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Climate Change Putting a Damper on Global Food Production

Rising temperatures have taken a disproportionate toll on the food supplies of already-warm countries, far outpacing the declining growth found in the United States and Europe. And it may get worse.

(CN) --- Despite continuous technological advancements, global farming productivity has dropped an average of 21% since 1961 because of climate change. That’s like losing seven years of productivity gains in the last 60 years.

Higher temperatures, less water for irrigation and unpredictable weather patterns have slowed down agriculture around the world in recent decades. That’s a problem in Iowa but could spell disaster in places like Sudan and Mali, where nearly a third of productivity gains have been forfeited.

Climate change has hit agriculture in warmer regions like Africa, Latin America and the Caribbean particularly hard, with those areas seeing 26-34% declines in productivity. The United States has been less affected, with declines ranging from 5-15% --- but this trend is expected to worsen as temperatures continue to soar.

Continuous advances in farming technology are the only reason nearly 8 billion people can inhabit Earth today, but those advances have been unevenly distributed and regions that need them most have also seen the biggest effects of climate change. With the global population projected to increase to 10 billion by 2050, something has to give.

In an effort to calculate the damage, researchers from the University of Maryland collaborated with Cornell University researchers to quantify the human effects of climate change on agriculture in a study published Thursday in the journal Nature Climate Change. They say this new approach allowed them to compare productivity declines in the United States with those of other regions around the world.

"We find that anthropogenic climate change has already slowed down global agricultural productivity growth," said study author and Cornell University economist Ariel Ortiz-Bobea in an email. " What that means is that because of climate change we are able to produce less food than we would have been able to produce in a world without climate change and using the same inputs. The effect of the slowdown we document is about seven years of lost productivity growth over the past 60 years."

Quantifying agricultural productivity can be tricky for economists because not all factors affecting crop output are under the control of farmers, such as the weather and water for irrigation. That led the researchers to pioneer a new method of calculating productivity by incorporating historical weather data, which hadn’t previously been done. According to Ortiz-Bobea, the planet is already an average of 1.8% Fahrenheit warmer than it would be without atmospheric greenhouse gases, and it’s not slowing down.

Scientists and economists from both universities teamed up and developed a detailed model of the yearly changes in weather and productivity compared with climate models covering the last 60 years. That gave them a number economists call the “total factor productivity,” which can help quantify the toll climate change is taking on the agriculture sector.

"When a farmer makes an economic decision like what to plant in June, we won't necessarily know the outcome of that decision until six months later," co-author Robert Chambers, professor in Agriculture and Resource Economics at the University of Maryland said in a statement accompanying the study. "Productivity is essentially a calculation of your inputs compared to your outputs, and in most industries, the only way to get growth is with new inputs. Agricultural productivity measurement hasn't historically incorporated weather data, but we want to see the trends for these inputs that are out of the farmer's control."

Previous studies focused mainly on cereal crops, but those results are of limited value in assessing worldwide agricultural productivity as cereal crops only account for around 20% of global food production. The authors believe more research is needed on the impacts of climate change to non-staple crops --- which is where their total factor productivity measurement comes in.

"I think it is important for people to understand that climate change is not something only happening or affecting future generations. It already has happened. And we are in the middle of it. We are being affected and studies like this are trying to quantify this effect that is upon us,” Ortiz-Bobea said in the email.

“Importantly, R&D [research and development] takes many years to translate into higher productivity,” Ortiz-Bobea continued. “So all the R&D we do now will only have effects decades from now. So there is no time to lose to better prepare the global ag sector for a changing climate. Some countries are extremely ill prepared for this and industrialized nations need to realize that helping other countries meet this challenge is also in their best interest.”

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