25 Aug 2014

Global Climate Change and Agriculture: An Analysis !

Global-Climate-Change-and-Agriculture

Climate change has now become the regional, national and global concern as evidenced by several physical and biological changes in almost all parts of the planet, thus more precisely it is known as global climate change. The reasons of global climate change are both global warming which is mainly resulted from enhanced green house effect owing to excess emission of greenhouse gases in the atmosphere, and global dimming due to increasing the level of gaseous pollutants and aerosols in the air mainly through anthropogenic activities. Thus global climate change which is likely to pose serious physical, biological, political and socio-economic problems at national and global levels has been resulted from various human activities for their development on the cost of environment; hence efforts need to be made to overcome these serious problems for sustaining the future generation on this bountiful and beautiful planet earth.

Since climate change is likely to affect the society and economy of the country through agriculture, industry, environment etc. It is now imperative for all of us including academician, politicians and social activists to have some knowledge about the climate change and its cause and consequences. Not only changing climate has several impacts on agriculture, but several agricultural practices like land clearing, irrigation, animal husbandry and cultivation of puddle crop like paddy (rice). So there is a need of hour to establish proper harmony between agriculture and environment and for that, general awareness and understanding of adaptation and mitigation strategies are required.

Risk-in-the-agriculture-sector
Ø  What is climate?

Climate is long term atmospheric phenomena and processes over a large scale area, distinct from weather, which is short term and over small scale area. Climate determining factors are; latitude, altitude, distance from sea coast, vegetation over area, rainfall and composition of gases in air over an area.

Here we need to understand subtle difference between climate change and climatic variability:

v  Climate change is the variation in either mean state of the climatic variables (temperature, rainfall, gases concentration in air) for an extending period, typically over decades.
v  Climate variability refers to sudden and discontinuous change over month or so, without any specific trend of temporal change.

Global-Climate-Change-and-Agriculture

Global-Climate-Change-and-AgricultureSo heavy rainfall, drought frequency, high or low temperature, within year does not mean climate is changing, it is all about variability. But global mean temperature is increasing over decades, sea level is rising due to glacier melts, are all about climate change. Agriculture and environment can adjust itself for climate variability within years but climate change has long consequences and caste effect on sustainability of agro-ecosystems.

Ø  Climate change

Primarily it consists of Global Warming, due to excess emission of green house gases (CO2, CH4, N2O. O3, CFCs) and Global Cooling or Dimming, due to excess emission of gaseous air pollutants (SO2, Aerosols, Suspended particulates matter).There are evidences of climate changes:

Ø  LONG TERM EVIDENCES:

1) Instrumental records:  temperature, precipitation,   humidity, wind, sunshine and atmospheric pressure value obtained through standard equipments.
2)  Tree rings
3)  Ice cores
4)  Pollen analysis
5)  Beetles
6)  Sea sediments

Global-Climate-Change-and-Agriculture
Ø  CURRENT  EVIDENCES :

1) Extreme weathers:  Numerous changes in weather events like droughts, heavy precipitation, heat waves and cyclones. In India .in 2012 we have flooding events in Jaisalmer (drought prone area) and drier spells in Maansiraam and Cherapunji (wettest areas). Droughts in Southern Africa, Mediterranean and southern Asia in recent years are current evidences of climate change. Super cyclones in eastern coast of India during last decade, east European floods of 1998, 2000 and 2002 and monsoon based flooding in Bihar and Assam state of India as well as several states of Bangladesh in recent years.
2) The decline of winter:  Average Arctic temperatures increased at almost twice the global rate in past 100 years, glaciers are melting seal level is rising and span of winter is decreasing gradually.
3) Global temperatures : Since 1979, land temperatures has increased about twice as fast as ocean temperature ( 0.25 C per decade against 0.13 C per decade) and global average temperature near earth surface rose by 0.74C +- 0.18C  during 20th century relative to period 1860-1900 .(IPCC , 2007)
4)  Shift in natural world:  In alpines, some planet species have been migrating up to four meter due to high temperature on lower altitude. Apple cultivation in Shimla is shifting to higher altitude like Kashmir.
5)   Concentration of green house gases: CO2 level in atmosphere has increased from 280 ppm in 1850 to 398 ppm in 2013 and with @2.33 ppm every year in last decade due to urbanization and vehicular pollution. Similarly CH4, O3, CFCs and N2O has increased substantially.

Greenhouse-gas-emissions-by-sectors

Ø  Impacts of climate change:

a) Physical impacts: melting of glaciers, loss of water and stored moisture due to high temp, coastal inundation, occurrence of natural calamities, pole-ward expansion of arable land, change in soil nutrient dynamics. Destabilization in local climates.
b) Biological impacts: crop productivity is affected due to changing CO2  and temp, crop produce  quality is reduced, chemical integrity of tissue is degrading, loss of biodiversity, geographical shifting of temperate crops, spread of disease and insect pest
c) Social impact: migration of population from warmer prone areas to other place
d) Economic impact: reduction in agricultural income due to low productivity and higher cost of crop production

Global-Climate-Change-and-Agriculture

Ø  Adaptation to climate change:

1)  Changing land-use management
2)  Diversifying crop and livestock
3)  Harnessing indigenous technical knowledge
4)  Developing insurance and forecast systems
5)  Financial support to farmers through better support price  of agricultural produces
6) Adaptation in agriculture: more spending on irrigation,  weather control, developing drought and heat tolerant  crop varieties, rescheduling of dates of sowing, fertilizer  doses and time of application.

Global-Climate-Change-and-AgricultureCrops have natural adaptation capabilities but in due course of fast change we have to intervene in genetic and biotechnological adaptations supported by crop insurance, subsidies, support prices and credits.

Ø  Mitigation for climate change:

1)   Improve management of rice paddies management
2)   Improve management of livestock
3)   Increase soil organic carbon through carbon sequestration
4)   Improve energy use efficiency in agriculture
5)   Improve land use pattern

Global-Climate-Change-and-AgricultureØ  Conclusion:

Agriculture in India and other developing countries is at present undergoing rapid transformation due to changing demands, markets and agricultural technologies. Pace of these changes is likely to increase in near future and these changes may perhaps be more important under climate change scenarios. So, need of integrated assessment of climate change and impact on agricultural production and need to prepare for adaptation and mitigation strategies in near future. It requires infrastructure, technical human resource and international partnerships supported by mainstreaming adaptation in current policy consideration such as in weather watch groups and increase reliability of forecasting system with agricultural intelligence system.

What is your view on climate change and its causes?

How global warming can be controlled?

How climate change affects agriculture in the world and India?

(Written by Prakash Jha, an Alumnus of Dept. of Agriculture, BHU, Varanasi and currently JRF at IARI (Indian Agricultural Research Institute), New Delhi)







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