The world’s most ambitious climate target is under threat, both from physics and politics. But what would it mean for the planet and its inhabitants if humanity were to abandon the goal to limit global heating to 1.5C above preindustrial levels?

The inclusion of 1.5C (2.7F) was hailed as one of the great triumphs of the Paris climate agreement of 2015. Until then, international ambition had been limited to 2C (3.6F), much to the frustration of small island states and others on the frontline of climate disruption.

The lower target focused minds on the huge difference that half a degree makes, which was underlined by a special report three years later by the UN’s top science body, the Intergovernmental Panel on Climate Change (IPCC), which spelled out the growing risk of calamities beyond 1.5C and the urgent need to cut carbon emissions by almost half by 2030 to have any chance of preventing them.

The target was more a line in the sand than a cliff edge, but it is fast becoming a milestone on the road to climate perdition.

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Food, Water and Conflict

Drought, storms and flooding become more frequent and severe with each extra fraction of a degree of warming.

For example, the IPCC has calculated that an extreme heat event that would occur only once in a decade in a climate without human influence would happen 4.1 times a decade at 1.5C of warming, and 5.6 times at 2C.

Those worst affected are usually least to blame – the climate-vulnerable people living in countries with poor economies and weaker healthcare systems.

Seventy million more people in Africa are projected to suffer acute food security at 2C than 1.5C, according to Catherine Nakalembe, who heads the Africa programme of NASA Harvest.

At the lower temperature, she said, computer models indicate severe drought is 30% less likely than at 2C in southern Africa, while in west Africa yields of maize and sorghum could be 40% to 50% lower at 2C than 1.5C. Water scarcity would also affect 50% fewer people at the lower target.

With greater food insecurity comes an increased risk of conflict and a greater incentive to migrate. Even at current levels, disasters are striking different parts of the continent in rapid succession, such as the dire drought that brought misery to much of east Africa in 2019, or the cyclone – named Idai – that devastated southern Africa the same year.

“I’m afraid things are only getting worse. These events wipe out entire livelihoods and happen so frequently that there’s no time to recover,” said Nakalembe. “Every fraction of a degree matters because it can make a big difference in the severity of the impacts of climate change.”

Image: The Guardian