Seite - 16 - in options, Band summer 2020

Adecade ago, three of the world’s great wheat-growing regions were struck, in the same year, by separate weather disasters. Russia endured a heatwave that affected over a third of its cultivable land. Harvest rains reduced Canada’s wheat quality to that of animal feed. In Western Australia, intense drought shrank wheat production. Normally, regions buffer each other. But this time, multiple failures led to export bans. Prices spiked. Hunger, a disaster in itself, can have knock-on effects such as political unrest and migration. It would therefore be useful to know whether, as climate changes, extreme weather will increasingly affect multiple places at once. IIASA researcher Franziska Gaupp has shown that this is already happening. Gaupp’s research is part of a growing body of IIASA research that can help policymakers and communities take the right action in response to climate change as it gathers pace, increasingly puts pressure on systems, and threatens survival. Gaupp gathered rainfall, temperature, and solar radiation data going back to 1967, as well as soy, maize, wheat, and rice yield data for the major agricultural breadbaskets of the world. She found that the likelihood of the weather being bad enough to impact crop yields in more than one place has increased over time. For example, the chance that wheat crops would fail simultaneously in the breadbaskets she had chosen was 0.3% before 1990 and 1.2% afterwards; while the chance of wheat failing in three or four breadbaskets in the same year rose by 16%. It wasn’t all bad news, however. Simultaneous outbreaks of extra solar radiation boosted rice harvests around the world between the two periods, reducing the chances of multiple failures from 21% to 12%. This trend is likely to continue. Gaupp modeled the chances of simultaneous failures under global temperature rises of 1.5°C and 2°C. A cap at 1.5°C reduced the risk of multiple failures by about a quarter for each crop. Gaupp says the work should help governments and businesses identify risks and refine contingency plans. “Climate has an impact on yields, and then this impacts prices; prices can have policy implications like trade bans or a change in policy towards crop storage, while huge price spikes can become a humanitarian crisis,” she says. The impacts of climate change can’t always be expressed in economic terms, but one advantage of assessing the financial impact is that it helps determine whether it is cheaper to cut emissions and take adaptive measures – or to do nothing, and just absorb the cost of the damage. EXPLORING THE ECONOMICS OF CLIMATE CHANGE Climate change not only poses a threat to the planet and to people, it is also affecting economic stability. IIASA researchers are investigating how this can be addressed and what it will cost. 16 Options Summer 2020 www.iiasa.ac.at