Shared Socioeconomic Pathways and Representative Concentration Pathways

If predicting weather forecast for next week is complicated, predicting climatic conditions for the next decades is impossible. However, while there is no crystal ball to predict what the future will look like, scientists have developed sophisticated models that can predict climatic conditions under alternative, plausible, scenarios. Recently two main modelling exercises were completed, which allow exploring widely different future scenarios. The “Representative Concentration Pathways” (RCPs) describe different levels of greenhouse gases, and associated climatic conditions, that might occur in the future. The “Shared Socioeconomic Pathways” (SSPs) look at different ways in which alternative RCP conditions will affect human societies worldwide, and how these societies will mitigate the effects of climate change or adapt to such effects. 

Projected emission of CO2 under five alternative scenarios, source: IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. doi:10.1017/9781009157896.001.

Many combinations of SSP-RCP scenarios are theoretically possible, but it is worth considering two extreme examples here.

Scenario SSP1 Sustainability – “Taking the Green Road” – Associated with RCPs 1.9 and 2.6

This narrative describes a world in which national and international organizations (public and private) cooperate to achieve the Sustainable Development Goals (SDGs) and the Paris Agreement, fostering changes in policies and institutions at all levels. Due to a better management of human and financial resources, significant improvements are made towards research and development of environmentally friendly technologies. These changes will induce a demographic transition, a reduced emphasis on rapid economic growth in favor of higher environmental sustainability, and a growth of green economy. This narrative aligns with the goals set under the Paris Agreement of limiting global warming to no more than 1.5°C (SSP1-1.9) or 2°C (SSP1-2.6) from pre-industrial levels.

Scenario SSP5 Fossil fuel development – “Taking the highway” – Associated to RCP 8.5

This narrative is driven by accelerated globalization, economic growth and the economic success of industrialized and emerging economies. Competitive markets, innovation and participatory societies are considered the key to economic development. While strong investments in health, education, and institutions are made to enhance human and social capital, the push for economic and social development is coupled with the exploitation of abundant fossil fuel resources and the adoption of an intensive lifestyles around the world. There is relatively little effort to avoid potential global environmental impacts due to a perceived trade-off with economic growth. This condition is coupled with the lack of global environmental concern resulting in potentially high challenges to mitigation. There is high faith in the ability to effectively manage social and ecological systems by developing new technologies. This scenario corresponds to the pathway with the highest greenhouse gas emissions, where global warming is projected to be between 4.1 and 4.7°C by 2100 (more than double the Paris limits).

Find out more about the SSPs here.