Aerial view of the Amazon Rainforest, near Manaus: Expanding the agricultural area initially means reducing forest areas, as has been observed for decades in Brazil, for example.
Photo: © Neil Palmer (CIAT).

Impacts of climate change on global agriculture

A study by scientists from the Ludwig-Maximilian University (LMU) Munich pinpoints the winners and losers of climate change.

Climate change will affect agriculture the world over, but there will be winners. This is the finding of a study by geographers of the Ludwig-Maximilian University (LMU) Munich, Germany, published in September 2014 in the journal PLOS ONE.

Worldwide, about one third of land areas suitable for agriculture are already being farmed, according to a simulation made by LMU geoscientists. The simulation shows that the altered agricultural conditions due to climate change will improve by the year 2100, especially in the northern regions of the globe (Canada, Russia, China). In contrast, conditions in the Mediterranean region or parts of sub-Saharan Africa will greatly deteriorate in part unless there are adaption measures such as additional irrigation. 

In this context, scientists investigated the 16 globally significant crops, including maize, rice, soya and wheat. They found that worldwide an area of approximately 80 million square kilometres is potentially suitable for cropping when the areas irrigated nowadays, such as the land along the Nile, are included. This corresponds to more than half of the total land surface of the earth.  However, at the present time about one third of this area is classified as protected areas or dense forest. If these are to be conserved, only about 54 million square kilometres are available and of these 91 per cent are already being farmed today.

The problem of land expansion

Expanding the agricultural area initially means reducing forest areas, as has been observed for decades in Brazil or Indonesia, for example. But exactly these areas provide valuable eco-systemic services, one of which is to regulate the climate. Should this natural regulation disappear, entire regions could become infertile in future, say the scientists. Therefore, to achieve a global increase in agricultural production alternatives to land expansion have to be identified. This requires exact knowledge of the agricultural potential of every area of the land surface. The scientists aim to create the basic conditions necessary for land use to be optimised while conserving the ecosystems, and in this way raise agricultural efficiency.

For their simulations the LMU research scientists used date from the global climate model ECHAM5 which forecasts climate change in various scenarios according to the increase in carbon dioxide emissions. In the A1B scenario chosen by the LMU researchers calculated that the global agricultural land surface that can be used for agriculture increases up to the year 2100 by some five million square kilometres. But most of the additional areas obtained are only moderately suitable for agriculture. The scientists say that above all there will be a decrease in the amount of very suitable cropping areas. In the tropics of Brazil, Asia and Central Africa climate change will lead to a considerable decline in the ability to crop multiple harvests each year. 

(LMU/ile)