False-colour image of the UK acquired on 8th January 2010, following heavy snow storms which saw the UK blanketed in snow. These images were captured by the Advanced Along-Track Scanning Radiometer (AATSR) instrument on board ESA’s ENVISAT satellite. The images were generated using three spectral channels: red - 0.87 microns; green - 0.67 microns; blue - 0.55 microns. Vegetated surfaces are much 'brighter' in the near infra red region (0.87 micron channel) than in the visible regions, therefore these regions appear more ‘red’. (Images courtesy of G. Corlett, University of Leicester)
Climate change researchers faced more public humiliation this week, as claims that the Himalayan glaciers were set to melt by 2035 were shown to be unfounded. The Intergovernmental Panel on Climate Change (IPCC), a United Nations body, included the claim in a 2007 report aimed to feed into international negotiations.
However, after questions about the claims were raised shortly prior to December’s Copenhagen summit, it emerged that they were not based on the usual peer-reviewed sources that the IPCC uses. Instead, the source referred to was a 2005 report by the Worldwide Fund for Nature. In turn, that report cited as its source a 1999 New Scientist article reporting claims made by a researcher made in a brief telephone interview, that never made it into an academic journal.
“Clear and well-established standards of evidence were not applied properly,” the IPCC said in response to the news. “The IPCC regrets this.” Nevertheless, it also stressed that it stood by its ultimate conclusion on glaciers:
“Widespread mass losses from glaciers and reductions in snow cover over recent decades are projected to accelerate throughout the 21st century, reducing water availability, hydropower potential, and changing seasonality of flows in regions supplied by meltwater from major mountain ranges (e.g. Hindu-Kush, Himalaya, Andes), where more than one-sixth of the world population currently lives.”
With the IPCC having jointly won joint the 2007 Nobel peace prize with Al Gore for its efforts to disseminate knowledge on climate change, this is rightly judged to be a big knock to its credibility. Yet, the IPCC itself had already pointed out that climate science and scientists can be fallible, pointing out 54 ‘key uncertainties’ in the very same report containing the incorrect glacier claims. In this week’s Nature, Quirin Schiermeier points out that although these do not undermine the fundamental conclusion that humans are warming the climate, they do hamper efforts to plan for the future.
Schiermeier picks up on four major areas. In regional climate prediction, basic models don’t get more accurate than 1-3° of latitude, or 70-210 miles. This is especially troublesome in regions with varied terrain, for example when dealing with areas where two climatically different plains are separated by a mountain plateau. In precipitation, while models agree that global warming will dry equatorial areas and make areas nearer the poles wetter, they don’t agree on much else. Researchers are especially worried as their estimates for how much precipitation was due to change until now are already too small. In the third area, airborne liquid or solid particles in the form of atmospheric aerosols are thought to block and reflect heat from the sun. There is a great deal of uncertainty about how large an impact these have, especially given that nobody knows accurately how many particles are up there.
Tree rings are a particular cause for consternation. Used by modern researchers to get information about temperatures for the years before humanity had thermometers, some trees at northern latitudes now seem to be responding differently to temperature. No-one yet knows why and as long as this is the case, although evidence suggests that 1998 was the warmest year in a millennium, there will remain doubt. Yet even studies raising uncertainties show the current warming to be unprecedented, Schiermeier reports, and the IPCC again stands by its assertion that there is a greater than 90% chance that this is caused by human-produced increases in greenhouse gases.
The UK has recently been glacial: this has been picked upon by some as another reason why global warming is over-hyped. Contrary to such suggestions, Philip Eden, the president of the UK’s Royal Meteorological Society, chose to emphasise that the wonderful satellite photo above of the recent cold snap is “certainly not evidence that ‘climate change’ has ceased”. Instead he cites a number of factors, including a weak jet-stream and a blocking high-pressure system making it easier for cold Arctic winds to reach where I live than warmer Atlantic air. “Such year-to-year, regional anomalies are intrinsic; it is the long-term, global trend that is important when assessing climate change,” Eden said.