Climate Scenarios

The so-called Representative Concentration Paths (RCPs) were developed for the fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). They describe different levels of greenhouse gases-induced radiation drives that might occur in the period 2011 till 2100. However, they did not include any socioeconomic “narratives” to go alongside them. Over the past few years, an international team of climate scientists, economists and energy system modelers developed a range of new “pathways” that examine how global society, demographics and economics might change over the next century. They are known as the “Shared Socioeconomic Pathways” (SSPs). The SSPs were published in 2017 (Riahi et al., 2017) and they will play a major role in the IPCC Sixth Assessment Report in 2021/2022.


SSPs are baseline scenarios that describe future developments in the absence of new climate policies, beyond those already in place today. They offer five pathways that the world could take. The five SSPs differ mainly in population growth, urbanization, economic growth, investments in education and health, energy system and land use, rate of technological development as well as drivers of demand, such as lifestyle changes (Riahi et al., 2017).

As the RCPs the SSPs are also not complete in their design, as these are only social futures with do not include climate change impacts. Moreover, no mitigation or adaption measures are implemented in these (O'Neill et al., 2020). Therefore, ClimateImpactsOnline uses three SSP–RCP combination to visualize climate data corresponding to different socioeconomic and radiation scenarios.


“Sustainability” SSP1 - 2.6

The low climate change scenario (SSP1) presents a relatively sustainable path, often referred to as “Taking the Green Road”. The scenario assumes high investments in education and health. These lead to an acceleration of the demographic transition and to a slower population growth, especially in the developing countries. In total there is 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. The SSP1 baseline scenario has low challenges to climate mitigation and adaption, as climate targets can be reached globally (O’Neill et al., 2017). The SSP1 is combined with an forcing output of 2.6 Watt per square meter in 2100.

“Regional Rivalry” SSP3 - 7.0

The moderate climate change scenario (SSP3) also refered to as “Regional Rivalry” is characterized by resurgent nationalism and regional conflicts. This pushes countries to increasingly focus on domestic or, at most, regional issues. For example energy and food security goals are achieved only in their own region. Investments in education and technological development decline. Economic development is slow, consumption is material-intensive, and inequalities get worse over time. Furthermore, population growth is low in industrialized and high in developing countries. Overall SSP3 is characterized by a low international priority for addressing environmental concerns (Fujimori et al., 2017). The SSP3 scenario is combined with a forcing level of 7 Watt per square meter.

“Fossil-fueled Development” SSP5 - 8.5

The extreme scenario (SSP5) is characterized by rapid technological progress and development of human capital. Global markets are increasingly integrated. There are also strong investments in health, education, and institutions to enhance human and social capital. At the same time, this is coupled with the exploitation of abundant fossil fuel resources and the adoption of resource and energy intensive lifestyles all around the world. There is faith in the ability to manage social and ecological systems, including by geo-engineering if necessary (Kriegler et al., 2017). ClimateImpactsOnline uses the combination of the SSP5 scenario with an level of greenhhouse gases-induced radiation of 8.5 Watt per square meter.

See also:

SSP Database

The Shared Socio-Economic Pathways (SSPs): An Overview (Poster)
Sources:

O’Neill, B.C., Carter, T.R., Ebi, K. et al. Achievements and needs for the climate change scenario framework. Nat. Clim. Chang. 10, 1074–1084 (2020). https://doi.org/10.1038/s41558-020-00952-0

Riahi, K. et al., The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview, Global Environmental Change, Volume 42, 153-168 (2017). https://doi.org/10.1016/j.gloenvcha.2016.05.009.