Abstract for: In Sum, Nations Will Likely Fulfill Their Pledges to Reduce Greenhouse Gas Emissions: A Stock-and-Flow-Based View
Emission reduction pledges of almost all UN member states, intended nationally determined contributions (INDCs), were signed in December 2015. If they are met, world temperature will stabilize at about 3°C warmer than pre-industrial levels. But will they be met? Commonly, business-as-usual scenarios predict 5–6°C warming and limiting warming to 3°C is regarded to be an arduous task. We however find that achieving the 3°C warming indeed results from business-as-usual past trends in energy investments. Using a stock-and-flow framework for estimating average energy capacity additions for five regions of the world, we conclude that extrapolation past investment trends also gives a 3°C warming, implying that, in sum, INDCs will likely be met. But limiting warming to 3°C is clearly not enough: We use the same stock-and-flow model to show that a combination of increased energy efficiency, facing out all fossil investments before 2030 and implementation of carbon capture and storage is required to limit global warming to 2°C.