Increased rainfall and hot weather under rising emissions

A new study is warning that “wet-hot” conditions could be on the rise, with extreme heat and rainfall projected to increase. The forecasts might initially sound more enticing than drought, but these extremes can cause devastating disasters.

A study published in Earth’s Future has used modelling to predict that much of the world will see more frequent heatwaves and precipitation.

“These compound climate extremes have attracted considerable attention in recent decades due to their disproportionate pressures on the agricultural, industrial and ecosystems sectors – much more than individual extreme events alone,” says lead author Haijiang Wu, a researcher at China’s Northwest A&F University.

Specifically, the researchers warn that heatwaves can dry out soil and make it worse at absorbing water, meaning heavy rainfall is more likely to cause floods and crop failure.

As the atmosphere heats, it can hold more water in it, making more precipitation likely.

The researchers ran climate models under the  in the “Representative Concentration Pathway 8.5” (RCP8.5) scenario.

This scenario, developed by the Intergovernmental Panel on Climate Change, models global heating if emissions aren’t curbed at all. It’s consistent with a global average temperature rise of more than 4°C by 2100: Climate Action Tracker estimates the world is headed for under 3°C based on current policies and actions.

In their modelling, the researchers found that some regions (South Africa, the Amazon and parts of Europe) will get drier, but most places (including Australia, eastern and southern Africa, and central Africa) will get more precipitation.

The researchers point out that many of these extremes are likely to hit highly populated areas, and places that already produce much of the world’s food.

“Given the fact that the risk of compound wet-hot extremes in a warming climate is larger than compound dry-hot extremes, these wet-hot extremes should be included in risk management strategies,” says Wu.

“If we overlook the risk of compound wet-hot extremes and fail to take sufficient early warning, the impacts on water-food-energy security would be unimaginable.”

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