The IPCC Sixth Assessment Report (AR6) assesses five main Shared Socio-economic Pathway (SSP) scenarios: SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5. They range from very low to very high greenhouse gas emissions and are used to project possible climate futures.
How the scenarios work
Each scenario combines assumptions about population, economic development, technology, energy use and climate-change mitigation. In a label such as SSP2-4.5, “SSP2” identifies the socio-economic pathway, while “4.5” represents approximate radiative forcing in 2100, measured in .
| AR6 scenario | Emissions pathway and implications |
|---|---|
| SSP1-1.9 | Very low emissions; rapid reductions, net-zero carbon dioxide around 2050 and later net-negative emissions. Designed to limit warming to approximately . |
