Projecting Energy and Climate for the 21st Century

Abstract: The growing evidence of severe climate change impacts on human life and the global economy has created the increasing need for an assessment of low-carbon pathways. While the ultimate goal of zero- or near-zero global emissions is clear, the timing and trajectory to achieve low-carbon economic system is not. Projecting energy and climate is getting more challenging because the current energy and emission policies diverge further and further from the stated long-term policy goals. We provide a discussion of descriptive and prescriptive approaches to energy and climate forecasts. While the fundamental uncertainties are unavoidable, a group of scenarios that project the entire range of plausible developments provides better guidance for decision-making than any (or several) individual scenario(s). We offer an example of an integrated approach from the MIT Joint Program Outlook that can be used for a quantitative analysis of decision-making risks associated with different energy pathways. Despite the broad variety of scenarios, the article finds some robust findings for the energy system.