Energy > Climate Change
August 2018
The impact of climate change on world agriculture
Rising temperatures, changing precipitation patterns, and more extreme weather events will negatively impact the world’s ability to produce food. At the same time the demand for food will grow due to an increasing world population and rising incomes in the developing world. Meeting this challenge will depend on agriculture’s ability to adapt to a changing climate while developing and adopting the technologies needed to meet the increase in food demand.
World food production relies on regions of the world highly suitable for rain fed agriculture. These regions require a combination of four factors; the proper amount of precipitation, temperature levels for optimum plant growth, soils suitable for agriculture production, and terrain suitable for agricultural practices. Regions of the world containing these factors include the U.S. Midwest, portions of Brazil and Argentina, Europe, sub-Saharan Africa, India and Eastern China.
As temperatures rise and rainfall patterns shift, the productivity of these regions will be negatively impacted. The impact of higher temperature on crops will depend on the crops optimal temperature for growth and reproduction. A small rise in temperatures in many prime growing regions will slightly increase yields, but more significant temperature rises will lead to yield declines.
Regions of the earth in the mid to upper latitudes may benefit from more heat and a longer growing season. But regions at lower latitudes are especially vulnerable because they already suffer from intense heat. This loss is expected to more than offset any advantage in the upper latitudes.
Less precipitation in an area due to climate change will usually lead to a decrease in productivity. The extreme example is droughts. However, more precipitation may not improve agricultural productivity. If the precipitation increase leads to more water-logged soils and flooding, productivity will decline.
Irrigation can provide a short-term solution for a few decades, but it often does not provide a permanent or sustainable solution. We see numerous regions of the world where widespread irrigation faces challenges relating to water supply (e.g., aquifer depletion, competing uses for reservoir water) or salinization of land under long-term irrigation. Numerous past civilizations that thrived and expanded based on irrigated agriculture eventually collapsed because of the long-term unsustainability of irrigated agriculture.
The sustainability of irrigation is especially of concern where groundwater from underground aquifers is used. Over half of the world’s largest aquifers are being drained faster than they are being refilled.
Climate change will be of special concern in poor countries with subsistence agriculture. In these countries, the ability to adapt to a changing climate is more limited than in the U.S. and other industrialized countries.
Don Hofstrand, retired extension agricultural business specialist, agdm@iastate.edu
