Global warming expected to boost wheat yields, but will also increase price volatility: study

SINGAPORE – Global warming is likely to boost crop yields in some countries, helped in part by higher levels of carbon dioxide (CO2), which increases plant growth and helps them become more efficient in the ‘use of water.

The results may look promising, given the current spike in food prices around the world.

But there’s a catch – despite higher yields, future spikes in world wheat prices are likely to get worse, according to a recent study by an international team of researchers.

They found that in high latitude regions such as the United States, northern China and parts of Australia, wheat yields will increase slightly overall in a 2°C warmer world than in pre-industrial times.

The study, led by Professor Zhang Tianyi, an agrometeorologist at the Institute of Atmospheric Physics of the Chinese Academy of Sciences in Beijing, focuses on what could happen to wheat production around the world, as well as prices world grain.

An agrometeorologist examines the relationship between weather and climate, crop and animal production, and soil management.

Professor Zhang’s team looked not only at expected wheat yields in a 2 degree Celsius world, but also at the impact of climate change on wheat prices and the global wheat market. For example, which countries would benefit from higher yields, and which countries would face lower yields and be more dependent on imports.

The team found that higher CO2 levels would lead to a 1.7% increase in global average yield under 2°C warming, compared to the current climate. Professor Zhang explained that this means higher grain production per hectare.

High temperatures hurt wheat yields, but higher CO2 levels can offset this, the authors said in the study published in the journal One Earth. Plants need CO2 as part of photosynthesis to make sugars. More CO2 tends to increase plant productivity, at least up to a point, they said.

But increases in global output do not necessarily translate into lower consumer prices, the authors found. Computer modeling results suggest that global wheat price spikes would become higher and more frequent. Indeed, wheat yields are expected to increase in high latitude wheat exporting countries, but decrease in low latitude wheat importing countries, such as India and parts of Africa, including Egypt.

This would lead to higher prices in importing countries.

Professor Zhang’s team found that a 2 degree Celsius world would lead to higher international demand for wheat and higher consumer prices in importing countries.

To calculate the results, the team divided the world into 51 socio-economic regions, including not only the major wheat-producing countries, but also the major exporting and importing countries in each continent.

Professor Zhang explained that the team ran complex computer models simulating a large number of wheat growing seasons that mimicked all combinations of climatic stresses under current climate conditions and for a 2 degree Celsius warmer climate.

Teresa H. Sadler