Where agriculture meets water security: the challenges for Canada

Transcription

1 Where agriculture meets water security: the challenges for Canada Howard Wheater, Canada Excellence Research Chair

2 Water security has many meanings

3 Water security a working defini8on sustainable use and protec1on of water resources, safeguarding access to water func1ons and services for humans and the environment, and protec1on against water- related hazards (flood and drought).

4 Water is essen<al for society: Clean drinking water Food 70-80% of the world s water use is for irriga8on Energy produc8on hydropower and cooling for thermal sta8ons; water supply and treatment is a major energy user Industry Environment And Floods are one of the world s most damaging natural hazards

5 Global water challenges Current issues: 900 million lack access to clean drinking water billion live in water stressed areas unsustainable use of water declining groundwater levels, dry rivers increasing compe<<on for water resources at local, regional and interna8onal scales degrada<on of water quality from over- abstrac8on and pollu8on

6 And the future for water: Increased demand o o o o Popula8on growth Economic development Agriculture Energy Environmental change o o Land use and land management change Climate change 6 billion in water- scarce areas by 2050?

7 Water futures and Canadian agriculture Popula8on growth and changing diet are projected to double world food needs by 2050 (FAO, 2009) Climate change will greatly affect global food produc8on This will present Canada with major opportuni8es But Climate change effects are uncertain; extremes are expected to increase Intensifica8on of global popula8on and agriculture is having important environmental impacts

8 Some observa8ons about climate futures

9 Change in air temperature (K) (comparison with mean) CanESM2 model, RCP2.6 and RCP4.5 experiments, 11- year running mean Source: Canadian Centre for Climate Modeling and Analysis

10 Change in precipita<on (mm/day) (comparison with mean) CanESM2 model, RCP2.6 and RCP4.5 experiments, 11 year running mean Source: Canadian Centre for Climate Modeling and Analysis

11 Changes in global runoff (by 2090s) (after IPCC, 2007)

12 Precipitation change by GCM model ensemble Red precipita8on decrease very likely Blue - precipita8on increase very likely White disagreement about sign of precipita8on change (aaer IPCC 2007)

13 Differences between GCMs and RCMs Precipita8on Change in Summer (JJA) % CGCM3 (GCM) and CRCM (RCM) minus GCM (Canada) RCM (Canada) NARCCAP, 2011

14 Differences between RCMs Temperature Change in Summer (JJA) 0 C HRM3 (UK) and CRCM (Canada) minus HRM3 (UK) CRCM (Canada) NARCCAP, 2011

15 Water and agriculture in the Prairies Saskatchewan River Basin

16 The prairie provinces of Canada depend on the South Saskatchewan river o 75% of South Saskatchewan River water comes from the Rockies (40-50% of basin does not contribute to river flows) o < 1% of flow originates in Saskatchewan, but 70% of popula8on uses river water o 86% of consump8on of South Saskatchewan River goes to irriga8on

17 But: The South Saskatchewan river has reached limits for use in southern Alberta Climate change and land management are changing the land and its water in complex ways, affec8ng river flows and prairie hydrology Pollu8on is changing its water quality Water governance in the prairie provinces is complex and fragmented Extreme events are damaging and expected to increase

18 Glaciers are Changing in Western Canada Glacier retreat and volume loss has been widespread in Western Canada Some glaciers have retreated up to one to two km since early 1950s Total glacier covered area has declined by 5 15% over the period The rela8ve loss of ice volume is likely greater than this amount

19 Marmot Creek Research Basin

20 Temperature Trends at Eleva<on Marmot Creek, Present Winters are warmer by 3 to 4 o C since the 1960s Harder & Pomeroy

21 South Saskatchewan River natural and actual flow leaving Alberta Natural flow: 12% decline over 90 years; Actual flow: 15% decline over 30 years

22 Floods

23 Annual Flows, Souris River

24 Prairie Drought of Most Expensive Natural Disaster in Canadian History $5.8 billion decline in GDP $3.6 billion drop in agricultural produc8on, ,000 jobs lost BC, Alberta forest fires Saskatchewan dust storms

25 Some conclusions for water quan<ty Rocky Mountain water is essen8al for Prairies water supply, yet climate is warming, river flows are reducing, and water use is increasing. An8cipated climate change will drama8cally reduce mountain snow water supplies and the 8ming of river flows. Climate warming is shiaing snowfall to rainfall over much of the Prairies effects on agriculture are uncertain The prairies are vulnerable to floods and droughts, yet the frequency and intensity of extremes is expected to increase.

26 What about environmental quality? Lake Winnipeg algal blooms covered 15,000 km 2 in 2007 Photo: Reuters Image: Greenpeace Canada

27 South SK River Basin Water Quality Monitoring

28 Total Phosphorous Concentra8on ( ) Concentra8on (mg/l) AB Surface Water Quality Guideline (0.05 mg/l) Bow Rive r Calgary Oldman Red Dee r R iver South Saskatchew an River Red Deer Saskatoon L. Diefenbaker River Medicine Hat Lethbridge

29 Smith Creek effects of agricultural drainage?

30 Conclusions for environmental quality Agriculture has adapted to climate variability, but effects on environment of land management change are not well understood Nutrient loads arise from sewage effluents, fer8lizers and manures. There are increasing pressures on the environment and poten8al for toxic algal blooms, but much remains to be done to evaluate risk and beneficial management prac8ces. Risks to humans and the environment from exo8c chemicals (e.g. human and veterinary pharmaceu8cals), and pathogens remain to be evaluated.

31 The challenges for Canadian agriculture World food needs will double by 2050 and climate change will greatly affect global food produc8on; this will present Canada with major opportuni8es But While temperature increases and precipita8on change may be rela8vely benign for Canada, climate change effects are uncertain; extremes are expected to increase Irrigated agriculture will face increasing compe88on from other water uses Intensifica8on of agriculture is having important environmental impacts; these affect social capital and must be addressed and managed

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