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Carbon Brief Staff

10.06.2011 | 11:00am
Food and farmingFood, hunger and climate change
FOOD AND FARMING | June 10. 2011. 11:00
Food, hunger and climate change

A slew of new reports have again highlighted the perilous state of the global food system.

As the world struggles through the second global food crisis in three years, some argue this should be a wake up call to revitalize and stabilize global food production and trade.

The question now is whether climate change will make such crises more common.

So far this year 44 million people have been pushed into extreme poverty by increased food costs, adding to the nearly one billion starving and 2.5 billion malnourished people around the world.

Global cereal prices increased 71 percent in the year to April 2011, more than three times higher than a decade ago. And the cost of meat hit an all-time high in May. Prices are set to continue rising, with Oxfam warning of a doubling in global food prices by 2030.

During the last food price spike in 2008 experts mostly agreed on the causes: a combination of commodity speculation, global economic crisis, energy costs, increased biofuel production and increased demand from emerging economies.

That crisis resulted in riots in 30 countries and 100 million people being pushed into extreme poverty. The high cost of food was a factor in the Tunisian and Egyptian protests that ignited the ‘Arab Spring’.


This time the short-term and underlying economic causes remain the same. But there is a growing consensus that the on-going crisis is being exacerbated by climate change.

In May the UN Food and Agriculture Organisation warned of unrest as global food prices hit record highs inflamed by drought in Europe. The Guardian reported:

“Food prices are expected to hit new highs in the coming weeks, tightening the squeeze on UK households and potentially triggering further unrest in developing countries unless there is heavy rainfall across drought-affected Europe, the United Nations has warned.

“â?¦The average global price of cereals jumped by 71% to a new record in the year to April, more than three times higher than a decade ago, according to latest UN figures, prompting its Food and Agriculture Organisation to warn that Europe faces a pivotal few weeks.”

Now scientists have for the first time demonstrated a link between global warming and crop yields. A new study, Climate Trends and Global Crop Production Since 1980 by Lobell, Schlenker and Wolfram, was published in Science last month and reported in New Scientist.

The gains from technological improvements have, since 1980, been offset by the losses to staple crop yields caused by temperature rises.

The study used statistical models to calculate staple crop yields in every country in the world since 1980 as technology improved, if temperature and rain had remained at 1980 levels. This was compared to real-world yields.

They found maize yields were 5.5 percent lower and wheat 3.8 percent lower than if temperature and rainfall had remained at 1980 levels. “In most places we see temperature trends, and they have significantly reduced yield growth,” Schlenker said. Dr. Lobell told the New York Times: “I think there’s been an under-recognition of just how sensitive crops are to heat, and how fast heat exposure is increasing.”

Another new study also points to the effects on yields of climate change. Trnka et al, in “Global Change Biology” found climate change is increasing the risk of  “extremely unfavorable years in many climate zones” resulting in unpredictable yield variability.

However, uncertainty associated with relying on modelling means this and the Lobell paper are open to criticism.

The changing climate is not the main cause of hunger. Currently the world produces more than enough food, although growth in food production is slowing. The current crisis is one of economics and politics. As UN Assistant Secretary-General for economic development, Jomo Kwame Sundaram, wrote recently:

“Lack of food is rarely the reason that people go hungry. The world today produces enough food to feed everyone. The problem is that more and more people simply cannot afford to buy the food they need.”

But climate change is making the crisis worse and could become an increasingly important factor in global food security. Sundaram added:

“Other factors have contributed to the food crisis. Climate changes resulting from greenhouse-gas emissions exacerbate water-supply problems, accelerate desertification and water stress, and worsen the unpredictability and severity of weather events, all of which adversely affect agriculture in much of the world.”

In its ” Growing a Better Future” report published last week, Oxfam projected food prices will double by 2030 and climate change will be responsible for half that increase. The report said climate change poses a grave threat to food production by applying a “brake” on crop yield growth:

“Estimates suggest that rice yields may decline by 10 per cent for each 1°C rise in dry-growing season minimum temperatures. Modelling has found that countries in sub-Saharan Africa could experience catastrophic declines in yield of 20-30 per cent by 2080, rising as high as 50 per cent in Sudan and Senegal.”

Green revolution

It is now accepted that the upward trend in yields brought about by the technological advances of the “green revolution” has plateaued [pfd].

Oxfam also identifies extreme weather events as a major threat to harvests and future food security.  Changing seasons with “longer, hotter dry periods and unpredictable rainfall patterns” are making farming more difficult in poor and developing countries.

Examples like the 2010 heatwave in Russia show how extreme weather events have a knock on effect on the global food system. Food production was hit to such an extent the government banned grain exports.

Other recent extreme weather events thought collectively to have contributed to the current price crisis include the huge floods in Pakistan, Australia, and Brasil.

Joe Romm, blogging at the Guardian in February, said:

“When the real food instability comes – if, for instance, the US or Chinese breadbasket gets hit by the type of heatwave Russia just did – the big grain producers will ban exports, to make sure their people are fed. In this scenario, if you don’t have your own food supplies or an important export item to barter – particularly oil – your country is going to have big, big problems feeding its people.”

In its recent report [pdf], the UN Conference on Trade and Development looked at the effects on developing countries. It says the regions most at risk from disruption to food security are those already affected by hunger.  In many underdeveloped countries agriculture remains the key economic sector. And price spikes and volatility in food markets hit poor countries hardest:

“Global warming has the potential to damage irreversibly the natural resource base on which agriculture depends, with grave consequences for food security. Climate change could reduce total agricultural production in many developing countries by up to 50 per cent in the next few decades, in particular in South Asia and sub-Saharan Africa. At the same time, the population of these countries is projected to nearly double, creating huge tensions between food supply and demand. Although food could be theoretically imported from temperate-zone countries that may benefit from global warming, this may simply be unaffordable given the huge demand, low purchasing power and expected food price increases.”


The Climate Change Agriculture and Food Security research institute also highlighted the vulnerability of underdeveloped regions in its study published on 3rd June.

Using models and indicators of food problems the CCAFS scientists created detailed maps pinpointing areas of vulnerability. The study mapped areas of the world at risk of crossing “climate thresholds” that could diminish food production; areas sensitive to climate change because of the large areas of land devoted to agriculture; and maps of regions with long histories of food insecurity.

When the maps are put together they reveal parts of the world most vulnerable to climate effects on food production. The report highlighted particular regions of South Asia and sub-Saharan Africa as most at risk.

Patti Kristjanson, one of the researchers, said:

“We are starting to see much more clearly where the effect of climate change on agriculture could intensify hunger and poverty, but only if we fail to pursue appropriate adaptation strategies. Farmers already adapt to variable weather patterns by changing their planting schedules or moving animals to different grazing areas. What this study suggests is that the speed of climate shifts and the magnitude of the changes required to adapt could be much greater. In some places, farmers might need to consider entirely new crops or new farming systems.”

The recent literature also looks at agriculture’s effect on climate change. The energy intensive agricultural methods we use to produce our food make a significant contribution to greenhouse gas emissions : between 17 and 32 percent of all human-induced greenhouse gas emissions.

UNCTAD agrees [pdf]:

“Agriculture is a very GHG-emission-intensive sector. Although agriculture’s share in global GDP is just about 4 per cent, agriculture accounts for about 13-32 per cent of global GHG emissions.”

In this identification of agriculture as part of the problem lies a potential solution to food insecurity that also addresses climate change:

“Under a business-as-usual scenario, agricultural GHG emissions are predicted to rise by almost 40 per cent till 2030. Further chemicalization and industrialization of agricultural production that cannot but reinforce this trend are therefore steps in the wrong direction. If properly transformed, agriculture can be turned from being a climate-change problem to becoming an essential part of its solution. The key problems of climate change, hunger and poverty, economic, social and gender inequity, poor health and nutrition, and environmental sustainability are inter-related and need to be solved by leveraging agriculture’s multi-functionality.

“Thus a much more holistic approach is required that not only sees the farmer as a producer of food and agricultural commodities, but also as manager of sustainable agro-ecological systems. The required transformation, however, is much more profound than simply tweaking the existing industrial agricultural systems.”



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