Friday, May 2, 2008

Climate Science, Fantasy and Reality

In November last year, less than six months ago, the world's most recognized and esteemed climate scientists and other members of the Intergovernmental Panel on Climate Change gathered in Valencia, Spain to formally ratify the AR4 Synthesis Report on climate change. According to information presented on the title page of this report the authors of the draft from which the report was put together included Dr. Rajendra Pachauri, Chairman of the IPCC and Dr. Stephen Schneider, the prominent environmental biologist and climate scientist. In Section 3.2 of the report, titled "Projections of future changes in climate" (page 45) the report states:

For the next two decades a warming of about 0.2°C per decade is projected for a range of SRES emissions scenarios . . . Since the IPCC’s first report in 1990, assessed projections have suggested global averaged temperature increases between about 0.15 and 0.3°C per decade from 1990 to 2005. This can now be compared with observed values of about 0.2°C per decade, strengthening confidence in near-term projections [my emphasis].

Six months is apparently a long time in climate science. According to the abstract of a letter published in the May 1, 2008 edition of Nature five European-based scientists make the following rather fascinating forecast for global temperatures over the next decade:

Our results suggest that global surface temperature may not increase over the next decade, as natural climate variations in the North Atlantic and tropical Pacific temporarily offset the projected anthropogenic warming.

Hmmm, projections of a continued, reasonably steady increase in global temperatures made just six months ago are now, apparently, way, way past their pull date. But, don't be fooled by this short term inability to get it even remotely right - the long term consensus projections remain correct! Indeed, the media spin process already underway from climate scientists suggests a perception of the forecast's likely accuracy as well as a deep concern for the effect it will have on public opinion. In an astonishing piece of journalistic nonsense on the BBC website, an article by Richard Black acknowledges that the Atlantic Multidecadal Oscillation (AMO) may be responsible for the increase in temperatures during the 1940's but then stops short of suggesting that the same could have been the case for the warming period from the mid-1970's to the recent past. He then quotes Noel Keenlyside of the Leibniz Institute of Marine Sciences, one of the authors of the above noted Nature letter:

"One message from our study is that in the short term, you can see changes in the global mean temperature that you might not expect given the reports of the Intergovernmental Panel on Climate Change (IPCC) . . . In the long term, radiative forcing (the Earth's energy balance) dominates. But it's important for policymakers to realise the pattern."

Ah, yes, the pattern itself is crystal clear even if we are confused about the short term details. An easily arranged visit to the UK's Hadley Centre website suggests just how much the short term details are indeed confused. Prominately displayed second from the top under "Latest News and Events" is the tag titled "Climate Change and Global Variability". Click on this and you can quickly read the following piece of spin:

"There are a number of natural factors contributing to so-called interannual variability, the single most important being the El Niño Southern Oscillation or ENSO. The global climate is currently being influenced by the cold phase of this oscillation, known as La Niña (see Met Office: Expert speaks on La Niña).

The current La Niña began to develop in early 2007, having a significant cooling effect on the global average temperature. Despite this, 2007 was one of the ten warmest years since global records began in 1850 with a temperature some 0.4 °C above average.

The La Niña has strengthened further during early 2008 and is now the strongest since 1988/89, significantly contributing to a lower January temperature in 2008 compared to recent years. In addition, global average temperature has been influenced by very cold land temperatures in parts of the northern hemisphere and extensive snow cover.

However, once La Niña declines, it is very likely that renewed warming will occur as was the case when the Earth emerged from the strong La Niña events of 1989 and 1999."

Note that this posting was made on March 5th, less than two months ago. While in line with the IPCC's pronouncement made the previous November, the posting looks more than a little silly given the Nature letter noted above. One wonders how long this post will stay on the Hadley Centre website. At least it is preserved here for posterity.

Getting back to the BBC piece, we come just a bit later to the following desparate spin line by Mr. Black:

"The projection [of cooling temperatures over the next decade] does not come as a surprise to climate scientists, though it may to a public that has perhaps become used to the idea that the rapid temperature rises seen through the 1990s are a permanent phenomenon."

The only comment needed here is a reference to the IPCC statement made six months ago made above. Just six months ago, climate scientists had "strengthened confidence" in near term projections of monotonic temperature increases; however they are in no way surprised that their "strengthened confidence" in these projections has been revealed so quickly to be completely incorrect.

Regarding monotonic temperature increases, a piece by Andrew Revkin in the New York Times regarding the
Nature letter produces a quote by Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research in Boulder, Colo.:

“Too many think global warming means monotonic relentless warming everywhere year after year,” Dr. Trenberth said. “It does not happen that way.”

Roger Pieke Sr. has an interesting reaction to this comment in his blog:

This is an amazing error [by Trenberth]. Global warming does require a more-or-less monotonic increase in warming (in the absence of a major volcanic eruption) as illustrated in all available multi-decadal global model runs . . . . This essentially monotonic report is even emphasized in the 2007 IPCC Summary for Policymakers".

There you have it - climate science, fantasy and reality. Much more to come!!

No comments: