Upload
christina-dian-parmionova
View
214
Download
0
Embed Size (px)
DESCRIPTION
Professor Malin Falkenmark, Senior Scientific Advisor at Stockholm International Water Institute, Stockholm University, Sweden - Growing water scarcity in agriculture – future challenge to global water security ----PLENARY: Global change and the evidence base for strategic policy and business decisions ---Plenary to take stock of the evidence and trends in water insecurity in regions confronting rapid global change across interacting climate, economic and demographic risks and uncertainties
Citation preview
Growing water scarcity in agriculture
- future challenge to global water security
By Professor Malin Falkenmark
Stockholm International Water Institute and Stockholm Resilience Center
Why agriculture?
70 times more water than households
3000 kcal/p d
/20 % anim prot
--> 3500 l/p d or 1300 m3/p yr.
Water security - what risks to cope with?
Aim = successful management of water for
- food……….green+ blue
- humans…..blue
A. Green water risks B. Blue water risks C. Regional risks D. Global risks
Risk 1. Too little annual rainfall
* par&cular exposure of semi-‐arid zone
Rainfall changes around red line of critical importance for crop production impact
From IWMI 2007
Risk 2. Dryspells
0
1
2
3
4
1960 1970 1980 1990 2000Year
Dry
spel
l >1
4 d
ays
du
rin
g c
rop
sea
son Maradi
Zinder
Linear (Maradi)
Linear (Zinder)
Number of dryspells during crop season > 14 days
1
2
3
nat.green
degraded green nat blue
drought risk
fourfold African vulnerability
Risk 3. Droughts
famine
• huge water losses -‐ blue water loss -‐ green water loss
• poor root water
uptake Farming systems in Subsah. Africa
RAIN
1
2
3
green loss
plant uptake blue
losses water partitioning
Result: poor yields -‐ why?
scale: 1 cube = 1 million cubic meter/yr 1 dot = 100 persons
Risk1. : When population grows water crowding increases
Risk 2: When demand grows
water stress increases
> 2000
1000-2000
600-1000
P/flow unit agr trade ---->
1900-2005
groundw ----->
(from Kummu et al)
irrig ----->
200 m3/p yr municipal/ industrial use
demand- driven
population driven
%
vulnerable triangle
1000 p/flow unit
Result: River basin closure
p/flow unit
Country food water availability 2050 cropland water, km3/yr
--> Blue
Blue+ green
% of world pop a. 46 % b. 14 % c. 21 % d. 19 %
Water requirement 1300 m3/p yr
Crrying capacity overshoot 2050
!"#$!
$"%%!
$&'('%()
!"#&)
&')
)*(
(!'
!"#$%&'(")*+",*-.../01*2"'&%*#"#*345*6(%%(")
+,"-./0-1"2-3
45.-6/"72-3
45.-6/"78..96
45.-6/:0;<
=>.-6/2-3
=>.-6/72-3
=>.-6/7?..96
=>.-6/:0;<
+-"@A/A
!"#$%
&"#'(
#%)&#*
%
!"')!
$$%
*+*
+!*
!"#$%&'(")*+",*-.../0.1*2"'&%*#"#*340*5(%%(")
,-"./01.2"3.4
56/.70"83.4
56/.70"89//:7
56/.70;1<=
>?/.703.4
>?/.7083.4
>?/.708@//:7
>?/.70;1<=
,."AB0B
!"#$%
&"'(&
'#)'&$
*'
!"+*+
$'+
$#+
'!%
!"#$%&'(")*+",*--../01*2"'&%*#"#*34-*5(%%(")
,-"./01.2"3.4
56/.70"83.4
56/.70"89//:7
56/.70;1<=
>?/.703.4
>?/.7083.4
>?/.708@//:7
>?/.70;1<=
,."AB0B
25 % yield gap closure
bln people
3.0
4.4
1.5 3.3
4.1
1.5 3.7
3.6
1.5
3000 kcal/p d 20 % animal food
3000 kcal/p d 5 % animal food
2200 kcal/p d 5 % animal food
Bloodstream of the biosphere
Maximized cons use:
max 5000 km3/yr
Terrestrial Ecosystems
Atmosphere
Continents
Sea
Aquatic Ecosystems
Ecosystem
Goods/Services
Ecosystem
Goods/Services Society
a
c
.
.
Consumptive Use b .
Water Withdrawals
Waste Water Return Flows
Planetary Freshwater Boundary - env flow > 0
Water-security means coping with:
A. Green water risks: crop water deficiency dryspells, drought, aridification
B. Blue water risks: water crowding, water stress irrigation limitations, competing sectors environmental flow constraints, basin closure
C. Regional risks: carrying capacity overshoot food trade
D. Global risks: consumptive use constraints food, carbon-seq., fuelwood