The US Environmental Protection Agency has made its much-anticipated decision that greenhouse gases should be regulated under the Clean Air Act, which it enforces.
This is important for two reasons: it clears the way for regulation on carbon emissions, and it is also a formal declaration that carbon dioxide and five other greenhouse gases are endangering health and wellbeing.
It could also have implications for the passage through Congress of the energy measures, including a cap and trade regime, proposed by the Obama administration.
However as Marc Ambinder points out, not only is there still some way to go before it is known whether the decision actually affects carbon emitters, but how it affects them will depend very much on how the EPA decides to use the Clean Air Act. For example, the EPA’s background information on the decision specifically refers to “the combined emissions of CO2, CH4, N2O, and HFCs from new motor vehicles and motor vehicle engines” as contributing to the threat of climate change.
From the EPA announcement:
The proposed endangerment finding now enters the public comment period, which is the next step in the deliberative process EPA must undertake before issuing final findings. Today’s proposed finding does not include any proposed regulations. Before taking any steps to reduce greenhouse gases under the Clean Air Act, EPA would conduct an appropriate process and consider stakeholder input. Notwithstanding this required regulatory process, both President Obama and Administrator Jackson have repeatedly indicated their preference for comprehensive legislation to address this issue and create the framework for a clean energy economy.