John Holdren, recently confirmed as President Obama’s science adviser, has said in an interview that discussions at the White House include looking at geoengineering options to reduce the effects of global warming. He stressed that it would be a last resort, but can’t be ruled out of discussion if the failure to cut greenhouse gas emissions continues. He is concerned that several tipping points could be fast approaching, with chances of “really intolerable consequences”, instancing the possible loss of Arctic summer sea ice within six years, the release of frozen methane from thawing permafrost in Siberia, and more and bigger wildfires worldwide. He would much prefer to see the problem solved by reducing emissions of greenhouse gases, but global warming is happening so fast that geoengineering has to be looked at. “We don’t have the luxury … of ruling any approach off the table.”
Holdren mentioned two geoengineering options in the interview. One was shooting sulphur particles into the upper atmosphere, mimicking the effect of volcanoes in screening out the incoming sunlight. There could be grave side effects to such an operation. Studies indicate they might include eating away a large chunk of the ozone layer above the poles and causing the Mediterranean and the Mideast to be much drier. The other option mentioned was the so-called artificial trees proposed by Lackner to strip CO2 from the atmosphere for sequestration.
The Presidential science adviser is leaving no doubt as to how seriously he regards the threat of climate change. The geoengineering options are not offered as optimistic alternatives to emissions reduction, but as emergency measures we may be forced to try if we fail to reduce emissions. The interview was cheering in its indication that the full reality of global warming is understood in the White House but sobering in its acknowledgment that desperate measures may have to be considered. Scientific reality has been admitted to the White House, but it is not yet clear to what extent Congress has put out the welcome mat. If legislation doesn’t soon produce major emission reductions desperate measures become more likely.
Hot Topic’s review of Fixing Climate described the CO2 stripping process Holdren referred to, and this post explored it further. It would require major construction efforts and careful attention to safe CO2 storage, but it looks a much less risky process than some of the other geoengineering proposals. Its scale is more modest, aiming at restoring balance by taking back some of the excess carbon we have released into the atmosphere. Its risks seem confined to the safety of the sequestration.