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Thread: 450 ppm - when will we reach it?

  1. #1 450 ppm - when will we reach it? 
    Forum Professor
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    According to Tim Flannery we're there now.

    Flannery, whose recent book "The Weather Makers: How Man Is Changing the Climate and What It Means for Life on Earth," made best-seller lists worldwide, said the data showed that the amount of carbon dioxide and other greenhouse gas emissions had reached about 455 parts per million by mid-2005, well ahead of scientists' previous calculations.
    http://ap.google.com/article/ALeqM5j...gCvrwD8S5K5NG0


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  3. #2  
    Forum Isotope Bunbury's Avatar
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    Apparently Mr. Flannery has got his knickers in a twist. The CO2 equivalent that he quotes does not account for negative forcings from aerosols and sulfates so overstates the effective value.

    The important number is CO2_e (Total) which is around 375 ppmv. Stabilisation scenarios of 450 ppmv or 550 ppmv are therefore still within reach. Claims that we have passed the first target are simply incorrect, however, that is not to say they are easily achievable. It is even more of a stretch to state that we have all of a sudden gone past the 'dangerous' level. It is still not clear what that level is, but if you take a conventional 450 ppmv CO2_e value (which will lead to a net equilibrium warming of ~ 2 deg C above pre-industrial levels), we are still a number of years from that, and we have (probably) not yet committed ourselves to reaching it.
    http://www.realclimate.org/index.php...switch_lang/sk

    All is not yet lost. We still have a little time to figure out how to stick all the new CO2 in the ground instead of into the air.

    http://wpweb2.tepper.cmu.edu/ceic/pd...uestration.pdf


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  4. #3  
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    Evidently some scientists (one such proponent being in East Anglia) are thinking along the lines you mention.

    Scientists are considering a plan to combat climate change by dumping millions of tons of iron into the ocean to alter its chemical make-up.
    This plan is in the mobilisation stage.

    http://www.timesonline.co.uk/tol/new...cle2511952.ece

    Looks like a bumpy ride ahead.

    Here's a commentary:

    http://sciencenow.sciencemag.org/cgi...ll/2007/1010/2

    The prospect of selling carbon credits earned through iron dumps has attracted a number of commercial ventures, including Climos. But critics, including some leading oceanographers, say corporate profits could taint research, or that the risks, which could include the growth of harmful algal blooms, outweigh the possible benefits.
    Once the ocean becomes a place to fertilise, in order to make carbon credits (one small transaction away from cash) I fear we are in over our heads.
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