In his recent piece, Lomborg suggests that gas is the best short-term hope of breaking the emission lock. To quote, ‘Look[ing] at the dramatic reduction in US emissions since 2008 … shows that there is one other solution to CO2 apart from wars and recessions: fracking, a new technology to get gas out of the ground cheaper and more plentifully.’
The key is the explicit assertion that Lomborg makes, that there has a ‘dramatic reduction in US emissions since 2008’. The implicit assertion is that, if there has, it is more than we would expect from economic factors alone.
In the spirit of the Skeptical Environmentalist these assertions are worth testing. To do so, we need to factor out the dominant economic signal, which is not inconsiderable. That is well illustrated by 2009 – the deepest recession in the US in over 30 years. In 2009, US emissions declined by about 6.6 percent on the back of a 2.6 percent reduction in GDP. As the figures below show, that reduction in emissions over the last five years is only marginally greater than would be expected from the economic slowdown alone.
So the short answer is that the US shale-gas revolution hasn’t substantially impacted the emissions intensity of the US economy, over and above that expected from the slowing economy.
In fact the impact has been effectively “squat all”, according to BP’s data . While both 2011 and 2012 show significantly negative residuals reflecting significant reductions in emission intensity, that was countered by the significant positive residual anomalies in years 2010 an 2013. The net result is that the average US emissions residual over the five year period is only -0.2 percent. While there has been a reduction in rate of growth in emissions over the period (-1.2 percent absolute), it can be accounted for almost entirely by the low average US economic activity (average GDP growth of 1.2 percent).
US emission data plotted as function of GDP in annual percentage change terms. The black line shows the best fit for the period 1982-2013 (red dots). The red lines intersect at the average, and span the ranges, for the period 2009 through 2013. The red solid circles for the years 2014 and 2015 are based on estimates from the EIA and World Bank respectively [see note 2]. Figure by Mike Sandiford, data from BP’s 2014 Statistical Review of World Energy and IMF’s World Economic Outlook .
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US residual emission plot. Despite significant inter-annual volatility for the years 2009 through 2013, the residual anomaly given by the intersection of the red lines is near zero. The projections for the years 2014 and 2015, suggest the emission intensity anomaly for the period 2009+ will be overall positive, reflecting an increase in the emission intensity of the economy, despite the much vaunted shale-gas revolution. The notes below  outline some of the causes for projected changes in US emissions in the next few years. Figure by Mike Sandiford, data from BP’s 2014 Statistical Review of World Energy and IMF’s World Economic Outlook .
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Going by US Energy Information Agency – or EIA – and World Bank projections, the next few years are not looking much better. The EIA predicts US energy sector emissions will rise again by 1.4 percent this year (2014), before falling marginally in 2015 . On the basis of World Bank assessments of GDP growth, the six-year average for the period 2009 though 2015 is set to be at or above trend (i.e., a slightly positive residual), in spite the much vaunted shale-gas revolution.
In reality, the emission reductions achieved by the US have resulted from sliding down the emission lock, rather than moving off it.
So much for the role of gas as a climate bridge.
While it might seem unrelentingly gloomy in terms of the climate implications, the concern in my talk at Norway was not entirely pessimistic. I was at pains to show that one country in particular had seemingly broken free of its emission lock, and it had nothing to do with gas.
The country in question was Australia.
One year further on, with an updated dataset courtesy of the latest release of BP’s Statistical Review of World Energy, the evidence is now even more clear.