Record-breaking heatwaves seen across the world this summer are set to repeat themselves due to human-caused climate change - even if we reached net zero today.
The summer of 2022 has set thousands of new temperature records across the United States alone, according to data from the National Oceanic and Atmospheric Administration (NOAA).
The mechanisms(机制) behind these heatwaves may vary by region, but, as with the "heat dome (热穹顶)" that broke temperature records in the Pacific northwest in 2021, air pressure systems are key.
"Partly, it's the large-scale weather patterns, " said Craig Clements, professor at San José State University. "Here in the California Bay Area, we have this high pressure ridge(高压脊), which is a big buildup of air, and that air tends to be still. Thus, there's no sea breeze that usually cools off San Francisco, and that really is triggering the extensive heat. We can just continue to heat it with the sun's input because there's no cloud cover. "
It's natural for these air pressure systems to change over time. On the West coast of the U. S. , low pressure systems bring rain and cooler temperatures due to air from the north, with high pressure systems following behind.
However, Clements notes that these weather patterns are becoming more pronounced and lasting longer. They're also becoming less "natural".
"At this stage, the 'natural cycle' no longer applies." said Chris E. Forest, professor at Pennsylvania State University. "Across the globe, the likelihood of breaking weather extremes is directly related to the impact of climate change related to multiple causes, but primarily, increasing heat-trapping gases like CO2 and changes in landscape and landcover."
Brian Hoskins, professor at the University of Reading in the U. K. , echoed the point." We know of no natural cycles that would lead to such records, " he said. "I consider that it is virtually impossible that they would have happened without human-caused climate change."
In the long term, even if we got to net zero emissions today, it will take the next 30 to 50 years until we start to see 'stabilized' global temperatures and the future extremes will be worsened by each degree of warming.
