Defining climate change scenario characteristics with a phase space of cumulative primary energy and carbon intensity

Abstract

Climate change modeling relies on projections of future greenhouse gas emissions and other phenomena leading to changes in planetary radiative forcing. Scenarios of socio-technical development consistent with end-of-century forcing levels are commonly produced by integrated assessment models. However, outlooks for forcing from fossil energy combustion can also be presented and defined in terms of two essential components: total energy use this century and the carbon intensity of that energy. This formulation allows a phase space diagram to succinctly describe a broad range of possible outcomes for carbon emissions from the future energy system. In the following paper, we demonstrate this phase space method with the Representative Concentration Pathways (RCPs) as used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5).The resulting RCP phase space is applied to map IPCC Working Group III (WGIII) reference case 'no policy' scenarios. Once these scenarios are described as coordinates in the phase space, data mining techniques can readily distill their core features. Accordingly, we conduct a k-means cluster analysis to distinguish the shared outlooks of these scenarios for oil, gas and coal resource use. As a whole, the AR5 database depicts a transition toward re-carbonization, where a world without climate policy inevitably leads to an energy supply with increasing carbon intensity. This orientation runs counter to the experienced 'dynamics as usual' of gradual decarbonization, suggesting climate change targets outlined in the Paris Accord are more readily achievable than projected to date.

How Much Human-Caused Global Warming Should We Expect with Business-As-Usual (BAU) Climate Policies? A Semi-Empirical Assessment

“…This suggests that the CO 2 concentrations of the RCP 6.0 scenario are actually a reasonable estimate of "Business-As-Usual" for the 21st century. This is consistent with several recent articles that argue that RCP 8.5 implies a dramatic increase in CO 2 emissions relative to "Business-As-Usual", e.g., [63][64][65][66]. Readers might wonder why the RCP 6.0 CO 2 concentrations match so well with our BAU projection when the RCP 6.0 emissions projections curve in Figure 2d was lower than our BAU projection.…”

“…The RCP 8.5 scenario implies a growth in emissions much greater than BAU. This agrees with several recent articles pointing out that RCP 8.5 substantially overestimates CO 2 emissions relative to BAU, e.g., [63][64][65][66]. Meanwhile, all of the other scenarios imply that emissions are substantially decreasing relative to BAU over the 21st century.…”

Future Predictions of Rainfall and Temperature Using GCM and ANN for Arid Regions: A Case Study for the Qassim Region, Saudi Arabia

“…The future projections for the periods 2011-2045, 2046-2079, and 2080-2099 from these GCMs were downscaled using LARS WG 5.5 for three emissions scenarios A1B, A2, and B1 (the details of which can be found in the IPCC-Assessment Report 5 (AR5) and [4,[55][56][57][58][59]). A brief explanation of these scenarios is provided below.…”

“…With the passage of time, there was advancement in research on driving forces of emissions and assessment methods. A new set of four emission scenarios based on socioeconomic storylines was published by IPCC which are described in the Special Report on Emissions Scenarios (SRES) [4,[55][56][57][58][59]. Another set of emission scenarios, called concentration pathways (RCPs), were developed on the basis of radiative forcing [55,58].…”

“…Climate projections using four RCPs formed the basis of the Coupled Model Inter-comparison Project 5 (CMIP5) [55]. These projections were analyzed extensively for the IPCC fifth assessment report [57][58][59]. According to Sanderson et al [55], no liking or disliking is attached to the SRES or RCPs.…”