Blogging has been a little light recently (apologies!), but here are a few pieces that have caught our eye this week.

First up, the Columbia Journalism Review has a two-parter on journalistic coverage of climate change inspired by comments from Jeff Huggins on the Andy Revkin's Dot Earth blog. The key issues CJR addresses are familiar ones to readers here: how to communicate mainstream science in a way that doesn't distort the reality of the consensus on many issues in favour of controversy on more cutting-edge topics. Definitely worth a read, and proof (if such were needed) that commenting on blogs can make a difference to coverage.

Next, the role of CO₂ as a long-term climate forcing. The old CO₂ lead/lag issue keeps making the rounds as a contrarian talking point (and made a brief resurgence here in comments this week) despite the fact that the existence of impact of climate on the carbon cycle in no way invalidates the impact of CO₂ (as a greenhouse gas) on climate. However, there is a nice paper in Nature this week (Lunt et al, 2008) which looks at the various proposed triggers for the onset of the quaternary glaciations at the end of the Pliocene (~3 million years ago). These triggers involve, permanent El Nino events, the closing of the Isthmus of Panama, changes in orbital forcing, tectonic uplift of the Rocky mountains - and long-term decreases in CO₂ as a function of very slow variations in sea floor spreading and chemical weathering. Lunt et al find that only the change in CO2 (400 ppm to 280 ppm) can explain the changes in the ice sheet. None of the other ideas come even close.

Thus, it looks very much like the climate changed radically due to this externally forced drift in CO₂ (and tectonic is external for climate purposes on this timescale). As a corollary, this is an expansion of the idea we discussed a few months back, that the long term changes in the Earth system due to external forcings might be well be larger than the classical (Charney) sensitivity we often talk about.

Third. There has been a lot of discussion on energy futures in the comments - Nature had a good rundown of the scientific constraints on the different prospects. But this video is a quite entertaining discussion of why we just can't get our heads around the issue from Dan Gilbert (h/t GH).

Finally, a commentary on the prospects for continued employment as an Arctic ice expert (h/t Climate Feedback).

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This web survey asks about your attitudes to climate change and carbon offsetting. Your help in completing this web survey will be invaluable for the study.

The Cambridge Climate Summit 'Entrepreneurship for a Zero Carbon Society' aims to step-up collaborations and understanding between policy, academia and business through enabling the latest research and ideas to be presented by international experts from the key fields involved in tackling climate change.

The Summit is designed to bring together cutting-edge energy research and innovative businesses to move the highly multidisciplinary clean energy innovation community forward on the scale required for a carbon free future. Relevant fields also include environmental tax reform and commercialization of low-carbon technologies. Pioneering technologies will be showcased by industrial participants as well as the latest student research in these areas.

All who are interested in politics, policy making, science, engineering, energy supply and green-technology are welcome. Held in the historic city of Cambridge amongst its impressive ancient and modern buildings, the meeting includes a banquet and plenty of opportunity for relaxed discussion and networking. We look forward to seeing you in September...

This is a continuation of the previous (and now unwieldy) post on the current Arctic situation. We'll have a proper round up in a few weeks.

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Geoengineering is increasingly being discussed (not so sotto voce any more) in many forums. The current wave of interest has been piqued by Paul Crutzen's 2005 editorial and a number of workshops (commentary) and high profile advocacy. But most of the discussion has occurred in almost total ignorance of the consequences of embarking on such a course.

A wider range of people have now started to publish relevant studies - showing clearly the value of continued research on the topic - and a key one came out this week in JGR-Atmospheres. Robock et al used a coupled GCM with interactive aerosols to see what would happen if they injected huge amounts of SO₂ (the precursor of sulphate aerosols) into the tropical or Arctic stratosphere. This is the most talked about (and most feasible) geoengineering idea, based on the cooling impacts of large tropical volcanic eruptions (like Mt. Pinatubo in 1991). Bottom line? This is no panacea.

Figure 1: Results from Robock et al showing the imapct on temperature of their scenarios.

So what are the problems? Robock's study looks at a subset of the potential ones - in particular, the impacts on precipitation. These arise because evaporation is more sensitive to changes in solar radiation than it is to long-wave radiation - so increasing LW and decreasing SW (as you would have in a geo-engineered future) gives a net reduction in evaporation even if the temperatures stay pretty constant. In the experiments they report on, there is a substantial reduction in rainfall in the northern tropics (especially the Sahel and the monsoonal belts). This is actually quite a robust result: reductions in tropical precipitation were reported in simpler tests of this idea in papers by Matthews and Caldiera and Bala et al.

Figure 2: The impact on precipitation in the geoengineered case compared to the control (no GHGs or geoengineering).

Other problems relate to the speed of any recovery if geo-engineering efforts should falter (let's really talk about rapid climate change!), and impacts on stratospheric ozone, increases in acid rain in polar regions, possible indirect aerosol effects on high cirrus clouds (hopefully other studies in future will better quantify these). But the results so far give a flavour of the kind of issues any geoengineering implementation will involve. Notably, how does anyone balance temperature changes that effect ice sheets versus the failure of the Indian Monsoon? The Amazon drying up versus the North Atlantic overturning circulation? It would make the current international climate negotiators seem rather like medieval theologians.

Recently I heard geo-engineering likened to climate change methadone - an emergency treatment to substitute one addiction (carbon emissions) with another. This seems rather apt, and like the analogous situation with heroin, methadone isn't going to be a cure.

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The International Geological Congress (IGC) is sometimes referred to as the geologists' equivalent of the Olympic Games and is an extremely large gathering of geologists from all over the world, taking place at 4-year intervals. This time, the IGC took place in Lillestrøm, a small place just outside Oslo, Norway (August 6-14). The congress was opened by the Norwegian King (before he continued to the real games in Beijing), and was attended by some 6,000 scientists from 113 countries. Even the Danish Minister of Energy & Climate participated in a panel discussion on climate change. In other words, this was a serious meeting.

I didn't attend the meeting myself, but the scientific programme for the session on climate, shows that the 'climate contrarians' were quite well represented. The organizers probably wanted to give room to “other views”. Together with web cast of the panel discussion on climate change (by the way, you may need Windows to view this because of the video format…), the proportion of attendees with a skeptical attitude to the notion of anthropogenic global warming appeared to be notably higher than in other conferences, such as the European Geosciences Union or European Meteorological Society, or indeed the scientific literature. So be it.

Svensmark was there, even though he's not a geologist, and said that he didn't understand what he was doing on the panel. He didn't say much during the panel debate, apart from that clouds are not well described by GCMs (which is true and discussed in the latest IPCC report), and that the 90% confidence in the human influence on recent trends is derived only from models (not true). There is an irony in that, whereas detailed microphysics in clouds are not well understood (hence the uncertainties in the GCMs), Svensmark's own hypothesis hinges entirely on the cloud response to cosmic rays (which is even less well understood).

Robert Carter said a great deal more than Svensmark on the panel. He made a point of the last couple of years being cold. But he did not appear to understand Jansen's explanation of the difference between trends and natural variability (see here). What really struck me was not who was saying what, but the intellectual level of discussion: the debate often got stuck at misunderstood trivialities which for a long time have been regarded as solved or explained in the climate research community. When you keep starting at square one, you'll never make much progress.

Other statements did not have a scientific basis (e.g. Morner popped out from the crowd and said that the sea levels are not rising - not true - and then saluted the panel). Thus the debate seemed to be a step backwards towards confusion rather than a progress towards resolution.

What is going on? Is there a higher proportion of geologists that have a completely different view on climate change, or was this a biased representation of the community? The thought of stifling a scientific debate by insisting on outrageous or ignorant claims also has struck me.

Update: Marc Roberts sent along this mildly relevant cartoon:

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Recently we received a request for setting up a glossary-only search mechanism, or perhaps one web page with a long list of glossary entries with hot links to full explanations. The glossary that we already have is a good start, but we are all busy and it's hard to find the time for extending this.

But there are also a number of external web pages which provide climate-related glossaries, such as the NOAA (they also have a seperate page for paleo-stuff), the Bureau of Meteorology (Australia, and there is even one by the Australian EPA), the Environmental Protection Agency (EPA, the U.S.), and the Western Regional Climate Center (WRCC, the U.S.). Wikipedia also has a glossary for climatological terms.

For those who seek the explanation for more bureaucratic terms, both the EU and the UNFCCC provide glossaries that may be useful.

Furthermore, there are some nice resources available, such as the Encyclopedia of Earth.

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It is with great pleasure that the University of Cambridge announces the first international “Entrepreneurship for a Zero Carbon Society” summit, to be held between the 22nd — 24th September 2008, inline with Cambridge’s 800 year celebration.

Registration is now open see: www.cambridgeclimate.com

(more…)

We often discuss the issues that arise in doing interdisciplinary work in climate science, and Liz Moyer and I have a commentary on that just out in Nature Reports Climate Change. Normally I don't mention these kinds of pieces on the blog, but in this case the editors commissioned a nice cartoon (from Mark Roberts) illustrating our point. I liked the cartoon a lot, and so it deserves as wide an audience as possible.

A bit of context is probably useful. The three main protagonists are representative of the somewhat different foci of paleo-climatologists, climate modellers and economists. Very broadly speaking, paleo-climate science is built around the analysis of single location time series (often from holes that are drilled). Climate modellers spend a lot of time trying to see what is coming up in all its complexity, while economists tend to eschew complexity and look for insight in highly idealised situations. But in order to increase the credibility of models, they have to do well at simulating past climates and what might happen in the future is certainly informed by what has happened in the past. And in order to better understand the impacts of climate change and various proposed policies, economists will need to embrace the complexity of human-climate interactions while modellers need to better understand what aspects of climate really do make a difference. None of these things will happen if we continue to all look in different directions, and more problematically, fail to support and reward those scientists who want to bridge the divides. Sea monsters notwithstanding.

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Professor Andrew Watkinson, of the University of East Anglia and the Tyndall Centre Director, has today been appointed the first director of the UK's dynamic initiative in response to the real and urgent threats posed by our changing environment.

Living With Environmental Change (LWEC) is an unprecedented partnership of 17 research, business and policy-making organisations working together to find ways to adapt to the environmental changes that we face now and in the future. The programme, which has been driven forward by the Natural Environment Research Council, aims to ensure that policy-makers, businesses and individuals are best equipped to address challenges such as climate change, flooding, food and water shortages, globalisation and population growth.