The probability of record-shattering heat waves is increasing due to climate change, according to scientists who are measuring temperature predictions in a new way.
Researchers that looked into rate of warming, rather than how much warming has occurred, found that record-shattering heat waves occur in spurts during periods of accelerated climate warming, according to a study published Monday in Nature Climate Change.
Similar events as the back-to-back heat waves that have been occurring in the Western U.S., including triple-digit temperatures in the typically cool and wet Pacific Northwest, will become the norm if climate changes continue as business as usual, Erich Fischer, a climate scientist at ETH Zurich and the author of the study, told ABC News.
Under a high-emissions scenario, record-shattering heat extremes are two to seven times more probable from 2021 to 2050 and three to 21 times more probable between 2051 and 2080, according to the scientists.
Even if human-induced global warming was stabilized by aggressive mitigation, the frequency and intensity of heat waves would still be higher, but the probability of record-shattering events would be "notably reduced," scientists said.
The models initially found climate records decreasing until temperatures began ramping up in the 1980s with a much higher rate of warming, Fischer said. It was then that scientists began seeing a sudden number of heat records as well as a "very high speed of pace" of records shattering temperature ceilings.
"Without climate change, we should expect these records to become rarer and rarer," Fischer said, comparing the current climate to "an athlete on steroids," adding, "If the world record would be broken by that by the high margin, that would be very suspicious."
While the impact of climate change on heat waves is typically quantified by historical context -- or how much a current or future event compares to itself in a world with less or no climate change -- the changes can be marginal when measured in such a manner, the researchers said. Any given heat wave today would be hotter and more frequent than it would have been in the past.
Instead, looking at how heat extremes surpass or "shatter" the previous heat wave record could provide better insight into the driving mechanisms behind heat extremes -- and offer a crucial factor for officials to consider when planning strategies on how to deal with the new normal, the researchers said.
"The take-home message of our study is that it really is no longer enough to just look at past records or past measurements of weather..." Fischer said. "We need to prepare for something different."