Science clear on heat dome
Last week’s shockingly high temperatures in the northwestern US and Canada were — and are — frightening. Heat and the fires it caused killed hundreds of people, and are estimated to have killed a billion sea creatures. Daily temperature records were smashed by more than 9 degrees Farenheit in some places. In Lytton, British Columbia, the heat reached 121F. The wildfires that consumed the town produced their own thunderstorms, alongside thousands of lightning strikes.
An initial study shows human activity made this heat dome — in which a ridge of high pressure acts as a lid preventing warm air from escaping –at least 150 times more likely. The World Weather Attribution Group of scientists, who use computer climate models to assess global heating trends and extreme weather, have warned that last week exceeded even their worst-case scenarios. While it has long been recognised that the climate system has tipping points beyond which humans stand to lose control of what happens, scientists did not hide their alarm that an usually cool part of the Pacific northwest had been turned into a furnace.
The disturbing signs of climate disruption are not limited to North America. Pakistan and Siberia have also had record-breaking high temperatures within the last few weeks, as have Moscow, Helsinki and Estonia. In Madagascar, the worst drought in 40 years has left a million people facing food shortages. The climate author David Wallace-Wells suggested that current conditions should be regarded as heralding a “permanent emergencyî.” With policymakers struggling to absorb the very serious implications for human societies of current models, it is frankly difficult to take in the suggestion that these models may underestimate the threat. The prospect of the jet stream becoming locked, and weather systems such as tropical storms ceasing to move in the way to which we are accustomed, carries nightmarish possibilities.
If there is anything positive to be taken from this new information, and reports of the suffering and destruction caused by the heat, it can only be that it intensifies the pressure on policymakers to act. Last week, the Switzerland-based Financial Stability Board issued a warning in advance of a G20 meeting in Venice. It urged finance ministers and central banks to take more notice of “far-reachingî climate impacts. Just how far-reaching these impacts will be depends on decisions taken by governments in the next months and years. So far, binding commitments to make the cuts in carbon emissions that are needed to avoid temperature rises above 2C are notable by their absence. With every worrying piece of climate news, the stakes keep growing.
To avoid future heat domes, countries including the US and Canada must stop pumping so much energy into the climate system.
* Editorial from the Guardian