By Paul Homewood
It did not take Jeff Masters at Weather Underground to link the Alberta fires to climate change.
The Fort McMurray fire arrived months ahead of when summer wildfire typically races through the boreal forests of northern Alberta. A low-pressure center arcing far north of a typical early-May track brought hot southwest winds across the Fort McMurray region, which lies within the southern edge of the great boreal forests of northern Canada. Fort McMurray saw record daily highs of 91°F on Tuesday and 89°F on Wednesday. The city gets this warm on only about five days in a typical year, and those days are usually in July or August (even then, the average daily high is between 70°F and 75°F). The hot weather struck at an uncommonly bad time for wildfire risk: after winter snows had disappeared, but before the summer green-up had taken hold. Normally the window between these would be quite narrow, but snowfall was light this winter across the region, and it disappeared quickly during record warmth in April. From December through April, Fort McMurray recorded only 1.69” of precipitation, compared to the 1981-2010 average for that period of 3.22”.
Unfortunately for Masters, Bruce at Sunshine Hours has tracked down the daily temperature data for Fort McMurray from the the Canadian Government website here. Data is only available from 1908 to 1944, but, as the above table shows, temperatures of 91F in May are not unprecedented, with the 1930s and 40s particularly standing out.
The all time May high was an incredible 98.1F in May 1936. There was even a temperature of 95F recorded in April 1939.
As for rainfall, again the numbers quoted are not unprecedented. In 1943, for instance, precipitation only amounted to 37.9mm. or 1.49 inches from January to April. (Masters uses December to April numbers. which begs the question why? Was November wetter than normal? Normally meteorologists would either start in October (regarded as the start of the hydrological year), or January. This sounds suspiciously like data mining).
As for long term temperature trends in Alberta, Banff offers a long running record. According to GISS, below, temperatures in recent years appear no higher than in the 1930s.
To understand why the fire has been so catastrophic, we only need to consult the above article in the Edmonton Journal:
In 1971, more than half of Alberta’s boreal forest was deemed to be young, with about a third immature, five per cent mature and a small portion deemed “overmature”.
By 2011, that had changed to less than 10 per cent young, about a quarter immature, more than 40 per cent mature, and more than 20 per cent overmature.
“Before major wildfire suppression programs, boreal forests historically burned on an average cycle ranging from 50 to 200 years as a result of lightning and human-caused wildfires,” the panel found in a report released in 2012.
“Wildfire suppression has significantly reduced the area burned in Alberta’s boreal forest. However, due to reduced wildfire activity, forests of Alberta are ageing, which ultimately changes ecosystems and is beginning to increase the risk of large and potentially costly catastrophic wildfires.”
The panel reported that Alberta can expect more such dire situations due to humans living closer to the forest, and the aging of the Alberta forest.
“More Albertans are choosing to live, work, and play throughout the forested regions of the province, with investment and activity in Alberta’s wildlands accelerating. Experts say that climate change is increasing the wildfire threat, some aspects of which are already measurable with longer fire seasons and more extreme weather. As a result, the risk of wildfires, and the threat they pose to lives, homes, communities, and industry is increasing.”
In May 2011, the committee reported that “189 human-caused wildfires ignited across the province and threatened over 23 communities/locations (e.g., camps, worksites, parks, wildfire lookouts). Strong, sustained winds from the southeast created wildfire suppression challenges.”
The number of human-caused fires has been rising rapidly, from slightly more than 200 per year in 1993 to more than 1,100 a year by 2011. After human activity, lightning is the next biggest cause of wildfires, responsible for 40 per cent of them.
Before the Slave Lake fire, there had been few major wildfires in Alberta that took out homes.
“The last wildfire causing widespread damage to a community was in 1919 when the Town of Lac La Biche was destroyed, and 14 people lost their lives. Since 1919, and prior to the 2011 wildfires in the Slave Lake area, the most significant losses were experienced in 2001 when a wildfire destroyed 10 homes in the hamlet of Chisholm.”
But wildfires were to be expected.
“Wildfire is a natural part of the life cycle of the boreal forest; many of the vegetation species, including trees, are well adapted to large, intense wildfires. These boreal wildfires typically burn as ‘crown fires,’ and are responsible for most of the area burned in the boreal forests of North America, Europe and Asia. Intense wildfires consume forest canopy and can spread from treetop to treetop, releasing huge quantities of sparks, smoke and other gases.”
Forestry experts are well aware that wildfire suppression, which started to become common after the war, simply increases the amount of combustible material in forests, thus making fires much more powerful.
And as Bernie Schmitte, forestry manager in Fort McMurray, explained:
“The boreal forest is a fire-dependant ecosystem. The spruce trees, pine trees, they like to burn,”
“They have to burn to regenerate themselves, and those species have adapted themselves to fire. Their cones have adapted so they open up after the fire has left, and the trees have adapted in that once they’re old and need to be replaced, they’re available to fire so they burn.”
There is a much bigger proportion of older trees now because of earlier fire suppression, and it is these that are most combustible.
Meanwhile, if we look at wildfire trends in Alberta up to 2014, we find nothing remarkable at all.
And it is a similar picture for Canada as a whole:
Of course, the Fort McMurray fire is big news simply because so many people now live there, as a result of the oil sands revolution there. Only a few years ago, the place was no more than a small village.
Masters finishes his highly misleading account by saying:
In their deadline coverage of the Fort McMurray event, journalists such as Andrew Freedman (Mashable) have done a laudable job pointing out the complex but real connections between climate change and wildfire. We have much more to learn about exactly why and how the atmosphere is moving in directions that favor devastating fire–but for now, perhaps it’s enough simply to know that the dice are being loaded. Together with the many other threats posed by climate change, this should be more than enough motivation to get serious about emission cuts. The vast and profound effects of human-produced greenhouse gases–from intensified downpours and drought impacts to ocean acidification and sea-level rise–call for a sustained commitment to change that transcends any single disaster, even one as compelling as the nightmare unfolding in Fort McMurray.
This is one more reminder that you can’t rely on Weather Underground for the truth.