Tác động của biến đổi khí hậu đối với sản xuất nông nghiệp ở đồng bằng sông Cửu Long

^7l!)'^J

DIA PHUONG

TAC DdNG CUA BIEN DO! 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 khi 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 pho. Doi vdi Dong bang sdng Ciiu Long
(DBSCL) • vung san xuat ndng nghiep trong diem cua ca nUdc, hnh ht/dng cua nhQng hien ti/dng thdi
tiet cUc doan nay iat cang nghiem trpng...
Bi^n Ooi khi hau 8di vffi OBSCl

hufing nang nhit. Khi nudc bien ding
cao 1 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 khi
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 khi 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 trong mua khd
Theo Uy ban lien chinh phij ve se gia ting tU 33-35"C len 35-37°C;
bidn ddi khi 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 3 vung chau
hudng giim vao dau v i gtiJa vu he
thd dupc xdp trong nhdm cue ky nguy
thu nhung gia tang mdt chut vio cudi
cap do bien ddi khf hau la: vung ha 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 2 tuin
cCia Ngin hang the gidi cung cho thay, le. Tong quit cho thiy, dien bidn khf
Viet Nam nam trong nhdm 5 qudc gia hiu hien nay va tUdng lai la nhQng
chju inh hufing Idn nhat do bien ddi yeu td bit ldi cho sin xuat, sinh ke va
khi hiu. Tai Viet Nam, 2 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 khi dd ra
Biln Ddng va mpt phan nhd ra Vjnh
Thii Lan. Diy l i mdt vung dat thap
v i bang phang, cao dp trung binh
phd bidn tQ 1 ddn 2 m so vdi mUc
nudc biln, dUdc boi tu bdi phij sa cCia
sdng Mekong. Vung ddng bang cd

didn tich gin 4 trieu ha (39.734 km^),
trong dd cd tren 2,4 trieu ha dit canh
tic nong nghiep v i gan 700 ngan ha
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 do ddng gdp 90%
IUdng gao xuat khau cua Viet Nam ra
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 8 ndm 20]6

tic ddng cua bidn ddi khi 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 ha 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 ha.

Anh hiAUng cua bi^nfleikhi hiofltos a
mat hAng nghi0piiiBBSCL
Tic dpng den san xuat va ddi
song
DUdi tic ddng cua bidn ddi khi
hau, 6 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 trong 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 2 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 ngay
diem din v i thj din ngheo se l i ddi cing phQc tap, inh hufing ddn khi
tUdng chju nhieu tdn thUdng ning ne nang thim canh, tang vu v i lim giim
do thidu ngudn dinh dudng, thieu khi 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 do bien ddi khi hiu
va nudc bien ding ldn cic dd thj vung nang suit cay trong
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 nay 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) trong
thj se bj xau di do 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
ha. Neu tinh trang han - man tidp tuc gia tang hd hap. Nhdm ciy C3 (lua,
diln ra 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 khi 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
khi ning phii nght tdi trong hien t^ii niy ehi xay ra khi cd diJ nUdc tudi
v i tUdng lai.
trong sudt mua trdng. Nhdm ciy C4
Ngoai cic yeu td inh hudng nhu (mia, bip...}, trong dieu kidn CO^ hidn
ndu tren ddl vdi cay liJa, nudi trdng nay (350 ppm), fi inh sing manh v i
thuy san..., khi muc nudc bien ding nhipt dd cao, nhdm nay 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 ngay c i khi klidng C3.6 cUdng dp inh sing cao, hfl hap
cd cic trin bao Idn. Ngoai ra, do 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 do nhiet dp tdi hio
v i bd bao, mUe nudc biln ding cao cija quang hdp S nhdm C4 thip hdn
lim eho khi nang tieu thoit nUdc ra nhidt dd tdi hio cua hd hap, nen khi
bien giam, keo theo mUc nUdc cic gia tang nhidt dd, chat bpt se bi mat
con 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 khi 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 trong tUdng lai,
khi nhipt dd ting them 1°C va COj,
ting gip ddi, xim nhap co dai cung
se tram trpng trong 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 ra vao miia he,
nhung trong tUdng lai co thl xiy ra
vao mua mUa khi nhidt dp v i dp am
giim. Nan cio cio, chiu chau cd the
cung trfi nen trim trong 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
trong 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 do 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 trong tUdng lai
dUdc dy doin l i se inh hudng len
ddng, thuc vat cua vting duyen hii.
Cac loai ciy chju min se phit trien
tdt hdn v i rUng lan ra biln. NgUdc
lai, cic thuc vit cin sdng trong nude

So 8 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 nhau.
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 trong 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 ra nhieu phUdng cich
khac nhau 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 nay. 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 khi hau va nUdc
bien dang. Nflng dan viing DBSCL
hien nay 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 do 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 ngay 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 nay cic tinh/
thanh 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 trong cpn^
ddng. NhUng, tic dflng cua bidn doi
khi 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 nhau. 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 khi 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 8 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 khi ning
chiu dung ngUdng thdi tiet, khi 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 ha tang phu hdp vdi dieu kien
bidn ddi khf hau v i nude biln ding
trong tUdng lai; Idng ghep cac bien
phip thieh nghi vdi bien ddi khi hau
vio ke ho^eh phit then kinh td - xa
hfli cfia dja phUdng; xay dyng va duy
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 trong va ngoai nUfic ^