The study was published as a cover story on Science Advances. The source of image: Science Advances

Is it possible that the global major grain producing areas have been hit badly at the same time? Your answer must be “That’s impossible”. Since “God closes a door, will open a window”, people always have bread to eat.

In the past few decades, the international food trade is constantly booming in the global grain and agriculture system. According to the statistics, the fraction of food produced for human consumption that is traded internationally rose from 15% in 1986 to 23% in 2009. Almost everyone agrees that the global major grain producing areas which are geographically distant from each other, such as the United States, China, and Argentina, will not suffer crop failures at the same time.

However, according to a new research by International Research Institute for Climate and Society (IRICS), Columbia University, USA, International Food Policy Research Institute (IFPRI) and Huazhong Agricultural University (HZAU), the climate events like El Niño Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) might result in synchronous crop failures worldwide, which broke our stereotypes. Recently, the relevant academic achievement has been published on Science Advances as a cover story.

Climate variability intensifies grain supply variability

Stable grain supply is a major issue of food security.

“Food supply is both a global and a local issue.” Weston Anderson, the postdoctoral researcher of IRICS, Columbia University and the first author of the paper, told China Science Daily about the research motivation. “With global climate change, the food system will attract more and more attention.”

This is a fact. In recent years, with the growing global grain trade, the global food supply system has been gradually established, and more and more countries rely on food import.

“One major characteristic of current global food system is the highly concentration of exporting countries.” Xie Wei, the researcher at the School of Advanced Agricultural Sciences and China Center for Agricultural Policy of Peking University, told China Science Daily.

Therefore, the stability of regional grain supply depends not only on local production and consumption. In fact, food supply in many places depends on the global market.

“In order to understand how local food supplies are changing, we really need to take a close look at global food production.” Anderson believes that the stability of the global agricultural system depends on a great possibility that low yields in one part of the world will be compensated by high yields in other regions.

Up till now, it has been believed that a series of occasional and catastrophic climate events will lead to severe crop failures. “People used to only focus on the impact of climate disasters on food production in their own country, but now, the concentration of exporting countries will expand the risk to the whole world.” Xie Wei said. You Liangzhi, One of the authors of the paper, the Senior Researcher of IFPRI and the Joint Dean of Macro Agriculture Research Institute (MARI), HZAU, said “It is possible that the global major food producing areas will be destroyed at the same time. Although this possibility is rather low under the current climate conditions and the major grain areas are isolated, if we do not take action, they will be more and more commonly related to climate phenomena.”

In the past, many studies showed that climate variability has an impact on crop yield in major crop producing areas. For example, El Niño is associated with low crop yields, but it is not clear how severe crop failures are caused by climate modes compared to other factors.

“It is crucial to understand the severity of climate variability compared to other factors, because people need to decide how to allocate the limited resources more effectively to prevent crop failure.” Anderson said. One way to avoid synchronous crop failures is to know the causes of crop failures and try to predict these possible events.

How is the impact of climate variability?

The climate change on a global scale has led to more frequent extreme events such as floods, droughts and high temperatures, which have changed the crop yield, quality and distribution of diseases and pests, making the global food crisis constantly approaching.

The researchers examined the effects of ENSO, Indian Ocean Dipole (IOD) and common climate fluctuations on global corn, soybean and wheat yields. They analyzed how the climate variability affected drought and heat conditions in major planting areas.

The results show that the ENSO, IOD and NAO have effects in at least one research area, but only ENSO has significant impact on global food production.

Among them, the ENSO in 1983 was the most significant climate phenomenon that can lead to the global synchronous crop failure.

The researchers employ national and regional crop yield data from 1980 to 2010 to estimate how climate modes affect crop yield variability during that period. For example, climate modes account for 18% of variability of global maize production but only 7 and 6% of variability of global soybean and wheat production. The risk of synchronous failure of soybean and wheat is low. The climate change is likely to have a greater impact on agriculture in some areas. In most parts of Africa and northeast Brazil, climate variability accounts for 40% - 65% of crop yield variability. In other regions, it is as low as 10%.

Anderson explains that by linking how the known predictable climate modes affect high temperatures and droughts with the observed crop yield declines, it is possible to understand not only the extent to which climate patterns affect crop yields, but also how they affect them. Of course, climate modes are only one of the factors that affect crop yields.

In addition, the study shows that seasonal forecast is an effective tool to stabilize food production, and the possibility of reducing climate risk can be achieved through seasonal prediction.

“We found that predictable climate change modes would affect the local crop yields and these impacts have a significant influence on a global scale, particularly for maize. These results highlight the importance of seasonal forecasting as a tool to improve food security. In particular, we know about the El Niño and La Niña phenomena, and their impacts on the climate of the growing season are predictable.” Anderson said.

Eliminating barriers and cooperation is the fundamental principle

Experts interviewed said that the global cooperation was an effective way to maintain the stability of the global food supply system.

“To eliminate trade barriers, promote global agricultural integration, and continue to support China’s agriculture going global.” Xie Wei said.

You Liangzhi has been deeply engaged in agricultural development in Africa for a long time. He suggests that it is necessary to strengthen scientific and technological innovation, improve food reserves, promote food diversification, and it is also necessary to focus on poverty and inequality.

Global Report on food crises 2017 by UN highlights that it is essential to strengthen cooperation between humanitarian, development and peace practitioners in order to reverse and prevent the food crisis. Strengthening the construction of a global network to food crisis will benefit the people in real need.

You Liangzhi said, “The most affected areas are the poor areas, whose livelihood depends on crop production, while their contribution to climate change is the least. This risk is further exacerbated by the challenges posed by the lack of infrastructure and resources.”

“Now it’s just a phenomenon. We hope to figure out the role of food trade and the impact of centennial climate phenomenon on global food, so as to put forward the effective countermeasures.” You Liangzhi said.

The paper related information: http://doi.org/10.1126/sciadv.aaw1976

China Science Daily (Agricultural science and technology, 5th Edition, July 23, 2019)

The source: http://news.sciencenet.cn/sbhtmlnews/2019/7/348016.shtm?from=singlemessage&isappinstalled=0

Written by Lidong Zhao