|July 11, 2019|
Alaska chokes on wildfires as heat waves dry out the Arctic
|Under the choking black smoke from the bog and forest fires in Siberia and Alaska, it can feel like the Earth itself is burning. The normally moist, black organic peat soil and lush forests have been drying, and when they catch fire, they burn relentlessly.|
Global warming has been thawing tundra and drying vast stretches of the far-northern boreal forests, and it also has spurred more thunderstorms with lightning, which triggered many of the fires burning in Alaska this year, said Brian Brettschneider, a climate scientist with the International Arctic Research Center who closely tracks Alaskan and Arctic extreme weather.
So far this year, wildfires have scorched more than 1.2 million acres in Alaska, making it one of the state's three biggest fire years on record to this date, with high fire danger expected to persist in the weeks ahead.
Several studies, as well as ongoing satellite monitoring, show that fires are spreading farther north into the Arctic, burning more intensely and starting earlier in the year, in line with what climate models have long suggested would happen as sea ice dwindles and ocean and air temperatures rise.
"When it comes to the Arctic heat waves, the wildfires, am I surprised? No --- this was long predicted. Am I worried? Yes," said Pennsylvania State University climate scientist Michael Mann.
A region of Alaska about the size of California has been sizzling under an intense, record-length heat wave for weeks. And it isn't just the land that's warming: the northern coast is losing its sea ice about two months earlier than average and ocean surface temperatures are as much as 9 degrees Fahrenheit above normal in the Chukchi Sea. Across the state:
*For the first time in the 95-year record, the year-long July-to-June average temperature for Alaska as a whole was above freezing, showing the persistence of much warmer than average temperatures over the state.
*For the year to date, the Alaska statewide average temperature was 7.9°F above average, according to NOAA's latest National State of the Climate report.
*During the last 67 years, Anchorage saw a total of 17 days with a temperature of 81°F or above. This year, 81 was the average temperature for a 12-day stretch in late June and early July, Brettschneider posted on Twitter.
*On July 4, Anchorage hit 90°F, breaking the city's all-time record by 5 degrees.
In Anchorage this time of year, "our normal high is 66 (degrees Fahrenheit), and today, it's already 74 or 75 degrees at 10:30 in the morning," Brettschneider said via Skype on July 8.
Sitting outside in the morning in a T-shirt and sweating is not normal in Anchorage, he said. "We keep our doors and windows closed at night to keep the smoke out. This morning I got up and it was 80 degrees in the house," he said.
The large Arctic fires in June could be a sign of a climate tipping point, said Thomas Smith, a climate researcher at the London School of Economics and Political Science.
Responding to a post about the record Arctic wildfire activity on Twitter, Smith wrote that if temperatures stay above a certain temperature threshold long enough, fuels dry out and become ignitable.
"It really is unprecedented, a word we should not use lightly," he wrote. "It may be that in most previous years, temperatures have never been warm enough to drive off moisture from the winter frost and snowpack. The ground is likely covered in mosses that act as a sponge, staying moist all summer long before freezing again in winter. But now that sponge is drying out."
Amid all of this, scientists in Alaska are worried about the future of scientific research at the region's universities---the state legislature is struggling to get enough votes by Friday to override a veto by the Republican governor that would effectively slash state funding for the university system by 41 percent.
June's Unprecedented Smoke & Fire Intensity
There are seasonal and regional nuances, and natural climate cycles are also a factor, but wildfire experts in Alaska are generally expecting conflagrations to increase through at least 2100, said Scott Rupp, deputy director of the International Arctic Research Center.
A 2016 paper in the Bulletin of the American Meteorological Society showed that human-caused climate change increased the risk of extreme fire seasons in Alaska by 34 percent to 60 percent by drying out fuels, he said. Trees, grass, shrubs and tundra are more flammable with warmer temperatures if the warmth is not offset by wetter conditions.
"A rule of thumb is that, for every 1 degree Celsius temperature increase, you need a 15 percent increase in precipitation to offset the drying effects," he said. "In interior Alaska we have seen increases of 2-3 degrees Celsius over the past 40 years." Precipitation has not increased enough to offset the warming, so fire conditions are worsening, he said.
A European climate-monitoring satellite this week confirmed that the recent levels of smoke emissions and fire intensity in Alaska and throughout the Arctic were unprecedented for June, said Mark Parrington, a senior scientist with the ECMWF and Copernicus Atmosphere Monitoring Service.
Reinforcing the link between extreme heat and wildfires, the Copernicus monitoring shows that the June wildfires in Siberia started burning in a region that was a global hotspot at the time---during Earth's warmest June on record, Parrington said.
"I am concerned about how bad it can potentially get in terms of the size of the fires and the impact of smoke pollution in the Arctic, which is often thought of as a remote and pristine environment," Parrington said. "We know that the Arctic climate has been changing at a much faster rate than the rest of the world, and it is worrying to think that we could now be witnessing the effect of this directly in the Arctic Circle."
New Threats to Alaska & Places Not Used to Fires
Several recent studies have shown serious health risks from wildfire smoke that increasingly hangs in noxious shrouds over fire-prone regions like Southern Alaska.
The heat and smoke combined have prompted public health warnings against strenuous outdoor activity in places like Fairbanks, which also struggles with soot air pollution in winter. The wildfires also emit greenhouse gases that warm the planet, they damage forests that would otherwise remove CO2, and they inject soot into the atmosphere that can have complex effects on warming.
"We passed a million acres, and the potential for continued extreme fire activity will be sticking with us for the foreseeable future," Rupp said. "Fairbanks in particular is surrounded by fire, and residents are dealing with the worst air quality anywhere on the globe. That is likely not to change for some time."
Around the world, global warming has clearly contributed to an increase in extreme fires in most biomes, from tropical rainforests to boreal evergreen forests, and they are often linked with heat waves, said University of Tasmania fire geographer David Bowman.
That poses new fire threats to places that aren't used to seeing much fire at all, including temperate mid-latitude forests near regions with dense populations, as shown by unusual wildfires in places like Germany during last summer's European heat wave and drought.
"We crossed the line in the last few years," said Bowman. "It's hard to keep pace with the growth of unusually extreme fires burning across South America, Australia and western North America. Fires are starting to burn more in places with vegetation that isn't by nature highly combustible."
Bowman analyzed the growth of Earth's most intense fires between 2002 and 2013 in a study showing a close link between disastrous fires and extreme droughts and heat waves. It projected that the number of days conducive to extreme fires would increase by 20 to 50 percent globally by mid-century.
Oceans Heat, Sea Ice---It's all Connected
It's not only land areas that are heating up. The ocean around Alaska has also been running a fever for months, and it's all connected.
Summer ocean heat waves contribute land heat waves; in the fall, warmer ocean and land temperatures delay the freeze-up of ice near the shore, which leads to even more heat buildup in the ocean, part of the death spiral of the Arctic climate system as we know it, now headed toward an uncertain future, according to scientists.
The changes in ocean temperatures and sea ice extent likely represent a climate shift for Alaska, said Rick Thoman, with the International Arctic Research Center.
"But there's no reason to think that we're at a new equilibrium," he said. He likens it to a five-year-old on an escalator: "The climate will likely feature big swings all the while trending up. Sure, the 5-year can run up or down and so get to the top faster or slower, but in the end the escalator 'wins.'"
More directly, the warm ocean temperatures have resulted in significant die-offs of large numbers of animals in Western Alaska, Thoman said. The reports of dead fish, marine mammals and birds are piling up on the Local Environmental Observer network, a citizen science database that helps resource agencies track impacts in far-flung locations across the vast state.
Kotzebue, a coastal town in Northwestern Alaska, has reported above average temperatures for more than 112 days in a row, and there's no doubt warm ocean waters are influencing those readings, said Mark Serreze, director of the National Snow and Ice Data Center.
"It's a two-way street. Fires are linked to warming, but fires also deposit dark soot on the ocean and hastens sea ice melt. Fire also alters landscape to hasten thaw of permafrost. And the permafrost is not coming back," he said.
Thoman added, "In many areas, it is clear we've crossed thresholds and the change is abrupt, for example multiple aspects (extent, thickness, volume) of sea ice. Given the amount of heat going into the ocean, it's not physically reasonable to expect the system to 'go back' for any length of time."
Blows to Universities & Alaskan Ways of Life
The spiraling cycle of climate impacts is bad enough, but Alaska is also facing a political attack on its science institutions, said Uma Bhatt, chair of the atmospheric sciences department at the University of Alaska Fairbanks. Gov. Mike Dunleavy's budget battle with the state legislature could result in big cuts to university funding, including climate research.
"What keeps me up at night is that the climate problem is a complex problem. It's not just a science problem, it's a social problem and a political problem," Bhatt said. "I should be doing climate research rather than worrying about whether the university will be standing."
Concerns about climate change impacts are growing in the state, she said.
"I talk to a lot of people in rural areas, and they are concerned about how ecosystem services are changing. There is a notable population in Alaska who live a subsistence lifestyle, hunting and fishing, and that is changing. It's changing fast, within a generation, so the knowledge about things like hunting in the coastal ice will have to shift very quickly," she said.
Even if people and communities can at least partly adapt, some things will disappear forever.
"You can never get back that plants and animals that will go extinct because of global warming," she said.