A temperature of 54.4°C (130°F) was recorded in Death Valley, California, at 15:41 on Sunday 16 August. While the reading is still to be formally verified, it would probably set a record for the highest temperature ever recorded, with scientists linking the extreme heat with climate change.
The hottest temperature on record is often considered to be 56.7°C (134°F), set in July 1913 also in Death Valley, but that reading may be inaccurate. A detailed analysis in 2016 concluded that the reading was “essentially not possible from a meteorological perspective” and likely to be an error. With the 1913 reading discounted, along with another incorrect reading in Libya and other inaccurate readings, this weekend’s temperature may be the highest ever accurately recorded.
Extreme heat like this is a predictable and well-established consequence of climate change caused by human activities. Climate change has already driven at least 82% of heat records, according to a 2017 study led by Stanford University. Separate analysis has confirmed that the highest daily average temperatures are higher than they were a century ago, in almost the entire world. Record-breaking heat now happens about twice as often as record-breaking cold; without human-caused warming the ratio would be even.
Professor Michael Mann, Director of the Earth System Science Center, Pennsylvania State University, US, said:
“As the planet continues to warm, it is inevitable that we will continue to see records fall. It now appears that we’ve crossed yet another worrying threshold, setting the apparent hottest temperature ever recorded on this planet since valid records have been kept, a scorching 130F (54.4C) in Death Valley CA. Of course, that record too shall fall soon enough if we continue to pollute the atmosphere with carbon dioxide from the burning of fossil fuels and other human activities.”
Dr Friederike Otto, acting director of Oxford’s Environmental Change Institute, said:
“What we see this year is another summer of extreme heatwaves in Europe after 2018 and 2019 and across the Northern hemisphere like 2018. Most of these heatwaves individually are not very exceptional in today’s climate, but would have been rare without climate change. In a stable climate you do expect heat and cold records to be broken by roughly the same frequency the longer the record gets. When we have an underlying warming trend, we expect to see heat records being broken much more frequently – which is exactly what is happening now, so it is not a surprise to see a new all-time heat record being broken and also heatwaves occurring at the same time.
“The evidence that these heat waves and records are happening more and more and are being increasingly hot because of the warmer climate is absolutely non-refutable. Climate change is a real game changer when it comes to heatwaves and it is the certain connection between all of these heatwaves and records. It is also very important to highlight that an absolute heat record makes a great headline, but this is not why we need to care about heatwaves, heatwaves are killers across the globe and our awareness and preparedness is nowhere near where it needs to be in a 1 degree warmer world, let alone under future warming, to prevent premature death.”
Dr Michael Wehner, Senior Staff Scientist, Lawrence Berkeley National Laboratory, said:
“The human influence on heatwaves is clear. For most of California, climate change has caused rare heatwaves to be from 3 to 4 degrees Fahrenheit warmer.”
This year is quite likely to be the hottest on record, despite not experiencing a major El Niño event, which boosts global temperatures. An unprecedented heatwave in Siberia, was “almost impossible” without climate change, according to analysis by the World Weather Attribution group.