How Climate Change will Reduce Crop Yields and Spike Food Prices

A new study shows how climate change will impact global food security, particularly by reducing crop yields and increasing crop yield volatility. This, in turn, will have a strong effect on the prices of basic staples, particularly corn and rice. We speak Michelle Tigchelaar, one of the report’s authors

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Story Transcript

GREG WILPERT: It’s The Real News Network. I’m Greg Wilpert.

With global temperatures on the rise, climate change is affecting every aspect of our daily lives. Food production is especially sensitive to climate change. Several new studies highlight this issue. One such study shows how climate change will make rice less nutritious. Another study shows how climate change will affect the geography of fisheries, and thereby spark fishing wars between countries. And a third study by Michelle Tigchelaar, shows how a warming world will disrupt global food production. Her article, “Climate change could heighten the risk of global food production shocks,” examines how climate change will contribute to lower, more volatile, or failed crop yields.

We’re now joined from Seattle by Michelle Tigchelaar. She is the author of the aforementioned study, and a research associate at the University of Washington, where she studies the effects of climate change on global food security. Thanks for joining us today, Michelle.

MICHELLE TIGCHELAAR: Thank you. Happy to be here.

GREG WILPERT: So your study examines how climate change will affect different parts of the world in terms of food production. Currently the Paris Climate Agreement aims at keeping the global temperature rise to less than 2 degrees Celsius above pre-industrial levels. Give us a brief summary of what you find such a temperature increase, of let’s say 2 degrees Celsius, would mean for global food production.

MICHELLE TIGCHELAAR: Yeah. So in our study we did look at what a 2 degree warmer world would mean for food production, and we also looked at what a 4 degree warmer world would look like for food production. And we see that in both of those worlds, crop yields would be significantly lower, and also that it really matters if we do 2 or 4 degrees warming. Just underscoring how important the Paris agreement is. And in our study was specifically looked at corn, which is currently the most grown crop in the world. And we found that with a 2 degree warming, global corn yields decline between 10 and 20 percent, and also yields become more volatile. So this means that the risk of having crop failures becomes larger in a 2 degree warmer world.

GREG WILPERT: So, and of course you’re looking at the global situation, but you also look at different regions. And do you see a correlation between the richer and the poorer areas of the world and how the adverse effects of climate change affect their food production? That is, in northern countries, which tend to be wealthier, could they actually benefit from hotter summers and winters, whereas the southern regions would suffer more from climate change, in terms of food security?

MICHELLE TIGCHELAAR: Yeah. So actually, in the case of corn what is really interesting is that just four countries, the United States, China, Brazil, and Argentina, actually produce more than two thirds of the world’s corn. So the production is highly concentrated in just a few locations. And we were expecting that especially for the United States, since it’s currently not as warm, maybe the effects wouldn’t be as bad. But we find that for the U.S. in particular, for the U.S. and China, and those other countries, we actually get relatively similar effects of warming on crop yields. Which is really bad news for those countries themselves, but also for the poorer countries in which many people, especially urban consumers, are really dependent on the prices of food in international food markets. So even if they don’t live in the United States they are affected by crop losses in in the United States.

GREG WILPERT: Give us just some of the key numbers. I saw that in the summary of your research you mentioned some concrete percentages as to how big an effect that 2 degree increase would have on the reduction or volatility of food production in those crops, and how much a 4 degree increase would do. Just give us a couple of those highlights.

MICHELLE TIGCHELAAR: Yeah. So one interesting statistic that we looked at is what is the probability that 4 countries at the same time, the four main exporting countries, would have crop failures larger than 10 percent at the same time? And this is really relevant because of that effect of then prices in the international food markets. And we found that this probability of those four countries at the same time having such a big crop loss is essentially zero, because weather is relatively independent between U.S. and China, so the chances of that happening at the same time is low. But in a two degree warmer world that probability increases to 7 percent, and then in a 4 degree warmer world, that probability increases to 86 percent.

GREG WILPERT: So, you make also a very important point that our corn production, for example, is not just expected to decline with the rising temperatures, but that production volatility is supposed to rise, as well. And I’m wondering if globalization, and faster shipping, and instant communication might perhaps mitigate that volatility in food production. So first of all, why do you expect volatility to increase? And second, why is it dangerous that this volatility increases, and could perhaps changes in distribution mitigate that effect?

MICHELLE TIGCHELAAR: Sure. So in terms of your first question, why do we expect volatility to increase. Sort of conceptually you think you can think of it as there is an optimum temperature at which a crop can grow, and beyond that optimum temperature, yields rapidly decline. So if you go beyond the optimum temperature, if you have year-to-year variability in temperatures, you’re going to be increasing the variability of those yields.

And why this matters is because because of the fact that, first of all, it matters to individual farmers and the consistency of their income, especially in places where there is no crop insurance. But it also matters for international grain markets, and corn is heavily traded, and is a product that is used for many different end uses, such as animal feed, and also as a biofuel. So therefore the price of corn is tightly related to the price of other commodities in the market.

In terms of your question about can we mitigate this in terms of more efficient shipping or communication, we’ve actually seen prices of crops and volatility of food prices increase over the last couple of decades as markets have become more tightly connected. And what is especially interesting here is that the actual response of countries to initial price shocks, in response to, say, a yield drop, is really important in determining what the overall prices will be in the international market. So in the 2006-2008 food crisis there was actually only a relatively small reduction in crop yield, but the food price change was enormous because all these countries ended up closing off their markets for trade.

GREG WILPERT: Finally, what other effects might climate change have on global food security? In the introduction I also mentioned two other studies, one that shows how fisheries will be negatively affected by warming oceans, and one that talks about how the nutritional quality of rice crops will be diminished. What other effects do we know about?

MICHELLE TIGCHELAAR: Well, there are probably many different effects. There have been a number of studies that have looked at crop yields for the main staple crops, but also, you know, if you want to think about fruits and flowering, there’s a whole seasonality there that might be affected. Some interesting areas of research that I’m currently contributing to include looking at how crop pests will respond to warming. We know that ectotherms thrive in a warmer environment, so the pressure of pests on crops is expected to increase. And I think it would also be really important to look at the effects of warming on agricultural workers. I was just reading an article on how a drought in Honduras had taken away the livelihood of farmers there, and then leading to a large migration to towards the United States.

GREG WILPERT: OK, we’re going to leave it there for now. I’m speaking to Michelle Tigchelaar, a research associate at the University of Washington. Thanks, Michelle, for having joined us today.

MICHELLE TIGCHELAAR: Yeah, thank you for having me.

GREG WILPERT: And thank you for joining The Real News Network. Also, if you like stories such as this one, I want to remind you that we recently started our summer fundraiser, and need your help to reach our goal of raising $200000. Every dollar that you donate will be matched. Unlike practically all other news outlets, we do not accept support from governments or corporations. Please do what you can today.