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Climate variability and the vulnerability of food and farming

Climate research has focused on the impacts of higher mean temps. This review finds this has limited our understanding of how variability, such as heat waves will impact farming systems.

Climate research has so far been focusing most of its attention on the impacts from higher mean temperatures worldwide. According to a new research review this has limited our understanding on how climate variability, such as heat waves or flooding, will impact the farming system, both now and in the future.

At this stage, climate science is not able to tell us a great deal about how the agriculture sector will be affected by an increasingly variable climate. But despite little progress, there are still a number of things scientists can do to not only advance the research on climate variability but also to support communities adapt to climate change. This argues a newly released review, “Climate variability and vulnerability to climate change”, published in Global Change Biology earlier this year.

By not being able to investigate both the effects, and combined impacts, of climate variability such as heat waves, intensified precipitation and flash floods and an increased global mean temperature, the full impacts of climate change on a biological and human system are seriously being underestimated, the review continues.

As an example, the authors mention that if changes only in climatic means are taken into consideration and climate variability is ignored, projections for crop yields in parts of East Africa may be under estimated by between 4 and 27 percent, depending on the crop.

The article outlines five areas that need increased attention if we are to successfully address the above-mentioned environmental, health and food security challenges:

  • Through a re-prioritized research agenda, ensure that the knowledge and data gaps around the effects of climate variability and extreme events on biological systems are addressed.
  • Improve available impact models, especially on crops and livestock, at all scales.
  • Improve the monitoring of local conditions, to improve our understanding and models that will help guide effective adaptation. Improved models would also help feed in important data to yield early-warning systems and locally appropriate indices for weather-based crop and livestock insurance schemes.
  • Strengthen efforts being made to adapting biological and food systems to the increasingly variable climate and to increasingly frequent extreme events.
  • Generate synergies and improve the communication between scientists and decision makers, as well as between natural and social scientists. There is a great deal that can be done on the co-generation of information and its communication in appropriate ways, and in engaging meaningfully with decision makers at local and national policy levels.

What do we know and what are we still searching for?

“What we still need to know is, how will changes in climate variability play out, i.e. will annual rainfall amounts become increasingly erratic, or will there be more extreme heat stress days? And the second is, how will increasingly erratic rainfall or more heat stress days affect crops and livestock? We know little about the first, and through physiology and modellinga few things about the second and not much if anything about how these things interact with each other,” says Philip Thornton.

”One major and immediate challenge is to use the information we do have, about climate variability and its impacts, to help us better understand extreme events. Our recent work for the IPCC identified extreme events as a major risk factor for agriculture under climate change,” says Andy Challinor co-author of the review, as well as co-author to the chapter “Food Security and Food Production Systems”, included in the recently released IPCC report “Climate Change 2014: Impacts, Adaptation, and Vulnerability”.

The authors mention that we do know that shifts between new extreme high and low temperatures, could impact how crops grow and under what time frame. Earlier flowering and maturity of several crops have been documented in recent decades, often associated with higher temperature.

Also, increases in maximum temperatures can lead to severe yield reductions and reproductive failure in many crops, further affecting billions of people depending on farming as their main livelihood and food source.

Why so little research on climate variability?

“Research on impacts and effects from climate variability is currently being constrained by lack of information and models. By outlining what we know, as well as the data we still need, we hope that this review will push the research community to reframe some of its research questions to better integrate climate variability,” says Philip Thornton, co-author of the review and Theme Leader at the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS).

One major challenge right now is to understand how to tackle the uncertainty around projecting variability and changes. This needs to be overcome, while strengthening the confidence in projecting climate extreme events and their magnitude. The fact that this is a highly complex and challenging area, with a lot of uncertainty, is likely the reason to why research hasn’t really progressed.

Download article:Thornton P, Ericksen PJ, Herrero M, Challinor AJ. 2014. Climate variability and vulnerability to climate change: a review. Global Change Biology.

Read the rest of this story on the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) blog: What are the long-term effects from flash floods and heat waves on agriculture?

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