Questions about Climate Change, Agriculture and Food Security

For an "Environment and Society Class" a student from UNC Chapel Hill interviews me, via email, on potential impacts climate change on food security. Here are her questions (in italic) and my answers:

What do you think the biggest climate change-induced threat to agriculture is for the future of food security?

This is a good question and one I think about a lot. Climate change poses many potential threats to food security. Many and perhaps most of these threats may well be resolved in one way or another, but it’s hard to tell. At this point in time, I have a hard time ranking the threats. But here are the ones I think about most:
  • Agronomically, the regions likely to be hardest hit from climate changes are countries in the tropic and sub-tropic regions of the world. These regions are also where most very poor countries reside. This is bad news and poses a big potential threat.
  • It is very important to remember that we live in a global world and food prices are connected. So poor countries in tropical and subtropical regions will be affected strongly by impacts in richer countries with more temperate climates and more robust agricultural production. This means climate change impacts in countries like the U.S., the world’s largest producer, are also very important. Indeed, I would argue that one should focus first on the world’s potential production under climate change rather than how production impacts align with countries’ current wealth or food security. Now, and even more so in the future, food will spread around the globe via trade. It is the aggregate sum of impacts that matters most, in my view.
  • My own research with Wolfram Schlenker suggests climate change impacts on the U.S. could be much more severe than previously believed. This web page includes another paper that explains why we believe some earlier results were misleading, links to some other papers, and a lot of data.
  • Despite the first and third bullets, the global impacts of climate change remain unclear. I would guess that Northern Europe, Ukraine, Northern China, Canada, and perhaps other parts of the world, will gain tremendously from warming. And scientists might develop more drought/heat resistant crops.
  • Undoubtedly, the face of agriculture will change dramatically as the planet warms. We will grow different things in different places. I think trade is going to be essential. In light of these changes, a large potential threat is political instability. In the future, like the past, severe food shortages, malnutrition, and starvation will likely stem from political obstacles that prevent trade and delivery of food aid.
  • If it turns out that climate change will be have a large negative impact on food production globally (which remains uncertain), a key obstacle to food security could be severe income inequality. Even with sharp declines in food production, there will be enough to feed the world if we choose to eat different things, and in particular, less meat. It takes 5-10 calories of grass and grains to make one calorie of meat. So if we were to consume more plants and less meat, there would almost surely be enough food for everyone. I believe this kind of adjustment would happen naturally through a market system if income inequality were not so high. As grain calories become scarcer, price would rise, meat prices would rise even more, and we’d all substitute toward a more sustainable more plant-based diet (healthier too, it seems). But incomes are very unequal. So unequal that if the price of grains triples, this pushes many of those living on less that $2/day (about half the world) into severe malnutrition. At the same time, the price of a Big Mac would go up very little, in relative terms, maybe 0.25 cents. This won’t cause much substitution of corn meal for beef by relatively rich consumers in the United States. So, good global development policy is probably good climate change policy. It surely would make adjustment to warmer temperatures a lot easier.
Do you believe that those with the least food security (particularly in lower latitudes) will suffer disproportionately from the negative impact of climate change on agriculture? Why or why not?

Yes, they probably will. I think this has more to do with the fact that they are poor than the fact that the poor tend to live in regions of the world that will likely be adversely effected by climate change, but both matter.

Do you think that GMOs and hybrid crops are the best way to counteract the increasing occurrence of droughts, floods, etc.? What are some alternatives?

I think the easiest way to adapt to climate change is to simply change the locations and seasons where and when crops are grown. GMOs may help. But I think there is a lot of uncertainty about GMOs at this point. I’ll believe it when I see hard data. So far we just have lofty promises. I believe technological changes can be amazing. But it also seems those innovations tend to be in places we don’t always expect.

I believe the greatest potential for GMOs is for poorer developing countries. In a nutshell, GMOs can make it a lot easier to grow a high-yield crop. This means less-educated farmers with fewer skills or access to key inputs can grow a crop more like those in richer countries. This has been proven. Unfortunately, there is less incentive for seed companies to market to poorer countries. That might change.

How will declining agricultural productivity in the tropics affect the development of countries such as India and China?

It’s hard to say. India and China are huge success stories (or at least were before the current crisis). I would think there is a lot of potential in these countries, but they will likely face their own challenges with climate change. I guess I’d say India and China are the greatest hopes and the greatest uncertainties. I should also say I have a lot more to learn about these countries, both economically and agronomically speaking.

How will shortened growing seasons in the tropics and lengthened growing seasons in higher latitudes change political relations between developing and developed nations in terms of access to water and food?

I’m bad with politics, but your question underscores my point above: trade and political stability are currently essential and will be even more important in the future and with climate change. Income equality probably has a lot to do with political stability.

I’ll repeat: Whatever makes for good development policy is probably good climate-change policy. I’m not sure what good development policy may be—it’s difficult and controversial subject with widely varying points of view.

What policies could we implement or change to help reduce the negative impact that climate change has had on water supply?

This sounds like a local issue, and one not necessarily tied to climate change, since you use the words “has had”. Up to this point, outside of the arctic regions, it’s hard to say which droughts are due to human-induced climate change and which would have happened anyway. Let’s just say projected changes are much bigger than anything seen yet.

Population growth puts natural strain on water resources too. So, if you're thinking about local water issues in North Carolina, well this is a very different can of worms. Water policy gets complicated quickly and really depends on the location. I come from California where things are probably much worse and more complicated legally and politically than they are here in North Carolina.

While it’s easier said than done, I would say that, in general, it is important to have water policies that work toward pricing water appropriately. In a drought, or if water becomes generally more scarce, water should have a very high price, for residences, businesses and for farmers. And that price should be the same for all users. Usually that’s not the way things are done. For many, the price is literally zero. Pricing water appropriately is difficult to do given the way surface water rights have been historically allotted and the fact that groundwater extractions are not typically monitored or priced.


  1. Yes, over one generation or maybe two at present AGW velocity (though assuming no positive feedbacks seems foolish esp given melting Arctic), grain yields *might* increase. Any longer than that and basic stuff like melting glaciers and coastal farms flooded necessitates extreme improvements in a wide variety of food infrastructures just to breakeven.


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