Drylands face 4°C warming under Paris Agreement goal

Millet producer: third-world nations with extensive drylands will likely be hardest hit by global warming, says a new Chinese-US study.
Millet producer: third-world nations with extensive drylands will likely be hardest hit by global warming, says a new Chinese-US study.
The Paris Agreement’s goal of limiting average global warming to less than two degrees Celsius is insufficient to protect the world’s drylands, a new study says.

The study, published online in Nature Climate Change on 24 April 2017, also suggests that reducing the global warming target to 1.5 degrees Celsius is beneficial to both drylands and humid regions.

These findings are important for Asia-Pacific, a region with both dry and humid lands. The regions surrounding the Thar desert in western India are dry, while the north-east is among the wettest areas in the world. The South-East Asian countries are extremely humid.

Drylands cover 41 percent of earth’s surface area. Low soil moisture content, sparse vegetation cover and thin clouds enhance surface warming in these regions defined by scanty rainfall. Over the past century, surface warming over drylands has been 20-40 percent higher than [that over] humid lands, and the trend is increasing.

By simulating conditions under two degrees Celsius of mean global warming, the researchers, from China and the US, found that the drylands would get hotter by 3.2-4 degrees Celsius compared to pre-industrial era temperature, while humid temperatures in humid areas would increase by 2.4 – 2.6 degrees Celsius.

Despite emitting significantly less greenhouse gases, drylands will end up receiving the brunt of human-induced climate change. The consequences [would likely] be disastrous, as drylands are home to more than two billion people, 90 percent of whom live in developing countries. It is probable that the resulting temperature increase would result in reduced maize yields and longer droughts, and create climatic conditions conducive to malaria transmission.

Moreover, countries with drylands do not get enough consideration in global climate dialogues like the Paris Agreement.

“Most of the countries with drylands are developing countries with poor representation,” says Jianping Huang, director and chief scientist at the Key Laboratory for Semi-Arid Climate Change in China, who conceived the study.

He believes that reducing the warming target to 1.5 degrees Celsius could reduce the burden on drylands and benefit humid countries as well

Shalander Kumar, principal scientist at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in India, says that the study gives a better understanding of regional contributions and impacts of climate change on humid and dryland regions.

Kumar, however, says crop yield variation is much more complex. “Changes in rainfall distribution are likely to affect crop yields significantly while the increased levels of carbon dioxide may have a positive impact on crop yields.”

This article was produced by SciDev.Net’s Asia & Pacific desk and published on SciDev.Net on 15 March 2017. It is republished here courtesy of SciDev.Net’s Creative Commons license.


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