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Nature on stunning new climate feedback: Beetle tree kill releases more carbon than fires

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"Nature on stunning new climate feedback: Beetle tree kill releases more carbon than fires"

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He that troubleth his own house shall inherit the wind.” A Biblical proverb for our times, it turns out….

The bark beetle is devastating North American trees (see “Climate-Driven Pest Devours N. American Forests“).

beetle.jpgGlobal warming has created a perfect climate for these beetles — Milder winters since 1994 have reduced the winter death rate of beetle larvae in Wyoming from 80% per year to under 10%, and hotter, drier summers have made trees weaker, less able to fight off beetles. [Picture shows forests turned red by beetle.]

New reseach published in the journal Nature, “Mountain pine beetle and forest carbon feedback to climate change,” (subs. req’d, abstract reprinted below), quantifies the current and future impact just from the beetle’s warming-driven devastation in British Columbia:

the cumulative impact of the beetle outbreak in the affected region during 2000–2020 will be 270 megatonnes (Mt) carbon (or 36 g carbon m-2 yr-1 on average over 374,000 km2 of forest). This impact converted the forest from a small net carbon sink to a large net carbon source.

No wonder the carbon sinks are saturating faster than we thought (see here) — unmodeled impacts of climate change are destroying them:

Insect outbreaks such as this represent an important mechanism by which climate change may undermine the ability of northern forests to take up and store atmospheric carbon, and such impacts should be accounted for in large-scale modelling analyses.

Any “good news” here? Only if you like very dark irony. The accompanying news story (here, subs. req’d) notes:

Even if climate change brings further warm winters to the region, however, experts think this infestation has probably peaked. Mountain pine beetles can only reproduce in the largest trees, which were abundant thanks to a growth spurt after wildfires raged across western North America 80 to 140 years ago. Soon 80 to 90% of those large trees will be gone, Kurz says. “The beetle will eat itself out of house and home, and the population will eventually collapse.”

Hmm. “Eat itself out of house and home. Does the bark beetle sound like any other species we know? Finally, the species formerly known as homo sapiens sapiens is no longer alone in its self-destructive quest to destroy its habitat. Inhert the wind, indeed.

“The pine beetle infestation is the first major climate change crisis in Canada” notes Doug McArthur, a professor at Simon Fraser University in Vancouver. “We’re seeing changes in [mountain pine beetle] activity from Canada to Mexico,” said Forest Service researcher Jesse Logan in July 2004 (here), “and the common thing is warming temperatures.” In a May 2006 speech on climate change, Senator Lisa Murkowski of Alaska pointed out that the tremendous recent warming had opened the door to the “voracious spruce bark beetle,” which devastated over three million acres in Alaska, “providing dry fuel for outbreaks of enormous wild fires.”

A 2005 study, led by the University of Arizona, with Los Alamos National Laboratory and the U.S. Geological Survey, “Regional vegetation die-off in response to global-change-type drought,” examined a huge three-million acre die-off of vegetation in 2002-2003 “in response to drought and associated bark beetle infestations” in the Four Corners area (Arizona, New Mexico, Colorado, and Utah). This drought was not quite as dry as the one in that region in the 1950s, but it was much warmer, hence it was a global-warming-type drought. The recent drought had “nearly complete tree mortality across many size and age classes” whereas “most of the patchy mortality in the 1950s was associated with trees [greater than] 100 years old.”

Most of this tree death was caused by bark beetle infestation, and “such outbreaks are tightly tied to drought-induced water stress.” Healthy trees defend themselves by drowning the tiny pine beetles in resin. Without water, weakened, parched trees are easy meals for bugs.

One final note: This catastrophic climate change impact and its carbon-cycle feedback were not foreseen even a decade ago — which suggests future climate impacts will bring other equally unpleasant surprises, especially if we don’t reverse our emissions path immediately.

Here is the full Nature abstract:

The mountain pine beetle (Dendroctonus ponderosae Hopkins, Coleoptera: Curculionidae, Scolytinae) is a native insect of the pine forests of western North America, and its populations periodically erupt into large-scale outbreaks. During outbreaks, the resulting widespread tree mortality reduces forest carbon uptake and increases future emissions from the decay of killed trees. The impacts of insects on forest carbon dynamics, however, are generally ignored in large-scale modelling analyses. The current outbreak in British Columbia, Canada, is an order of magnitude larger in area and severity than all previous recorded outbreaks. Here we estimate that the cumulative impact of the beetle outbreak in the affected region during 2000–2020 will be 270 megatonnes (Mt) carbon (or 36 g carbon m-2 yr-1 on average over 374,000 km2 of forest). This impact converted the forest from a small net carbon sink to a large net carbon source both during and immediately after the outbreak. In the worst year, the impacts resulting from the beetle outbreak in British Columbia were equivalent to 75% of the average annual direct forest fire emissions from all of Canada during 1959–1999. The resulting reduction in net primary production was of similar magnitude to increases observed during the 1980s and 1990s as a result of global change. Climate change has contributed to the unprecedented extent and severity of this outbreak. Insect outbreaks such as this represent an important mechanism by which climate change may undermine the ability of northern forests to take up and store atmospheric carbon, and such impacts should be accounted for in large-scale modelling analyses.

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18 Responses to Nature on stunning new climate feedback: Beetle tree kill releases more carbon than fires

  1. Sorghum Crow says:

    And don’t forget that the beetle-killed trees are excellent fuel for forest fires. I was in Idaho last summer and some of the forests provided a perfect air-fuel mix for enormous fires. This summer may be a bad one for fires and CO2.

  2. Mauri Pelto says:

    I have hiked the same trails in the North Cascades of Washington to reach the glaciers we measure, every year for 25 years. After the warmth of 2003-2005 bark beetles have moved in and devastated the trees in one of the valleys, they will I suppose eat their way through the system, but in the meantime the forest is dying, and then forest fire danger will go up etc. I have a hard time seeing a silver lining to this. The unprecedented size of this outbreak, according to a seventy year resident of the valley, is in step with the rapid glacier loss in the same valley. Not as photogenic as some global warming impacts, but faster.

  3. Pahbs says:

    I been examining this damage in B.C. with satellite data from 2000-2006. The amount of damaged forest and the spread is starting and occurs across a regional scale. We are talking around 9-10 million hectares of insect damaged/destroyed trees.

  4. tidal says:

    Joe said: “This catastrophic climate change impact and its carbon-cycle feedback were not foreseen even a decade ago — which suggests future climate impacts will bring other equally unpleasant surprises, especially if we don’t reverse our emissions path immediately.”

    Kind of reminds one of “unknown unknowns”… and, grimly, they don’t seem to be symmetrically balanced in terms of good news/bad news surprises…

    And of course, there was this from last year:
    “Hurricane Katrina killed or severely damaged 320 million large trees in Gulf Coast forests, which weakened the role the forests play in storing carbon from the atmosphere. The damage has led to these forests releasing large quantities of carbon dioxide into the atmosphere. ”
    http://www.nasa.gov/mission_pages/hurricanes/archives/2007/katrina_carbon.html
    “trees killed by Katrina will release about as much global warming pollution into the air as all the trees across the nation soak in over the course of one year, according to a study by Jeff Chambers, a Tulane University biology professor.” http://www.npr.org/templates/story/story.php?storyId=17814049

  5. greg says:

    And what of the CO2 emmissions from the inevitable fires? I wonder at the possibility that while large fires will indeed release a pulse of CO2, the long term impacts might be less clear. fire will open up some of these now dead forests and release a mighty amount of nutrients; the natural outcome will be millions fo acres of rapidly growing, carbon fixing saplings. While the entire saga will likely still be a net atmospheric CO2 contributor, we ought not assume that the long term impacts of the fire itself will augment this problem. In fact, there is large likelihood that fire suppression is a part of the problem here. natural, uninterupted fire cycles might have created a greater patchwork of forest ages that could have slowed the beetles’ progression.

    My point: don’t let’s get all down on fire.

    In fact, even the beetles are a great regulator of landscape level diversity. Clearly the problem is a climate change mediated population explosion that is scary is hell, but the beetles themselves ain’t all bad (I am not suggesting this post says otherwise; I just feel compelled to defend the little critters: this is OUR fault).

  6. David B. Benson says:

    Source of biomass for bio-energy?

  7. paulm says:

    I think we are on the other side of a tipping point here. see …

    http://uk.reuters.com/article/environmentNews/idUKL1629341920080417

    Basically we are now hot enough that forest are going to be burning out of control from now on with dire consequences (Beetle or not).

  8. HumansFirst - EarthSecond says:

    What you are descibing is the perfect script for another science fiction movie. Maybe Al Gore could direct.

    The earth is still recovering from the Little Ice Age. There is nothing unusual about the earth’s current temperatures. It has been warmer in the recent past. This is just more speculative hand-wringing alarmism with a big dab of science fiction; fear mongering at its worst.

    I guess it helps sell books, huh Joe?

  9. Joe says:

    HumansLast: The Earth is now overshooting any recent temperatures. And T is rising much faster than it has before.

    Helps sell books, HumansLast? Who knew you were a comedian?

  10. Robert says:

    270MT is not good news, but is small beer compared to the 8000MT of fossil fuel we burn each year.

    The situation in Indonesia is worse.

    http://www.wetlands.org/publication.aspx?id=51a80e5f-4479-4200-9be0-66f1aa9f9ca9

    **************************************************************
    It was found that current likely CO2 emissions of drained peatlands caused by decomposition only, amounts to 632 Mt/y (between 355 and 874 Mt/y). This emission will increase in coming decades unless land management practices and peatland development plans are changed, and will continue well beyond the 21st century.
    In addition, over 1997-2006 an estimated average of 1400 Mt/y in CO2 emissions was caused by peatland fires that are also associated with drainage and degradation. The current total peatland CO2 emission of 2000 Mt/y equals almost 8% of global emissions from fossil fuel burning. These emissions have been rapidly increasing since 1985 and will further increase unless action is taken. Over 90% of this emission originates from Indonesia, which puts the country in 3rd place (after the USA and China) in the global CO2 emission ranking.
    **************************************************************

  11. HumansFirst EarthSecond says:

    Joe,

    I’m not quitting my day job.

    So I take that to mean book sales are not in the “robust” catagory? Try a different topic next time. Maybe a survivalist cookbook, with a chapter on cannibalistic delicacies? (Ted Turner could assist with some recipes)

    What about Holocene Maximum? Medieval warm period?

    Astrophysicists are predicting another “little ice age” soon.

  12. Eli Rabett says:

    Every bit helps or hurts. You can see this with the fisking that Joe Romm’s wedge proposals met. Yes we might need more, we also might need less, but to refuse to do anything because we need to wait for the perfect proposal is to guarantee failure. It is not unreasonable to suspect the motives for these demands are to avoid taking any action. We need to start taking action now.

  13. David B. Benson says:

    HumansFirst EarthSecond wrote “Astrophysicists are predicting another “little ice age” soon.”

    I don’t believe you.

  14. Ludwig says:

    David B. Benson: The Livingston and Penn paper (National Solar Observatory in Tucson) entitled: “Sunspots may vanish by 2015″ is suggesting that another “litttle ice age” could happen soon.

  15. Bill McEwen says:

    25 million acres in Canada. 1.5 million acres in Colorado. .5 million acres
    in S. CA. This is just part of the toll on the western North American continent because of these climate-forced, temperature driven bark beetle
    infestations. And who is going to guarantee these ecosystems are going to
    return when we’re changing the whole climate system that made them possible in the first place?
    In the Colorado Rockies, the bark beetle infestations are already impacting
    key watersheds that feed water to millions of Westerners. How soon will
    these catastrophic beetle infestations devastate the California Sierra’s, our
    other key watershed? What will this very abrupt, non-linear series of events mean for already decreasing snowpack, and streamflow? These
    bark beetle infestations, and the other FOREST DISTURBANCE REGIMES
    such as drought and fire are striking at the very heart of our civilization.
    Water is life, so they say. What do we do when the watersheds have all
    been destroyed?

  16. kiwichick says:

    water

    www ceto.com.au

  17. Find out what the US Forest Service has done recently about beetle kill – you’ll be amazed:

    NPR – ODC for Pine beetles – listen about pre-arming trees to fight pine beetles visit http://tinyurl.com/maszre