Slide 1: Impact of Global Climate Change
Agriculture Slide 2: Climate
Climate is the average weather of given region or area over a given period of time. It is a result of delicate balance between the sun, atmosphere, oceans, water system, topography, plants and all living organisms Climate change Climate change refers to the variation in the earth’s global climate or in regional climates over time. It describes changes in the variability or average state of the atmosphere over time scales ranging from decades to millions of years Slide 3: Atmospheric composition (Dry atmosphere by volume) Source: IPCC, 2001 Causes of climate change : Causes of climate change Continental drift
and asteroids Natural Human-induced Burning of fossil fuel
Change in land use pattern
Transportation Overview on greenhouse gases conc., life time and their global warming potential (GWP) : Overview on greenhouse gases conc., life time and their global warming potential (GWP) Source: IPCC, 2000 Slide 7: Variation of the some atmospheric constituents during last century Sulochana Gadgil, 1995 Estimates of future levels of CO2 : Estimates of future levels of CO2 Source: IPCC, 2000 Slide 9: Direct observations of recent climate change Global average air temperature
•Updated 100-year linear trend of 0.74 [0.56 to 0.92] oC
•Larger than corresponding trend of 0.6 [0.4 to 0.8] oC
for 1901-2000 given in TAR
•Average ocean temperature increased to depths of at
least 3000 m –ocean has absorbed 80% of heat added
> seawater expansion and SLR IPCC, 2007 Slide 10: IPCC, 2007 Slide 12: All India mean annual surface temperature anomalies Pant and Rupakumar, 1997 Heavier precipitation,more intense and longer droughts…. : Heavier precipitation,more intense and longer droughts…. Slide 14: EVIDENCE ON LOSS OF BIODIVERSITY Since the 1950s, Europe has lost more than half of its wetlands and most high–nature–value farmland; and many of the EU’s marine ecosystems are degraded.
At the species level, 42% of Europe’s native mammals, 43% of birds, 45% of butterflies, 30% of amphibians, 45% of reptiles and 52% of freshwater fish are threatened with extinction; most major marine fish stocks are below safe biological limits.
Some 800 plant species in Europe are at risk of global extinction.
This loss of species and decline in species’ abundance is accompanied by significant loss of genetic diversity.
Since the late 1970s, an area of tropical rain forest larger than the EU has been destroyed, largely for timber, crops such as palm oil and soy bean, and cattle ranching.
Other diverse ecosystems, such as wetlands, drylands, islands, temperate forest
Mangroves and coral reefs, are suffering proportionate losses. Species’ extinction rates are now around 100 times greater than that shown in fossil records and are projected to accelerate, threatening a new ‘mass extinction’ of a kind not seen since the disappearance of the dinosaurs. Slide 15: Climate change and extreme events Climate change scenarios for India : Climate change scenarios for India Source: Lal et al., 2001 Slide 17: Stress on the land and water resources
Threat to ecosystems and biodiversity
Agriculture: Yields of major crops expected to decline
Greater vulnerability to extreme climate events like typhoons, cyclones, droughts and floods, particularly in coastal areas
Potential for drier conditions in arid and semi- arid parts of India Source: Pachauri, 2006 Some Specific Impacts on India Impact on Agriculture : Impact on Agriculture Slide 19: Factors effecting crop production in changing climate Slide 21: EVIDENCES ON AGRICULTURE Most studies and models on impacts of climate change on agricultural production indicate that there will be negative effects on crop yields over the next century. Saseendran et al., have reported decrease in rice yields by 3% to 10% under a scenario of 1.50C rise in temperature and a 2 mm day-1 increase in precipitation. Yield losses of winter wheat would be more than that of rice and that the associated economic impacts would affect the lower income groups of the society more adversely.(Kumar and Parikh (1997, 1998) Shifting of wheat sowing time from mid November to mid December.
Cultivation of temperate fruits in much higher altitude than earlier Fankhauser (1995) has estimated the annual forestry losses to be US$1.8 billion in the OECD and US$2 billion for the world as a whole due to the climate change.
Increased temperature and a decreased precipitation, could have adverse effect on forests.[Ravindranath N H and Sukumar R (1998)] IPCC (1992) carried out the study at Orissa and West Bengal, that the absence of protection, a 1m sea level rise would inundate 1700 km2 of predominantly prime agricultural land. The 1999 tropical cyclone that hit Orissa resulted in a death of thousands of people, implies related to variability. Changes in cropping pattern from wheat to maize in Bihar. Slide 22: Impact of climate change on soil Slide 23: Rise in atmospheric CO2 concentration
increases photosynthetic rates and water-use efficiencies
increase in organic matter supply to soils. increase in temperature
increases and extended periods in which soils are warm
Increase microbial activity (in temperate and cold soils) Organic matter content: Microbial activity: increase the quantity of plant nutrients cycling Brinkman et. al.,(1990) Slide 24: Phosphorus: Elevated atmospheric CO2 increases plant demand for phosphorous (P) beside other nutrient elements.
Norisada et al., (2006)
Increased uptake of P by plants grown under elevated atmospheric CO2.
Norby et al., (1986)
Increase in P use efficiency by plants grown under CO2 concentration of 600 ppm as compared to that grown under 350 ppm CO2.
Nikolaus et al., (1996) Elevated CO2 increase root phosphatase activity. Barrett et. al.,(1998) Slide 25: Changes in clay mineral surfaces: 1) Hydrolysis- removes silica and basic cations.
2) Cheluviation- removes Al and Fe.
3) Ferrolysis- decreases CEC by altering Al interlayering
4) Dissolution of clay minerals- produces Al salt and amorphous silica
5) Reverse weathering- creates montmorillonite. Soil reaction: Soils would not be subject to rapid pH changes Exceptions- acid sulphate soils, in some coastal plains-under long dry spells. Brinkman et. al.,(1990) Slide 26: Effect of different CO2 conc. on rate of photosynthesis in C3 and C4 plants Source: FAO, 1999 Slide 27: Source: Aggarwal and Mall , 2002 Potential impact of climate change on wheat production in India Potential impact of climate change on wheat production in India : Potential impact of climate change on wheat production in India Source: Aggarwal and Mall, 2002 Slide 29: Potential impact of climate change on rice and maize production in India Source: Aggarwal and Mall 2002 Slide 30: Potential impact of climate change on wheat production in Punjab and Haryana Source: Aggarwal and Mall, 2002 Estimated impact of heat wave in March 2004 on wheat production : Estimated impact of heat wave in March 2004 on wheat production Source: Aggarwal et al., 2004 Slide 32: Impacts on Pests Slide 33: Drought proofing by mixed cropping
Frost management by irrigation
Heat stress alleviation by frequent irrigation
Shelter belts MITIGATION Slide 34: Invent short duration varieties/crops
Altering fertiliser rates to maintain grain or fruit quality and be more suited to the prevailing climate
Altering amounts and timing of irrigation
Conserve soil moisture (e.g. crop residue retention)
Altering the timing or location of cropping activities Slide 35: Conservation Agriculture Multi-cropping and rotation Minimum tillage Water harvesting and optimisation Mulching Future research : Future research Vulnerabilities of agricultural systems
New cultivars and technology
Awareness Slide 37: Positive effects:
Increase in CO2 concentration will benefit much more for C3 plants. This was higher at high latitudes
Increase in length of growing season at higher latitudes due to extended the frost-free growing season and rise in temperatures
Shortening of crop growth cycle
Less grain filling period due warming leads to reduction in yields
Increase in extremes of weather elements
Poor vernalization CONCLUTIONS Slide 38: Thank You In