Tuesday, March 23, 2010

the so-called “greenhouse gases”

not being a climate scientist, i cant tell if greenhouse gases are causing “global warming” or not, although evidence points in that direction…and being in the lake erie snow belt, where we have five months of winter, i really dont care if it warms a little…if lower manhattan floods, let them figure it out, no great loss to humanity…but recent stories indicating rapidly rising levels of greenhouse gases seem like they should be a cause for concern…lets review what we know…

first, ill link you to “The History of Atmospheric Carbon Dioxide on Earth”  excerpts follow:

The recent history of atmospheric carbon dioxide

Charles Keeling began precise monthly measurements of the concentration of carbon dioxide in 1958. He was the first to do so systematically and so his data have come to be known as the "The Keeling Curve." Learn more about Charles Keeling at http://scrippsco2.ucsd.edu/home/index.php �The measurements were made at the Mauna Loa Astronomical Observatory which is at the summit of an inactive volcano in Hawaii. Mauna Loa was chosen because it is far from major sources or sinks of carbon dioxide. Carbon dioxide concentrations measured at Mauna Loa are a good proxy for the average of the whole Earth.

keeling curve, atmospheric carbon dioxide

noaalogo (15K)

The black wiggles are a continuous record of the concentration of carbon dioxide in the Earth's atmosphere from 1958 to May 2007. NOAA (National Oceanic & Atmospheric Administration, which is a branch of the U.S. Department of Commerce) is the original source of the data which may be found at http://www.esrl.noaa.gov/gmd/ccgg/trends/ This is data collected by competent scientists and it is not controversial.

The black wiggles record the breathing of all the plants and animals on Earth. Plants must inhale carbon dioxide to grow and as they do so, they remove carbon dioxide from the atmosphere.  There are more plants growing in the Northern Hemisphere because there is more land mass in the Northern Hemisphere, as a glance at a globe will confirm. When all the plants in the Northern Hemisphere are growing during the summer, they remove significant amounts of carbon dioxide. The maximums occurs every year in May, at the beginning of the growing season. The minimums occurs every year in November, at the end of the growing season. All of this is quite visible on the graph.

If the general trend continues, the concentration of carbon dioxide will be 400 PPM within ten years. It is hard to avoid this conclusion. Nothing short of a large volcanic eruption or a nuclear war or a large meteorite strike would change this conclusion.

now, lets compare the above levels to some historical data:

Atmospheric carbon dioxide during the last four ice ages.

icecore data, atmospheric carbon dioxide

This graph puts it all together. It is a record of the concentration of carbon dioxide during the past four ice ages. The green part is from: http://www.ncdc.noaa.gov/paleo/icecore/antarctica/vostok/vostok_co2.html                                 The data comes from air bubbles trapped in ice taken from a two kilometer hole drilled into the Antarctic ice sheet. It is like the preceding Keeling curve except that it extends 415,000 years back in time instead of 50 years. The Keeling curve has been added to the right side as indicated by the black and red. The horizontal scale prevents showing any detail.

At 400 PPM, the amount of carbon dioxide currently in the atmosphere is unprecedented, at least in the past 415,000 years. The last time it reached even 300 PPM was 325,000 years ago.

for more information, read the entire History of Atmospheric Carbon Dioxide on Earth

so, since that report was prepared 3 years ago, where do we stand today? an article from reuters brings us up to date: CO2 at new highs despite economic slowdown - Levels of the main greenhouse gas in the atmosphere have risen to new highs in 2010 despite an economic slowdown in many nations that braked industrial output, data showed on Monday. Carbon dioxide, measured at Norway's Zeppelin station on the Arctic Svalbard archipelago, rose to a median 393.71 parts per million of the atmosphere in the first two weeks of March from 393.17 in the same period of 2009, extending years of gains"

ok, CO2 is now at levels never seen in history, and we seem to be surviving…but a few weeks back, another story broke, indicating that atmospheric methane is starting to get out of hand too…

Methane levels may see 'runaway' rise, scientists warn - Atmospheric levels of methane, the greenhouse gas which is much more powerful than carbon dioxide, have risen significantly for the last three years running, scientists will disclose today – leading to fears that a major global-warming "feedback" is beginning to kick in. For some time there has been concern that the vast amounts of methane, or "natural gas", locked up in the frozen tundra of the Arctic could be released as the permafrost is melted by global warming. This would give a huge further impetus to climate change, an effect sometimes referred to as "the methane time bomb". This is because methane (CH4) is even more effective at retaining the Sun's heat in the atmosphere than CO2, the main focus of international climate concern for the last two decades. Over a relatively short period, such as 20 years, CH4 has a global warming potential more than 60 times as powerful as CO2, although it decays more quickly.

and it also appears that the aforementioned “feedback loop” is already feeding back:

Science stunner: Vast East Siberian Arctic Shelf methane stores destabilizing and venting - NSF issues world a wake-up call: "Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.” (link to this report for NSF diagrams & video) Research published in Friday’s journal Science finds a key “lid” on “the large sub-sea permafrost carbon reservoir” near Eastern Siberia “is clearly perforated, and sedimentary CH4 [methane] is escaping to the atmosphere.” Scientists learned last year that the permafrost permamelt contains a staggering “1.5 trillion tons of frozen carbon, about twice as much carbon as contained in the atmosphere,” much of which would be released as methane.  Methane is  is 25 times as potent a heat-trapping gas as CO2 over a 100 year time horizon, but 72 times as potent over 20 years! The carbon is locked in a freezer in the part of the planet warming up the fastest (see “Tundra 4: Permafrost loss linked to Arctic sea ice loss“).  Half the land-based permafrost would vanish by mid-century on our current emissions path (see “Tundra, Part 2: The point of no return” and below).  No climate model currently incorporates the amplifying feedback from methane released by a defrosting tundra.

so, the atmosphere is growing increasingly strange, & it appears we may already have a runaway situation with these gases…as i dont see a solution at hand, this report is just FYI…but just in case they’re right about these gases causing an abrupt warming, dont be buying any florida real estate…

3 comments:

  1. Where is the tipping point? If we get to close to the brink, is there a turning point?
    Or will the planet [regulate its self] the way Greenspan said the financial markets would regulate its self.

    ReplyDelete
  2. Scientific American is asking the same question:
    Is Earth past the tipping point?

    ReplyDelete
  3. Since we are now outside the realm of recorded human experience we can only guess. It would appear that we're past the point of no return already.

    ReplyDelete