Shared Socioeconomic Pathways (SSPs)
Five Shared Socioeconomic Pathways (SSPs) have been developed. The SSPs are storylines describing alternative combinations of socioeconomic challenges for mitigation and adaption to climate change.
SSP1, the ‘green road’ scenario, assumes minor challenges to mitigation and adaptation. This results in an improvement of the global commons, an increase in investments in education and health leading to an acceleration of the demographic transition. Economic growth is devalued in favor of a broader emphasis on human well-being. Inequality both within and between countries declines.
SSP2, the ‘middle of the road’ scenario, broadly assumes a continuation of current trends. Under this scenario, economic growth and development is uneven, with some countries making relatively good progress, while others do not. Progress towards achieving the Sustainable Development Goals is slower.
SSP3, the ‘rocky road’ scenario, sees conflicts and rivalry, both regional and global, as a result from resurgent nationalism, concerns about competitiveness and security. Socioeconomic challenges to mitigation and adaptation are bigger. Countries’ main focus are national interests, leading to reduced support for international institutions and cooperation. Investments in education and technological development decline. Inequalities persist or worsen, population growth is low in industrialized and high in developing countries, resulting in strong environmental degradation in some regions.
SSP4, the inequality scenario, ‘a road divided’, assumes low socio-economic challenges for mitigation, high challenges for adaptation. Unequal distribution of resources within and between countries, highly unequal investments in human capital result in increased inequality, especially in poorer countries. The gap between internationally connected society and fragmented lower-income, poorly educated societies broadens. Social cohesion breaks down, conflict and unrest increase.
SSP5, ‘taking the highway’ is the fossil-fueled development scenario. Socio-economic challenges for mitigation are large, challenges for adaption are low. Competitive markets, innovation, rapid technological progress and development of human capital are seen as the road to sustainable development. Investments in health and education are high. Countries become richer and more equal at the price of substantial environmental degradation.