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.
(more…)

A firm called planktos.com is getting a lot of airplay for their bid to create a carbon offset product based on fertilizing the ocean. In certain parts of the ocean, surface waters already contain most of the ingredients for a plankton bloom; all they lack is trace amounts of iron. For each 1 atom of iron added in such a place, phytoplankton take up 50,000 atoms of carbon. What could be better?
(more…)

Guest commentary from Juliane Fry, UC Berkeley

On February 9, The Virgin Group chairman Sir Richard Branson announced a $25 million prize for anyone who can demonstrate “a commercially viable design which results in the removal of anthropogenic, atmospheric greenhouse gases so as to contribute materially to the stability of Earth’s climate.” At the press conference announcing this “Virgin Earth Challenge”, Branson was joined by Al Gore, and the panel of judges for the competition includes additional climate change celebrities: James Hansen, James Lovelock, Tim Flannery, and Sir Crispin Tickell.

The goal of the competition is to find a method that will remove at least 1 billion tons of carbon per year from the atmosphere. It will be very interesting to see what ideas come to the fore to scrub CO₂ from the atmosphere. $25m should encourage some creativity! (and of course, once working should bring in a significant amount of carbon offset money). A ruckus was caused last year when discussion of injecting SO₂ into the stratosphere to form reflective sulfate aerosols to mask global warming made scientists feel they needed to state their position on this controversial, poorly understood proposal. During the discussion, a New York Times feature (described here ) discussed various “geo-engineering” alternatives to exert a cooling effect to mask global warming. At least in this case, we are not seeking to add something new and uncertain to the atmosphere, but rather, remove something that we added.

There was an interesting article in the NY Times this week on possible geo-engineering solutions to the global warming problem. The story revolves around a paper that Paul Crutzen (Nobel Prize winner for chemistry related to the CFC/ozone depletion link) has written about deliberately adding sulphate aerosols in the stratosphere to increase the albedo and cool the planet - analogous to the natural effects of volcanoes. The paper is being published in Climatic Change, but unusually, with a suite of commentary articles by other scientists. This is because geo-engineering solutions do not have a good pedigree and, regardless of their merit or true potential, are often seized upon by people who for various reasons do not want to reduce greenhouse gas emissions. However, these ideas keep popping up naturally since significant emission cuts continue to be seen as difficult to acheive, and so should be considered fairly. After all, if there was a cheaper way to deal with the CO₂ problem, or even a way to buy time, shouldn't we take it? (more…)