The Intergovernmental Panel on Climate Change (IPCC) adopted four possible trajectories that the world might face in the future. The Representative Concentrations Pathway (RPC) scenarios were created to simulate future scenarios related to the global temperature around the year 2100 after greenhouse gases emissions by humans. They are four greenhouse gas concentration trajectories. These trajectories are based on the fact that the last three decades have been successively warmer since 1850 and also based in a few assumptions encountered in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (AR5).
The RCPs are directly related to the climate models that simulate changes on the climate considering the anthropogenic influence. And both claim that if the emissions of greenhouse gases continue, further warming will happen together with the continuing changes in the components of the climate system. As well as the assumption that the reductions of these greenhouse gas emissions will just happen if there is a limitation of this climate change.
These pathways are used for research and also for climate modeling based in the global energy imbalance. There are four Representative Concentration Pathways (RCP): RCP2.6, RCP4.5, RCP6 and RCP8.5. These values represent the possible range of radiative forcing in 2100 (+2.6, +4.5, +6.0, and +8.5 W/m2, respectively). They show from more optimistic to more pessimistic possibilities for the consequences of global warming in the near future. The values are related to pre-industrial records and they can be seen below:
Table 1. Projected change in climate (reproduced from IPCC, 2013: Summary for Policymakers).
According to IPCC, the surface temperature of the Earth until the end of the 21st century:
Global mean sea level
According to IPCC, all the RCP scenarios assume that the global mean sea level will very likely exceed during the 21st century.