS ca Trung tm Hadley Vng quc Anh PRECIS (Providing Regional Climates for Impacts Studies) l m hnh ng lc kh hu khu vc c xy dng bi Trung tm Nghin cu Kh hu ton cu Hadley. M hnh c dng xy dng cc kch bn BKH cho khu vc nh v c th chy trn my tnh c nhn. S tnh v min tnh ca m hnh PRECIS c trnh by trong Hnh 2.6. M hnh s dng h ta lai (Hybrid, ) gm 19 mc thng ng vi miKch bn bin i kh hu, nc bin dng cho Vit Nam 31


mc , k (k = 1, ..., 19) xc nh bi s kt hp tuyn tnh gia cao a hnh v cc mc kh p. Li ngang l li xen k, cc bin v hng nh nhit , kh p, m c xc nh ti tm li cn cc thnh phn hu hng c xc nh ti cc im nt li. PRECIS s dng php chiu cc quay, m bo cho s n nh m hnh m khng cn ti php lc phi vt l. Cc s tham s ha vt l c xt n l: S my v ging thy; S bc x; S sol kh; S lp bin; S b mt t; S sng trng trng (Hnh 2.7). iu kin bin xung quanh c ly t m hnh ton cu hoc d liu phn tch, bao gm gi, nhit , m, p sut b mt, Kt qu ca m hnh gm khong hn 100 bin kh tng, trong nhit trung bnh, cao nht, thp nht b mt v lng ma theo ngy, thng, nm c dng trong xy dng kch bn BKH.

Hnh 2.6. S tnh v min tnh ca m hnh PRECIS

Hnh 2.7. Cc qu trnh vt l c xt n trong m hnh PRECIS Min tnh cho Vit Nam c xy dng vi phm vi khng gian trong khong:Kch bn bin i kh hu, nc bin dng cho Vit Nam 32


4N-36oN, 93-120oE, phn gii ngang 25 x 25km, bao gm 140 x 160 nt li. M hnh c s dng tnh ton cho 2 thi k: (1) Thi k c s c la chn theo 2 phng n l 1961-1990 v 1980-1999, v (2) Thi k tng lai, c la chn l thi k 2000-2100 i vi cc kch bn pht thi trung bnh v cao. Cc mc thi gian trong tng lai c xc nh theo khong 20 nm mt: 2000-2019, 2020-2039, 2040-2059, 2060-2079 v 2080-2100. La chn phng php xy dng kch bn bin i kh hu cho Vit Nam Vic la chn phng php xy dng kch bn BKH cho Vit Nam c da trn mc ph hp ca cc phng php vi iu kin kh hu Vit Nam, mc chi tit v tnh y ca kch bn, tnh k tha v cc phng php c s dng trong kch bn cng b nm 2009 v kh nng ch ng cp nht trong tng lai. Cc phng php c dng xy dng kch bn BKH cho Vit Nam bao gm: Phng php chi tit ha thng k c dng tnh ton cho kch bn nhit , lng ma trung bnh ma, nm i vi cc kch bn thp, trung bnh v cao; M hnh AGCM/MRI c dng tnh ton cho kch bn nhit , lng ma trung bnh ma, nm i vi kch bn trung bnh v m hnh PRECIS c dng tnh ton cho kch bn nhit , lng ma trung bnh ma, nm v cc tr i vi kch bn trung bnh. Cc phn mm SDSM, SIMCLIM c dng tham kho. Thi k c s so snh s thay i ca kh hu l giai on 1980-1999, y cng giai on c IPCC dng trong bo co ln th t. 2.3.2. Cc phng php xy dng kch bn nc bin dng Cc phng php chnh nhm xy dng kch bn nc bin dng ton cu cng nh khu vc bao gm: Phng php chi tit ho thng k (MAGICC, SIMCLIM, SLRPP) v ng dng sn phm ca cc m hnh s tr. quy m to cu, Rahmstorf (2007) xy dng phng php thng k bn thc nghim tnh mc nc bin dng. Phng php ny da vo mi quan h gia nhit trung bnh v mc nc bin ton cu trong qu kh c tnh cho tng lai. Kt qu tnh ton c so snh vi s liu thc o (Hnh 2.8). Aslak Grinsted (2009) dng phng trnh phi tuyn bn tham s xy dng quan h gia nhit v mc nc bin ton cu trong 2000 nm v tnh ton mc nc trong qu kh v

Hnh 2.8. Phng php tnh v kch bn nc bin dng ca Rahmstorf, 2007



tng lai. Nhiu m hnh s tr c pht trin tnh ton xy dng kch bn nc bin dng vi s kt hp gia gia m hnh kh hu v m hnh i dng i vi cc kch bn pht thi kh nh knh khc nhau, v d trn hnh 2.9 l kch bn mc nc bin dng nm 2100 quy m ton cu ca Trung tm Nghin cu Kh quyn Quc gia, Hoa K (NCAR). Trong nghin cu xy dng kch bn nc bin dng cho cc khu vc, Joanne (2008) s dng ch (SLRRP) t

Hnh 2.9. Kch bn mc nc bin dng nm 2100 quy m ton cu (NCAR)

i s dng l cc kch bn nc bin dng cho cc khu vc d i a cht ti khu vc . Thomas W. Doyle (2010) tnh ton kch bn nc bin dng cho vng ng bng sng M Kng trn c s tng hp cc yu t: (1) Bin thin mc nc bin trong qu kh ti khu vc; (2) Mc st ln ca khu vc; (3) Xu th mc nc bin dng theo s liu quan trc; (4) Kch bn mc nc bin ton cu ca IPCC theo cc kch bn pht thi A1FI v B1 (Hnh 2.10).

Hnh 2.10. Mt kch bn nc bin dng theo phng php ca Doyle

Hnh 2.11. Phng php chi tit ha Trong kch bn nc bin dng thng k cho mc nc bin dng ca Vng quc Anh nm 2009 (UKCP09), kch bn mc nc bin cho 4 khu vc mc nc bin trung bnh ton cu c chit xut t 11 m hnh s tr kt hp vi c tnh ca IPCC (2007) vKch bn bin i kh hu, nc bin dng cho Vit Nam 34


nc bin dng do qu trnh tan bng v nhng nghin cu v bin i, st ln a cht cho 4 khu vc khc nhau. Nhn chung, khi tnh ton kch bn mc nc bin dng cho khu vc nh, cc nghin cu trn th gii thng s dng cc yu t a phng nh tc bin i mc nc trong qu kh v s dch chuyn a cht ti khu vc nhm hiu chnh cc kch bn nc bin dng quy m ton cu t phng php thng k hoc cc m hnh s tr. La chn phng php u im ca phng php s tr l c th m t c qu trnh mc nc bin dng ti tng khu vc c th vi cc thi k dng rt theo chu k kh hu. Nhc im ca phng php ny l cha m t ng c qu trnh tan bng nn cc kt qu thng thin thp khi kim chng vi s liu thc o. Mt khc, do m hnh l quy m ton cu nn i hi khi lng tnh ton qu ln, yu cu phi c h thng siu my tnh chy trong thi gian kh di. Trn c s k tha kch bn nc bin dng do bin i kh hu c cng b nm 2009 v yu cu chi tit ho ca kch bn cp nht cng nh kh nng p dng cc phng php tnh ton kch bn nc bin dng trong iu kin hin nay Vit Nam, phng php chi tit ha thng k c la chn. Kch bn mc nc bin dng c xy dng trn c s mi quan h thng k gia mc nc bin thc o, c tnh t v tinh trong qu kh tng khu vc ca Vit Nam vi mc nc bin ton cu (Hnh 2.11). Kt qu c chit xut t 10 m hnh s tr ton cu (Hnh 2.12, Bng 2.1) v cc phng php khc, nh m hnh SIMCLIM, c s dng tham kho. Bng 2.1. Cc h thng m hnh c tham kho trong xy dng kch bn nc bin dng cho Vit Nam Quc gia Na Uy c c - Hn Quc M M M Nht Bn Nht Bn M Anh phn gii ti khu vc Vit Nam 1 x 1 1 x 1 2,5 x 1 1 x 1 1 x 1 4 x 5 1,4 x 1,4 2,5 x 2 1 x 1 1,25 x 1,25

TT 1 2 3 4 5 6 7 8 9 10

Tn M hnh BCCR-BCM2.0 ECHAM5/MPI-OM MIUB-ECHO-G GFDL-CM2.0 GFDL-CM2.1 GISS-ER MIROC3.2 MRI-CGCM2.3.2 NCAR - PCM UKMO-HadCM3



Bo co ln th t ca IPCC c tnh mc nc bin dng khong 26-59cm vo nm 2100, tuy nhin khng loi tr kh nng tc cao hn. Cc nghin cu gn y cho thy mc nc bin dng nhanh hn so vi nhn nh ca IPCC. Hnh 2.13 cho thy mc nc thc o nhng nm gn y nm cn trn ca kch bn nc bin dng ca IPCC trong cng thi k. Nhiu nghin cu cho thy vo cui th k 21 mc nc bin c th dng t 1m (Horton, 2007); 1,4m (Rahmstof, 2007) n 2,1m (Grinsted, 2009) nh th hin trong Hnh 2.14. T nhng phn tch, nhn nh trn, kt qu tnh ton kch bn nc bin dng ton cu theo m hnh MAGICC (Hnh 2.15) c la chn lm u vo tnh ton kch bn nc bin dng cho Vit Nam. Xc nh cc khu vc ven bin c mc nc bin dng khc nhau S liu mc nc thc o ti cc trm hi vn, s liu quan trc t v tinh v kt qu tnh ton nc bin dng t cc m hnh s tr cho vng ven bin Vit Nam c s dng xc nh cc khu vc ven bin c s ng nht v xu th bin i mc nc bin trong qu kh v d on cho tng lai. Kt qu cho thy c 7 khu vc ven bin c s ng nht v xu th bin i mc nc bin nh sau: 1) Khu vc ven bin bc Vnh Bc B, t Mng Ci n Hn Du (gm

Hnh 2.12. Mc nc bin dng cui th k 21 theo kch bn trung bnh ca cc m hnh s tr

Hnh 2.13. So snh kch bn mc nc bin dng (IPCC) v s liu o c

Hnh 2.14. Mc nc bin dng cui th k XXI t cc nghin cu khc nhau100 Kch bn A1FI_Cn trn Kch bn B2_Cn trn Kch bn A1FI_Cn di Kch bn B2_Cn di Kch bn B1_Cn di

Mc tng mc nc (cm)

80

Kch bn B1_Cn trn

60

40

20

0 2000

2010

2020

2030

2040

2050 Nm

2060

2070

2080

2090

2100

Hnh 2.15. Kch bn mc nc bin ton cu theo cc kch bn pht thi



tnh Qung Ninh v pha Bc thnh ph Hi Phng); 2) Khu vc ven bin ng bng sng Hng v Bc Trung B, t Hn Du n o Ngang (gm pha Nam thnh ph Hi Phng, cc tnh Thi Bnh, Nam nh, Ninh Bnh, Thanh Ha, Ngh An v H Tnh); 3) Khu vc ven bin pha Nam Vnh Bc B, t o Ngang n o Hi Vn (gm cc tnh Qung Bnh, Qung Tr v Tha Thin - Hu; 4) Khu vc ven bin pha Bc ca Nam Trung B, t o Hi Vn n Mi i Lnh (gm Thnh ph Nng, tnh Qung Nam, Qung Ngi, Bnh nh v Ph Yn); 5) Khu vc ven bin pha Nam ca Nam Trung B, t Mi i Lnh n Mi K G (gm cc tnh Khnh Ha, Ninh Thun v Bc Bnh Thun); 6) Khu vc ven bin ng Nam B, t Mi K G n Mi C Mau (gm Nam Bnh Thun v cc tnh B Ra Vng Tu, TP H Ch Minh, Tin Giang, Tr Vinh, Bn Tre, Sc Trng, Bc Liu, C Mau); 7) Khu vc ven bin Ty, t Mi C Mau n H Tin (gm cc tnh C Mau v Kin Giang). 2.3.3. Phng php xy dng cc bn nguy c ngp Bn nguy c ngp theo cc mc nc bin dng c xy dng ch ra cc khu vc c nguy c b tc ng trc tip do nc bin dng. D liu c dng xy dng bn nguy c ngp bao gm : - Bn s a hnh cc tnh ven bin t l 1:10.000, Cc o c v Bn B Ti nguyn v Mi trng (2010). - Bn a hnh t l 1:5.000 vng ng bng sng Cu Long thuc d n cp nh nc "Xy dng c s d liu h thng thng tin a hnh - thu vn c bn phc v phng chng l lt v pht trin kinh t - x hi vng ng bng sng Cu Long", Trung tm Vin thm Quc gia - B Ti nguyn Mi trng (2008). - D liu nn a l v giao thng cc tnh ven bin t l 1:25.000, Nh xut bn Bn - B Ti nguyn v Mi trng. - S liu v din tch v dn s cc tnh ven bin, Tng cc Thng k (2009). Mi bn cho mt khu vc c xy dng da trn mt gi tr duy nht ca mc nc p dng trn ton vng th hin ca bn . V c bn, phng php ny l nng b mt nc theo mt gi tr c la chn. Cch tip cn ny c s dng ph bin nht trong xy dng bn nguy c ngp do nc bin dng. Cc lp thng tin c nhp vo h thng GIS, th hin bn nguy c ngp v c trnh by theo quy nh ca bn chuyn ban hnh.Kch bn bin i kh hu, nc bin dng cho Vit Nam 37


2.4. Mt s lu v cc kch bn bin i kh hu, nc bin dng v bn nguy c ngp Cc kch bn ni chung v kch bn BKH lun tn ti nhng im cha chc chn, v th tnh cha chc chn ca cc kch bn BKH cn c xt n trong nh gi tc ng, tnh d b tn thng v xc nh cc gii php thch ng vi BKH. V c bn, tnh cha chc chn trong cc kch bn BKH lin quan n tnh cha chc chn trong xc nh cc kch bn pht thi kh nh knh, nng kh nh knh trong kh quyn trong tng lai, nhng hiu bit cn hn ch v h thng kh hu ton cu v khu vc, phng php xy dng cc kch bn. V cc kch bn pht thi kh nh knh Tnh cha chc chn ca cc kch bn pht thi kh nh knh c cho l nguyn nhn chnh gy ra nhng im khng chc chn ca cc kch bn BKH. Nhng im cha chc chn ca cc kch bn pht thi kh nh knh lin quan n cc mi quan h rng buc gia s tng dn s, pht trin kinh t - x hi v thay i cng ngh trong tng lai. khc phc vn ny cc kch bn bin i kh hu, nc bin dng c xy dng da theo cc kch bn pht thi kh nh knh khc nhau, t kch bn thp n cc kch bn cao (theo cc h kch bn chnh A1, A2, B1 v B2). V nng kh nh knh trong kh quyn Tnh cha chc chn v nng kh nh knh trong kh quyn lin quan n nhng hn ch trong hiu bit v cc qu trnh vt l v ha hc trong kh quyn. Do vy, s tn ti nhng im cha chc chc tim n trong cc kt qu xy dng kch bn BKH, nc bin dng. Ngoi ra, tnh cha chc chn cn lin quan n vic cha tnh n nhng nh hng ca bc x n nng sol kh lm thay i nng kh quyn. Cc m hnh ng lc ton cu ngy cng c gng m phng y hn cc qu trnh vt l v ha hc trong kh quyn. V kh nng m phng ca cc m hnh kh hu ton cu Cc m hnh ton cu thng kh c th m phng y v chnh xc cc qu trnh trong kh quyn, v th c nhng sai s nht nh, cc m hnh khc nhau c th cho kt qu khc nhau. khc phc, cn s dng kt qu ca nhiu m hnh a ra cc khong gi tr. Ngoi ra, phng php t hp cng c th c p dng i vi cc kt qu khc nhau, trong cc kch bn thnh phn c th c to ra bng cch thay i iu kin u vo ca m hnh ton cu hoc s dng cc m hnh ton cu khc nhau. V cc phng php khu vc ha kh hu Nhn chung, cc phng php khu vc ha thng c cc sai s tnh ton. i vi phng php ng lc, sai s l do tnh cha hon ho ca cc s vt l, ng lc v nhng thay i bn trong ca m hnh. Bn cnh , nhng im chaKch bn bin i kh hu, nc bin dng cho Vit Nam 38


chc chn ca m hnh ton cu cng gp phn lm tng thm mc sai s ca m hnh khu vc. i vi phng php chi tit ha thng k: S ph hp ca cc hm chuyn c nhn nh thng qua ln ca h s tng quan tuyn tnh gia nhit , lng ma m phng, phn tch bng m hnh ton cu v quan trc Vit Nam. i vi nhit , h s tng quan dao ng trong khong 0,65-0,95. Cc hm chuyn l ng tin cy, nht l vo cc thng ma ng. i vi lng ma, h s tng quan dao ng trong khong t 0,4-0,7 vo ma kh v khong 0-0,2 vo cc thng ma ma. Cc hm chuyn tin cy vo ma kh v cha ng tin cy vo ma ma. i vi sn phm ca m hnh AGCM/MRI: Kt qu kim nh m hnh cho thi k 1979-2003 cho thy m hnh m phng kh tt bin trnh nm ca nhit , tuy nhin vn tn ti sai s gia gi tr nhit tnh ton v thc o i vi cc trm thuc khu vc Trung B v Nam B. Bin trnh nm ca lng ma c m phng kh tt i vi cc trm thuc Bc B, Trung B, Ty Nguyn v Nam B, nhng lng ma vo thi k cao im ma ma Nam Trung B c nhiu sai s. i vi m hnh PRECIS: S liu ti phn tch vi phn gii 0,5 x 0,5 kinh v v s liu thc o ti cc trm Vit Nam c dng kim nh m hnh. M hnh m phng kh tt nhit (gi tr, bin trnh nm v phn b theo khng gian). M hnh m phng tt bin trnh nm ca lng ma Bc B v Nam B, m phng c cc tm ma ln pha Bc, nhng thin thp i vi lng ma cho khu vc Trung B v Nam B, m phng khng tt lng ma vo cc thng cao im ma ma Trung B. V cc kch bn nc bin dng S cha chc chn trong tnh ton nc bin dng cho tng lai quy m ton cu do hai nguyn nhn c bn sau: (1) S cha chc chn ca m hnh kh hu v y l u vo cho cc m hnh tnh ton nc bin dng; (2) Hiu bit cha y v cc qu trnh tan bng. V chnh xc ca cc bn nguy c ngp Mc chnh xc ca bn nguy c ngp ph thuc vo mc chnh xc ca bn a hnh.



3. KCH BN BIN I KH HU, NC BIN DNG CHO VIT NAM 3.1. Kch bn bin i kh hu i vi nhit 3.1.1. Nhit trung bnh a) Ma ng (thng XII-II) Theo kch bn pht thi thp, n cui th k 21, trn a phn din tch nc ta, nhit ma ng tng t 1,6 n 2,2oC so vi thi k c s 19801999. phn ln din tch Ty Nguyn, cc nam Trung B v Nam B c nhit tng t hn, t 1 n 1,6oC. Khu vc tnh Sn La c nhit tng nhiu nht, trn 2,5oC (Hnh 3.1). Theo kch bn pht thi trung bnh, vo gia th k 21, nhit tng t 1,4 n 1,8oC trn i b phn din tch pha Bc (t Nng tr ra). Hu khp din tch pha Nam (t Qung Nam tr vo) c mc tng t nh hn 1,0 n 1,4oC (Hnh 3.2). Vo cui th k 21, nhit tng t 2,5 n 3,1oC trn a phn din tch nc ta. Ring khu vc pha Ty tnh Lo Cai, pha Nam tnh in Bin v hu ht din tch cc tnh Sn La, Qung Bnh v Qung Tr c mc tng cao hn 3,1oC. Phn ln din tch pha Nam (t Qung Nam tr vo) c mc tng nhit t 1,6 n 2,5oC. Mt phn nh din tch tnh Lm ng v khu vc pha Bc ca Ty Nam B c mc tng t 1,0 n 1,6oC (Hnh 3.3). Nh vy, mc tng nhit pha Bc cao hn pha Nam.

Hnh 3.1. Mc tng nhit trung bnh ma ng (oC) vo cui th k 21 theo kch bn pht thi thp

Hnh 3.2. Mc tng nhit trung bnh ma ng (oC) vo gia th k 21 theo kch bn pht thi trung bnh



Theo kch bn pht thi cao, vo cui th k 21, trn phn ln din tch nc ta nhit ma ng tng t 2,8 n trn 3,7oC. Ring khu vc tnh Lo Cai, Nam in Bin, Sn La v khu vc t Nam H Tnh n Qung Tr c nhit tng trn 3,7oC. Phn ln din tch khu vc t Khnh Ha tr vo c mc tng thp hn, t 1,6 n 2,8oC (Hnh 3.4).

Hnh 3.3. Mc tng nhit trung bnh ma ng (oC) vo cui th k 21 theo kch bn pht thi trung bnh



b) Ma xun (thng III V)

Hnh 3.4. Mc tng nhit trung bnh ma ng (oC) vo cui th k 21 theo kch bn pht thi cao Theo kch bn pht thi thp, vo cui th k 21, nhit ma xun tng t 1,6 n 2,2oC a phn din tch nc ta so vi thi k c s 1980-1999. Khu vc Qung Bnh n Qung Tr c mc tng t 2,2 n trn 2,8oC. Mt vi ni thuc Bc B, mt phn din tch Nam Trung B, a phn din tch Ty Nguyn v Ty Nam B c mc tng nhit thp nht, t 1,0 - 1,6oC (Hnh 3.5). Theo kch bn pht thi trung bnh, vo gia th k 21, nhit tng t 1,2 n 1,6oC a phn din tch nc ta. Khu vc Qung Bnh n Qung Tr c mc tng t 1,6 n trn 2,2oC. a phn din tch Ty Nguyn v Ty Nam B c mc tng t di 1,0 n 1,2oC (Hnh 3.6). Vo cui th k 21, nhit tng t 2,2 n 3,1oC i b phn din tch

Hnh 3.5. Mc tng nhit trung bnh ma xun (oC) vo cui th k 21 theo kch bn pht thi thp

Hnh 3.6. Mc tng nhit trung bnh ma xun (oC) vo gia th k 21 theo kch bn pht thi trung bnh



nc ta. Khu vc t Nam H Tnh n Qung Tr c mc tng cao nht, t 3,1 n trn 3,4oC. Mt phn din tch Ty Nguyn v a phn din tch Ty Nam B c nhit tng thp nht, t 1,3 n 2,2oC (Hnh 3.7).

Hnh 3.7. Mc tng nhit trung bnh ma xun (oC) vo cui th k 21 theo kch bn pht thi trung bnh Theo kch bn pht thi cao, tnh n cui th k 21, nhit ma xun tng t 2,8 n trn 3,7oC trn i b phn din tch nc ta. Mt phn din tch Ty Nguyn v Ty Nam B c mc tng t trn 1,3 n 2,8oC (Hnh 3.8).Kch bn bin i kh hu, nc bin dng cho Vit Nam 43


c) Ma h (thng VI-VIII) Theo kch bn pht thi thp, n cui th k 21, nhit ma h tng t 1,0 n 1,6oC phn ln din tch nc ta; tng t 1,6 n 2,5oC trn khu vc t H Tnh n Qung Tr, mt phn din tch thuc Ty Nguyn v Nam Trung B v a phn din tch Nam B (Hnh 3.9). Theo kch bn pht thi trung bnh, vo gia th k 21, trn a phn din tch nc ta nhit tng t 1,0 n 1,4oC. Khu vc t H Tnh n Qung Tr, mt phn nh din tch Ty Nguyn, cc nam Trung B v ng Nam B c nhit tng t 1,4 n trn 1,8oC (Hnh 3.10). Vo cui th k 21, nhit tng t 1,6 n 3,1oC trn i b phn din tch c nc. Khu vc t H Tnh n Qung Tr, mt phn din tch thuc Ty Nguyn v ng

Hnh 3.8. Mc tng nhit trung bnh ma xun (oC) vo cui th k 21 theo kch bn pht thi cao

Hnh 3.9. Mc tng nhit trung bnh ma h (oC) vo cui th k 21 theo kch bn pht thi thp

Hnh 3.10. Mc tng nhit trung bnh ma h (oC) vo gia th k 21 theo kch bn pht thi trung bnh



Nam B c mc tng t 3,1 n trn 3,7oC; mc tng nhit t 1,0 n 1,6oC xy ra pha Bc Ty Bc B v hu ht din tch t Tha Thin - Hu n Kon Tum (Hnh 3.11).

Hnh 3.11. Mc tng nhit trung bnh ma h (oC) vo cui th k 21 theo kch bn pht thi trung bnh Theo kch bn pht thi cao, vo cui th k 21, nhit tng t 2,2 n trn 3,7 C trn i b phn din tch nc ta. Khu vc pha Bc Ty Bc B v t Tha Thin Hu n Kon Tum c mc tng t 1,0 n 2,2oC (Hnh 3.12).o



d) Ma thu (thng IX-XI) Theo kch bn pht thi thp, vo cui th k 21, trn hu khp din tch nc ta, nhit ma thu tng t 1,3 n 2,2oC, trong pha Bc (t Qung Nam tr ra) v khu vc Nam B, tng ch yu t 1,6 n 2,2oC; khu vc Nam Trung B v Ty Nguyn c mc tng ch yu t 1,0 n 1,6oC (Hnh 3.13). Theo kch bn trung bnh, vo gia th k 21, nhit ma thu trn hu ht din tch nc ta tng t 1,0 n 1,6oC, trong mt phn din tch thuc Ty Nguyn, Nam Trung B v Ty Nam B c nhit tng t 1,0 n 1,2oC (Hnh 3.14).

Hnh 3.12. Mc tng nhit trung bnh ma h (oC) vo cui th k 21 theo kch bn pht thi cao

Hnh 3.13. Mc tng nhit trung bnh ma thu (oC) vo cui th k 21 theo kch bn pht thi thp

Hnh 3.14. Mc tng nhit trung bnh ma thu (oC) vo gia th k 21 theo kch bn pht thi trung bnh

Vo cui th k 21, trn hu khp din tch c nc c nhit tng t 1,6Kch bn bin i kh hu, nc bin dng cho Vit Nam 46


n 2,8oC. mt vi ni thuc Bc B, khu vc t nam H Tnh n Qung Tr v mt phn nh din tch Nam B c mc tng t 2,8 n trn 3,1 oC. Mt phn nh din tch thuc Ty Nguyn v Ty Nam B c mc t 1,0 n 1,6oC (Hnh 3.15).

Hnh 3.15. Mc tng nhit trung bnh ma thu (oC) vo cui th k 21 theo kch bn pht thi trung bnh Theo kch bn pht thi cao, vo cui th k 21, nhit ma thu tng t 2,5 n trn 3,7oC so vi thi k c s 1980-1999 hu khp din tch nc ta, mtKch bn bin i kh hu, nc bin dng cho Vit Nam 47


phn din tch Ty Nguyn c tng t 1,3 n trn 2,5 oC (Hnh 3.16). e) Trung bnh nm Theo kch bn pht thi thp, n cui th k 21, nhit trung bnh nm tng t 1,6 n ln hn 2,2oC trn i b phn din tch pha Bc (t Tha Thin Hu tr ra). Mc tng nhit t 1,0 n 1,6oC i b phn din tch pha Nam (t Qung Nam tr vo Hnh 3.17). Theo kch bn pht thi trung bnh, vo gia th k 21, trn a phn din tch nc ta, nhit trung bnh nm c mc tng t 1,2 n 1,6oC. Khu vc t H Tnh n Qung Tr c nhit tng cao hn, t 1,6 n trn 1,8oC. a phn din tch Ty Nguyn, cc nam Trung B v Nam B c mc tng thp hn, t di 1,0 n 1,2oC (Hnh 3.18).

Hnh 3.16. Mc tng nhit trung bnh ma thu (oC) vo cui th k 21 theo kch bn pht thi cao

Hnh 3.17. Mc tng nhit trung bnh Hnh 3.18. Mc tng nhit trung bnh nm (oC) vo cui th k 21 theo kch nm (oC) vo gia th k 21 theo kch bn pht thi thp bn pht thi trung bnh



n cui th k 21, nhit tng t 1,9 n 3,1oC hu khp din tch c nc, ni c mc tng cao nht l khu vc t H Tnh n Qung Tr vi mc tng trn 3,1oC. Mt phn din tch Ty Nguyn v Ty Nam B c mc tng thp nht, t 1,6 n 1,9oC (Hnh 3.19).

Hnh 3.19. Mc tng nhit trung bnh nm (oC) vo cui th k 21 theo kch bn pht thi trung bnh Theo kch bn pht thi cao, n cui th k 21, nhit trung bnh nm c mc tng ch yu t 2,5 n cao hn 3,7oC trn hu ht din tch nc ta. Ni cKch bn bin i kh hu, nc bin dng cho Vit Nam 49


mc tng thp nht, t 1,6 n 2,5oC l mt phn din tch thuc Ty Nguyn v Ty Nam B (Hnh 3.20). 3.1.2. Nhit cc tr a) Nhit cc tr ma ng (thng XII-II) Theo kch bn pht thi trung bnh, vo gia th k 21, nhit thp nht trung bnh ma ng tng t 1,0 n 1,2oC trn hu ht din tch t Khnh Ha tr ra; tng t 1,2 n 1,5oC trn khu vc t Ninh Thun tr vo (Hnh 3.21a). Nhit cao nht trung bnh tng t 1,2 n 2,2oC trn hu ht din tch pha Bc (t Ngh An tr ra), khu vc tnh Bnh Thun v Nam B; tng t 0 n 1,2oC hu khp din tch Trung B v Ty Nguyn (Hnh 3.21b).

Hnh 3.20. Mc tng nhit trung bnh nm (oC) vo cui th k 21 theo kch bn pht thi cao

a)

b)

Hnh 3.21. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma ng vo gia th k 21 theo kch bn pht thi trung bnh Vo cui th k 21, trn i b phn din tch khu vc t Bc Ph Yn tr ra, nhit thp nht trung bnh ma ng tng t 2,0 n 2,2oC; mt phn din tch ng Bc B, Nam Ty Nguyn, cc nam Trung B v Nam B c mc tng t 2,2 n trn 3,0oC. Nhit cao nht trung bnh tng t 2,2 n 3,2oC trn a phn din tch t Ngh An tr ra v khu vc Nam B; tng t 2,0 n 2,2oC trn hu ht dinKch bn bin i kh hu, nc bin dng cho Vit Nam 50


tch Trung B v Ty Nguyn (Hnh 3.22).

a)

b)

Hnh 3.22. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma ng vo cui th k 21 theo kch bn pht thi trung bnh b) Nhit cc tr ma h (thng VI-VIII) Theo kch bn pht thi trung bnh, vo gia th k 21, nhit thp nht trung bnh ma h c th tng t 1,7 n trn 2,0oC ng Bc B, i b phn din tch t Tha Thin Hu n Ninh Thun; tng t 1,2 n 1,7 oC Ty Bc B, Bc Trung B, Ty Nguyn v Nam B. Nhit cao nht trung bnh ma h ch yu tng t 1,2 n trn 2,0oC ng Bc B v hu ht din tch pha Nam (t Tha Thin Hu tr vo); tng t 1,0 n 1,2oC Ty Bc B, phn ln din tch thuc Bc Trung B v Ty Nguyn. Vo cui th k 21, nhit thp nht trung bnh ma h tng t 2,7 n trn o 3,2 C ng Bc B v i b phn din tch Trung B; tng t 2,0 n 2,7oC Ty Bc B, mt phn din tch Trung B, Ty Nguyn v Nam B. Nhit cao nht trung bnh tng t 2,2 n 3,2oC ng Bc B v Trung B; tng t 2,0 n 2,2oC Ty Bc B, Ty Nguyn v Nam B (Hnh 3.24). c) Nhit cc tr nm Theo kch bn pht thi trung bnh, vo gia th k 21, nhit thp nht trung bnh nm tng t 1,0 n 1,7oC trn i b phn din tch nc ta; tng t 1,7 n 2,0oC mt phn nh din tch Nam Ty Nguyn v Nam B. Nhit cao nht trung bnh nm tng t 1,0 n 1,7oC trn phn ln din tch lnh th; tng t 1,7 n 2,2oC ng Bc B, mt phn din tch Nam Ty Nguyn v Nam B (Hnh 3.25).Kch bn bin i kh hu, nc bin dng cho Vit Nam 51


a)

b)

Hnh 3.23. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma h vo gia th k 21 theo kch bn pht thi trung bnh

a)

b)

Hnh 3.24. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) trong ma h vo cui th k 21 theo kch bn pht thi trung bnh Vo cui th k 21, nhit thp nht trung bnh nm tng t 2,2 n 3,0oC; trong , a phn din tch Bc B, Nam Ty Nguyn v Nam B c mc tng cao hn so vi cc khu vc khc (t 2,7 n 3,0 oC). Nhit cao nht trung bnh nm tng t 2,0 n 3,2oC, trong khu vc ng Bc B v a phn din tch Nam BKch bn bin i kh hu, nc bin dng cho Vit Nam 52


c mc tng cao nht, t 2,7 n 3,2oC (Hnh 3.26).

a)

b)

Hnh 3.25. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) nm vo gia th k 21 theo kch bn pht thi trung bnh

a)

b)

Hnh 3.26. Mc tng nhit ti thp trung bnh (a) v ti cao trung bnh (b) nm vo cui th k 21 theo kch bn pht thi trung bnh Vo cui th k 21, s ngy nng nng (nhit cao nht trn 35oC) tng t 10 n 20 ngy trn phn ln din tch c nc. a phn din tch Bc B v mt phn nh din tch Ty Nguyn c mc tng t 1 n 10 ngy (Hnh 3.27).



Hnh 3.27. Mc tng s ngy c nhit cao nht trn 35oC vo cui th k 21 theo kch bn pht thi trung bnh Bng 3.1 trnh by mc tng nhit (oC) trung bnh nm ca tng thp k ca th k 21 so vi thi k 1980-1999 theo kch bn pht thi trung bnh (B2) cho 63 tnh, thnh ph trc thuc trung ng. i vi cc mc thi gian vo gia v cui th k 21 c b sung khong dao ng ca mc tng nhit , v d vo nm 2050, Lai Chu, mc tng nhit dao ng trong khong t 1,0 n 1,6 oC, nhng kh nng cao nht c th xy ra l 1,2oC.



Bng 3.1. Mc tng nhit ( oC) trung bnh nm so vi thi k 1980-1999 theo kch bn pht thi trung bnh (B2)STT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 Tnh, thnh ph 2020 2030 2040 Lai Chu in Bin Sn La Ha Bnh H Giang Cao Bng Lo Cai Yn Bi Tuyn Quang Bc Kn Thi Nguyn Lng Sn Ph Th Bc Giang Qung Ninh Vnh Phc Bc Ninh H Ni Hng Yn Hi Dng Hi Phng H Nam Thi Bnh Nam nh Ninh Bnh Thanh Ha Ngh An H Tnh Qung Bnh Qung Tr Tha Thin - Hu Nng Qung Nam Qung Ngi Bnh nh Ph Yn Khnh Ha Ninh Thun Bnh Thun Kon Tum Gia Lai k Lk k Nng Lm ng Ty Ninh Bnh Dng Bnh Phc Tp. H Ch Minh ng Nai B Ra - Vng Tu Long An ng Thp Tin Giang Bn Tre Vnh Long Tr Vinh An Giang Cn Th Hu Giang Sc Trng Bc Liu Kin Giang C Mau 0,5 0,5 0,6 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,5 0,4 0,5 0,5 0,5 0,5 0,5 0,6 0,7 0,6 0,5 0,5 0,4 0,5 0,4 0,5 0,5 0,5 0,5 0,3 0,5 0,5 0,4 0,3 0,5 0,6 0,6 0,5 0,5 0,4 0,4 0,3 0,5 0,4 0,4 0,4 0,3 0,3 0,4 0,5 0,5 0,3 0,5 0,7 0,8 0,8 0,7 0,7 0,7 0,8 0,7 0,7 0,7 0,8 0,7 0,8

Kịch bản BĐKH và nước biển dâng cho Việt Nam 2011

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