Maize, rice, wheat: alarm at rising climate risk to vital crops – in Utah, yields could fall to 10%

By James Ayre, Clean Technica, July 19th, 2017 

Agricultural yields in certain “hot spots” within the US will be severely diminished by 2050 as a result of the impact that climate change will have on water availability and irrigation, according to a new study from MIT.

The hot spots in question are, unsurprisingly, mostly within the Southwestern US, where agriculture and ranching are already highly dependent upon unsustainable groundwater extraction rates.

To put a specific figure to that assertion: the study predicts that reduced precipitation levels in the region will result in cotton yields there falling to less than 10% of the crop yield that’s expected under optimal irrigation conditions.

Also, Utah’s maize yields — which are already only around 40% the optimal expected yield — are predicted to fall to around 10% of the optimal expected yield by the middle of the century.

The press release provides more: “In the Northwest, water shortages to the Great Basin region will lead to large reductions in irrigated forage, such as hay, grasses, and other crops grown to feed live stock. In contrast, the researchers predict a decrease in water stress for irrigation in the the southern Plains, which will lead to greater yields of irrigated sorghum and soybean.

“In predicting how climate will affect irrigated crop yields in the future, the researchers also consider factors such as population and economic growth, as well as competing demands for water from various socioeconomic sectors, which are themselves projected to change as the climate warms. … To do this, the researchers used a model of 99 major river basins in the country, which they combined with the MIT Integrated Global System Model-Community Atmosphere Model — a set of models that simulates the evolution of economic, demographic, trade, and technological processes.”

The study reiterates a point that many in the climate research sector have made in recent years: the Southwestern US, along with the mountain states, will be facing increasingly bad conditions as time goes by. This will lead directly to mass migrations out of the regions in question, to other already overpopulated parts of the country. Mass migrations out of coastal regions will add to this social disaster, as will falling agricultural yields themselves.

The new findings are detailed in a paper published in the journal Earth’s Future.

By Robin McKie, The Guardian, 15 July 2017 

Simultaneous harvest failures in key regions would bring global famine, says the Met Office.

A villager lifts up fallen corn plants after a flood at a farm in Jianhe county, Guizhou province, China in July 2017.
A villager lifts up fallen corn plants after a flood at a farm in Jianhe county, Guizhou province, China in July 2017. Photograph: Reuters

The newly published research, by Met Office scientists, used advanced climate modelling to show that extreme weather events could devastate food production if they occurred in several key areas at the same time. Such an outcome could trigger widespread famine.

The scientists, led by Chris Kent, of the Met Office, focused their initial efforts on how extreme weather would affect maize, one of the world’s most widely grown crops. Heat and drought were the prime risks, although flooding was also included in the analysis.

“The impact would be felt at a global scale,” Kent told the Observer. “This is the first time we have been able to quantify the risk. It hasn’t been observed in the last 30 years, but the indications are that it is possible in the current climate.”

An example of the kind of disaster that could occur is provided by the maize harvests that failed last year in Africa. Communities in Zambia, Congo, Zimbabwe, Mozambique and Madagascar were affected and six million people were left on the brink of starvation. A joint failure of China and America’s maize harvest would have a far greater impact.

Drought-damaged corn stalks at a farm in Missouri Valley, Iowa.
Having studied the risks facing maize production, the group is now following up this work by studying climate impacts on the world’s other staple crops – in particular rice, wheat and soya beans – in order to assess how weather extremes could affect their production.

According to the UN Food and Agriculture Organisation, maize, rice and wheat together make up 51% of the world’s calorie intake. Billions of people rely on these crops for survival. Any  disruption to their production would have calamitous consequences.

The trouble is that crop-growing methods and locations have changed considerably over time, as has the climate and the probability of extreme events, Kent told the Observer. “This means the number of relevant observations to the present-day growing of stable crops has been reduced, and that limits our ability to have useful estimates of the risks to the growing of these crops.”

To get round this problem, the team ran 1,400 climate model simulations on the Met Office’s new supercomputer to understand how climate might vary in the next few years and found that the probability of severe drought was higher than if estimated solely from past observations. The scientists concluded that current agricultural policies could considerably underestimate the true risk of climate-related shocks to maize growing and food supply.

A double whammy like this has never happened in the past, but the work by the Met Office indicates that there is now a real risk. In addition, there may be risks of similar events affecting rice, wheat or soya harvests. These are now being studied by the Met Office, which is also working with researchers in China in a bid to understand climate risks that might affect agricultural production.

“We have found that we are not as resilient as we thought when it comes to crop growing,” said Kirsty Lewis, science manager for the Met Office’s climate security team. “We have to understand the risks we face or there is a real danger we could get caught out. For now we don’t have the means to quantity the risks. We have to put that right.”