Representative Concentration Pathway

Representative Concentration Pathway. It is a set of standardized greenhouse gas concentration trajectories developed for climate modeling and research. These pathways describe potential future climates based on different levels of radiative forcing by the year 2100. They were created to facilitate coordinated climate change assessments and replace earlier scenario frameworks like the Special Report on Emissions Scenarios.

Definition and Overview

A Representative Concentration Pathway defines a specific time series of emissions, concentrations, and land-use change leading to a particular level of radiative forcing. The concept was established by the research community to support the work of the Intergovernmental Panel on Climate Change. These trajectories are not predictions but rather plausible scenarios used to explore future climate system behavior. They provide a crucial input for complex Earth system models run by institutions like the National Center for Atmospheric Research.

Development and Scenarios

The development process was a major international effort coordinated by the Integrated Assessment Modeling Consortium. This work involved numerous research teams from organizations such as the International Institute for Applied Systems Analysis and the Potsdam Institute for Climate Impact Research. The scenarios integrate socioeconomic data with projections of technological change and energy systems. This process improved upon the methods used for the earlier Special Report on Emissions Scenarios from the late 1990s.

Key Pathways and Characteristics

Four primary pathways form the core of the framework, each denoted by its approximate radiative forcing level in watts per square meter by 2100. The high-mitigation scenario projects strong declines in emissions due to policies and shifts toward renewable energy. An intermediate pathway assumes some stabilization of atmospheric concentrations through moderate climate policy. A higher scenario continues significant fossil fuel use without stringent global agreements. The pathway with very high greenhouse gas levels represents a baseline with little concerted action.

Role in Climate Models

These pathways serve as standard inputs for major model intercomparison projects like the Coupled Model Intercomparison Project Phase 5 and its successor, Coupled Model Intercomparison Project Phase 6. Modeling centers worldwide, including the Met Office Hadley Centre and the Max Planck Institute for Meteorology, use them to run simulations. The standardized inputs allow for direct comparison of climate projections across different general circulation models. This consistency was vital for the assessment reports produced by the Intergovernmental Panel on Climate Change.

Impacts and Projections

Projections based on these pathways inform global risks such as sea level rise, which threatens regions like the Maldives and Bangladesh. Higher pathways project more severe impacts on biodiversity and increased frequency of extreme weather events like those analyzed by the World Meteorological Organization. They also project significant effects on agricultural yields, water resources, and public health. These impact studies feed into international climate negotiations under the United Nations Framework Convention on Climate Change.

Comparison with Other Scenarios

The framework succeeded the older Special Report on Emissions Scenarios, offering more integrated and policy-relevant pathways. It is now often used in combination with the newer Shared Socioeconomic Pathways, which provide detailed narratives about future societal development. While the older scenarios focused more on emissions, the newer framework explicitly describes concentrations and radiative forcing. This evolution allows for more robust analysis of climate impacts and mitigation strategies for bodies like the International Energy Agency. Category:Climate change assessment and attribution Category:Climate change terminology