More Broken Panes in the Greenhouse

Apologies for my lack of blogging activity of late - I've had a busy Christmas period on both the work and home fronts. Some friends even managed to hold a pre-Chrsitmas BBQ on 22nd December - no, not a result of global warming in the UK, just a cool, pleasant evening and the heat from the BBQ itself.

Despite science historian Naomi Oreskes’s claim, repeated ad nauseum by greenhouse industry beneficiaries that there are few or no peer reviewed papers that dispute the still undefined ‘consensus’ on anthropogenic global climate change, such papers have not been hard to find during 2007. Some of the more recent papers containing inconvenient results, that I haven’t previously blogged, are briefly described below:

Surface:troposphere warming

According to climate models of enhanced greenhouse warming, the tropical troposphere should warm more than the surface. Recent publications have contradictory results despite using essentially the same data. The latest paper on this subject, by Douglass et al, suggests that model results and observed temperature trends are in disagreement in most of the tropical troposphere.

Interestingly, a poster presented by Penner and Andronova at the recent AGU meeting, entitled ‘Tropical atmosphere radiative budget 1985-2005’ seems to reconcile the differences between surface and troposheric warming, supporting the Douglass et al data, without necessarily disproving enhanced greenhouse warming.

Steve McIntyre of Climate Audit attended the conference and the following is extracted from his write-up:

"the tropical atmosphere has absorbed less energy and the Earth’s surface has gained energy which is consistent with the temperature increase in the tropics;

the tropical atmosphere has recently become less reflective and more absorbing while the Earth’s surface gained radiative energy; thus, the tropical atmosphere had recently become more transparent to the incoming radiation and there is an overall brightening of the Earth’s system;

none of the IPCC AR4 models simulates the overall brightening of the Earth system. The majority of the models show a loss of radiative energy by the tropical energy in the post-Pinatubo period, suggesting that the models have still not properly captured the feedbacks between temperature change and clouds."

Of course, there are also unresolved issues regarding a potential warm bias in the surface temperature data.

Climate sensitivity to CO2

A new paper by Chylek et al entitled:

Limits on climate sensitivity derived from recent satellite and surface observations

The climate sensitivity of 0.29 to 0.48 K/Wm-2 translates to warming between 1.1 and 1.8 deg C for doubling of CO2, supporting values close to the lower end of the IPCC range of 2 to 4.5 deg C. - Petr Chylek

Hurricanes

HURRICANES HAVE NOT INCREASED IN THE NORTH ATLANTIC

By William M. Briggs, Statistician

My paper on this subject will finally appear in the Journal of Climate soon. Download it here.

The gist is that the evidence shows that hurricanes have not increased in either number of intensity in the North Atlantic. I've only used data through 2006; which is to say, not this year's. But if I were to, then, since the number and intensity of storms this past year were nothing special, the evidence would be even more conclusive that not much is going on.

Now, I did find that there were some changes in certain characteristics of North Atlantic storms. There is some evidence that the probability that strong (what are called Category 4 or 5) storms evolving from ordinary hurricanes has increased. But, there has also been an increase in storms not reaching hurricane level. Which is to say, that the only clear signal is that there has been an increase in the variability of intensity of tropical cyclones.

Of course, I do not say why this increase has happened. Well, I suggest why it has: changes in instrumentation quality and frequency since the late 1960s (which is when satellites first went up, allowing us to finally observe better). This is in line with what others, like Chris Landsea at the Hurricane Center, have found.

I also have done the same set of models of global hurricanes. I found the same thing. I'm scheduled to give a talk on this at the American Meteorological Society's annual meeting in January 2008 in New Orleans. That paper is here.

In another paper, Vecchi and Soden find natural climate variations have bigger effect on hurricane activity than global warming:

Vecchi, G.A. and B.J. Soden. 2007. Effect of remote sea surface temperature change on tropical cyclone potential intensity. Nature, 450, 1066-1071.