Here’s a not-bold prediction: China’s approach to climate change mitigation will be a defining issue of the decade for which we have just embarked. Part two of this series continues to look at why climate change might be pushing China to the precipice of its path toward economic growth.

The impact of climate change on Chinese agriculture will primarily be experienced in two forms.

First, climate change threatens to cut agricultural production by 5 to 10 percent in China by 2030.[1] This will greatly exacerbate an already delicate food security situation in a country which already has to feed 20 percent of the world’s population on 7 percent of the planet’s arable land. Of particular concern, rising temperatures have already pushed back wheat-yield growth by 2.4 percent between 1979 and 2000.

Second, but more indirectly, the projected 3° to 6 °C warming will greatly increase the demand for fresh water for the purposes of agricultural irrigation. This promises to further stretch the already stressed water resources discussed in Part 1 of this series. The hotter and drier environment brought about by the just 1°C surface warming likely to be experienced in Eastern China by the 2020s, for example, would increase the amount of water needed for irrigation there by 6 to 10 percent.

The Figure above illustrates how a dramatic spike in the number of “hot days”  (days with temperatures exceeding 30°C) over the course of the 21^st century will be the primary mechanism driving higher irrigation demand. With increasing scarcity of fresh water supplies predicted in the coming decades, much uncertainty exists as to whether this ballooning demand for irrigation water can be met. If it is not, the further decline in food production that will almost assuredly result will likely cause a substantial spike in food prices. Global cereal prices are already expected to triple by the 2080s according to the 2007 IPCC Report. With 400 million people still living in poverty and extremely vulnerable to even small food price increases, a nation that is best known for dynamic economic growth and development by current generations may very well be similarly well-known for dynamic hunger and starvation by future generations.

It is important to note that declining food production in China due to climate change carries with it both tremendous uncertainties and risks. This is true for a number of reasons. First, current literature and definitive data on the impact of climate change on food productivity is severely lacking. It is very hard, for example, to separate the influences of climate change variables from those of different management practices and modern inputs such as chemical fertilizer, pesticide, machinery, and seeds.

Second, the interdependency of the world food system makes it extremely difficult to predict where and in what quantities tomorrow’s food supplies will come. Even if China has a reduced ability to feed its own people, it is possible that China can turn to other areas in the world where food productivity has perhaps increased. Such uncertainty is true of many of the other impactshighlighted in this series, but is particularly important for issues of food security.

Still, the unfortunate truth remains that this uncertainty only increases the risk posed by climate change.

- Matt

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[1] The 5 to 10 percent decrease in Chinese agricultural production is an aggregate projection. In some parts of East and South-East Asia, agricultural production is estimated to increase by up to 20 percent. By contrast, production could decrease by 30 percent in Central and South Asia. The sum is still a substantial net-decrease in production (Canziani et al. 2007 p. 479).