Haewon McJeon

TL;DR: It is important to understand what these INDCs collectively deliver in terms of how much do they reduce the probability of the highest levels of global mean surface temperature change and improve the odds of achieving the international goal of limiting temperature change to under 2°C relative to preindustrial levels.

TL;DR: In this article, the authors describe the SSP4 as implemented by the Global Change Assessment Model (GCAM), the marker model for this scenario, using demographic and economic assumptions, in combination with technology and non-climate policy assumptions to develop a quantitative representation of energy, land-use and land-cover, and emissions consistent with the shared socioeconomic path 4 narrative.

TL;DR: It is shown that market-driven increases in global supplies of unconventional natural gas do not discernibly reduce the trajectory of greenhouse gas emissions or climate forcing, and although market penetration of globally abundant gas may substantially change the future energy system, it is not necessarily an effective substitute for climate change mitigation policy.

TL;DR: GCAM v5.1 as discussed by the authors is a market equilibrium model, is global in scope, and operates from 1990 to 2100 in 5-year time steps, which can be used to examine, for example, how changes in population, income, or technology cost might alter crop production, energy demand, or water withdrawals, or changes in one region's demand for energy affect energy, water, and land in other regions.

TL;DR: This article used four integrated assessment models to produce metrics of Paris Agreement pledges, and show differentiated effort across countries: wealthier countries pledge to undertake greater emission reductions with higher costs, suggesting insufficient global ambition in light of leaders' climate goals.