Heat, wildfires, flooding point to global warming: experts
The summer of 2018 just a harbinger of what’s to come, climatologists warn
Climate experts say it’s all part of a trend the planet has been experiencing for the past 30 years, one we should expect to continue over the coming decades.
“It’s not new weather, just a more extreme (version) of the old weather. The weather seems more energized, more ramped up,” says David Phillips, a senior climatologist with Environment Canada.
The sizzling heat and heavy rains fit the pattern of global warming caused by increased greenhouse gases, climatologists say.
It’s a pattern that has had grave consequences this year.
Hundreds have died across the globe this summer, including in Quebec. There’s been flooding in Ireland, fires in Greece.
We’ve seen temperatures in Sweden’s northern region, inside the Arctic Circle, reach 32 C (nearly 90 F). Dubai, a hot city to begin with, saw scorching temperatures of 50 C in June.
California’s Death Valley topped that in July with temperatures that reached as high as 53 C.
That state, which saw it’s hottest July ever with an average temperature of 27 C, has experienced the worst wildfires in its history as a result.
Phillips noted that earlier this week, nine out of 10 Canadian provinces were in the grip of a heat wave — and the 10th had a heat warning.
It’s something you don’t often see in Canada, he says.
Worldwide, it’s the large area covered by the pattern of the heat this summer, plus the intensity of the heat and its duration — we’ve seen hot temperatures across Canada since May, Phillips notes — that all point to a warming pattern, he says.
The U.S. government’s National Oceanic and Atmospheric Administration (NOAA) found that in the U.S., the average temperature across the country in July was 25 C — 1.9 degrees above average.
That’s the 11 warmest average for the month in more than 100 years of the agency’s recorded temperatures.
Ahira Sanchez, a climatologist with NOAA, points out that 2014 set a record for global temperatures, 2015 broke that record, and 2016 broke the record again.
Last year was the third warmest year globally, according to a study headed by NOAA with input from more than 500 scientists in 65 countries. Published by the American Meteorological Society, the study found temperatures were 0.38 to
0.48 of a degree C above the 19812010 average.
The report also noted that last year’s levels of greenhouse gases, including methane, nitrous oxide and carbon dioxide, were at all-time highs.
The sea level had also risen to an all-time high — about 7.7 cm higher than in 1993, the study found. The globe’s sea level has risen an average rate of 3.1 cm per decade, the study noted.
Environment Canada’s Phillips says lots of reliable data on rising sea levels and global temperatures over time make it easier to point to climate change.
However, flooding events like Tuesday’s in Toronto, and the 97 millimetres that fell here in July 2013, are harder to connect to climate change because they are localized and don’t happen as often, Phillips points out.
But the general rule is that warmer air holds more moisture, therefore it stands to reason that persistent heat waves will result in heavier downpours like Tuesday’s, experts argue.
Tuesday’s flooding was a result of a localized “shower cell” that began around the Vaughan/City of Toronto border near Steeles Ave.
The cell intensified significantly and moved slowly southward, with Toronto’s downtown core and the lakefront taking the brunt of it, says Geoff Coulson, a meteorologist with Environment Canada.
The impact — flooded streets, flood damage to ceilings and basements in homes and businesses, and overburdened sewers — makes these downpours seem intense, but the infrastructure and green space in Toronto isn’t adequate to keep up with the amount of rain we saw this week, Environment Canada’s experts argue.