Impact of Climate Change on Agriculture

Climate change, also called global warming, refers to the rise in average surface temperatures on Earth. An overwhelming scientific consensus maintains that climate change is due primarily to the human use of fossil fuels, which releases carbon dioxide and other greenhouse gases into the air. The primary greenhouse gases in Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. These gases have the ability to absorb the spectrum of infrared light and contribute to the warming of our atmosphere , which can have a range of effects on ecosystems, including rising sea levels, floods, severe weather events, and droughts that render landscapes more susceptible to wildfires. Other human activities, such as agriculture and deforestation, also contribute to the proliferation of greenhouse gases that cause climate change.

Warmer air can hold a higher water content, which makes rainfall patterns more extreme. Climate change is having serious impacts on the world’s water systems through more flooding and droughts. Extremes of drought and flooding will become more common, causing displacement and conflict.

Even small increases in Earth’s temperature caused by climate change can have severe effects. The earth’s average temperature has gone up 1.4° F over the past century and is expected to rise as much as 11.5° F over the next. In reality, the average temperature during the last Ice Age was about 4º F lower than it is today. The United Nations Framework Convention on Climate Change (UNFCCC) defines it as a change of climate that is attributed directly or indirectly to human activity, altering the composition of the global atmosphere.

It has been estimated that if greenhouse gas emissions continue at the present rate, Earth’s surface temperature could exceed historical values as early as 2047, with potentially harmful effects on ecosystems, biodiversity and the livelihoods of people worldwide.

Agriculture is the backbone of Indian Economy. About 65% of Indian population depends directly on agriculture and it accounts for around 22% of GDP. Rainfed agriculture occupies 67 percent net sown area, contributing 44 percent of food grains and supporting 40 percent of the population.

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Uneven rainfall patterns, increased temperature, elevated CO2 content in the atmosphere are important climatic parameters which affects the crop production. Research studies indicate that weathering parameters influence strongly (67%) compared to other factors like soil and nutrient management (33%) during the cropping season. The Intergovernmental Panel on Climate Change (IPCC) projected that the global mean surface temperature will likely rise and may result into uneven climatic changes. This rising temperature may affect crop yield at large scale. It has been reported over 20th century that rising temperature plays an important role towards global warming as compared to precipitation. Researchers have confirmed that crop yield falls by 3% to 5% for every 1°F increase in the temperature.

Recently published article in ‘The Guardian’ states that the suicides of nearly 60,000 Indian farmers is linked to climate change. The survey says that the rising temperatures and the resultant stress on India’s agricultural sector may have contributed to increase in suicides over the past 30 years.

Illustrating the extreme sensitivity of the Indian agricultural industry to spikes in temperature, the study from the University of California, Berkeley, found an increase of just 1C on an average day during the growing season was associated with 67 more suicides. Also reported that rainfall increases of as little as 1cm each year were associated with an average 7% drop in the suicide rate.

A recently published special issue on climate change in ‘Down To Earth’ magazine states that the climate change had significant impact on agriculture that leads to 1.5 per cent loss in India’s GDP. Their research findings are important and eye-opener. It states that the by 2030, rice and wheat are likely to see about 6-10 per cent decrease in yields. The crops like rice, wheat, maize and sorghum shall be severely affected by the extreme weather events, however crops like soybean and gram are likely to benefit from higher level of CO2 in atmosphere, which helps in CO2 fertilisation.

The rising temperature has adverse effect on flowering and leads to pests and disease buildup. Flood and excess rain over a short duration of time cause extensive damage to crops. Extreme weather events have caught attention of agrarian experts and scientists alike and they are now focussing on natural farming to arrest the impacts of climate change.

The experts in this field says that effect of climate change on crops mainly depends on the net sown area and the geographical location of a region where a particular crop is sown. Mustard, may experience a neutral-to-positive impact in northern India, especially in Punjab and Haryana, where winter temperature is very low. A 1°C rise in temperature won’t have much impact on production. However, a similar rise in temperature in eastern and central India will have a negative impact.

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Interestingly, Potato production may be positively impacted by elevated CO2 concentration, as reported by the experts at the Central Potato Research Institute, where they claimed that potato yield will increase by 11.12 per cent at elevated CO2 of 550 PPM and 1°C rise in temperature. However, further increase in CO2 with a likely rise in temperature by 3°C will result in decline in production by 13.72 per cent in the year 2050.

It is logical that the Kharif crops will be affected more by rainfall variability, while Rabi crops by minimum temperature. Wheat is likely to be negatively impacted in Rabi season due to terminal heat stress with 1°C rise in temperature results in loss of 4 metric tonnes (MT) of wheat. Similarly, legumes are going to be benefitted because of elevated level of atmospheric CO2.

An area is believed to be water-stressed when annual water supplies drop below 1,700 cubic metres per person per year. We are soon going to be in a situation where there will be wars for water. Much of the prosperity in the last two decades is because of groundwater exploitation, however the rainfed agriculture is being severly affected due to flactuations in the rainfall pattern. This year Vidharbha region in Maharashtra faced a severe drought and dryspell was prominant during crucial stage of the plant growth like flowering stage in soyabean and boll formation stage in cotton. Additionally this region had unexpected delayed rains at the time of first picking of cotton that spoiled the produce to the great extent.

The agriculture should  sustain despite adverse climatic conditions and produce enough food to feed the mankind.  The natural farming using climate-tolerant or stress tolerant crop varieties is upcoming area of research. Efficient water and nutrient management options to enhance use efficiency, evaluation of carbon sequestration potential of different land use systems, understanding opportunities offered by conservation agriculture and agro-forestry and identifying cost-effective methane emission reduction practices in ruminants and in rice paddy are few important mitigation options that needs to be considered.