A
Dangerous Dance of Frost and Flame: More Than 100 Wildfires Now
Raging Along Siberian Melt-Freeze Line
(Multiple wildfires raging in the Amur region of Russia on April 23, 2014. Image source: LANCE-MODIS.)
23
April, 2013
Anomalous,
global-warming-enhanced, fires continued to erupt across Eastern
Russia this week, chasing a rapidly receding freeze line north and
into zones still frozen, but starting to shake off ice cover far too
soon for comfort.
According
to reports from Radio
Free Europe,
more than 5,000 pieces of heavy equipment and many more firefighters
are now battling blazes throughout Siberia this week. As of April
20th, more than 100 blazes were reported in numerous regions
including: the Orenburg area around Lake Baikal, the Amur region, the
Birobidzhan Autonomous Oblast, the Primorsky Krai, and the Far
Eastern region of Russia.
The
fires come as temperatures ranging from 5-18 C above average
continued throughout a region that has experienced hotter than normal
temperatures all winter and on into spring of 2014.
For
example, the average April high temperature for the region of Lake
Baikal is typically a frigid 28 F, while this week is expected to see
highs in the lower to middle 40s. Further east, the temperature
extremes are more radical. In Amur Blagoveshchensk, the average low
is about 27 degrees F for this time of year, the average high, about
50. But today the low was 52 and the high is forecast to be 78 — 25
and 28 degrees above average respectively.
All
across Eastern Russia, the story is the same: above average warmth,
early thaw, summer-like temperatures in spring time. It has been this
way day after day, month after month. Since 2010, the story has
mostly been the same: early thaw, record or near record heat, amazing
fire hazard. Even more concerning, the situation is steadily growing
worse.
How
Global Warming is Turning the Siberian Tundra into a Firetrap
Winters
during cold regions are typically comparatively dry events. Though
snows may pile up, the water content of the snows amount to much less
moisture than it would seem. During spring, a gradual thaw ensures
this moisture keeps the thin, top layer of soil above the permafrost
(called the active layer) from drying out too rapidly. Typically only
inches to a few feet in depth, this layer is far more susceptible to
drying than a deeper layer with access to greater moisture sources at
depth. But only frozen or melting permafrost currently rest below the
active layer, creating a moisture barrier or worse — adding a
potential fuel source for wildfires.
(Eastern Russia in a hot zone. Hot atmospheric ridge and coincident extreme temperature anomalies stretching from Southeast Asia, up through China and Eastern Russia and on up through the polar region. Information Source: NOAA Global Forecast Systems Model. Image source: University of Maine.)
In
years of warmer than usual temperatures, as has happened more and
more often under the current regime of human-caused warming, the thaw
occurs rapidly and the active layer quickly dries out. This loss of
moisture amplifies into a kind of tundra drought that can block
atmospheric moisture flows and prevent rainfall, compounding the
drying problem until the more energetic storms of summer arrive.
In
addition, expanding zones of thawing permafrost provide two added
fuel sources for wildfires. Tundra melt in high water content areas
forms into wet thermokarsts, mires or melt ponds that vent methane
gas in high enough concentration to burn. Tundra melt that rapidly
dries after thaw forms into a peat-like basement layer that can burn
and smolder for long periods once ignited.
On
average, temperatures have been rising by about .4 C per decade
throughout Siberia. So almost every spring now falls into what would
typically be called a hot year. In addition, amplification of Jet
Stream wave patterns deliver proportionately more heat to regions in
the up-slope of these high amplitude atmospheric pulses, forming hot,
high pressure ridges. And this year, the heat ridge has consistently
formed over China, Mongolia and Eastern Siberia — the region of the
current large fire outbreaks.
(Siberian wildfires burning on the shores of still-frozen Lake Baikal in southern Siberia on April 23, 2014. Image source: LANCE-MODIS.)
As
a result, what we are seeing is an extraordinary outbreak of intense
wildfires directly adjacent to still melting snow and frozen lakes. A
surreal event that reminds one of the ever-at-war frost and fire
giants of ancient Viking legend. But these giants, the fire giants at
least, are a direct result of an ongoing and ever increasing
human-caused heating of our world.
Links:
No comments:
Post a Comment
Note: only a member of this blog may post a comment.