Half of world's population could face climate-induced food crisis by 2100

Jan 08, 2009

Rapidly warming climate is likely to seriously alter crop yields in the tropics and subtropics by the end of this century and, without adaptation, will leave half the world's population facing serious food shortages, new research shows.

To compound matters, the population of this equatorial belt - from about 35 degrees north latitude to 35 degrees south latitude - is among the poorest on Earth and is growing faster than anywhere else.

"The stresses on global food production from temperature alone are going to be huge, and that doesn't take into account water supplies stressed by the higher temperatures," said David Battisti, a University of Washington atmospheric sciences professor.

Battisti is lead author of the study in the Jan. 9 edition of Science. He collaborated with Rosamond Naylor, director of Stanford University's Program on Food Security and the Environment, to examine the impact of climate change on the world's food security.

"This is a compelling reason for us to invest in adaptation, because it is clear that this is the direction we are going in terms of temperature and it will take decades to develop new food crop varieties that can better withstand a warmer climate," Naylor said.

"We are taking the worst of what we've seen historically and saying that in the future it is going to be a lot worse unless there is some kind of adaptation."

By combining direct observations with data from 23 global climate models that contributed to Nobel prize-winning research in 2007, Battisti and Naylor determined there is greater than a 90 percent probability that by 2100 the lowest growing-season temperatures in the tropics and subtropics will be higher than any temperatures recorded there to date.

They used the data as a filter to view historic instances of severe food insecurity, and concluded such instances are likely to become more commonplace. Those include severe episodes in France in 2003 and the Ukraine in 1972. In the case of the Ukraine, a near-record heat wave reduced wheat yields and contributed to disruptions in the global cereal market that lasted two years.

"I think what startled me the most is that when we looked at our historic examples there were ways to address the problem within a given year. People could always turn somewhere else to find food," Naylor said. "But in the future there's not going to be any place to turn unless we rethink our food supplies."

The serious climate issues won't be limited to the tropics, the scientists conclude. As an example, they cite record temperatures that struck Western Europe in June, July and August of 2003, killing an estimated 52,000 people. The summer-long heat wave in France and Italy cut wheat yields and fodder production by one-third. In France alone, temperatures were nearly 6.5 degrees Fahrenheit above the long-term mean, and the scientists say such temperatures could be normal for France by 2100.

In the tropics, the higher temperatures can be expected to cut yields of the primary food crops, maize and rice, by 20 to 40 percent, the researchers said. But rising temperatures also are likely to play havoc with soil moisture, cutting yields even further.

"We have to be rethinking agriculture systems as a whole, not only thinking about new varieties but also recognizing that many people will just move out of agriculture, and even move from the lands where they live now," Naylor said.

Currently 3 billion people live in the tropics and subtropics, and their number is expected to nearly double by the end of the century. The area stretches from the southern United States to northern Argentina and southern Brazil, from northern India and southern China to southern Australia and all of Africa.

The scientists said that many who now live in these areas subsist on less than $2 a day and depend largely on agriculture for their livelihoods.

"When all the signs point in the same direction, and in this case it's a bad direction, you pretty much know what's going to happen," Battisti said. "You are talking about hundreds of millions of additional people looking for food because they won't be able to find it where they find it now."

He said wheat makes up one-quarter of the calories consumed in India, but growth in wheat yields there have been stagnant for the last decade.

Temperature increases from climate change are expected to be less in equatorial regions than at higher latitudes, but because average temperatures in the tropics today are much higher than at midlatitudes, rising temperature will have a greater impact on crop yields in the tropics.

Recent UW research has shown that even with much smaller temperature increases in the tropics, the impacts of warmer climate will be greater there because life in the tropics does not encounter much temperature variation and so is less adaptable. That makes an even stronger case to begin now searching for ways to deal with substantially warmer conditions, Battisti said.

"You can let it happen and painfully adapt, or you can plan for it," he said. "You also could mitigate it and not let it happen in the first place, but we're not doing a very good job of that."

Source: University of Washington

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User comments : 13

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3.4 / 5 (5) Jan 08, 2009
I wonder if this takes into account the greening of North Africa due to increased rainfall as predicted by the current models.
2 / 5 (5) Jan 08, 2009
lets see that greening first
3.4 / 5 (5) Jan 08, 2009
lets see that greening first

Then let's see the rainfall.
4 / 5 (3) Jan 08, 2009
increased vegetation cover is already being observed in the northern latitudes. The planet has frequently dealt with climate change and will undoubtedly recover in due time. The transition period is however a cause for some concern. The research in this article is trying to anticipate the nature of these changes. To simply ignore this potential threat would be reckless and by paying attention to it we only invoke the ire of those entrenched few who shout "alarmist" at anything they don't like the sound of. Lets face it, they're pissed off anyway :-)
3 / 5 (6) Jan 08, 2009
The Earth is COOLING, and has been for a while now. Ironically, continued cooling would be much worse than warming for food production. It's just as well that the increased CO2 levels will help to offset this by increasing plant growth (this has already been observed).
4 / 5 (1) Jan 08, 2009
Couldn't the higher amount of warming in Canada and Russia and their increased output make up for it? (Maybe?)

Also, we're talking about 100 years into the future, I'm pretty sure that it'll balance itself out given a century. If this was in ten years there might be something to worry about, but given the amount of time over which the six degree increase takes place, assuming it does, the whole thing doesn't seem that worrisome.

Then again, I live in an area where growing crops would (assuming there is significant warming) be made easier, so I suppose that might explain my lack of alarm.
4 / 5 (5) Jan 09, 2009
Well one established fact that's agreed upon by both sides of the debate is that if there is warming at play that the effects will be seen at the coldest and driest points in the system. The same can be said for cooling.

Now during the real peak of AGW reporting and news there were multiple effects that were attributed to warming, for example ice sheet loss, sea ice loss, heavier precipitation at the poles, etc. All of which were seen and documented as well as expected by AGW theory. The issue I see is that some AGW theorists take these observations, which we have little recorded history of, and report exagerated consequences then tie the observations to elements of the climate system that are not well understood and attempt to create and enforce new policy. I'm a skeptic, but I do not dismiss all AGW theories and theorists offhand. We need more research and knowledge of the occurances and understanding of the system before we can take drastic measures that could have an immediate and detrimental effect on society.
3.7 / 5 (3) Jan 09, 2009
I believe that I can safely predict that half of the world's population will eat less than the median for the whole population.
5 / 5 (2) Jan 09, 2009
Rick69, that is a bold prediction, but nonetheless I agree.

I have already faced climate related food crises. Growing up in Ohio, we regularly faced long cold winters locked indoors. As a result we often packed on weight from eating for lack of better things to do. I call this Climate Weight Change. I used to call it Global Fattening, but that implied too many things that couldn't be proven.

This particular crisis had many dire consequences: Decreased motivation, increased napping, shortness of breath after climbing stairs, reduced reaction time, muscle deterioation, and increased cholesterol and blood pressure. Furthermore, when intimately involved with a woman suffering the same crisis, the additional effect of decreased sex drive was common.

I hope the governments of the world act swiftly and thoroughly to resolve this crisis. Probably some sort of tax would be the best solution.
2.3 / 5 (3) Jan 09, 2009
Ummm, I'll catch some flames for this I'm sure, and no I'm not a heartless bastard, but lets face it, its the excessive human population and its assault on climate damaging resources that is the very problem, the food shortages are simply the "cure"

Humans will not have to do anything to curb emissions as nature itself is going to mitigate human expansion the only question is, HOW SOON?

Have a nice weekend...

1 / 5 (3) Jan 09, 2009
To M_N:

As someone who has been around more than 15 years and traveled extensively I can tell you and skeptics like you straight up that the world is NOT COOLING its getting HOTTER and DRIER. I know this from personal experience and you can know it from the atmospheric data collected by many observational organizations.

The skeptics are afflicted with an unusual urge to believe that thousands of scientists around the world whose reputations are at stake have something to gain by being DEAD WRONG about this issue. The data which will be collected and the effects seen well within the tenure of their careers. That individuals like you exist is more mind boggling than belief in santa claus and the tooth fairy.

4.2 / 5 (5) Jan 09, 2009
To M_N:

As someone who has been around more than 15 years and traveled extensively I can tell you and skeptics like you straight up that the world is NOT COOLING its getting HOTTER and DRIER. I know this from personal experience and you can know it from the atmospheric data collected by many observational organizations.

The skeptics are afflicted with an unusual urge to believe that thousands of scientists around the world whose reputations are at stake have something to gain by being DEAD WRONG about this issue. The data which will be collected and the effects seen well within the tenure of their careers. That individuals like you exist is more mind boggling than belief in santa claus and the tooth fairy.

Cosmic, I'm sorry but your statement on the stance of skeptics is inaccurate and insulting. A scientist who creates a scare gains notoriety and in the case of funding, affluence and popularity through continuing the scare. They have everything to lose about being dead wrong which is why you see the very same scientists who cried alarm at global cooling in the 70's crying alarm at global warming now, even though it is completely contrary to their research two decades prior. For the sake of clarity, I am in no way saying that all AGW proponent scientists are involved in this.

To say that the skeptics of the AGW theory are baseless and uninformed is also inaccurate as many of the world's leading climatologists are involved in the debate and arguing against AGW.

Lawrence Solomon keeps a blog speaking about the many AGW skeptics he has interviewed in the course of his research.


5 / 5 (3) Jan 11, 2009
Oh please, why must people resort to scaremongering? Can we affect a reduction in solar flare activity? I think not! Case closed.

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