A record-breaking heat wave hit the western US and Canada in late June. (file)
Washington:
The record-breaking heat wave in the western United States and Canada in late June would have been “nearly impossible” without human-caused climate change, according to an analysis by a group of leading climate scientists.
The World Weather Attribution Group said global warming due to greenhouse gas emissions has made a heat wave at least 150 times more likely.
Temperatures broke by several degrees in the Pacific Northwest regions of both countries, including the Canadian record of 49.6 °C in the village of Litton, which was later destroyed in wildfires.
“There is no doubt that climate change has played an important role here,” said Friedrich Otto, a climatologist at the University of Oxford, during a press conference discussing the findings.
To test whether climate change played a role, scientists used historical observations and computer simulations to compare the climate to today, after about 1.2 °C (2.2 °F) of global warming since the late 1800s. analysed, with past climate .
They found that the observations were so extreme that they were far beyond the range of temperatures observed historically. But looking at today’s environment, it was estimated that this event could happen once in a thousand years.
Looking to the future, if the planet warmed by two degrees Celsius (3.6 degrees Fahrenheit) – which at current rates could happen as early as the 2040s – such heat waves would occur every five to ten years in and around are one degree Celsius (1.8 degrees Fahrenheit) hotter.
two principles
The heat wave meant North America had the hottest June on record last month, according to data released by the European Union’s climate monitoring service on Wednesday.
The death toll is not yet known, but is believed to be in the hundreds.
The researchers suggested two broad explanations of how climate change further increased the likelihood of a hot summer.
The first was that, while climate change made the event more likely, it remains an extreme outlier.
In this explanation, a pre-existing drought that deprived the region of evaporative cooling, together with a slow-moving high-pressure system in the atmosphere called the “heat dome”, was supercharged by climate change.
According to this theory, without the effects of climate change, the maximum temperature would have been about 2 °C (3.6 °F) lower.
The second hypothesis is more frightening: that the climate system has crossed a threshold where a small amount of overall global warming is now leading to a faster increase in extreme temperatures than has been observed so far.
“Everybody is really concerned about the effects of these events because it’s something that no one has seen that no one thought possible,” said co-author Geert Jan van Oldenborg from the Royal Netherlands Meteorological Institute.
“We don’t perceive heat waves as we thought,” he said, adding that this could mean those in other high-latitude locations such as northern Europe, the rest of the Americas, China, and Such a temperature is also possible. Japan.
This meant that adaptation plans needed to be designed for temperatures above the range seen in the past, the team warned.
(Except for the title, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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