Wednesday, May 29, 2019
Not 2 Green | Vulnerability
Future climate-related risks, vulnerabilities and impacts are estimated in the AR5 ( and soon AR6 ) through experiments, analogies and models, as in previous assessments. ‘ Experiments ’ involve deliberately changing one or more climate-system factors affecting a subject of interest to reflect anticipated future conditions, while holding the other factors affecting the subject constant. ‘ Analogies ’ make use of existing variations and are used when controlled experiments are impractical due to ethical constraints, the large area or long time required or high system complexity. Two types of analogies are used in projections of climate and impacts. Spatial analogies identify another part of the world currently experiencing similar conditions to those anticipated to be experienced in the future. Temporal analogies use changes in the past, sometimes inferred from paleo-ecological data, to make inferences about changes in the future. ‘ Models ’ are typically numerical simulations of real-world systems, calibrated and validated using observations from experiments or analogies, and then run using input data representing future climate. Quantitative and descriptive models are often used together.
The Representative Concentration Pathways (RCPs) describe four different 21st century pathways of greenhouse gas (GHG) emissions and atmospheric concentrations, air pollutant emissions and land use. The RCPs have been developed using Integrated Assessment Models (IAMs) as input to a wide range of climate model simulations to project their consequences for the climate system.
Coupled Model Intercomparison Project - 6