Leaking methane isn't the only reason natural gas may not reduce GHG emissions: gas also competes against low-carbon renewable energy sources. Across a range of gas supplies, our modeling 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.
Because climate warming is proportional to cumulative GHG emissions, we know how long a 'runway' we have before we reach any given level of warming. The question is how to divvy up that runway among countries given that industrialized countries don't want to stop emitting and developing countries want to start emitting more. Here, we describe a quantitative method for doing the sharing.
As of 2012, power plants existing worldwide represent roughly 300 billion tons of future CO2 emissions, assuming individual plants operate for a lifetime of 40 years. Moreover, committed emissions from the power sector have been growing globally at a rate of about 4% per year. This paper presents a formal method of commitment accounting that can inform public policy by quantifying future emissions implied by current investments.
Clearing and use of land produce GHG emissions, but these emissions happen over long periods of time. And during that time, the land may be useds in different ways to produce different products (e.g., corn, soybean, beef, wood, etc.) In this review, we demonstrate several methods of assigning land use emissions to specific products, and show that different methods have dramatically different results. Analysts should communicate their choices and consider the implications in light of their goals.