GLOBAL WARMING vis-à-vis AGRICULTURE: A SWIFT BROWSE
S.K.T. Nasar*, B. Bagchi* and Reshma Nasar **
*Formerly of Directorate of Research, Bidhan Chandra Krishi Viswavidyalaya, Kalyani
*** Directorate of Fisheries, Government of West Bengal, Balurghat
Unsettled debates about the prospect of global warming continue, yet it is generally agreed that prediction of the long-term future of mankind in a shifting scenario with certainty is exceedingly difficult. Biological, technological, socioeconomic and intergovernmental survival strategy and the unprecedented reaction of global warming to alterations at any level of organisation from subatomic particles to biome to the universe make the situation quite complex for quantification.
The challenge is to profitably manage the interface between all aspects of global warming, climate change, international trade, dynamics of multinational socioeconomics vis-à-vis agricultural systems. Considerations about increasing tropospheric CO2 and CH4 concentrations, depleting O3 shield, loss of biodiversity, eutrophication, and varying water, soil and air physico-biochemical properties are also included. Aspects such as imminent land-use change, transformation of agrobiodiversity, ocean warming, carbon sequestration, recycling of polluting chemicals, global clean-food & nutrition security, and global-to-local equity, accessibility and sustainability are as important.
IPCC (2007) 1 has identified the risk to world agriculture as the most important among potential damages from global warming. Other concerns include sea level rise, species loss, loss of water supply, hurricane damage, and impact on human health and loss of life, forest loss, and increased electricity requirements. Three major issues - carbon fertilization, irrigation and feedback from international trade have been highlighted.
IPCC 1 has found that global warming has raised worldwide temperatures in decadal averages causing unprecedented climate change. Erratic behaviour of climate has reached serious proportions. Analysis of climate change in India 2 for 1901-2005 suggests an increase of annual mean temperature to 0.51 oC being consistently above normal since 1993. Over parts of Rajasthan, Gujarat and Bihar decreasing trends are observed. Season-wise, maximum rise in mean temperature was observed during the post-monsoon season (0.7 oC) followed by winter season (0.67 oC), pre-monsoon season (0.5 oC) and monsoon season (0.3 oC). An informal analysis of the Ganga-Brahmaputra basin (Khan, SA, unpublished) found a span-reduction of winter cold and an unprecedented pattern of erratic and concentrated precipitation. This is largely similar to all India figures. Climatic warming necessitates short duration and drought tolerant or resistant crops. Traditional rabi crops may need to be carefully replaced by new varieties to perform well under shorter periods of and erratic winter cold. Adverse effects of warming and unpredictable climate conditions on water bodies and aqua-agriculture are already showing. The temperature of entire water column is not directly affected but evaporation loss and drawl for irrigation purposes reduce the volume thereby altering bio-physicochemical, faunal and vegetational structure of the water body. Eutrophication ensues quickly in shallow waters.
Linear trend (1891-2004) 2 over the north Indian Ocean as a whole, the Bay of Bengal and the Arabian Sea for different seasons, generally, shows a significant decreasing trend of tropical cyclones with a distinct decadal variability. An increasing trend in the frequency of tropical cyclones over Bay of Bengal in May and November, the principal cyclone months, is observed.
Warming beyond optimal temperatures reduce yields since crops speed through their development 3. Cline 3 notes further that evapotranspiration accelerates when temperatures rise. He emphasises carbon emission that can also help agriculture by enhancing photosynthesis in many important C3 crops such as wheat, rice, soybean etc. This phenomenon does not much help C4 crops, sugar cane, maize etc. Elevated atmospheric CO2 lower protein concentrations of major food crops 4 like barley, rice, wheat, soybean and potato.
Carbon capture and storage (CCS) 3 is the capture of CO2 from large point sources such as fossil fuel power plants and storing it instead of releasing it into the atmosphere. Commercially viable systems are not available. CO2 in - and by agrosystems gain importance for two reasons- one, Soil organic C (SOC) pools can add to global warming, and two, CO2 injection into the atmosphere can be reversed by agricultural best management practices (BMP) acting as a CCS system. Different components of SOC pools [total organic C, oxidizable organic C, and its four fractions of very labile (Cfrac1), labile (Cfrac2), less labile (Cfrac3), and nonlabile C (Cfrac4); microbial biomass C, and mineralisable C] were, for the first time, duly considered in an elaborate long-term fertility experiment 5. A major finding for public utility is that rational management of agrosystems can effectively sequester C and that balanced organic fertilisation with FYM is suitable for sustaining crop productivity of the rice–wheat system. Recommendations that organic C fertilisation of agrosystems can sustain agriculture through adversity of global warming should be transformed into mass action. Globally, a reduction in agricultural productivity without C fertilization is projected to be more than the reduction with C fertilization. Scanty and unreliable data are available on aquatic system.
Water availability for irrigation is in crisis. Water tables are lowering and surface waters are evaporating unproductively. Narrow-span precipitations cause soil erosion and this green water is lost to agriculture. Rain water harvesting, water shed protection and micro-damming have been recommended on the basis of successful experiments. New less water-requiring and soil-moisture retaining agronomic practices are desired.
Current climate models mostly ignore the specific role that soil microbes play in the release of carbon dioxide 6 despite possibility of a positive feedback loop - where increased warming causes more carbon dioxide to be released from the soil which causes even more warming. Sufficient information is also unavailable on the trends of reaction to global warming and climate change in respect of lower- and microorganisms and on extracellular DNA in marine biofilms and in soils 7.
An imminent change in agrobiodiversity in response to the global warming is the development of new dynamics of weed flora because of strong genetic diversity of weed species in general 8. A range of C3 and C4 weeds are available in and around agronomic systems. NEWSS 9 has considered many aspects of the effect of climate change on weeds but vital considerations on aquatic and swamp weeds are missing. Weeds play a range of roles such as moisture conservation, altering the dynamics of soil microflora and microfauna; some selected weed species can be used for new purposes like feed and fodder, recycling of pollutants etc.
Globalised trading systems are shifting fast with rising fossil fuel prices and spiraling energy demand. International need for food-on-demand and bio-energy will also help change the face of existing agroecosystems around the world.
Agricultural researches require reprioritising in due consideration of technical, social and economic aspects keeping in view global market forces and long-term sustainability. Appropriate agricultural knowledge, science and technology (AKST) to match the twin challenge of global warming and international trade in agriculture are required.
References
1. Intergovernmental Panel on Climate Change 2007 Fourth Assessment Report (IPCC 2007).
2. IMD, Pune 2008; http://www.imdpune.gov.in/research/ncc/climatereserch/climateresearch.html
3. Cline, William R. 2008 Global Warming and Agriculture, Finance and Development (A quarterly magazine of the IMF March 2008), Volume 45, Number 1
4. Daniel R. Taub, Brian Miller, Holly Allen 2008 Effects of elevated CO2 on the protein concentration of food crops: a meta-analysis; Global Change Biology 14 (3), 565–575
5. Majumder Bidisha, Mandal Biswapati, Bandyopadhyay P. K., Gangopadhyay A., Mani P. K., Kundu, A. L. and Mazumdar D. 2008 Organic Amendments Influence Soil Organic Carbon Pools and Crop Productivity in Nineteen-Year-Old Rice–Wheat Agroecosystem; SSSAJ: Volume 72: Number 3 • May–June 2008
6. Nicole Miller 2007 Researcher seeks ‘missing piece’ in climate change models; In Univ. Wisconsin-Madison News, Feb. 13, 2007
7. Ascher J., Ceccherini M.T., Nannipieri P., Pietramellara G. 2005 Extracellular DNA rise up in soil by water capillarity, Geophysical Research Abstracts, Vol. 7, 07946, 2005
8. Ziska, Lewis H. 2004 Climate Change Impacts on Weeds In Climate Change and Agriculture: Promoting Practical and Profitable Responses
9. See 62nd Annual NEWSS Meeting 2008
Presentation at CWSS biennial Conference and two-day training programme “ BMP on Agricultural Inputs”May 21& 22, 2008 at FTC (Lake Hall), BCKV, Kalyani, West Bengal, India
S.K.T. Nasar*, B. Bagchi* and Reshma Nasar **
*Formerly of Directorate of Research, Bidhan Chandra Krishi Viswavidyalaya, Kalyani
*** Directorate of Fisheries, Government of West Bengal, Balurghat
(Pages XXIII-XXIV: In Souvenir on the occasion of 5th Annual Conference of Crop and Weed Science Society [CWSS] National Symposium on "Agriculture in the Paradigm of Intergenerational Equity" at FTC [Lake Hall] of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India on 22-23 May 2009)
SummaryUnsettled debates about the prospect of global warming continue, yet it is generally agreed that prediction of the long-term future of mankind in a shifting scenario with certainty is exceedingly difficult. Biological, technological, socioeconomic and intergovernmental survival strategy and the unprecedented reaction of global warming to alterations at any level of organisation from subatomic particles to biome to the universe make the situation quite complex for quantification.
The challenge is to profitably manage the interface between all aspects of global warming, climate change, international trade, dynamics of multinational socioeconomics vis-à-vis agricultural systems. Considerations about increasing tropospheric CO2 and CH4 concentrations, depleting O3 shield, loss of biodiversity, eutrophication, and varying water, soil and air physico-biochemical properties are also included. Aspects such as imminent land-use change, transformation of agrobiodiversity, ocean warming, carbon sequestration, recycling of polluting chemicals, global clean-food & nutrition security, and global-to-local equity, accessibility and sustainability are as important.
IPCC (2007) 1 has identified the risk to world agriculture as the most important among potential damages from global warming. Other concerns include sea level rise, species loss, loss of water supply, hurricane damage, and impact on human health and loss of life, forest loss, and increased electricity requirements. Three major issues - carbon fertilization, irrigation and feedback from international trade have been highlighted.
IPCC 1 has found that global warming has raised worldwide temperatures in decadal averages causing unprecedented climate change. Erratic behaviour of climate has reached serious proportions. Analysis of climate change in India 2 for 1901-2005 suggests an increase of annual mean temperature to 0.51 oC being consistently above normal since 1993. Over parts of Rajasthan, Gujarat and Bihar decreasing trends are observed. Season-wise, maximum rise in mean temperature was observed during the post-monsoon season (0.7 oC) followed by winter season (0.67 oC), pre-monsoon season (0.5 oC) and monsoon season (0.3 oC). An informal analysis of the Ganga-Brahmaputra basin (Khan, SA, unpublished) found a span-reduction of winter cold and an unprecedented pattern of erratic and concentrated precipitation. This is largely similar to all India figures. Climatic warming necessitates short duration and drought tolerant or resistant crops. Traditional rabi crops may need to be carefully replaced by new varieties to perform well under shorter periods of and erratic winter cold. Adverse effects of warming and unpredictable climate conditions on water bodies and aqua-agriculture are already showing. The temperature of entire water column is not directly affected but evaporation loss and drawl for irrigation purposes reduce the volume thereby altering bio-physicochemical, faunal and vegetational structure of the water body. Eutrophication ensues quickly in shallow waters.
Linear trend (1891-2004) 2 over the north Indian Ocean as a whole, the Bay of Bengal and the Arabian Sea for different seasons, generally, shows a significant decreasing trend of tropical cyclones with a distinct decadal variability. An increasing trend in the frequency of tropical cyclones over Bay of Bengal in May and November, the principal cyclone months, is observed.
Warming beyond optimal temperatures reduce yields since crops speed through their development 3. Cline 3 notes further that evapotranspiration accelerates when temperatures rise. He emphasises carbon emission that can also help agriculture by enhancing photosynthesis in many important C3 crops such as wheat, rice, soybean etc. This phenomenon does not much help C4 crops, sugar cane, maize etc. Elevated atmospheric CO2 lower protein concentrations of major food crops 4 like barley, rice, wheat, soybean and potato.
Carbon capture and storage (CCS) 3 is the capture of CO2 from large point sources such as fossil fuel power plants and storing it instead of releasing it into the atmosphere. Commercially viable systems are not available. CO2 in - and by agrosystems gain importance for two reasons- one, Soil organic C (SOC) pools can add to global warming, and two, CO2 injection into the atmosphere can be reversed by agricultural best management practices (BMP) acting as a CCS system. Different components of SOC pools [total organic C, oxidizable organic C, and its four fractions of very labile (Cfrac1), labile (Cfrac2), less labile (Cfrac3), and nonlabile C (Cfrac4); microbial biomass C, and mineralisable C] were, for the first time, duly considered in an elaborate long-term fertility experiment 5. A major finding for public utility is that rational management of agrosystems can effectively sequester C and that balanced organic fertilisation with FYM is suitable for sustaining crop productivity of the rice–wheat system. Recommendations that organic C fertilisation of agrosystems can sustain agriculture through adversity of global warming should be transformed into mass action. Globally, a reduction in agricultural productivity without C fertilization is projected to be more than the reduction with C fertilization. Scanty and unreliable data are available on aquatic system.
Water availability for irrigation is in crisis. Water tables are lowering and surface waters are evaporating unproductively. Narrow-span precipitations cause soil erosion and this green water is lost to agriculture. Rain water harvesting, water shed protection and micro-damming have been recommended on the basis of successful experiments. New less water-requiring and soil-moisture retaining agronomic practices are desired.
Current climate models mostly ignore the specific role that soil microbes play in the release of carbon dioxide 6 despite possibility of a positive feedback loop - where increased warming causes more carbon dioxide to be released from the soil which causes even more warming. Sufficient information is also unavailable on the trends of reaction to global warming and climate change in respect of lower- and microorganisms and on extracellular DNA in marine biofilms and in soils 7.
An imminent change in agrobiodiversity in response to the global warming is the development of new dynamics of weed flora because of strong genetic diversity of weed species in general 8. A range of C3 and C4 weeds are available in and around agronomic systems. NEWSS 9 has considered many aspects of the effect of climate change on weeds but vital considerations on aquatic and swamp weeds are missing. Weeds play a range of roles such as moisture conservation, altering the dynamics of soil microflora and microfauna; some selected weed species can be used for new purposes like feed and fodder, recycling of pollutants etc.
Globalised trading systems are shifting fast with rising fossil fuel prices and spiraling energy demand. International need for food-on-demand and bio-energy will also help change the face of existing agroecosystems around the world.
Agricultural researches require reprioritising in due consideration of technical, social and economic aspects keeping in view global market forces and long-term sustainability. Appropriate agricultural knowledge, science and technology (AKST) to match the twin challenge of global warming and international trade in agriculture are required.
References
1. Intergovernmental Panel on Climate Change 2007 Fourth Assessment Report (IPCC 2007).
2. IMD, Pune 2008; http://www.imdpune.gov.in/research/ncc/climatereserch/climateresearch.html
3. Cline, William R. 2008 Global Warming and Agriculture, Finance and Development (A quarterly magazine of the IMF March 2008), Volume 45, Number 1
4. Daniel R. Taub, Brian Miller, Holly Allen 2008 Effects of elevated CO2 on the protein concentration of food crops: a meta-analysis; Global Change Biology 14 (3), 565–575
5. Majumder Bidisha, Mandal Biswapati, Bandyopadhyay P. K., Gangopadhyay A., Mani P. K., Kundu, A. L. and Mazumdar D. 2008 Organic Amendments Influence Soil Organic Carbon Pools and Crop Productivity in Nineteen-Year-Old Rice–Wheat Agroecosystem; SSSAJ: Volume 72: Number 3 • May–June 2008
6. Nicole Miller 2007 Researcher seeks ‘missing piece’ in climate change models; In Univ. Wisconsin-Madison News, Feb. 13, 2007
7. Ascher J., Ceccherini M.T., Nannipieri P., Pietramellara G. 2005 Extracellular DNA rise up in soil by water capillarity, Geophysical Research Abstracts, Vol. 7, 07946, 2005
8. Ziska, Lewis H. 2004 Climate Change Impacts on Weeds In Climate Change and Agriculture: Promoting Practical and Profitable Responses
9. See 62nd Annual NEWSS Meeting 2008
Presentation at CWSS biennial Conference and two-day training programme “ BMP on Agricultural Inputs”May 21& 22, 2008 at FTC (Lake Hall), BCKV, Kalyani, West Bengal, India
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