How will climate change affect crop yields in the future?

How much will climate change affect food production? Will it hurt or benefit crop yields? Can we feed 8, 9, or 10 billion people in a warmer world?

These are crucial questions that I’m trying to tackle in a three-part series on climate change and agriculture.

In my first article, I discussed the different ways climate change impacts crop yields and the effect they have already had on global food production. In this installment, we’ll look at how climate change could affect crop yields in the future.

As a quick reminder, there are three ways that CO2 emissions and climate change can affect agriculture.

First, plants can benefit from higher CO2 levels in the atmosphere; this is called “carbon fertilization”. Wheat and rice — so-called “C3” crops — can significantly benefit from more CO2. Maize, millet, and sorghum — “C4” crops — benefit very little, except under drought conditions.

Second, crops are affected by higher temperatures. This can increase or decrease yields depending on the type of crop and where in the world it is grown. For farmers in temperate climates, where temperatures are lower than the “optimal” for that crop, moderate climate change can potentially increase average yields. For farmers in the tropics or subtropics where temperatures are already at or past the “optimal”, higher temperatures will directly reduce yields.

Finally, crops are affected by water availability. Yields decline significantly under water stress and the opposite — flood and waterlogging — so crop productivity will decrease if climate change increases the frequency or intensity of these events.

The ultimate impact on crop yields combines all of the above. They can either offset or boost one another. Considering just one could lead to the wrong conclusions. That’s why we get oversimplified and opposing headlines, such as “More CO2 and climate change is good for agriculture” or “Higher temperatures will cause crop yields to collapse worldwide.”

The reality is more complex. Some crops in some places could benefit. Elsewhere, crop yields are at risk of a severe decline. Extreme events pose additional risks that could destabilize food systems in the future.