Adapting Growing Seasons to Climate Change can Boost yields of World’s Staple Crops

By Alison Doody

Rising global temperatures due to climate change are changing the growth cycles of crops worldwide. Recent records from Europe show that wild and cultivated plants are growing earlier and faster due to increased temperatures.

Farmers also influence the timing of crops and tend to grow their crops when weather conditions are more favorable. With these periods shifting due to climate change, sowing calendars are changing over time.

Over thousands of years of domesticating and then breeding crops, humans have also managed to artificially change how crop varieties respond to both temperature and day length, and in turn have been able to expand the area where crop species can be grown. Farmers can now choose varieties that mature at different rates and adapt them to their environment.

Including farmers’ decisions on when to grow crops and which varieties to cultivate are vital ingredients for understanding how climate change is impacting staple crops around the world and how adaptation might offset the negative effects.

In a ground-breaking study, a team of researchers from the Potsdam Institute for Climate Impact Research (PIK), the Technical University of Munich and the International Maize and Wheat Improvement Center (CIMMYT) investigated how farmers’ management decisions affect estimates of future global crop yields under climate change.

“For long time, the parametrization of global crop models regarding crop timing and phenology has been a challenge,” said Sara Minoli, first author of the study. “The publication of global calendars of sowing and harvest have allowed advancements in global-scale crop model and more accurate yield simulations, yet there is a knowledge gap on how crop calendars could evolve under climate change. If we want to study the future of agricultural production, we need models that can simulate not only crop growth, but also farmers’ management decisions.”

Using computer simulations and process-based models, the team projected the sowing and maturity calendars for five staple crops, maize, wheat, rice, sorghum and soybean, adapted to a historical climate period (1986–2005) and two future periods (2060–2079 and 2080–2099). The team then compared the crop growing periods and their corresponding yields under three scenarios: no adaptation, where farmers continue with historical sowing dates and varieties; timely adaptation, where farmers adapt sowing dates and varieties in response to changing climate; and delayed adaptation, where farmers delay changing their sowing dates and varieties by 20 years.

The results of the study, published last year in Nature Communications, revealed that sowing dates driven by temperature will have larger shifts than those driven by precipitation. The researchers found that adaptation could increase crop yields by 12 percent, compared to non-adaptation, with maize and rice showing the highest potential for increased crop yields at 17 percent. This in turn would reduce the negative impacts of climate change and increase the fertilization effect of increased levels of carbon dioxide (CO₂) in the atmosphere.