Climate Change and Farmland
In the News
June 26, 2011
Based on the calculations made in the study, regions characterized by high latitudes like Russia, China and the U.S. may experience an increase of total arable land by 37 to 67%, 22 to 36% and 4 to 17%, respectively. Meanwhile, tropical and sub-tropical regions may suffer from lost arable land at different levels depending on location. South America, for example, may lose 1 to 21% of its arable land, and Europe could lose 11 to 17%. Africa and India could lose 1 to 18% and 2 to 4%, respectively.
“Soil suitable for agriculture has a particular range of temperature during crop growth season; too high or too low (i.e., out of that range) will make the land less or not suitable. In the high latitude regions, quite a lot of land is currently frozen or with a temperature lower than a threshold for plant growth during most time of year. Climate change is likely to increase the temperature to the range that is suitable for plants. This may occur in the high latitude regions. While in the tropical or sub-tropical regions, rainfall decline may reduce the air humidity and soil wetness, which in turn affects land suitability for agriculture,” says Dr. Ximing Cai, the principle researcher of the study.
In addition to climate change, another major item influencing the future availability of cropland is population growth. When factoring land used for human settlements into the equation – and also to a lesser extent land used for natural conservation – net potential arable land may decrease even further globally. Assessed by subtracting human settlements and protected land from the global total, net potential arable land is estimated as 41.3 million km2 under the baseline scenario, and could decrease by 0.7 to 3.7 million km2 in other projected scenarios.
Although the magnitudes of the projected changes vary by scenario, the increasing or decreasing trends in arable land area are regionally consistent. The greatest potential for agricultural expansion lies in Africa and South America, with current cultivated land accounting for less than 20% of the net potential arable land.
“Large regional change with small world-wide change will affect regional agricultural structure (crop patterns), production and shift the current food production distribution, which will further change the world’s food demand and trade,” says Cai.
Cai says that there are definitely opportunities to increase the value of arable land through adaptive management practices. Some marginally suitable land where water is a constraint may be currently irrigated, for one. Other agricultural adaptation measures, like rainfall harvesting and water storage, may mitigate the negative impacts of climate change on land suitability and thus maintain current levels of available arable land.
The possible gains and losses of arable land in various regions worldwide may generate tremendous impacts in the upcoming decades upon regional and global agricultural commodity production, demand and trade – as well as on the planning and development of agricultural and engineering infrastructures. More research on these practices is needed, says Cai, to access their ability to alleviate the later century land changes the study is predicting.