Of possible interest to our readers, there was an interview yesterday on the BBC (“Today Programme”) regarding the supposed controversy about the “Hockey Stick”: A climate scientist Professor Michael Mann suggests global warming is caused by mankind (mp3 file). Also available on the BBC website is the real audio file of the interview.
Archives for February 2005
Nature this week published a letter from Dr. Huang (U. Mich) highlighting how this ‘brave new world’ of science blogging works. He writes:
I was concerned to find that … [a figure] included an outdated and erroneous reconstruction of borehole data. … In my view, the website should have used a later version … To be fair, the authors of the website added a correction after I drew their attention to this.
In an early post, we used a figure that contained a minor error regarding how a borehole temperature reconstruction had been scaled. This mistake had been properly corrected in the literature, and so this was indeed an oversight on our part. Dr Huang was kind enough to remind us of this and we amended the caption immediately to point this out and direct readers to the correction should they be interested. Since this mistake was not central to the point being made in the post, we left the original figure in place.
The Internet is nothing if not flexible, and unlike in journals where mistakes can persist an awfully long time, we are able to correct such problems very quickly. In this respect, Dr. Huang’s letter seems to indicate that things are actually working quite well here.
We would like to take this opportunity to re-iterate our commitment to getting the science right, and as importantly, getting it right in real-time. We welcome all corrections or clarifications and we will endeavour to fix any errors, great or small, as quickly as we can.
A lot of press and commentary came out this week concerning a presentation and press release from Tim Barnett and Scripps colleagues presenting at the AAAS meeting (The Independent, John Fleck ,(and again) David Appell…etc). Why did this get so much attention given that there is no actual paper yet?
by Gavin Schmidt and Caspar Amman
Due to popular demand, we have put together a ‘dummies guide’ which tries to describe what the actual issues are in the latest controversy, in language even our parents might understand. A pdf version is also available. More technical descriptions of the issues can be seen here and here.
This guide is in two parts, the first deals with the background to the technical issues raised by McIntyre and McKitrick (2005) (MM05), while the second part discusses the application of this to the original Mann, Bradley and Hughes (1998) (MBH98) reconstruction. The wider climate science context is discussed here, and the relationship to other recent reconstructions (the ‘Hockey Team’) can be seen here.
NB. All the data that were used in MBH98 are freely available for download at ftp://holocene.evsc.virginia.edu/pub/sdr/temp/nature/MANNETAL98/ (and also as supplementary data at Nature) along with a thorough description of the algorithm.
This is just to note some personnel changes at RealClimate. Amy Clement is unfortunately too overcommitted to be able to participate as much as she would like, and so is dropping out of the team. She states: “I fully support what the contributors of RealClimate are doing. It is a real service to both the community of climate scientists and to the general public”. To balance that, we welcome aboard paleoceanographer Thibault de Garidel (Rutgers) , who some francophiles may have noticed has been helping organise the French translations of some of the posts. And of course, if there are any other scientists out there who’d like to contribute, we would love to hear from you.
by William Connolley and Eric Steig
The 10th Feb edition of Nature has a nice paper “Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data” by Anders Moberg, DM. Sonechkin, K Holmgren, NM Datsenko, & W Karlin (doi:10.1038/nature03265). This paper takes a novel approach to the problem of reconstructing past temperatures from paleoclimate proxy data. A key result is a reconstruction showing more century-scale variability in mean Northern Hemisphere temperatures than is shown in previous reconstructions. This result will undoubtedly lead to much discussion and further debate over the validity of previous work. The result, though, does not fundamentally change one of the most discussed aspects of that previous work: temperatures since 1990 still appear to be the warmest in the last 2000 years.
Readers of the Feb. 14th, 2005 Wall Street Journal may have gotten the impression that RealClimate is in some way affiliated with an environmental organisation. We wish to stress that although our domain is being hosted by Environmental Media Services, and our initial press release was organised for us by Fenton Communications, neither organization was in any way involved in the initial planning for RealClimate, and have never had any editorial or other control over content. Neither Fenton nor EMS has ever paid any contributor to RealClimate.org any money for any purpose at any time. Neither do they pay us expenses, buy our lunch or contract us to do research. All of these facts have always been made clear to everyone who asked (see for instance: http://www.sciencemag.org/content/vol306/issue5705/netwatch.shtml).
Here’s a curious observation. Some commentators who for years have been vocally decrying the IPCC consensus are lining up to support the ‘Ruddiman’ hypothesis. A respected paleoceanographer, Bill Ruddiman has recently argued that humans have been altering the level of important greenhouse gases since the dawn of agriculture (5 to 8000 years ago), and in so doing have prevented a new ice age from establishing itself. This intriguing idea is laid out in a couple of recent papers (Ruddiman, 2003; Ruddiman et al, 2005) and has received a fair degree of media attention (e.g. here, and here).
The conference last week in Exeter on “Avoiding Dangerous Climate Change” grew out of a speech by UK Prime Minister Tony Blair. He asked “What level of greenhouse gases in the atmosphere is self-evidently too much?” and “What options do we have to avoid such levels?”. The first question is very interesting, but also very difficult. As Roger Pielke has noted the conference organisers actually choose three “key questions”:
- For different levels of climate change what are the key impacts, for different regions and sectors, and for the world as a whole?
- What would such levels of climate change imply in terms of greenhouse gas stabilisation concentrations and emission pathways required to achieve such levels?
- What technological options are there for achieving stabilisation of greenhouse gases at different stabilisation concentrations in the atmosphere, taking into account costs and uncertainties?
It is worth thinking about the difference between the initial aim and the “key questions” chosen. Question 1 is essentially IPCC WGII impacts); question 2 is firmly WGI (how-much-climate-change); question 3 is fairly WG III (mitigation, including technical options). I guess they switched questions 1 and 2 round to avoid making the identification too obvious. The conference steering committee report makes it very clear that they are building on the IPCC TAR foundation.