Saturday 28 June 2014

Wildfires in Central Siberia

Dozens of Massive Wildfires in Central Siberia Belch 1,200 Mile Smoke Plume Over Hot Tundra

1,200 mile smoke plume
(Dozens of monstrous fires belch a 1,200 mile plume of dark smoke over Central Siberia. Image source: LANCE MODIS.)
This winter, temperatures throughout large swaths of this typically frigid land of tundra and boreal forest ranged between 5 and 7 degrees Celsius above average. For brief periods spikes in the very extreme range of 20 degrees Celsius warmer than normal were not uncommon.
The unusual heat continued into spring igniting a mass of anomalous wildfires in April, a time when most of Siberia remains frozen. By May, more than a million acres had burned, all well before the typical peak of fire season in July and early August. But that was mere prelude to peak fire season, which we are starting to enter now.
Siberian Heatwave Spurs Massive Fires
The record heat this winter was simply the continuation of a long warming trend fueled by human greenhouse gas emissions. Each decade now has seen Siberia warm at a pace double the global average — more than 0.5 degrees Celsius every ten years. And this extra heat is fueling a terrifying intensification of wildfires, a trend that is expected to show at least a doubling of the annual acres burned in this far northern region by the end of this century.
This year’s early start to fire season may be setting the stage for a record or near record burning this year. And today we have a massive flare up of fires in Central Siberia under a broad heat dome over the region.
Temperatures beneath the dome earlier today were in the upper 80s and lower 90s, departures between 5 and 15 degrees Celsius above average for this time of year. This heat spike hit already warmed and dried lands. Lands filled with the added fuel of thawing tundra and the organic carbon and methane pockets beneath. Lands whose shallow surface layer is a tinder bed for flash fires.


Siberian Heat Dome
(Heat dome over Central Siberia in the upper right hand corner of this GFS based-temperature and weather graphic. Image source: University of Maine. Data source:NOAA/GFS.)

The result was the massive wildfire eruption seen in the satellite shot at the top of the page. A very intense set of enormous fires with fronts ranging from 3 to 34 miles burning through boreal forest and tundra land. This set of blazes is even more intense than those seen at this time during the record 2012 Siberian fire season, although it is worth noting that those fires hit extraordinary strength and size by early July and continued in a series of episodes through mid August. The result was massive smoke plumes eventually encircling the Arctic.

Typically, the fires fill the air with particulate and the moisture loading under the heat dome grows ever more intense. Often, and sooner rather than later, a frontal storm accompanied with intense rains sweeps in, catching up the smoke in its cloud mass even as the towering storms douse the raging fires. A song of flood and flame that has become all too common throughout the very rapidly changing Arctic.
In years of very extreme burning, the smoke-laden clouds darken, losing their white, reflective tops. This further amplifies warming over fire-prone areas, setting the stage for more fires. On the ground, the fires plunge ever deeper into the thawing tundra, seeking more and more fuel. In some cases, the fires are reported to have burned the ground to a depth of 3 feet or more, turning both Earth and Tundra into blackened soot while pumping heightening volumes of CO2 into the atmosphere. The dark smoke aloft lifts away, eventually finding a resting place on sea ice or glaciers. There the heating feedback continues over ominously Dark Snow.
The whole terrible process continues until the globe at last tilts away from the summer sun, shutting the whole dreadful feedback down. But each year, we fuel it more through our burning of fossil fuels. Each year, the global greenhouse gas heat forcing ratchets higher and more and more tundra land thaws as the burn line creeps north, providing ever more fuel for the Arctic flames.
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