Yesterday’s Wall Street Journal reports some suprising figures on US greenhouse emissions:

The Bush Administration announced last week that U.S. emissions of carbon dioxide fell by 1.8% from 2005 to 2006. Output of all greenhouse gases was down 1.5% last year. All this while the American economy grew by 2.9%. It’s the first time since 1990, when the U.N. began counting these things, that the U.S. has reduced emissions without also suffering a recession…

The EU hasn’t yet released figures for 2006. But from 2000 to 2005, the U.S. outperformed Western Europe. Carbon emissions were up 3.8% in the so-called EU-15 during those years, versus 2.5% in the U.S. Over the same period, there has been virtually no difference between the increase in all greenhouse emissions in the U.S. and EU-15.

The WSJ goes on to make some odd inferences from this:

the reductions were in part due to higher energy prices and favorable weather. But greater use of lower-carbon energy sources, including natural gas, also played a big role. The U.S. reduction also suggests that letting markets work through higher prices will reduce carbon emissions more than the cap and trade mandates favored by environmental lobbies and most Democrats. [emphasis added]

I’m not sure what the WSJ is suggesting here. Markets won’t just “work” and magically ascribe higher energy prices due to help save us from climate change. Governments actually need to somehow interfere in those markets to increase the prices of carbon-intensive energy sources. And there are two basic ways: impose a tax on emissions or require permits for emissions, issue a limited amount of permits and allow them to be traded (cap and trade). Either way, you’re putting a price on emissions: only after you’ve place some constraint on the market can you stand back and let the market “work” to find efficient ways to reduce emissions.

But I think these US figures are worth examining for a few reasons:

They suggest that emissions can be reduced without much of an impact on economic growth. Economic / Business consultants McKinsey have released a study this week that indicates that the US could reduce emissions substantially with little economic cost.
They suggest higher energy prices (and by inference a carbon tax) can be quite effective.
They might give us clues as to what sort of action could be effective. What was different about 2006 to previous years? Why did the use of natural gas for electricity generation increase?

If you’re interested, the full report is available (in pdf) from the US Energy Information Administration website.