So the researchers are playing catch up. But is does look that the Dutch engineer’s working assumption of 1.3–1.4 m sea level rise in 2100 CE is not so far off the mark.

Jeff,

4mm/yr would be if melting stops increasing today.

But melt is increasing with time.

If it increases at the same rate over the next century, we will
get 1 m by 2100.

But it is likely to increase faster …

Eric

The computer models aren’t as inaccurate as you may have been lead to believe. For example, let’s say you program all the variables, have the program ready, and want to know how well it might work.

Well… then you go back to 1800 and run the simulation to see if it gets accurate results about the weather for the last 208 years.

If it does, then you’re probably on the right track. If it doesn’t, you start over.

My understanding is that the computer models provide highly accurate results for the last 208 years. Are they likely to go badly wrong going forward…?

You’ll have to provide something concrete and scientific for me to believe it, and my understanding is that there is no such evidence.

This cancerous degeneration of the ice sheet is something not studied so much?

December 17th, 2008 at 6:42 pm
Jeff:

Yes, I meant linear increase. Should have been clearer. His point was one meter of SLR was “very likely” even if you do not take into account dynamic changes in ice sheets)

That one was bugging me. Thanks for the response.

Best comment in this thread so far. Thanks, Joe.

We are talking about alleged melting from the Greenland and Antarctic land based ice caps. There may be less sea ice in the arctic or melt pools on Greenland but that does not automatically mean the land based ice caps are experiencing a net loss in volume (i.e. the amount of melt is the greater than the new accumulation from snow fall).

Rignot has come up with a scheme that estimates numerous parameters with a climate model and claims that we have experienced a net loss ….

[JR: Rest of comment deleted because there is only so much disinformation any person can be expected to stomach. It isn't "alleged" -- it is actually confirmed by different methods. Again, I assume you self-medicate because modern medicine uses the same method Rignot does.]

More likely he is just calling for more measurement – just like every scientist does when they see something worth measuring. “Arbitrary number”? No.

If you don’t have any confidence in the models, just sit back and watch it happen. UIC’s cryosphere website shows the ice extent at both poles with daily updates. You can even see the ice melt pools on Greenland from Google Earth.

Or go to Glacier National Park and watch the glaciers melt.

As with most climate model outputs the 95% confidence intervals are likely large enough to cover any possible outcome from negative SLR to catastrophic postive SLR. This allows the modellers to claim that any real outcome is “consistent with” their models.

Of course, they don’t explain this detail to the press who merrily repeats the ‘average’ as if it was a proven fact when it really an arbitrary number that provides no useful information.