The honest broker quote mine
Ethon, hovering high above the Colorado train wreck has spotted a world class quote mine from the USCCSP chapter on abrupt climate change due to sea level rise. As pointed out first by Mary-Elena Carr at the Columbia Climate Blog, Roger Jr has engaged in Climate Cabala, reading the report to say
based on a tasty bit on page 92,
So when asked . . . how high will sea levels rise in the 21st century?
. . . the scientifically correct answer, according to this report, is “we don’t know.” It could be large, but it also could be similar to that of the 20th century (and I am implying nothing of probability here). Of course, such a situation lends itself to cherrypicking and political Rorschaching. So the proper response might be “Well, what do you want it to be?”
Considerable effort is now underway to improve the models, but it is far from complete, leaving us unable to make reliable predictions of ice-sheet responses to a warming climate if such glacier accelerations were to increase in size and frequency. It should be noted that there is also a large uncertainty in current model predictions of the atmosphere and ocean temperature changes which drive the ice-sheet changes, and this uncertainty could be as large as that on the marginal flow response.Of course, our honest broker (count your fingers bunnies) doesn't want you to RTFR, because if you did, you might see that the uncertainties all lie in the direction of much higher sea level rise than predicted in the AR4, in other words, the AR4 remains the minimum base for sea level rise and things could be worse, but are unlikely to be better. The report concludes that
Recent rapid changes at the edges of the Greenland and West Antarctic ice sheets show acceleration of flow and thinning, with the velocity of some glaciers increasing more than twofold. Glacier accelerations causing this imbalance have been related to enhanced surface meltwater production penetrating to the bed to lubricate glacier motion, and to ice-shelf removal, ice-front retreat, and glacier ungrounding that reduce resistance to flow. The present generation of models does not capture these processes. It is unclear whether this imbalance is a short-term natural adjustment or a response to recent climate change, but processes causing accelerations are enabled by warming, so these adjustments will very likely become more frequent in a warmer climate. The regions likely to experience future rapid changes in ice volume are those where ice is grounded well below sea level such as the West Antarctic Ice Sheet or large glaciers in Greenland like the Jakobshavn Isbrae that flow into the sea through a deep channel reaching far inland. Inclusion of these processes in models will likely lead to sea-level projections for the end of the 21st century that substantially exceed the projections presented in the IPCC AR4 report (0.28 ± 0.10 m to 0.42 ± 0.16 m rise).Even better, in the comments RP uses his misrepresentation to bash Joe Romm for actually having read the report, and accepts the acclimation of the crowd for his honest broker act.
Hat tip to the Columbia Climate blog
PS - if you wonder what Ethon has been up to