Ketan's Word List and RC Passage 12-08-2013
ketanbarde
You've probably heard that US carbon emissions have been falling.According to President Obama and energy commentators the world over, fracked shale gas has displaced dirty coal, in much the same way thatfossil fuels undercut whale oil a century earlier. Out with environmentally unfriendly old technologies and in with cleaner and more efficient new ones. Everyone wins – including the climate, thanks to the fact that gas produces only around half as much CO2 as coal does for each unit of power or heat created.
On the other hand, you may also have heard that US coal exports have increased as its domestic emissions have fallen. America currently has little in the way of gas export facilities but plenty of capacity for shipping coal to Asia, Europe and elsewhere. Those ports have been busy of late and the ripple effects are being felt far and wide. For instance, UK emissions shot up 4.5% last year, partly due to low coal prices made possible by surging US exports. So could it be that rising US gas production has increased the human contribution to global warming, even as American's own emissions have fallen?
This is an important question. There are legitimate and complex debates to be had about potential of natural gas as a 'transition fuel'; and about how gas's huge benefits over coal in terms of carbon emissions and air pollution should be weighed against the methane leaks and water pollution linked to fracking. But in the absence of a global emissions deal, those debates are largely academic unless producing more gas does actually lead to less coal use. So does it?
To explore this issue I propose considering an unfamiliar metric: not carbon emissions but carbon extraction. After all, the climate doesn't care where a unit of carbon is burned; just whether it comes out of the ground and enters the atmosphere. It makes sense to ask, therefore, whether the US is now extracting more or less carbon than it was before the shale gas boom. Has coal production fallen enough to offset rising gas production?
I've just had a go at working out the answer to this question by taking government data for US oil, coal and gas production and adding up the carbon that each fuel contains. The results are interesting.
First, let's look at the three fossil fuels individually. The graph below shows the carbon content of US-produced natural gas rising quickly since around 2005 as fracking rigs multiply, just as you'd expect. The same is true for oil, which had been on the wane since American crude production peaked in the early 1970s but is now rising again thanks to new fields and production techniques, bucking the bell-curve trend predicted by peak oil theory (for now at least). By contrast, coal extraction fell sharply after the 2008 financial crash but has been creeping back up since.
Shale gas fracking has helped US carbon emissions to fall. But American carbon extraction is still rising, undermining progress and increasing emissions overseas