A report in Science Magazine examines the effect of climate change on crop yields – for wheat, corn, soy, and rice – since 1980. While the report finds that, overall, crop yields have decreased by 3% for corn and 5% for wheat, some cite flaws in the way the study was conducted and its findings. The Economist cites a much more nuanced picture of this relationship, stating:
The analysis does not track changes over time in the areas being farmed, using instead a crop map from around 2000. And many agronomists hold that relying on year-to-year yield changes for modeling exaggerates the damage due to longer climate shifts. Farmers will tend to adapt. That said, subtler effects of climate change such as more sudden rains and particularly hot days with disproportionate effects on yield are left out, which might mean the study underestimates the effects.
Interestingly, the study finds that though in many countries the crop yield decreased, the United States has yet to demonstrate a similar decline (yet), a region that produces some 40% of the world’s corn and soybeans.
One of the key takeaways from the study and these articles about it is that technology has helped farmers overcome the challenges posed by climate change upon agriculture. Developments in irrigation, fertilizer and seeds have helped farmer increase crop yields in the face of climate change. One of CTED’s projects looks at how technology can help make inferences about localized climate and agricultural trends. Sunandan Chakraborty has developed a tool for using the internet to mine data to summarize important climate and agricultural trends for a specific area. The project has been tested across 605 districts in India, resulting in detection of trends that were later verified by government or other official sources. Taking the project to the next level, Sunandan hopes to incorporate predictability and add an early warning system capability for detecting drought, flood or other agricultural catastrophes.
For more info, Signs from Earth Notes has a great blog post with lots of links about the study.