Coup d'etat against congress who have been the ones holding up Obama's attempts to fight climate change. The EPA's ruling provides extra leverage against congress which means that Obama is likely to be able to go further in promising to cut emissions at Copenhagen.

It means nothing, the senate still needs to ratify any enforced emissions cuts. This means that Obama needs to keep congress on side not be taking pot shots at them.

On-road vehicles contribute more than 23 percent of total U.S. GHG emissions. EPA’s proposed GHG standards for light-duty vehicles, a subset of on-road vehicles, would reduce GHG emissions by nearly 950 million metric tons. This ruling makes higher standards much more likely. This is an area where the EPA has control over and it already imposes standards on other gases released so this will have an impact.

It is diifficult to tell how much in the way of emissions reductions this will create so making it difficult for Obama to negotiate on the basis of a set target for emissions cuts.

If the United States and other industrialized countries are responsible for the emission of climate-altering gases in a larger proportion than the rest of continents in the world, they have the moral obligation to change and improve their environmental politics and offer to the Copenhagen Conference more guarantees that their agreements will be honoured. They also should be committed to provide a share of finance to help developing countries who are paying for the waste of energy from the industrialized countries. Obama understands this and is willing to make much greater pledges than his predecessors, and indeed override congress if necessary. According to the New York Times “President Obama is pledging a provisional target for reduction of C02 emission in the United States, the first time inmore than 10 years that the US Administration has offered even a tentativepromise to reduce production of climate-altering gases, reducing the emissions in the range of 17% below 2005 levels by 2020 and 83% by 2050 but it will depend on whether the Democratic sponsors of the legislation can win 60 votes for the measure”.

The EPA is not catching up to the Supreme Court ruling, it is inline with the current administration's promise to make the environment a priority -- a far cry from the Bush administration. In 2007 when the Supreme Court ruled that the EPA could and should develop standards that big businesses would be held accountable to, the EPA conducted research and sent its findings to the White House. Apparently, an email from the EPA isn't high on the priority list -- and went unopened for some time.

What the US is catching up on is 8 years of neglecting environmental issues -- but, hopefully priorities have shifted.

The US Supreme court back in 2007 ruled that greenhouse gasses should be considered to be within the clean air act and therefore need much tighter regulation. This EPA ruling is simply playing catch up and will have little real impact.

No one is talking about immediate cuts at copenhagen, this makes future cuts possible which is all that is needed

The EPAs ruling does not immediatly mean that emissions reductions targets will be introduced. It simply makes such reductions more likely. Congress is still needed to pass the bills to introduce such regulation.

EPAs ruling may be opposed through the US court system. It is likely to be seen as a dictatorial ruling as it has not passed through congress. This means it is likely to be challenged. Unfortunatly in the US such challenges may well succede forcing the regulation to be scrapped. The government should not base any targets on such a shaky foundation as it may find that foundation collapses.