The prospect of geoengineering, the intentional large-scale manipulation of the climate to offset the effects of global warming, continues to draw the attention of top scientists and policymakers. The prestigious journal Science is publishing two papers on the subject in its next issue, and next week the Science Committee of the House of Representatives will hold its second hearing on the subject.

According to some climate models, climates could change very quickly as greenhouse gas emissions rise, such as when thawing permafrost releases methane (a powerful heat-trapping gas), or loss of ice causes the earth to absorb more heat. Such outcomes might not be very likely, but even the chance that they could happen has scientists worried, as they could lead to widespread severe drought and famine and rapid sea level rise, among other things. Even the most ambitious efforts to curb greenhouse emissions might not be enough to prevent disastrous climate change, some say. And ambitious efforts to cut emissions seem ever more unlikely, after the limited success of the recent summit in Copenhagen, and opposition to a climate change bill in the Senate.

In one of the Science articles, researchers say testing of geoengineering strategies may prove necessary, but before testing can occur, they say an international agreement should be reached. Such testing could cause changes in weather patterns that could hurt some countries, for example, and an agreement needs to be in place to establish standard testing procedures and methods for dealing with international disputes arising from such testing.

Such an agreement might be even more important if the argument of another Science paper proves to be correct. In that paper the researchers argue that the only way to effectively test geoengineering is through full scale implementation of a particular geoengineering scheme--and such a large deployment could have big, unforeseen consequences.