We present the results of a new bookkeeping model of land-use change emissions, BLUE, and use the model to show the large effects of different accounting decisions on estimated carbon fluxes.
US CO2 emissions dropped ~11% between 2007-2013; a trend has been widely attributed to the increased use of natural gas over coal. We decompose the drivers of the decline and show that the recent economic downturn and not the gas boom deserves most of the credit for the decrease in emissions.
Leaking methane isn't the only reason natural gas may not reduce GHG emissions: gas also competes against low-carbon renewable energy sources. This paper shows that abundant gas replaces both coal and renewables and in the end has little effect on future US GHG emissions even if there is no leakage. Policy may reduce emissions; cheap gas on its own won't.
Worldwide, existing power plants represent roughly 300 billion tons of future CO2 emissions if all plants operate for 40 years, and these "committed emissions" in the power sector have been growing at a rate of ~4% per year. This paper proposes tracking these commitments to quantify future emissions implied by current investments.