2021-2040: Near term impacts, assessed for the time period around 2030
2041-2060: Mid-term impacts, assessed for the time period around 2050
2081-2100: End-of-century impacts, assessed for the time period around 2090
The Below 2°C scenario is based on SSP1-2.6 results, which lead to a best estimate of 1.8°C temperature increase by the end of century
The No policy action scenario is based on SSP3-7.0 results. This higher warming scenario would lead to a median warming of 3.6°C temperature increase by the end of century, above the estimated temperature that current climate policies would achieve.
Ticking the Impacts at 1.5°C box makes the data explorer shows the impacts from the Below 2°C (SSP1-2.6) scenario in the near term (2021-2040) when temperatures are projected to reach an average of 1.5°C, indicative of the impacts at 1.5°C.
The climate research community developed a new framework for climate scenarios which combines future greenhouse gas emissions and their associated climate changes with alternative pathways of socioeconomic development. These pathways, called the Shared Socioeconomic Pathways[1] (SSPs), look at different ways the world may change in socioeconomic conditions such as population, economic growth, education, and urbanization, and the challenges that arise for climate mitigation and adaptation.
The world shifts gradually, but pervasively, toward a more sustainable path, emphasizing more inclusive development that respects perceived environmental boundaries. Management of the global commons slowly improves, educational and health investments accelerate the demographic transition, and the emphasis on economic growth shifts toward a broader emphasis on human well-being. Driven by an increasing commitment to achieving development goals, inequality is reduced both across and within countries. Consumption is oriented toward low material growth and lower resource and energy intensity.
A resurgent nationalism, concerns about competitiveness and security, and regional conflicts push countries to increasingly focus on domestic or, at most, regional issues. Policies shift over time to become increasingly oriented toward national and regional security issues. Countries focus on achieving energy and food security goals within their own regions at the expense of broader-based development. Investments in education and technological development decline. Economic development is slow, consumption is material-intensive, and inequalities persist or worsen over time. Population growth is low in industrialized and high in developing countries. A low international priority for addressing environmental concerns leads to strong environmental degradation in some regions.
While the baseline SSP scenarios portray a range of outcomes in the absence of additional climate policy, researchers also wanted to examine how different levels of climate mitigation and adaptation would fit into the future described by each SSP.
To model this, they used shared policy assumptions around how quickly international collaboration on climate policy could occur within each SSP, as well as respecting limitations imposed by the underlying assumptions around population growth, economic activity and technological development in each pathway.
The mitigation targets examined are defined by radiative forcing levels in 2100 (e.g. 2.6 or 7.0 watts per meter squared), which set a respective target level of atmospheric greenhouse gas concentrations.
The combinations of Shared Socioeconomic Pathways (SSPs) and mitigation targets are contained in the scenario labels SSP1-2.6 and SSP3-7.0.
More detailed information can be found in this Carbon Brief article: www.carbonbrief.org/explainer-how-shared-socioeconomic-pathways-explore-future-climate-change/
¹ Riahi et al. (2017), The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview, Global Environmental Change, https://doi.org/10.1016/j.gloenvcha.2016.05.009.