Desertification from 1950s onward

More arid climate types raises questions about future food production

A new study in Nature shows how the world’s dry and semi-arid climate regions have expanded since 1950, mainly due to human-induced climate change. This expansion of dry regions fits with basic climate predictions. But that the trend is so broadly observable is very worrying, especially for the future of agriculture.

In “Significant anthropogenic-induced changes of climate classes since 1950” Chan and Wu (2015) found that 5.7% of the global total land area has shifted toward warmer and drier climate types, and that this cannot be explained as natural variations. Worst impacted are highly populated mid-latitude continental climates and polar regions. According to the study, rising temperatures and decreasing precipitation both played a big role in semi-arid expansion in Asia and North America, while lack of precipitation played a bigger role in semi-arid climates in North Africa, South Africa och South America. The map below shows the globe broken down by climate types.

World Köppen-Geiger map, climate type B is expanding while E is shrinking.
Modified version. Source: University of Melbourne (CC BY-SA 3.0)

While semi-arid and arid regions (B) expand, extra heat in the polar regions (E) goes into thawing carbon rich frozen tundra, permafrost, with potential amplifying feedback's on climate. Even if climate predictions indeed foresaw some of this change I think many are still surprised how little global average temperature would have to increase to lead to such a massive change. Imagine how 2-3℃ would look like if “only” +0.85℃ warming (global average temperature) has lead to this!! Just look at the situation in the Middle East, with millions of refugees, lack of fresh water in almost every country that has over pumped their ground water to grow wheat in the desert for a growing population. Its insane.


Out of the ashes into the fire

0 kommentarer: