The intense heatwaves that have been engulfing the US, China and southern Europe in July 2023 are \u201cnot rare anymore\u201d in our current climate, a new rapid attribution study warns.<\/p>\n
July 2023 has seen unprecedented heat affecting much of the northern hemisphere, causing temperature records to tumble.<\/p>\n
China\u2019s\u00a0national temperature record\u00a0was shattered on 16 July when the mercury reached 52.2C.<\/p>\n
Meanwhile, nearly\u00a0one-third\u00a0of the US population were put under heat warnings earlier in the month as a \u201chistoric\u201d heatwave set<\/a> multiple heat records of above 100F (37.8C).<\/p>\n And\u00a0hospital cases\u00a0across southern Europe<\/a> have soared as the region swelters under the \u201cCerberus\u201d heatwave.<\/p>\n The\u00a0World Weather Attribution\u00a0service \u2013 a global network of scientists who investigate the influence of climate change on extreme weather events \u2013 finds that the heatwaves in the US and Europe would have been \u201cvirtually impossible\u201d in a world without climate change.<\/p>\n The heatwave in China was \u201cat least 50 times more likely\u201d due to climate change, it adds.<\/p>\n The warming effect of\u00a0El Ni\u00f1o\u00a0\u2013 a natural cycle of climate<\/a> variability \u2013 \u201clikely contributed some additional heat to the heatwaves in some regions\u201d, the study finds. But, during a press briefing, an author on the study explained that its impact is \u201cvery small compared to the effect of climate change\u201d.<\/p>\n The study finds that if average global<\/a> temperatures reach 2C above preindustrial temperatures \u2013 a 0.8C increase from today \u2013 extreme heat events on this scale could happen every 2-5 years.<\/p>\n Records topple Extreme weather events<\/a> across the globe this month have already featured on more than 114 frontpages in at least 84 newspapers, published across 32 countries,\u00a0Carbon Brief\u00a0analysis shows.<\/p>\n In the US, nearly\u00a0one-third\u00a0of the country\u2019s population were put under excessive-heat advisories, watches or warnings as a \u201chistoric\u201d heatwave set multiple heat records of above 100F (37.8C).<\/p>\n Temperatures at Furnace Creek in California\u2019s Death Valley, which holds the record for the hottest place on Earth, hit\u00a053.3C on 16 July, approaching the all-time high of 56.7C in July 1913. And, on 19 July, the city of Phoenix, recorded a peak temperature of at least 110F (43.3C) for the\u00a020th day in a row\u00a0\u2013 extending a record that had been broken the day before.<\/p>\n Across the Atlantic, southern Europe suffered through the \u201cCerberus\u201d heatwave, which saw temperatures rise up to\u00a010C above average, quickly followed by the \u201cCharon\u201d heatwave.<\/p>\n Temperatures\u00a0topped 40C\u00a0in parts of Spain, France, Italy, Greece and Bosnia, while Sicily saw temperatures as high as 115 degrees (46.3 C).<\/p>\n In Rome, a new record high temperature of\u00a041.8C\u00a0was recorded on 18 July. Most major cities in Italy were placed on \u201cred alert\u201d due to the intense heat, with forecasters reporting that parts of the Italian islands of Sardinia and Sicily could reach\u00a0highs of 49C.<\/p>\n And China<\/a> recorded its\u00a0highest ever temperature\u00a0on 16 July when the remote Sanbao township in the Turpan depression of Xinjiang saw temperatures climb to 52.2C. This broke the previous record of 50.3C, measured in 2015.<\/p>\n Meanwhile, Beijing topped its record for high-temperature days in a year on 18 July, which marked\u00a027 days above 35C.<\/p>\n Mapped These are the western US and Mexico over 1-18 July, southern Europe over 12-18 July and China<\/a> over 5-18 July.<\/p>\n Dr Frederieke Otto\u00a0is a senior lecturer in climate science at the Grantham Institute for Climate Change and the Environment at\u00a0Imperial College London\u00a0and co-author of the study. (Otto is also a Carbon<\/a> Brief\u00a0contributing editor.)<\/p>\n She told a press briefing that different time spans were chosen for different regions to reflect when the heatwaves had the greatest impact on people. However, she said that the final results of the study were \u201cnot very sensitive\u201d to the exact event definition.<\/p>\n The maps below show the average maximum temperatures (left) and difference compared to the 1950-2023 average (right) for the three regions and time periods chosen. Darker reds indicate hotter temperatures.<\/p>\n The warming effect of\u00a0El Ni\u00f1o\u00a0\u2013 a natural cycle of climate<\/a> variability \u2013 \u201clikely contributed some additional heat to the heatwaves in some regions,\u201d the study finds. But Otto told the press briefing that its impact is \u201cvery small compared to the effect of climate change\u201d.<\/p>\n Attribution To conduct\u00a0attribution studies, scientists use models to compare the world as it is today \u2013 in which global average temperatures have risen by 1.2C thanks to human activity<\/a> \u2013 to a \u201ccounterfactual\u201d world without human-caused climate change.<\/p>\n This study aimed to distinguish the \u201csignal\u201d of climate change in the 18-day, 7-day and 14-day heatwaves defined in the US, Europe and China, respectively.<\/p>\n The US and Europe would have been \u201cvirtually impossible\u201d in a world without climate change, the study finds. It adds that the heatwave in China was \u201cat least 50 times more likely\u201d due to climate change.<\/p>\n The July 2023 heatwaves in the US, Europe and China were also 2C, 2.5C and 1C hotter, respectively, than they would have been in a world without climate change, the authors find.<\/p>\n \u201cThese events are not rare anymore today,\u201d the authors warn<\/a>. In today\u2019s climate<\/a>, the extreme heat seen in the US, southern Europe and China can be expected once every 15, 10 and 5 years respectively.<\/p>\n The authors also warn that if global temperatures reach 2C above preindustrial temperatures \u2013 an increase of 0.8C from global average temperatures in today\u2019s climate<\/a> \u2013 extreme heat events on the scale of those in July 2023 could happen every 2-5 years.<\/p>\n (The authors started work on this study on 18 July. These findings are yet to be published in a peer-reviewed journal<\/a>. However, the methods used in the analysis have been published in\u00a0previous attribution studies.)<\/p>\n Heat preparedness However, she added that our societies and ecosystems<\/a> are \u201cmuch more vulnerable\u201d to the changes in temperature than previously thought.<\/p>\n Heatwaves are \u201camongst the deadliest natural hazards that we face each year,\u201d\u00a0Julie Arrighi\u00a0from the\u00a0Red Cross Red Crescent Climate<\/a> Centre\u00a0told the press briefing. She emphasised the importance of \u201chealth action plans\u201d, pointing out some measures that some countries are currently taking to limit the impact<\/a> of high temperatures.<\/p>\n For example, she explained Italian hospitals reported a\u00a0spike\u00a0in admissions during the heatwave and the government<\/a> activated a\u00a0heat code\u00a0to fast track patient access to emergency rooms.<\/p>\n Meanwhile, she said that power consumption \u201cincreased substantially\u201d in many urban centres in China. But power outages remained \u201cvery limited\u201d after measures including emergency generators and extra staff were rolled out.<\/p>\n
\n<\/strong>The first week of July 2023 was the Earth\u2019s\u00a0hottest on record. Across the planet, people are still\u00a0battling\u00a0with the impacts of extreme heat as temperature records continue to topple.<\/p>\n
\n<\/strong>To investigate the exceptional heat that has swept across much of the northern hemisphere over the past month, the World Weather Attribution service focuses on three separate regions and time periods where \u201canomalously high temperatures\u201d were reported and many people have been affected by the heat.<\/p>\n
\n<\/strong>Attribution\u00a0is a fast-growing field of climate science that aims to identify the \u201cfingerprint\u201d of climate change on extreme-weather events, such as heatwaves and droughts. In this study, the authors investigated the impact of climate change on extreme heat over the three study regions.<\/p>\n
\n<\/strong>For decades, climate scientists have been\u00a0predicting\u00a0a rise in the intensity and frequency of extreme heat events. As such, Otto told the press briefing that the findings of this study are \u201cabsolutely not a surprise\u201d, noting that we are seeing \u201cexactly what has been projected<\/a> in the past\u201d.<\/p>\n