Representative Concentration Pathways (RCPs)
Climate scenarios are used to represent a range of plausible outcomes for climate change depending on how our climate system responds to high levels of greenhouse gasses and how quickly we can act to limit our emissions globally. The four Representative Concentration Pathways (2.6, 4.5, 6.0, 8.5) are used by the Intergovernmental Panel on Climate Change as trajectories for the future of greenhouse gas concentrations in our atmosphere. Each pathway represents a possible global outcome based on the cumulative volume of emissions released by 2100. The higher-numbered RCP scenarios assume the release of more carbon dioxide into the atmosphere by humanity. Some of the most common options include RCP4.5, and RCP8.5, which are both used in ClimateCheck analysis.
The RCP scenarios are not predictions, which means that none are chosen as having more of a likelihood of occurring than the others. However, each scenario may be better or worse as a tool for modeling short, medium, and long-term emissions horizons.
Why We Use Multiple Scenarios
In ClimateCheck analysis for climate conditions through mid-century, we use multiple climate change scenarios to communicate uncertainty. RCPs, and emissions scenarios in general, help us understand what different futures could look like. The RCP scenarios are not predictions, but they provide a useful range of plausible outcomes for climate change based on different levels of greenhouse gas emissions.
Other Approaches
Some research indicates that other types of emissions scenarios may provide a more accurate picture than the RCPs. For example, the Shared Socioeconomic Pathways (SSPs) and the World Energy Outlook (WEO) each look at other types of factors, such as the influence of political and economic factors and technological innovation on future emissions levels. Some of our data also includes information on SSPs for this reason.
Conclusion
When communicating the potential impacts of climate change, it's important to acknowledge the uncertainty that exists around emissions projections and their associated climate scenarios. We choose to convey this uncertainty by using multiple scenarios and highlighting the range of outcomes they represent. This helps our users better understand the potential risks and opportunities associated with different emissions pathways and encourage them to take action to mitigate the most severe outcomes. However, it's also important to be clear about the limitations of each scenario and not overstate the likelihood of any one outcome.