'Climate change's role in July heat waves across Europe, China, America'

The fingerprints of climate change are all over the intense heat waves gripping the globe this month a new study finds Researchers say the deadly hot spells in the American Southwest and Southern Europe could not have happened without the continuing buildup of warming gases in the air AP reportedThese unusually strong heat waves are becoming more common Tuesdays study said The same research found the increase in heattrapping gases largely from the burning of coal oil and natural gas has made another heat wave the one in China 50 times more likely with the potential to occur every five years or soA stagnant atmosphere warmed by carbon dioxide and other gases also made the European heat wave 45 degrees Fahrenheit 25 degrees Celsius hotter the one in the United States and Mexico 36 degrees Fahrenheit 2 degrees Celsius warmer and the one in China one 18 degrees Fahrenheit 1 degree Celsius toastier the study foundSeveral climate scientists using tree rings and other standins for temperature records say this months heat is likely the hottest Earth has been in about 120000 years easily the hottest of human civilizationHad there been no climate change such an event would almost never have occurred said study lead author Mariam Zachariah a climate scientist at Imperial College of London She called heat waves in Europe and North America virtually impossible without the increase in heat from the mid 1800s Statistically the one in China could have happened without global warmingSince the advent of industrialscale burning the world has warmed 22 degrees Fahrenheit 12 degrees Celsius so they are not rare in todays climate and the role of climate change is absolutely overwhelming said Imperial College climate scientist Friederike Otto who leads the team of volunteer international scientists at World Weather Attribution who do these studiesThe particularly intense heat waves that Texas California Arizona New Mexico Nevada Baja California Sonora Chihuahua and Coahuila are now roasting through are likely to happen about once every 15 years in the current climate the study said But the climate is not stabilized even at this level If it warms a few more tenths of a degree this months heat will become even more common Otto said Phoenix has had a recordshattering 25 straight days of temperatures at or above 110 degrees Fahrenheit 433 degrees Celsius and more than a week when the nighttime temperature never dropped below 90 degrees Fahrenheit 322 CelsiusThe heat in Spain Italy Greece and some Balkan states is likely to reoccur every decade in the current climate the study saidBecause the weather attribution researchers started their analysis of three simultaneous heat waves on July 17 the results are not yet peer reviewed which is the gold standard for science But it used scientifically valid techniques the teams research regularly gets published and several outside experts told The Associated Press it makes senseThe way scientists do these rapid analyses is by comparing observations of current weather in the three regions to repeated computer simulations of a world that might have been without climate change said study coauthor Izidine Pinto a climate scientist at the Royal Netherlands Meteorological InstituteIn Europe and North America the study doesnt claim humancaused climate change is the sole cause of the heat waves but it is a necessary ingredient because natural causes and random chance couldnt produce this alone Texas state climatologist John NielsenGammon said the study was reasonable but looks at a broad area of the US Southwest so it may not be applicable to every single place in the areaIn the United States its clear that the entire southern tier is going to see the worst of the everworsening heat and this summer should be considered a serious wakeup call said University of Michigan environment dean Jonathan OverpeckWith heat waves the most important thing is that they kill people and they particularly kill and hurt and destroy lives and livelihoods of those most vulnerable Otto saidAP