From the Arctic to Africa to the Amazon, More Troubling Signs of Earth Carbon Store Instability
The
time for debate is over. The time for rapid response is now. The
Earth System just can’t take our fossil-fueled insults to her any
longer.
*****
(These
Arctic and Siberian wildfires just keep getting worse and worse, but
what’s really concerning is they’re burning a big hole through
one of the Earth’s largest carbon sinks, and as they do it, they’re
belching out huge plumes of greenhouse gasses. Image source: LANCE
MODIS.)
22
July, 2016
Carbon
Spikes over the Arctic, Africa, and the Amazon
Today,
climate change-enhanced wildfires in Siberia and Africa are belching
out two hellaciously huge smoke clouds (see images below). They’re
also spewing large plumes of methane and carbon dioxide, plainly
visible in the global atmospheric monitors. Surface methane readings
in these zones exceed 2,000 parts per billion, well above the global
atmospheric average.
Even
as the fires rage, bubbles of methane and carbon dioxide are
reportedly seeping up from beneath the tundra — generating
big blisters of these heat-trapping gasses that are causing sections
of the Arctic soil to jiggle like jelly.
Greenhouse gas content in the blisters is, according
to this Siberian Times report, 7,500
parts per million CO2 and 375 parts per million methane. That’s
about 19 times current atmospheric CO2 levels and 200 times current
atmospheric methane levels. Overall, these carbon jiggle mats add to
reports of methane bubbling up from Arctic lakes, methane blowholes,
and methane bubbling up from the Arctic Ocean in a context of very
rapid Arctic warming.
(Methane
spikes over Siberia, Africa and the Amazon correlate with wildfires
and extreme drought conditions associated with human-forced climate
change. Add in carbon dioxide spikes over the same regions of Africa
and the Amazon and it begins to look like a visible amplifying
feedback signal. Image source: The
Copernicus Observatory.)
Meanwhile, a
global warming-enhanced drying of the Amazon rainforest appears
to be squeezing a substantial amount of these hothouse gasses into
the Earth’s atmosphere. Copernicus Observatory surface monitors
indicate pools of 600 to 800 parts per million CO2 concentrations
near and around the Amazon rainforest. These 100- to 200-mile-wide
spikes in CO2 concentration are
1.5 to 2 times current atmospheric concentrations.
These very high CO2 levels occur even as methane readings over the
Amazon are also abnormally high, a possible precursor signal that the
NASA-predicted Amazon rainforest wildfires this summer may be
starting to ignite.
Any
one of these instances might be cause for some concern. Taking all
these various observations together looks like a clear signal that
the Earth is starting to produce an increasingly strong carbon
feedback response to human-forced warming. If true, that’s some
pretty terrible news.
Human-Forced
Warming Warps the Carbon Cycle
Each
summer, the boreal forests of the Northern Hemisphere take a big
breath. In the warmer airs, leaves unfurl, grasses grow, and all
kinds of CO2-respiring organisms take hold. Together, they produce a
frenzy of activity, a riot of life gathering great stores of energy
for the next plunge into winter. Over time, this natural capture of
CO2 stores this atmospheric carbon in plant matter that ultimately
becomes soil, permafrost, or is buried in the Earth in the form of
various hydrocarbon stores.
It’s
this annual great growth and greening that, in large part, drives the
seasonal up-and-down swings of the global carbon cycle — a cycle
that, under stable conditions, would generate an annual wave in
atmospheric CO2 concentrations running over a long-term flat line.
(Surface
CO2 readings show boreal forest uptake of CO2 over Siberia,
Scandinavia, and parts of North America. Note the CO2 surface
hot-spots over the fire zones in Central Africa and over the
drought-stricken Amazon rainforest. Image source: Copernicus
Observatory.)
Ever
since the advent of the Industrial Revolution, human fossil-fuel
burning has been adding carbon to the atmosphere. The result is that
these seasonal swings, driven by plant respiration, have overlaid a
significant upward trend in atmospheric carbon, one
that this year pushed peak atmospheric CO2 values to near 408 parts
per million.
This is a level not seen in about 15 million years.
That
increase in its turn has dramatically warmed the Earth — a result
that has its own larger impact on plants, on the cycles that
influence their ability to take in carbon, and even on the older
carbon that was long ago stored in plants but is now sequestered in
the soil, permafrost and oceans.
(LANCE
MODIS satellite
shot shows extensive wildfires spewing large plumes of smoke over
Siberia and Africa. Meanwhile, very dry conditions in the Amazon
appear to be generating understory fires even as carbon is baked out
of the Equatorial soil. Click image to zoom in.)
Warm
the world up, as humans have, and you generate what, in scientific
parlance, is a carbon feedback. Overall, the ocean can take in less
atmospheric carbon and increasingly bubbles with thawing methane, the
soils can store less carbon even as more is baked out in the heat,
the plants and peats on balance burn more than grow, permafrost thaws
and releases its own carbon. It is this carbon-cycle response to
warming that is expected to add more carbon dioxide and methane into
the atmosphere on top of that already being released through the
harmful processes of fossil-fuel extraction and burning.
Warming
Forces More Carbon Out of Lands and Seas, Keeps More in the
Atmosphere — But How Much is Still Pretty Uncertain
How
much heat-trapping carbon the Earth System will ultimately add to
human fossil-fuel emissions is kind of a big scientific question,
which is answered in large part by how much fossil fuels humans
ultimately burn and how much heat is ultimately added to the Earth’s
oceans, glaciers, and atmosphere.
(A
sampling of climate model-projected Earth System CO2 feedbacks to
human-forced climate change. Note the high level of variation in the
model projections. It’s also worth noting that these model
projections did not include difficult-to-assess permafrost and
hydrate responses to warming over the period through 2100. Image
source:
Back
in 2007, the
IPCC estimated that around 87 parts per million of additional CO2
would be added to the world’s airs by 2100 (under
an apparent assumed final human-driven CO2 accumulation of 700 ppm)
as a result of this kind of carbon feedback to human warming. This
implied about a 20-percent positive CO2 feedback to warming.
However, the model projections were wide-ranging (from 4 to 44
percent) and the overall assessment drew criticism due to a lack of
inclusion of permafrost and hydrate feedback estimates.
In 2012, the
IPCC produced a more uncertain, complex, and unclear set of
projections that
notably didn’t include permafrost carbon feedback or methane
hydrate feedback model projections, the scientific understanding of
which is apparently still developing. But despite a good deal of
specific-issue uncertainty, the consensus appeared to state that over
the medium- (21st century) and long-terms (multi-century), we’d
have a significant amount of extra carbon coming from the Earth
System as a result of responses to a human-warmed atmosphere and
ocean.
(African
wildfires, whose smoke plumes are visible here, are just one of many
sources of carbon spikes around the globe triggered by human-forced
climate change. Amazon rainforest next?
NASA
seems to think so.
Image source: LANCE
MODIS.)
Overall,
there’s a decent amount of support for the notion that the Earth
System is pretty sensitive to warming, that it tends to respond to
even a relatively small amount of initial incoming heat in ways that
produce a good deal of extra carbon in the atmosphere. After all,
only a small change in the way sunlight hits the Earth is enough to
end an ice age and pump an additional 100 parts per million of CO2
out of the Earth’s carbon stores as a result. The added heat
forcing provided by the current human fossil-fuel emission is far,
far greater than the one that ended the last ice age.
It
is in this understanding and context that we should consider what
appears to be an increasing number of Earth System responses to a
human-forced warming that has currently exceeded 1 degree Celsius
above 1880s averages. It’s easy to envision that these responses
would grow in number and intensity as the Earth continues to
warm toward 2 C above 19th-century averages.
Links/Attribution/Statements
Hat
tip to TodaysGuestis
Hat
tip to Colorado Bob
Hat
tip to DT Lange
No comments:
Post a Comment
Note: only a member of this blog may post a comment.