Archive for February, 2010

On “the real holes in climate science”

February 10, 2010

[This post is based on a question I got in response to a previous post but thought it deserved a short post on its own as there’s a few interesting points.]

There’s been a lot of bad press recently for climate science but a lot of has focused on very minor issues. For example, most of the coverage on the UEA CRU email leak/theft/hack (so-called climategate) has focused on what some of the “skeptic” community wished was in the emails rather than what was really there. The Guardian has gone over some of the issues from the leak in depth in a recent series of articles, although this seems like a lot of focus on old issues. As Prof. Phil Jones himself said in a recent interview in The Sunday Times: “I wish people would read my scientific papers rather than my emails”. Glaciergate was equally blown out of all proportion given that the original claim only appeared in one sentence in a 3000 page report.

In the midst of all this, Nature printed a nice feature looking at the real big gaps in climate science (Schiermeier 2010), but it is behind a paywall, which is a shame because it’s a good piece. So, I thought I’d provide a very quick summary here.

Regional climate prediction

We still don’t have sufficient computing power to run models at high enough resolution to make projections on the scale that would be useful to policy makers. This is clearly required to make big infrastructure decisions.

Precipitation

Projections of precipitation patterns are really hard to make as they depend on temperature changes, circulation changes, radiative balance changes and pollution (and, therefore, cloud condensation nuclei) changes. Yet precipitation changes will probably have the biggest impact on society.

Aerosols

The effect of aerosols (i.e. small solid particles or liquid droplets suspended in the atmosphere) is a big unknown. Different types do different things and its not really certain whether they have a generally cooling effect – by reflecting away solar radiation – or a warming effect – by promoting more cloud growth and trapping more terrestrial heat. That said, any cooling effect would be very unlikely to reverse the warming impact of greenhouse gases.

The tree-ring controversy

This relates mostly to the “hockey stick” graph and the reliability of the palaeoclimate data we use to put our current climate into perspective. It’s important that we learn from past climate changes as we only have one atmosphere and can’t do experiments with it. But it is not easy to get palaeoclimate data (tree rings, ice cores, sediment cores) or to interpret them properly.

So what is the “consensus”?

In a certain sense, when people talk about the “scientific consensus about climate change” they really mean little more than our understanding of the greenhouse effect, our impact on it and that things are very likely to get messy in the future. All the details are still very much under investigation.

Reference:

ResearchBlogging.orgSchiermeier, Q. (2010). The real holes in climate science Nature, 463 (7279), 284-287 DOI: 10.1038/463284a

Skepticism or denial?

February 3, 2010

Whilst I would describe myself as a scientific skeptic, in that I will try to investigate claims before coming to a judgement, I would not say I was a “climate change skeptic”. This term is often used to label those that are irrationally dismissive of the scientific evidence (or worse). Several commentators on climate issues, notably George Monbiot of the Guardian, have now started referring to many within this group as “climate change deniers” as it appears that any amount of evidence counter to their stance will alter their belief in that position. One prominent blogger, though, found the use of the denial tag unhelpful and has set himself the challenge, as a layperson, “to make sense of the global warming and climate change debates” via a new blog.

Now, though, we have an opportunity to test the scientific integrity of one of these skeptics. Anthony Watts, an American weather presenter, blogger and self proclaimed climate change skeptic, was instrumental in setting up a web campaign to survey the United States climatological surface station records – SurfaceStations.org. This is a laudable scientific aim, regardless of the fact that it was done in the belief that it would show that the surface temperature recording method was flawed and that the warming trend observed in the US was an artefact of the local micro-conditions.

The analysis on the website consists of quite a lot of not-very-scientific comments about photographs on how poorly sited some of these stations are. Watts has also published a report with some of the photographs alongside their temperature records. However, Matthew Menne (a scientist at the American National Climatic Data Center) and co-authors have published a peer reviewed, systematic analysis of the US surface station temperature records. The results show that the poorly located stations, as determined by SurfaceStations.org, actually show a negative bias relative to the well located sites. This means that the poorly located sites introduce an artificial cooling in the temperature record, not a warming as Watts predicted. Clearly, the uncovering of such a bias in the surface station network in the US means that the infrastructure requires tighter regulation as it is not, at certain locations, doing its job properly.

In this situation, I suspect that a true skeptic would be proud that their effort had highlighted a real issue and contributed to the scientific understanding. However, as SurfaceStations.org approached their investigation with the hypothesis that the network would introduce artificial warming, how will they react?

Reference:

ResearchBlogging.orgM. J. Menne, C. N. Williams, & M. A. Palecki (2010). On the reliability of the U.S. Surface Temperature Record Journal of Geophysical Research : doi:10.1029/2009JD013094

Links:

The paper can be found here
There is a more thorough analysis of the paper by the Skeptical Science blog
There is some comment in The Guardian’s Environment blog