The link between heat waves and global warming

In Saturday's Globe and Mail, Rex Murphy had yet another obtuse column speculating about global cooling, spurred by Toronto's cool, wet summer. While the errors in Murphy's supposedly ironic columns have not quite reached the level of George Will, in which a full-on intervention with the editorial board of the Washington Post now appears necessary, someone at the Globe and Mail could at least casually pull him aside and say "cut it out".

In this case, forget Mr. Murphy's apparent blindness to the constant flow of science and reporting on evidence for warming, nor the news that the combination of the decades-long warming trend and a developing El Nino event may make the next year one of the warmest, if not the warmest, year in the recorded history of the planet.

He doesn't appear to have even been reading or watching the national news. While his home and my hometown of Toronto has been cool and wet, Vancouver and western Canada have been in the midst of an unprecedented heat wave.

Fires burn throughout the BC interior. Water restrictions have placed in the Fraser Valley. On Saturday afternoon, Vancouver-ites put down the Globe and Mail to watch an impromptu lightning show upstage the planned Celebration of Light fireworks show (the photo shows the calm after the storm). That's right a thunderstorm here in placid, temperate Vancouver.

What's happening? On Sunday, I was asked the classic question "Is it global warming?" by a reporter from the local CBC affiliate.

I responded, as any climate scientist would, with a variation of Michael Tobis's old favourite: "no individual event can be attributed directly to climate change".

Yes, this the kind of weather we expect to see more frequently in the future. It won't happen every summer. And when it does happen, it won't happen everywhere. There will certainly be many summers when one part of the continent, say Vancouver, experiences typical "global warming" weather and another, say Toronto, experience old-fashioned cool summer, thanks to how the general warming trend affects upper-level atmospheric flow.

The "is it global warming?" question is bound to arise again and again over the next year. The answer is always going to be the same. Whether it is next year, ten years from now, or thirty years from now, we will not be able to definitively state with 100% certainty that a warm summer or a heat wave is due solely to climate change. That's the nature of this multifactorial beast known as the climate system.

What we will be able to say thirty years from now is that we should have spent more time trying to slow the warming trend, rather than arguing about the noise.