Climate models

Heat dome burning through climate models | Other voices


The insanely high temperatures of the past week in the northwestern United States and Canada were – and are – very frightening. The heat and the fires it caused killed hundreds of people and are believed to have killed a billion sea creatures. Daily temperature records have been broken by more than 5C (9F) in some places. In Lytton, British Columbia, the heat reached 49.6 ° C (121 ° F). The forest fires that consumed the city produced their own thunderstorms, as well as thousands of lightning strikes.

An early study shows that human activity has made this thermal dome – in which a high-pressure ridge acts as a cover preventing hot air from escaping – at least 150 times more likely. The World Weather Attribution Group of scientists, which uses computer climate models to assess global heating trends and extreme weather conditions, warned that last week had passed even their worst-case scenarios. While it has long been recognized that the climate system has thresholds or tipping points beyond which humans risk losing control of what happens, scientists have not hidden their concern that ‘a generally cold part of the Pacific Northwest had been turned into a furnace. A climatologist said that the prospect opened by the thermal dome “takes my breath away.”

The worrying signs of climate change are not limited to North America. Pakistan and Siberia have also seen record temperatures in recent weeks, as have Moscow, Helsinki and Estonia. In Madagascar, the worst drought in 40 years has left a million people facing food shortages. Climate author David Wallace-Wells suggested that current conditions should be seen as harbingers of a “permanent emergency.” As policymakers struggle to absorb the very serious implications for human societies of current models, it is frankly difficult to accept the suggestion that these models may underestimate the threat. The prospect of the jet stream locking up and weather systems such as tropical storms stop moving in the way we’re used to, carries nightmarish possibilities. Warmer weather is on its way to California, with most of the wildfire season ahead.

If there is anything positive to be learned from this new information and reports of the suffering and destruction caused by the heat, perhaps it is that it is stepping up the pressure on policymakers to take action. . The Switzerland-based Financial Stability Board issued a warning on Wednesday ahead of a G20 meeting in Venice this weekend. He urged finance ministers and central banks to take more account of “far-reaching” climate impacts. The magnitude of these impacts will depend on decisions taken by governments over the coming months and years. So far, the binding commitments to reduce carbon emissions needed to avoid temperature rises above 2 ° C stand out in their absence. With every worrying news about the climate, the stakes ahead of the November Cop26 conference keep growing.

Environmentalists used to shake their heads when very unusual weather conditions were reported in terms that ignored the contribution of climate change. Now, thanks to the science of attribution, the connection is firmly established. To avoid future thermal domes, countries like the United States and Canada must stop pumping so much energy into the climate system.


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