Global warming is real, and record summer temperatures could soon be the norm, not the exception
IN the town of Sodankylä, Finland, the thermometer on July 17 registered a record-breaking 32C, a remarkable figure given that Sodankyla is 95km north of the Arctic Circle, in a region known for winter snowmobiling and an abundance of reindeer.
This is a hot, strange and dangerous summer across the planet.
Greece is in mourning after scorching heat and high winds fuelled wildfires that have killed more than 80 people. Japan recorded its highest temperature in history, 41C, in a heat wave that killed 65 people in a week and hospitalised 22,000, shortly after catastrophic flooding killed 200.
Montreal hit 36.5C on July 2, its warmest temperature ever measured. Canadian health officials estimate as many as 70 people died in that heatwave.
In the United States, 35 weather stations in the past month have set new marks for warm overnight temperatures. Southern California has had record heat and widespread power outages. In Yosemite Valley, which is endangered by wildfires, park rangers have told everyone to flee.
The brutal weather has been supercharged by human-induced climate change, scientists say. Climate models for three decades have predicted exactly what the world is seeing this summer. And they predict that it will get hotter – what is a record today could some day be the norm.
“The old records belong to a world that no longer exists,” said Martin Hoerling, a research meteorologist at the National Oceanic and Atmospheric Administration in the US.
It’s not just heat. A warming world is prone to multiple types of extreme weather – heavier downpours, stronger hurricanes, longer droughts.
“You see roads melting, aeroplanes not being able to take off, there’s not enough water,” said Katharine Hayhoe, director of the Climate Science Centre at Texas Tech University.
“Climate change hits us at our Achilles heel. In the [United States] south-west, it’s water availability. On the Gulf coast, it’s hurricanes. In the east, it’s flooding. It’s exacerbating the risks we already face today.”
The proximate cause of the northern hemisphere bake-off is the unusual behaviour of the jet stream, a track of west-to-east prevailing wind at high altitude. The jet stream controls broad weather patterns, such as high-pressure and low-pressure systems. The extent of climate change’s influence on the jet stream is a subject of intense research. This summer, the jet stream has undulated in extreme waves that have tended to block weather systems from migrating. The result has been stagnant high-pressure and low-pressure systems with dire results, such as heatwaves in some places and flooding elsewhere.
“When those waves are very big – as they have been for the past few weeks – they tend to get stuck in place,” said Jennifer Francis, a professor of atmospheric science at Rutgers University in New Jersey. Last year, scientists published evidence that the conditions leading to “stuck jet streams” are becoming more common, with warming in the Arctic a likely culprit.
Gone are the days when scientists drew a bright line dividing weather and climate. Now researchers can examine a weather event and estimate how much climate change had to do with causing or exacerbating it.
Last year, when Hurricane Harvey broke the record for how much rain could fall from a single storm, researchers knew climate change had been a factor.
Months later, scientists presented findings that Harvey dumped at least 15pc more rain in Houston than it would have done without global warming. Theory, meet reality: When the atmosphere is warmer, it can hold more moisture.
Climate change does not cause hurricanes to spin up or thunderstorms to develop, but it can be an intensifier.
In Dallas, where the temperature passed 37C on 10 out of 11 days this month, three homeless people have died of heat-related causes in the past week, said Brenda Snitzer, executive director of the Stewpot, a downtown shelter.
In Phoenix, Arizona, where this week’s temperature hit 46.5C, Dustin Nye (36), who spent the day installing airconditioning units, said he has suffered heatstroke in the past and still gets woozy. “It takes a special breed to do this all day long in this heat,” he said. “You’ve really got to work up your endurance and just buckle down and deal with it.”
In Los Angeles, Marty Adams, chief operating officer of the Department of Water and Power, said: “It seems like every year, we’ve had some type of temperature anomaly that we normally would not have.” Residents of California beach cities such as Long Beach and Santa Monica, who normally rely on the ocean breeze to cool their homes, have added air-conditioning units, which strains the grid and has contributed to power outages, he said.
Said Hayhoe: “The biggest myth that the largest number of people have bought into is that ‘climate change doesn’t matter to me personally’.”
The heatwaves have hit hard where people don’t expect them – the Netherlands, Sweden, Britain, Ireland and Canada. “Our office doesn’t have air conditioning. I do have a fan,” said Geert Jan van Oldenborgh, a climate researcher at the Royal Netherlands Meteorological Institute. He spoke from Gouda, where the temperature hit 35.5C this week.
“This kind of event was a one-in-ahundred-year event in 1900,” he said. “It’s become 20 times more likely.”
It is Britain’s driest summer since modern records began in 1961. Reservoirs levels are declining rapidly, and water restrictions are in effect.
The UK’s national weather service urged people to avoid the sun this week, with temperatures expected to hit 36.5C.
As we know in Ireland, the sun-parched fields revealed a previously hidden footprint of a 5,000-year-old monument near Newgrange.
Human activity, primarily the burning of fossil fuels, has added greenhouse gases to the atmosphere, trapping heat and making extreme weather events even more extreme. The amount of CO2 in the atmosphere reached 410 parts per million in May, the highest the Mauna Loa Observatory in Hawaii had measured since Charles David Keeling started keeping records in 1958. Nasa estimates Earth has warmed almost 1C since the late 1800s. Of that, half has accrued since 1990 alone.
If nothing is done to curb greenhousegas emissions, scientists say, the global temperature increase could reach 5C by the end of the century, with higher spikes on land and at high latitudes.
The Paris Agreement, signed by every country in the world, is designed to limit that temperature spike through commitments to cut greenhouse-gas emissions over time. US President Donald Trump, who in the past has called global warming a hoax, has vowed to pull the United States out of the accord as soon as that becomes possible, in 2020.
The 2017 National Climate Assessment, released in November, concluded what it has for nearly three decades: Human-made climate change is real, and the impacts have already started. (©The Washington Post)
The biggest myth that the largest number of people have bought into is that ‘climate change doesn’t matter to me personally’