EU, U.S. carbon emissions on downward trend
Both European Union and U.S. carbon emissions have fallen sharply over the past five years, but working out whether that will continue requires teasing out short-term and one-off factors, and pinpointing lasting efficiency gains.
Some causes are temporary or one-off: clearly, over the last several years energy demand was lower as a result of the financial crisis; while the weather can have a large impact, including a mild 2011/2012 winter in the United States.
The U.S. shift to natural gas from coal, as a result of the shale energy revolution, has a few years to play out but will taper off and so could be seen as a medium-term factor.
Two trends are longer term: first, a shift towards renewable power, especially in the EU for the rest of this decade, and also in the United States if costs continue to fall; and second, a trend towards more energy efficiency.
Continuing, falling emissions have implications for fossil fuel demand, and where driven by efficiency, for competitiveness.
They may also allow developed countries to offer modest targets to curb greenhouse gases at long-running U.N.-backed climate talks, and so keep these ticking over.
The long-term trend for global greenhouse gases - and for expected climate change - will depend on emerging economies and how far investment in energy efficiency and low-carbon energy balance spending in oil and coal.
U.S. carbon emissions reached an 18-year low last year, the U.S. Energy Information Administration (EIA) government data body said on Monday, in its report: "U.S. Energy-Related Carbon Dioxide Emissions, 2012". (Chart 1)
Carbon dioxide (CO2) emissions have fallen in five out of the last seven years, and are now 12 percent below their highest level in 2007, suggesting that they may have peaked.
Most of the falls in the past five years were due to slower economic growth and a switch to natural gas and renewable power from coal.
Significantly, last year emissions fell even as the economy grew strongly, by 2.8 percent, and the biggest single factor was a decline in energy consumption, rather than a switch from coal to gas, according to the EIA.
In the European Union, greenhouse gas emissions including CO2 peaked three decades ago before east European countries switched to liberalised market economies, crushing their industrial output as a result.
More recently, emissions were flat until a sharp fall in 2007 as a result of the financial crisis and a shift to renewable power.