Planning for a future with rapidly changing socioeconomic conditions and rising global temperatures requires a crystal ball – or the development of climate models with the ability to detail scenarios that haven’t yet happened. 

Shared Socioeconomic Pathways (SSP’s) do just that by providing climate researchers and policy makers with 5 different scenarios of the future based upon a range of socio-economic factors including “sustainable development, regional rivalry, inequality, fossil-fueled development, and middle-of-the-road development.” (Riahi et al, 2017, p.153)  

Climate adaptation and mitigation policy, however, has deliberately been left out of the initial SSP framework, as SSP’s were created to answer the question: how might the world evolve in the absence of climate policy?  As Hausfather explains in his essay ‘How Shared Socioeconomic Pathways explore future climate change’, SSP’s “define different baseline worlds that might occur in the absence of any concerted international effort to address climate change, beyond those already adopted by countries.” (Hausfather, 2018)

In this way, SSP’s support planning for the future by assisting researchers in estimating mitigation and adaptation costs, quantifying global energy consumption and land use as well as gauging greenhouse gas and emissions output (Riahi et al., 2017, p.154) based upon the 5 different SSP scenarios.  These scenarios and their narratives are designed to assist researchers and policy makers in understanding the “range of futures in terms of the socioeconomic challenges they imply for mitigating and adapting to climate change” (Riahi et al., 2017, p.157).

SSP’s have developed alongside other scenario modeling, including that of Representative Concentration Pathways (RCP’s) which are used to describe possible futures based upon the levels of greenhouse gasses in the atmosphere and the amount of warming which may occur by the end of the century (Hausfather, 2018). The SSP framework has built upon the models provided by RCP’s by adding multiple socio-economic factors to create a more well-rounded narrative about how – and if – emissions can be reduced. 

The SSP framework has also allowed climate modelers to expand the range of mitigation targets beyond what was previously believed plausible. Researchers have developed a new pathway, called RCP1.9, which is focused on “limiting warming to below 1.5°C, the aspirational goal of the Paris Agreement” (Hausfather, 2018).  Previously, the lowest emission scenario believed to be achievable was RCP2.6, which reflected the ‘below 2°C’ target of the Paris Climate Agreement. RCP1.9 is reflected in the SSP1 scenario, titled “Taking the Green Road”, which offers low challenges to both mitigation and adaptation and where “the world shifts gradually, but pervasively, toward a more sustainable path, emphasizing more inclusive development that respects perceived environmental boundaries” (Riahi et al., 2017, p.157). SSP1 also highlights the importance of investments in education and health and focuses on decreasing inequality and consumption (Hausfather, 2018).

 It is important to note that achieving RCP1.9 or even RCP2.6, while possible, is extremely ambitious. According to Riahi et al., “achieving stringent climate targets requires a fundamental transformation of the energy system, including the rapid upscaling of low-carbon energy (renewables, nuclear and CCS)” (p.164).  SSP1, then, is a best-case scenario, assuming “substantial investments in education and health, rapid economic growth, and well-functioning institutions” (Hausfather, 2018).

Another optimistic scenario is titled SSP5, “Taking the Highway”.  While SSP1 focuses on sustainable development, SSP5 projects growth due to an increase in fossil fuel and other energy-intensive means.  However, SSP5 is considered optimistic due to the fact that it projects a heavy investment in technology and a push for economic development which has the potential to greatly increase climate mitigation and adaptation (for example, through geo-engineering and carbon-capture technology).  

By comparing these two scenarios, we can see that the SSP framework was created to project a broad range of futures depending on many different socio-economic factors. Ultimately, it is up to us to decide which future we want to pursue. Reaching ambitious targets like RCP1.9 or RCP2.6 by 2100 will require international collaboration, technological development, and drastically reduce emissions. As a precautionary approach, many researchers are focusing on a high-emissions scenario called RCP8.5 which features “assumptions of high population and slow technological progress, on the higher end of the range of possible baseline scenarios” (Hausfather, 2019).  The understanding is that while this is essentially a ‘no policy or ‘worst-case’ baseline scenario that is highly unlikely due to mitigation policy already set in place, it is better to assume the worst and adapt to what is projected to be a drastically changing climate than be underprepared and lack a clear mitigation and adaptation policy. 

SSP’s currently represent the most advanced modeling from which to build and implement adaptation and mitigation policies, and to “examine how global society, demographics, and economics might change over the next century” (Hausfather, 2018). Whether we strive for RCP1.9 and SSP1, or we continue with ‘business as usual’ has yet to be seen, but the SSP framework provides comprehensible narratives for all possible scenarios and gives researchers and policymakers alike a clearer picture of what the future may hold. 

References:

Hausfather, Z. (2018). Explainer: How ‘Shared Socioeconomic Pathways’ explore future climate change. Carbon Brief. https://www.carbonbrief.org/explainer-how-shared-socioeconomic-pathways-explore-future-climate-change

Hausfather, Z. (2019). Explainer: The high-emissions ‘RCP8.5’ global warming scenario. Carbon Brief. https://www.carbonbrief.org/explainer-the-high-emissions-rcp8-5-global-warming-scenario

Riahi, K., van Vuuren, D. P., Kriegler, E., Edmonds, J., O’neill, B. C., Fujimori, S., Bauer, N., Calvin, K., … Tavoni, M. (2017). The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview. Global environmental change, 42, 153-168. https://doi.org/10.1016/j.gloenvcha.2016.05.009

Cover Image: Gucklhorn, A. (2017) retrieved from https://unsplash.com/photos/Ilpf2eUPpUE