Bài viết trình bày biến đổi khí hậu với đồng bằng Sông Cửu Long; ảnh hưởng của biến đổi khí hậu đến sản xuất nông nghiệp từ đó đề xuất một số giải pháp hạn chế tác động của biến đổi khí hậu đến nông nghiệp tại đồng bằng sông Cửu Long.
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KHI HAU DOl V0I SAN XUAT N D N G NGHIEP Ql DdNG BANG SONG COU LONG GS.TS Le Quang Tn Vien tn/dng Vign Nghien ciiu bien ddi hgu TrUdng Dai hoc Can Tho NhQng nam gin day, cac hien tUdng thdi tiet ci/c doan nhU han han, lu lut, xam nhap man, nirdc bien dang dang khdng ngiTng gia tang tai nhieu tinh/thanh Doi vdi Dong bang sdng Ciiu Long (DBSCL) • vung san xuat ndng nghiep diem cua ca nUdc, hnh ht/dng cua nhQng hien ti/dng thdi tiet cUc doan iat cang nghiem trpng Bi^n Ooi hau 8di vffi OBSCl hufing nang nhit Khi nudc bien ding cao m, Udc chUng 5,3% dien tfch tu nhidn, 10,8% din sd, 10,2% GDP, 10,9% viJng dd thj, 7,2% dien tfch ndng nghidp v i 28,9% vijng dit thip se bj inh hudng Rui ro d DBSCL, bao gdm c i han hin v i 10 lyt, se gia tang vdi cic tran mua cd cUdng dp cao va cic ngiy han keo dii TU nim 2009, Trung tim START vung Ddng Nam A (Dai hoc Chulalongkorn, Thai Lan) v i Vien Nghien cUu bidn ddi hau (Trudng Dai hpc Cin Thd) da phdi hdp chay thC( md hinh khf hiu vung PRECIS vdi kjch ban A2 v i B2, dUa vao chudi sd lieu hiu giai doan 1980-2000 de phfing doin giai doan 2030-2040 Ket qui md hinh cho thay, nhieu khu vuc cua vung DBSCL se bj tic ddng sau: (i) Nhiet dp cao nhat trung binh mua khd Theo Uy ban lien chinh phij ve se gia ting tU 33-35"C len 35-37°C; bidn ddi hiu, qua phin tich v i (ii) LUdng mUa dau vu he thu (15/4phdng doin cac tic dflng cua nudc 15/5) se giim chUng 10-20%; (iii) Su phin bd mUa thing se cd khuynh bien ding da cdng nhan vung chau hudng giim vao dau v i gtiJa vu he thd dupc xdp nhdm cue ky nguy thu nhung gia tang mdt chut vio cudi cap bien ddi khf hau la: vung miJa mua; (iv) Tdng IUdng mUa nam lUu sdng Mekong (Viet Nam), sdng tai An Giang, Cin Thd va Sdc Trang Ganges - Brahmaputra (Bangladesh) se giim chUng 20%, thdi ky bit dau va sflng Nile (Ai Cap) Nghidn cUu mua mUa se tre hdn khoing tuin cCia Ngin hang the gidi cung cho thay, le Tong quit cho thiy, dien bidn khf Viet Nam nam nhdm qudc gia hiu hien va tUdng lai la nhQng chju inh hufing Idn nhat bien ddi yeu td bit ldi cho sin xuat, sinh ke va hiu Tai Viet Nam, vung Ddng ddi sdng cija ngudi din DBSCL Cic bang sdng Hdng va DBSCL chju inh DBSCL nam d cudi dong chiy ci^a sdng Mekong trUdc dd Biln Ddng va mpt phan nhd Vjnh Thii Lan Diy l i mdt vung dat thap v i bang phang, cao dp trung binh phd bidn tQ ddn m so vdi mUc nudc biln, dUdc boi tu bdi phij sa cCia sdng Mekong Vung ddng bang cd didn tich gin trieu (39.734 km^), dd cd tren 2,4 trieu dit canh tic nong nghiep v i gan 700 ngan dat nudi trdng thuy san Vung dat niy la ndi cU triJ v i sin xuat cija hdn 18 trieu din va dupc xem la vUa lua Idn nhat cDa c i nudc, cung cap 55% sin IUdng gao (trong ddng gdp 90% IUdng gao xuat khau cua Viet Nam the gidi), hdn 60% iUdng thuy sin v i hdn 70% IUdng trii cay cho c i nUdc 40 KHOAHOC , „ CDNG NGHE Viei iNam So ndm 20]6 tic ddng cua bidn ddi hiu co the lam kim ham cic ke hoach phat triln kinh te - xa hdi cOa cic dja phUdng Do dia the nam d vung cudi lUu, toan bd dong chiy lu tQ thUdng nguon tran vd viing DBSCL qua hai nhanh sdng Tien, sdng Hau v i phan tran bd chiy trdn dat lien vupt bien gidi giQa Campuchia va Viet Nam lim ngip nhieu vung dat trung, chij yeu l i vung TQ giic Long Xuyen - Hi Tien, vung Dong Thap MUdi va viJng trung glOa hai nhinh sdng Tien - sdng Hiu Mua lu bat dau tQ thing 7, gia ting din til thing 8-9, cao diem vio thing 10 vi giim dan vio thing 11-12 Binh quin vao miia mUa, lUu IUdng lu cao nhit la 139.000 mVs, gay ngip tQ 1,2 den 1,9 trieu Anh hiAUng cua bi^nfleikhi hiofltos a mat hAng nghi0piiiBBSCL Tic dpng den san xuat va ddi song DUdi tic ddng cua bidn ddi hau, DBSCL, Udc tfnh hing trim ngin hecta dat bj ngip, hang tridu ngudl cd the bj mat nha cljfa neu nUdc biln dang cao Sin IUdng IUdng thUc cd nguy cd giim siit Idn, de doa tdi an ninh IUdng thuc cua qudc gia Didn tfch canh tic ndng nghiep sfi dung ngudn nUdc ngpt nhu lua, miu, ciy an trai v i nudi trdng thuy sin se bj thu h^p, ning suit va sin lUdng se DIA PHUONG suy giim Ca nudc ngpt du kidn se an toin cua cac tuydn dd sdng d cac suy giim vi didn tfch dat ddng bing tinh phia bac, dd bao va bd bao fi cac va ddng sdng nhiem man gia ting tinh phia nam Bidn ddi khf hau cung NgUdc lai, c i nudc min, Id se phat lam thay ddi dieu kien sinh sdng cilia trien Dien tich nufli tflm, sd va hii cic loai sinh vit, dan den tinh trang sin khic cd thl se gia tang bien mit cija mpt sd loai v i ngUdc lai tUdng lai Cic vimg tai nguydn rdng, xuat hien nguy cd gia tang cic loai dit, nUdc, sinh vat hoang da, khoing "thidn djch" Trong thdi gian nam sin (than bim, cit d i xiy dQng ) trfi i^i day, djch riy nau, vang lim, se bj xam lin Ndng dan, ngu din, lun xoin l i fi DBSCL didn bien diem din v i thj din ngheo se l i ddi cing phQc tap, inh hufing ddn tUdng chju nhieu tdn thUdng ning ne nang thim canh, tang vu v i lim giim thidu ngudn dinh dudng, thieu sin IUdng lua Bidn ddi khf hiu cd the ning tii chfnh, thieu didu kien tiep cin tic dflng ddn thdi vu canh tic lua, lim thdng tin de cd thl ddi phd kip thdi vdi thay ddi cau true mua vu, quy hoach sQ thay ddl cCia thdi tiet va klii hau DU vung, ky thuit tudi tieu, siu bdnh, kien se cd su djch chuyen ddng di cU nang suit, sin lupng cOa ndng din fi cac vung ven biln bj Anh hudng den quang hdp vi tic dpng ning ne bien ddi hiu va nudc bien ding ldn cic dd thj vung nang suit cay phia bac v i phia tiy (nhu Chau Ddc, NhL?ng thay ddi ve cUdng dp va Long Xuydn, Cin Thd, VTnh Long, My thdi gian cd nang, thieu nudc, gia Tho, Tin An ) Dieu khidn cic tang IUdng khf CO^ (dy kidn tang tU quy hoach dd thj bj phi vd, trit tU x i 350 ppm ddn 700 ppm) va nhiet dp hdise la mdt thQ thach, mdi trudng dfl (dy kidn gia ting them ^°C) thj se bj xau di su gia ting cd hpc tUdng lai se inh hudng tdi vide tao ve din sd Thuc te cho thiy, mua khfl chit khd cua toan ciy va sin pham nam 2016, man da xam nhip siu den thu hoach Gia ting nhidt dp va 90 km vao cac tinh/thinh ven biln fi cudng dp inh sang lim gia tang DBSCL, vdi didn tich khoing 300.000 quang hdp nhUng ddng thdi cung lam Neu tinh trang han - man tidp tuc gia tang hd hap Nhdm ciy C3 (lua, diln nhU nim 2016 thi didn tich dau nanh, cay i n trii, ciy cho eu ) cic vimg trdng lua se bj anh hufing dUdc hufing ldi nhieu nhat tang rat ldn, Iim giim ning suit v i sin gap dfli ludng CO^ va nhiet dd, nang lupng Nhu viy, vide chpn tao va sQ suit chat khd toan cay cd thl gia tang dung cic loai gidng lua chju man l i 20-30% Tuy nhidn, nhQng dien bidn ning phii nght tdi hien t^ii niy ehi xay cd diJ nUdc tudi v i tUdng lai sudt mua trdng Nhdm ciy C4 Ngoai cic yeu td inh hudng nhu (mia, bip }, dieu kidn CO^ hidn ndu tren ddl vdi cay liJa, nudi trdng (350 ppm), fi inh sing manh v i thuy san , muc nudc bien ding nhipt dd cao, nhdm co quang hdp cdn lam hd thdng dd biln hidn tai cd v i sQ dung nudc hQu hidu hdn nhdm nguy cd trin v i vd c i klidng C3.6 cUdng dp inh sing cao, hfl hap cd cic trin bao Idn Ngoai ra, myc anh sing trd nen khdng ding ke Nhu nude biln ding cao lim che dp dong viy, ning suit chit khd cfia thuc vit chiy ven bd thay ddi se gay xdi lfi nhdm C4 cao hdn C3 fi cUdng dp anh bd, Ddi vdi hd thdng dd sdng, de bao sing cao Nhung nhiet dp tdi hio v i bd bao, mUe nudc biln ding cao cija quang hdp S nhdm C4 thip hdn lim eho nang tieu thoit nUdc nhidt dd tdi hio cua hd hap, nen bien giam, keo theo mUc nUdc cic gia tang nhidt dd, chat bpt se bi mat sdng ding len, ket hdp vdi sU gia nhidu hdn Do viy, nang suit cic loai ting ddng chiy lu tQ thupng ngudn se cay trdng cung cd sU thay ddi trudc lam eho dinh lu tang them, uy hiep sU nhOng didn bien bat thudng cua bien ddi hiu Anh hudng din c6 d^i, sau benh va da dang sinh hgc C6 dai da sd thudc nhdm C3, ndn se phit trien manh tUdng lai, nhipt dd ting them 1°C va COj, ting gip ddi, xim nhap co dai cung se tram trpng tUdng lai Nhieu nghidn cUu cho thay, gia tang nhidt dp giup cdn trimg rut ngan chu ky sinh trufing, gia tang mUe sinh nfi va mat sd nhanh chdng, Riy niu hai lua cd the manh lidt hdn v i nhieu ddng khing thudc cd cd hdi bpc phit hdn Djch ray thudng xay vao miia he, nhung tUdng lai co thl xiy vao mua mUa nhidt dp v i dp am giim Nan cio cio, chiu chau cd the cung trfi nen trim hdn Bidn ddi khf hiu va nudc biln ding se tic dpng len toan bo he sinh thii vdn rat nhay cam cua vung DBSCL Van de niy lim thay ddi ein cin thyc pham sinh quyen, lam mat tfnh da dang sinh hpc, datva rUng bi suy kiet: nhieu vung bao tdn dit ngip nudc nhu Tram Chim, U Minh ThUdng, Lang Sen, Tri Su, Hi Tien, Vo bdi, Bii Bdi, Dat Mui, Lung Ngpc Hoing se bi de dpa inh hufing, sy ben vQng trd nen mong manh hdn, mflt sd sinh vat cd the bj tidu diet, nhUng eijng se cd mdt sd cfln trung (nhU mudi) se gia ting sd IUdng, da dang sinh hpc bj de dpa, suy giam ve sd IUdng va chit lupng ngip nude v i klid han, tang thdm nguy cd diet chung ddi vdi ddng, thuc vat, lam bien mat cic ngudn gen quy hiem Cic loai thUc vit hang nien de dip Ung vdi mfli trudng mdi v i cd thdi gian tii cau true di truyen dip Qng mfli trudng mdi nhanh hdn thUc vit da nien ndn thdi gian tao loai mdi ngan hdn se gop phan vao sU da dang sinh hpc Thay doi thu^ tfnh cua cic ddng sdng, nudc biln ding cao va nudc man xim nhip nhieu tUdng lai dUdc dy doin l i se inh hudng len ddng, thuc vat cua vting duyen hii Cac loai ciy chju se phit trien tdt hdn v i rUng lan biln NgUdc lai, cic thuc vit cin sdng nude So nam 2016 KHOAHOC CldNGNGHfi Malm DIA PHUONG ngpt mdt thdi gian nhU ciy Tram hay ddng giim nhe va thfeh nghi deu tdn nudc Id nhu DUa nUdc, cay Bin se bj tai song song v i bd sung cho suy thoii neu miia khd han keo dai va nhiem man gia tang, chung cd khuynh hudng phit trien vao phia nfli dia, va nhu vay bd sdng vimg gin bien se bj xdi Ifi nhieu hdn tUdng lai Bixu^t mot SO giai phap De ddi phd vdi tinh trang dien bien bat thudng cDa khf hiu, ihdi tiet, DBSCL da tim nhieu phUdng cich khac dl sdng thfch nghi, die biet la cac bien phap bio ve miia ming va tai san; dong thdi cQng khai thic cac ngudn Idi tU bien ddi khf hau mang lai Quan diem "sdng chung vdi lu" kha quen thudc vdi ngudi dan fi diy tU bao ddi Hdn hai thap ky gin diy, didn bien thdi tiet va thien tai dang cd xu hudng thay ddi bat thudng fi nhidu ndi tren the gidi va Viet Nam Viing DBSCL da dUdc nhieu nha khoa hpc va cic td chUc qudc te cinh bio la ndi chju nhieu tic dpng tieu cUc cua hien tUdng bidn ddi hau va nUdc bien dang Nflng dan viing DBSCL hien vQa chju tac dpng cCia iii thUdng ngudn vio miia mua, vQa chju tic dflng cua sU xim nhap man vio miia khd va cac tic ddng didn bien thdi tidt cue doan khac Qua thue tiln, ngUdi ndng dan dang chuyen din qua cich sdng va sin xuat nflng nghidp phil hdp vdi hoan canh mdi dudi dieu kien khf hau mflt thay ddi nhanh hdn Lien quan den van de Qng phd vdi bidn ddi khf hau va nUdc biln dang fi viing DBSCL, hidn cic tinh/ phd chi mdi fi mQc phin tfch van de va nang cao nhin thQc ddi vdi cdng ddng Thue te, ngudi dan viing DBSCL da cd mflt sd phUdng cich ddi phd rieng, mang tinh ty phat hoac chpn lpc theo tinh thd nham giim thieu tie dpng v i thich nghi vdi bien ddi khf hiu Quan diem "sdng chung vdi bidn ddi khf hau" hidn chUa la mdt khau hieu ehfnh thUc tU cae cap chinh quydn nhung fi mflt sd ndi da dUdc ngUdi din va cac phUdng tien truydn thdng dai chiing noi den Sd dd minh hpa phfa dUdi cho thay c i hai hanh 42 K I N G NGHEviet Nam khf hiu eho ngudi din viing DBSCL, eac cap quin ly va ngudi dan dja Tr^ng cay quanh nha; Tfii suf dvng, tai cb^ rac thai, Qudc thai; Trir nirdv gia dinh, tilt Idem dung ni < Gia c&, thay iii Id^n true I CSng trinh thiiy igi Bi^n pbap cfing trinh Mo hinh sdng chung vdi bi^n doi khih$u cCia ngudi dSn vung DBSCL (Tuan, 2010) Mae dil sU bidn ddi nao mang tinh toan cau cting mang lai ca rui ro va cd hpi eho cic nhdm ldi fch cpn^ ddng NhUng, tic dflng cua bidn doi hiu dudng nhu mang nhidu bat ldi ehung cho c i xa hpi hdn la thuan ldi Do viy, viec giam nhe va thfch nghi phai dUdc nghien cQu va de xuit Ddi vdi cac qudc gia ngheo va tii nguydn han che, bien phap thfch nghi dUde eiiu trpng hdn la giam nhe mac dii c i hai cd the bd sung eho Thfch nghl vdi bien ddi khf hau ddi hoi phii cd mpt qua trinh liu dii Xay dung ke hoach hanh dflng thfch nghi vdi bidn ddi hau vQa mang tfnh cip bach trudc mat vda mang tfnh chien lUdc lau dii nham giQ dUdc sU phat tnen ben vQng kinh td - x i hfli cung nhu mdi trudng Bien ddi khf hau v i nUdc bien ding fi DBSCL la van de nghiem trpng mi cic cd quan hoach dinh chfnh sach, cac ehuyen gia quy hoach, gidi khoa hpc v i ngudi dan phai nhan thQc dUde Cic kjeh bin va tinh hudng tic dpng can phai dupc tidp tue phan tfch de cd cie dQ lieu thuydt phuc va khoa hpc hdn Cin cQ vao ket qua phan tieh ve mat dQ lieu, tidp den cin cd cic chu trUdng ung hp vide chia se thdng tin va tim phUdng each giam nhe, thfeh Qng Lien quan den viec tim kiem v i xic djnh bien phip thich nghi vdi bidn ddi So nam 2016 phQdng cin luu y mdt sd van de nhu: ghi nh|n cac hinh thQc thich nghi theo tap quin dia phUdng; xic djnh cac ddi tUdng chiu tdn thUdng, danh gia mQe dp tdn thUdng; tang cudng ning lyc, nhin thQc, y thQc va hanh vi bao vd moi trudng - sinh thii, giam thieu cic tic nhin lim khf hau xau hdn; de xuat v i thfi nghiem cic md hinh thich nghi vdi hoan canh mdi: cic kieu kien true nha, ngoai cinh, cic trang thiet bj phdng trinh thien tai fi mQc cpng ddng; nghien cQu, chpn tao cic gidng ciy trdng va vat nudi cd ning chiu dung ngUdng thdi tiet, hau khac nghiet hdn, dieu chinh lich thdi vu va ed ciu ciy trdng - vit nufli phii hdp; xiy dung quy chuin xay dyng cd sfi tang phu hdp vdi dieu kien bidn ddi khf hau v i nude biln ding tUdng lai; Idng ghep cac bien phip thieh nghi vdi bien ddi hau vio ke ho^eh phit then kinh td - xa hfli cfia dja phUdng; xay dyng va tri mang iudi thdng tin, nang cap he thdng cinh bio thdi tiet - thien tai; ting cudng hdp tic qudc td va qudc gia, thudng xuyen trao ddi, chia si thdng tin va ngoai nUfic ^ ... nang suit cay phia bac v i phia tiy (nhu Chau Ddc, NhL?ng thay ddi ve cUdng dp va Long Xuydn, Cin Thd, VTnh Long, My thdi gian cd nang, thieu nudc, gia Tho, Tin An ) Dieu khidn cic tang IUdng