Hansen 1: Sea Level Rise

Hansen has posted some important thoughts about sea level rise on his website. In particular he has shortened his “Scientific reticence and sea level rise” paper and New Scientist has published it. The key conclusion:

[I]ce sheets will respond in a non-linear fashion to global warming — and are already beginning to do so. There is enough information now, in my opinion, to make it a near certainty that business-as-usual [emissions] scenarios will lead to disastrous multi-metre sea level rise on the century time scale.

This lead directly to his emissions strategy:

The global community must aim to restrict any further global warming to less than 1 °C above the temperature in 2000. This implies a CO2 limit of about 450 parts per million or less. Such scenarios require almost immediate changes to get energy and greenhouse gas emissions onto a fundamentally different path.

Hansen also offers some useful thoughts about recent research on Greenland and has been misunderstood by the media.


One Response to Hansen 1: Sea Level Rise

  1. llewelly says:

    We know enough about the carbon cycle to say that at least of the
    order of a quarter of the CO2 emitted in burning fossil fuels under a
    BAU scenario will stay in the air for an eternity, the latter defined
    practically as more than 500 years.

    This implies, that whatever we do, CO2 levels will still exceed 305 ppm 500 years from now. 305 ppm was about the level CO2 peaked at during the Eemian. In addition to cutting emissions to slow warming, we must also prepare for Eemian climate and sea level.