Global Climate Change: is it worth brushing off?

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  • Sat, Feb 18, 2012 - 12:19am

    #1001
    Doug

    Doug

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    Mark

Do you have a good sense of how big a threat the thawing of the permafrost is with other releases of methane in northern climes?  Is it a tipping point problem, or is it happening slowly enough that there won’t be a self perpetuating cycle of heating before the methane is removed from the atmosphere?  BTW, how is it removed from the atmosphere?

Doug

  • Sat, Feb 18, 2012 - 01:39am

    #1002

    Stan Robertson

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    Doug

Doug wrote:

Do you have a good sense of how big a threat the thawing of the permafrost is with other releases of methane in northern climes?  Is it a tipping point problem, or is it happening slowly enough that there won’t be a self perpetuating cycle of heating before the methane is removed from the atmosphere?  BTW, how is it removed from the atmosphere?

Doug

It probably is no worse threat than it was 900 years ago when Greenland was home to a thriving agricultural community and the arctic was a good deal warmer than today. Mark should comment on that as well.

Stan

  • Sat, Feb 18, 2012 - 02:19am

    #1003
    Doug

    Doug

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    Stan

Stan Robertson wrote:
Doug wrote:

Do you have a good sense of how big a threat the thawing of the permafrost is with other releases of methane in northern climes?  Is it a tipping point problem, or is it happening slowly enough that there won’t be a self perpetuating cycle of heating before the methane is removed from the atmosphere?  BTW, how is it removed from the atmosphere?

Doug

It probably is no worse threat than it was 900 years ago when Greenland was home to a thriving agricultural community and the arctic was a good deal warmer than today. Mark should comment on that as well.

Stan

I’m not familiar with the particulars of Greenland when the Norse settled there, but it strikes me there may be some significant differences.  First is the speed with which the warming happened then and now.  If warming is gradual, releases of methane would also be gradual and could be removed from the atmosphere without reaching critical levels since persistence of methane is quite a bit less than CO2.  Warming is happening faster than most scientists predicted now, particularly in the Arctic, which might lead to greater concentrations of methane than during the Greenland warming.  BTW, agriculture is returning to Greenland now: 

http://www.environmentalgraffiti.com/ecology/greenland-is-green-again/392

This is all speculation, which is why I asked.

Doug

  • Sat, Feb 18, 2012 - 03:20am

    #1004

    Stan Robertson

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    Doug wrote:Stan Robertson

Doug wrote:
Stan Robertson wrote:
Doug wrote:

Do you have a good sense of how big a threat the thawing of the permafrost is with other releases of methane in northern climes?  Is it a tipping point problem, or is it happening slowly enough that there won’t be a self perpetuating cycle of heating before the methane is removed from the atmosphere?  BTW, how is it removed from the atmosphere?

Doug

It probably is no worse threat than it was 900 years ago when Greenland was home to a thriving agricultural community and the arctic was a good deal warmer than today. Mark should comment on that as well.

Stan

I’m not familiar with the particulars of Greenland when the Norse settled there, but it strikes me there may be some significant differences.  First is the speed with which the warming happened then and now.  If warming is gradual, releases of methane would also be gradual and could be removed from the atmosphere without reaching critical levels since persistence of methane is quite a bit less than CO2.  Warming is happening faster than most scientists predicted now, particularly in the Arctic, which might lead to greater concentrations of methane than during the Greenland warming.  BTW, agriculture is returning to Greenland now: 

http://www.environmentalgraffiti.com/ecology/greenland-is-green-again/392

This is all speculation, which is why I asked.

Doug

According to the temperature records that have been extracted from the Greenland ice cores, temperatures there appear to have risen about 0.8 C between 850 and 900 A.D.  That is about the same 0.16 C per decade rise that has occurred globally three times within the last 150 years (1860-1880, 1910-1940 and 1975-2000). I have not seen anything that gives the corresponding rates of these relatively recent temperature increases just specifically for Greenland. It might be higher, but if so, it likely was much the same in each of the periods of rapid rise within the last 150 years.

Stan

  • Sat, Feb 18, 2012 - 06:27am

    #1005

    Mark Cochrane

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    Methane from the permafrost

Doug and Stan,

This is one of the less well defined feedbacks. There is obvious melting. We have so-called drunken forests in the arctic where trees are tipping every which way as the underlying permafrost melts.

Various melt lakes and ponds are steadily bubbling methane. I’ve seen videos of scientists lighting off the bubbles (link).  I’ve also seen a somewhat alarming increase in the amount of melt ponds across siberia in recent years. (see image)

This is all concerning but we don’t have a good handle on why methane levels rise in spurts. Here is the most recent atmospheric concentrations at Mauna Loa. Got this image from Wikipedia.

Putting things in a longer perspective though this is 800,000 years of atmospheric concentrations of methane (image from CSIRO). 800,000 years below 750ppb and the a sudden increase to 1800 ppb in the modern era.

 

Concentration increases in the last century are not subtle. Methane is a more powerful greenhouse gas than CO2, generally considered about 20 times on a molecule to molecule basis, luckily there is about a thousand fold less of it than CO2.  The good news is that it oxidizes within a few decades. The bad news is that the byproducts are H2O and CO2, additional greenhouse gases.

If you want to see a worst case analysis, for a sudden 100-fold increase in arctic methane release, in case a tipping point is reached check out this link (link). The bottomline would be an increase to roughly an equivalent of 500-750ppm CO2. We are currently just north of 390ppm. This wouldn’t be a runaway greenhouse but it would be at worst case IPCC scenarios.

 

Mark

  • Sat, Feb 18, 2012 - 06:36am

    #1006

    Mark Cochrane

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    Methane from the permafrost

Doug and Stan, (hmm, not sure why it wouldn’t post the images, they show up on my screen but dissappear in the post – below I stick links to them instead.

This is one of the less well defined feedbacks. There is obvious melting. We have so-called drunken forests in the arctic where trees are tipping every which way as the underlying permafrost melts.

Scroll down to the drunk forests inthis link (link)

Various melt lakes and ponds are steadily bubbling methane. I’ve seen videos of scientists lighting off the bubbles (link).  I’ve also seen a somewhat alarming increase in the amount of melt ponds across siberia in recent years. (see image)

Scroll down to siberian melt lakes (link)

This is all concerning but we don’t have a good handle on why methane levels rise in spurts. Here is the most recent atmospheric concentrations at Mauna Loa. Got this image from Wikipedia.

Recent methane (bottom right is best image)

Putting things in a longer perspective though this is 800,000 years of atmospheric concentrations of methane (image from CSIRO). 800,000 years below 750ppb and the a sudden increase to 1800 ppb in the modern era.

See image here (link)

 

Concentration increases in the last century are not subtle. Methane is a more powerful greenhouse gas than CO2, generally considered about 20 times on a molecule to molecule basis, luckily there is about a thousand fold less of it than CO2.  The good news is that it oxidizes within a few decades. The bad news is that the byproducts are H2O and CO2, additional greenhouse gases.

If you want to see a worst case analysis, for a sudden 100-fold increase in arctic methane release, in case a tipping point is reached check out this link (link). The bottomline would be an increase to roughly an equivalent of 500-750ppm CO2. We are currently just north of 390ppm. This wouldn’t be a runaway greenhouse but it would be at worst case IPCC scenarios.

 

Mark

 

Trying again

  • Thu, Feb 23, 2012 - 10:22am

    #1007

    gyrogearloose

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    Not my comment

Hi Mark

My entire post was quoting from Dr Chris Martensons’ only comment in this thread.

I had posted it here in response to recent queries here as to his position on AGW, and it appeared they had not seen this posting by him.

 

Cheers Hamish

  • Sun, Feb 23, 2014 - 04:11am

    #1008

    scribe

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    Excellent Australian Video

I found this video, of the ABC's "Catalyst" program, an excellent summary of the climate situation.

  • Mon, Feb 24, 2014 - 10:57am

    #1009

    scribe

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    Please delete my account

No matter what I post, it is "moderated" i.e. deleted by the wankers who run this forum.

There is no value to being a member here.

Please delete my account and all details attached thereto.

Fcuk you very much.

  • Wed, Jan 28, 2015 - 06:22pm

    #1010

    AKGrannyWGrit

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    Climate Change

Soooo climate change may not be all the fault of humans and therefore we don't need to have big government telling us exactly what to do or we're all gong to die. Gosh I was sure the sky was falling and scientists were going to ride in on their white horse and save us from ourselves.   

http://heartland.org/lord-christopher-monckton

AK GrannyWGrit

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