RCP45

RCP45 is a greenhouse gas emissions scenario used in climate modeling. It is one of the Representative Concentration Pathways (RCPs) developed by the International Institute for Applied Systems Analysis (IIASA) and the Potsdam Institute for Climate Impact Research (PIK) for the Intergovernmental Panel on Climate Change (IPCC). The "4.5" in RCP45 refers to the approximate radiative forcing in watts per square meter (W/m2) at the end of the 21st century, which is projected to reach 4.5 W/m2 above pre-industrial levels.

This scenario assumes that global greenhouse gas emissions will peak around the mid-21st century and then decline. It represents a pathway where mitigation efforts are implemented, leading to a stabilization of greenhouse gas concentrations. RCP45 is considered a moderate mitigation scenario, falling between scenarios with very strong mitigation (like RCP2.6) and scenarios with no significant mitigation efforts (like RCP6.0 and RCP8.5).

Climate models utilize RCPs to simulate future climate changes under different emission trajectories. RCP45 provides a basis for understanding the potential impacts of climate change if the world follows a path of moderate emission reductions. This includes projecting changes in global temperatures, sea levels, and the frequency and intensity of extreme weather events. The RCPs are crucial tools for informing policy decisions related to climate change adaptation and mitigation.