Climate and food
Source: By Jaydev Jana: The Statesman
Agriculture as it exists today has been shaped by a climate system that has changed little over farming’s 11,000-year history. Crops were developed to maximise yields in this long-standing climatic regime. As the temperature rises, agriculture will be increasingly out of sync with its natural environment. Nowhere is this more evident than in the relationship between temperature and crop yields.
Climate undergoes natural changes and cycles. The warming of the earth depends on the balance of the energy that reaches the earth from the sun and the energy that is radiated away. Human and natural factors of climate change ~ known as “radiative forcing” ~ drive the balance up or down. Since the beginning of industrialisation in the mid-18th century, civilisation has been in collision with the natural world. This has caused considerable harm to the natural system. The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), released in 2007, established that anthropogenic greenhouse gases ~ carbon dioxide and other heat-trapping gas ~ are largely responsible for global warming; the radiative forcing from anthropogenic sources is over ten times higher than that from all natural components combined. The recently released IPCC report (AR5) entitled “Summary for Policymakers” states emphatically that the earth’s surface over each of the last three decades has been warmer than any preceding decades since 1880, and has warmed by 0.85 degree C since then. Even if we stop burning all fossil fuels tomorrow, the existing greenhouse gases would continue to warm the Earth for centuries. We have irreversibly committed future generations to a hotter world. The profoundly altered planet Earth has entered a new geological epoch aptly coined in 2000 by the Dutch Nobel laureate, Paul Crutzen, and his colleague Eugene F. Stoermer, an ecologist, as Anthropocene.
Although in general the effects of climate change are not as evident as the impact on the natural world, its severe effects on the natural and managed systems, on which we depend for food, fuel, and fibre are substantial. Climate change will pose sharp risks to the world’s food security in the coming decades, potentially pushing down crop production as well as pushing up prices at a time when the demand for food is expected to soar. It is reported that while climate change can reduce agricultural production by as much as 2 per cent over every decade for the rest of the century, the demand is expected to rise as much as 14 per cent. The world’s population is projected to grow to 9.6 billion in 2050, from 7.2 billion today, according to the UN. It is one of the most complex challenges the current century faces.
Climate change affects agriculture both by long-term changes in ecosystems and by increased frequency and severity of heat waves, drought, flooding, cyclones and outbreaks of plant diseases and infestations. Corn ~ the most widely grown crop in the world ~ appears to be most vulnerable to heat stress. Its yields decrease at a range of temperatures the earth has to contend with in summer. The climate scenario for 2020 predicts that in Mexico around 3 lakh hectares will be unsuitable for maize production, leading to an estimated yearly loss of $140 million and considerable socio-economic disruption. Oxfam-commissioned research suggests that the average price of staple food such as corn could be more than double in the next 20 years compared with the 2010 trend prices, with up to half of the predicted inflation resulting from changes in average temperatures and rainfall patterns.
Both the computer models and consistent observations confirm that global warming increases temperature at night more than during the day. A global review of the impact of climate change on crop yields between 1980 and 2010 showed that worldwide wheat production fell due to climate-related factors by 5.5 per cent. MS Swaminathan once remarked that a degree Celsius rise in temperature for India would mean seven million tonnes of less wheat production, leading to a financial loss of around $1.5 billion. India needs to protect its agriculture from the withering effects of drought, whose frequency is likely to increase. A report published by the Proceedings of the National Academy of Sciences (PNAS) reveals that rice yield declined by 10 per cent with each one degree Celsius increase in night-time temperatures during the dry part of the growing season, even though there were no significant drops in yields associated with increasing maximum temperatures during the day.
A team of Indian scientists once noted that since insects are cold-blooded, temperature is probably the single-most important environmental factor influencing insect behaviour, distribution, development, survival, and reproduction. It has also been estimated that with a 2 degree C temperature increase, insects might experience one to five additional lifecycles per season. Warmer conditions and longer dry seasons linked to climate change are leading to a drastic expansion in the range of insects harmful to food crops, sending them farther north in the northern hemisphere and farther south in the southern hemisphere, and into higher altitudes. These wide-range expansions have an economic impact as well, resulting in higher seed and insecticide costs, decreased yields, and the downstream effects of changes in crop yield variability.
Climate change is at once resulting in floods and desertification by altering the atmospheric circulation patterns and drying out the land and vegetation. Global warming accelerates evaporation of more water vapour from the oceans and also speeds up the evaporation of soil moisture. Once the vast basins of water vapour in the sky get filled with more water vapour, the intense downpours lead to extensive floods that rush across the land, eroding the soil and leaving less of the water to recharge the underground aquifers. Since the refilling of the vast atmospheric ‘basins’ of moisture takes a lot of time in between the intense downpours, the longer periods of warmer temperatures lead to drought ~ soil moisture disappears, the ground is baked, local temperatures rise higher still, and the top soil becomes more vulnerable to wind erosion. Land degradation affects around 1.5 billion people globally and due to drought and desertification every year, 12 million hectares are lost (23 hectares/minute), indeed an area over which 20 million tons of foodgrain could have been grown. A food crisis in the decades to come cannot be ruled out.
Aquaculture contributed around 46 per cent of the world’s fish supply in 2006. Fish and shellfish currently supply about 8 per cent of the animal protein consumed. Demand for fish from aquaculture is projected to increase, but climate change will affect aquaculture operations worldwide. Rising seas, more severe storms, and saltwater intrusion will damage aquaculture. A marginal rise in temperature means that tropical species of fish might migrate or become extinct. For instance, mackerel and oil sardines have already been moving northwards along the coasts of India due to the warming of ocean water.
We may follow the prescription of John F. Kennedy who once remarked: “Our problems are man-made; therefore they may be solved by man. And man can be as big as he wants. No problem of human destiny is beyond human beings.” A food system to feed 3 billion more people without further damaging the already stressed ecosystem would definitely be within our reach if we act now, act together and act differently. We need to act concertedly to evolve effective technologies and management practices for mitigation and adaptation. We should act together to develop arrangements for sharing of risks and exchange of knowledge, technology and information. And we must also act differently to build up infrastructure that can withstand new conditions and use limited resources sustainably. More than half a century ago, Albert Einstein had suggested that ‘we shall require a new manner of thinking, if mankind is to survive.’
Agriculture as it exists today has been shaped by a climate system that has changed little over farming’s 11,000-year history. Crops were developed to maximise yields in this long-standing climatic regime. As the temperature rises, agriculture will be increasingly out of sync with its natural environment. Nowhere is this more evident than in the relationship between temperature and crop yields.
Climate undergoes natural changes and cycles. The warming of the earth depends on the balance of the energy that reaches the earth from the sun and the energy that is radiated away. Human and natural factors of climate change ~ known as “radiative forcing” ~ drive the balance up or down. Since the beginning of industrialisation in the mid-18th century, civilisation has been in collision with the natural world. This has caused considerable harm to the natural system. The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), released in 2007, established that anthropogenic greenhouse gases ~ carbon dioxide and other heat-trapping gas ~ are largely responsible for global warming; the radiative forcing from anthropogenic sources is over ten times higher than that from all natural components combined. The recently released IPCC report (AR5) entitled “Summary for Policymakers” states emphatically that the earth’s surface over each of the last three decades has been warmer than any preceding decades since 1880, and has warmed by 0.85 degree C since then. Even if we stop burning all fossil fuels tomorrow, the existing greenhouse gases would continue to warm the Earth for centuries. We have irreversibly committed future generations to a hotter world. The profoundly altered planet Earth has entered a new geological epoch aptly coined in 2000 by the Dutch Nobel laureate, Paul Crutzen, and his colleague Eugene F. Stoermer, an ecologist, as Anthropocene.
Although in general the effects of climate change are not as evident as the impact on the natural world, its severe effects on the natural and managed systems, on which we depend for food, fuel, and fibre are substantial. Climate change will pose sharp risks to the world’s food security in the coming decades, potentially pushing down crop production as well as pushing up prices at a time when the demand for food is expected to soar. It is reported that while climate change can reduce agricultural production by as much as 2 per cent over every decade for the rest of the century, the demand is expected to rise as much as 14 per cent. The world’s population is projected to grow to 9.6 billion in 2050, from 7.2 billion today, according to the UN. It is one of the most complex challenges the current century faces.
Climate change affects agriculture both by long-term changes in ecosystems and by increased frequency and severity of heat waves, drought, flooding, cyclones and outbreaks of plant diseases and infestations. Corn ~ the most widely grown crop in the world ~ appears to be most vulnerable to heat stress. Its yields decrease at a range of temperatures the earth has to contend with in summer. The climate scenario for 2020 predicts that in Mexico around 3 lakh hectares will be unsuitable for maize production, leading to an estimated yearly loss of $140 million and considerable socio-economic disruption. Oxfam-commissioned research suggests that the average price of staple food such as corn could be more than double in the next 20 years compared with the 2010 trend prices, with up to half of the predicted inflation resulting from changes in average temperatures and rainfall patterns.
Both the computer models and consistent observations confirm that global warming increases temperature at night more than during the day. A global review of the impact of climate change on crop yields between 1980 and 2010 showed that worldwide wheat production fell due to climate-related factors by 5.5 per cent. MS Swaminathan once remarked that a degree Celsius rise in temperature for India would mean seven million tonnes of less wheat production, leading to a financial loss of around $1.5 billion. India needs to protect its agriculture from the withering effects of drought, whose frequency is likely to increase. A report published by the Proceedings of the National Academy of Sciences (PNAS) reveals that rice yield declined by 10 per cent with each one degree Celsius increase in night-time temperatures during the dry part of the growing season, even though there were no significant drops in yields associated with increasing maximum temperatures during the day.
A team of Indian scientists once noted that since insects are cold-blooded, temperature is probably the single-most important environmental factor influencing insect behaviour, distribution, development, survival, and reproduction. It has also been estimated that with a 2 degree C temperature increase, insects might experience one to five additional lifecycles per season. Warmer conditions and longer dry seasons linked to climate change are leading to a drastic expansion in the range of insects harmful to food crops, sending them farther north in the northern hemisphere and farther south in the southern hemisphere, and into higher altitudes. These wide-range expansions have an economic impact as well, resulting in higher seed and insecticide costs, decreased yields, and the downstream effects of changes in crop yield variability.
Climate change is at once resulting in floods and desertification by altering the atmospheric circulation patterns and drying out the land and vegetation. Global warming accelerates evaporation of more water vapour from the oceans and also speeds up the evaporation of soil moisture. Once the vast basins of water vapour in the sky get filled with more water vapour, the intense downpours lead to extensive floods that rush across the land, eroding the soil and leaving less of the water to recharge the underground aquifers. Since the refilling of the vast atmospheric ‘basins’ of moisture takes a lot of time in between the intense downpours, the longer periods of warmer temperatures lead to drought ~ soil moisture disappears, the ground is baked, local temperatures rise higher still, and the top soil becomes more vulnerable to wind erosion. Land degradation affects around 1.5 billion people globally and due to drought and desertification every year, 12 million hectares are lost (23 hectares/minute), indeed an area over which 20 million tons of foodgrain could have been grown. A food crisis in the decades to come cannot be ruled out.
Aquaculture contributed around 46 per cent of the world’s fish supply in 2006. Fish and shellfish currently supply about 8 per cent of the animal protein consumed. Demand for fish from aquaculture is projected to increase, but climate change will affect aquaculture operations worldwide. Rising seas, more severe storms, and saltwater intrusion will damage aquaculture. A marginal rise in temperature means that tropical species of fish might migrate or become extinct. For instance, mackerel and oil sardines have already been moving northwards along the coasts of India due to the warming of ocean water.
We may follow the prescription of John F. Kennedy who once remarked: “Our problems are man-made; therefore they may be solved by man. And man can be as big as he wants. No problem of human destiny is beyond human beings.” A food system to feed 3 billion more people without further damaging the already stressed ecosystem would definitely be within our reach if we act now, act together and act differently. We need to act concertedly to evolve effective technologies and management practices for mitigation and adaptation. We should act together to develop arrangements for sharing of risks and exchange of knowledge, technology and information. And we must also act differently to build up infrastructure that can withstand new conditions and use limited resources sustainably. More than half a century ago, Albert Einstein had suggested that ‘we shall require a new manner of thinking, if mankind is to survive.’
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