‘Dangerous levels’: Fossil fuel use behind Las Vegas heatwaves, report says

Extreme temperature episodes have become four times more likely since the year 2000, according to a weather research organization in a report released Wednesday.

The deadly heat that recently hit North and Central America was 35 times more likely due to human-induced climate change, according to an analysis by climate scientists from World Weather Attribution.

The study also says that the frequency of these extreme events has rapidly increased in recent years because of the use of fossil fuels.

Since March, North and Central America have been impacted by dangerous temperatures. In Mexico, there have been at least 125 heat deaths and 2,308 cases of heat stroke, power outages, wildfires, and mass die-off of endangered monkeys. In the southwest United States, more than 34 million people live in areas where authorities have issued heat alerts and dozens have suffered heat exhaustion at political rallies. May this year was the hottest May on record globally and the 13th consecutive month in a row a hottest month record was broken.

U.S. cities included in the study were Las Vegas and Phoenix, both experiencing the warmest June in their recorded weather history.

The forecast for Las Vegas shows highs around 110 degrees through the end of the month with overnight lows in the mid-80s.

“The results of our study should be taken as another warning that our climate is heating to dangerous levels,” said Izidine Pinto, a researcher at the Royal Netherlands Meteorological Institute. “Potentially deadly and record-breaking temperatures are occurring more and more frequently in the U.S., Mexico and Central America due to climate change.

“As long as humans fill the atmosphere with fossil fuel emissions, the heat will only get worse — vulnerable people will continue to die and the cost of living will continue to increase.”

Meteorologists at AccuWeather appear to agree with the WWA report.

“Since March 1st, Mexico City has averaged a whopping 9.4 degrees (5.2 Celsius) above the historical average which is extreme for a 3.5 month period,” Accu-Weather said in an email. “The city has also only received 36 percent of it normal rainfall during the period.

“The abnormal heat reached the southwest United States during June. Las Vegas was averaging 7.1 degrees above the historical average for the period, while Phoenix was 5.2 degrees above the historical average, leading to an early start to the extreme heat season. AccuWeather is predicting a below-average monsoon this year, which will also be conducive to a higher number of days with dangerous heat.”

International collaboration

World Weather Attribution is an international collaboration that studies and communicates the possible influence of climate change on extreme weather events, such as storms, extreme rainfall, heatwaves, and droughts.

The group has completed more than 70 studies on a range of extreme weather events around the world using peer-reviewed methods.

WWA uses weather observations and climate models to understand how climate change influences the intensity and likelihood of extreme weather events, according to their website.

The studies also assess the role of vulnerability and exposure in the extent of the impacts.

Most studies are performed rapidly, in the aftermath of extreme weather events — or even while they’re still happening — to answer the increasingly common question: “What was the role of climate change in this event?”

Formed in 2015, WWA has performed more than 70 attribution studies on heatwaves, extreme rainfall, drought, floods, wildfires and cold spells around the world.

More frequent, longer and hotter heat

Climate change, caused by burning oil, coal and gas, and other human activities like deforestation, is making heatwaves more frequent, longer and hotter around the world, the report stated.

To quantify the effect of human-caused warming on the extreme temperatures across North and Central America, scientists analyzed weather data and climate models using peer-reviewed methods to compare how these types of events have changed between today’s climate, with approximately 1.2°C of global warming, and the cooler pre-industrial climate.

The study focused on a region that includes the U.S. southwest and Mexico, as well as Guatemala, Belize, El Salvador and Honduras where temperatures were also extreme.

The researchers looked at the five-day maximum daytime and nighttime temperatures in May and June. High night temperatures are dangerous for human health, as the body cannot rest and recover, increasing the risk of stroke and other heat-related illnesses.

The analysis found that human-caused climate change is making dangerous May-June heat much more common. Maximum temperatures such as those seen in North and Central America are today 35 times more likely than in pre-industrial times.

The effect of climate change on night temperatures is even higher, with the analysis showing a 200-fold increase due to global warming.

Much of this change has happened in recent years, the analysis found.

In the year 2000, similar May-June heat was expected to occur about once every 60 years, roughly once in a lifetime. Today, with a further half-degree Celsius of warming since the turn of the millennium, it occurs about once every 15 years, meaning on average a person will experience it 5 or 6 times in their lifetime.

Contact Marvin Clemons at mclemons@reviewjournal.com.