Have you ever wondered how scientists predict future climate conditions?
Enter climate models—these super sophisticated tools crunch data from the Earth’s atmosphere, oceans, land and ice to help us understand how our climate behaved in the past and predict how it will change in the future. The models use mathematical representations and physical laws to simulate the interactions between different components of the climate system.
How do climate models work?
Scientists feed a wealth of data into climate models, like weather observations, satellite measurements and information about past climate conditions. Then they test their models by comparing outputs with observed data and seeing how closely the model can match past observations.
The models are like digital labs, where researchers can test scenarios—like what happens if we cut emissions, or if a volcano erupts—which can help us understand the bigger picture of how the climate will respond.
Meet CMIP: the global climate model collaboration
Climate science is a global endeavor that spans countries and continents. The Coupled Model Intercomparison Project (CMIP) is an international collaborative effort brings together experts worldwide and coordinates climate model experiments, providing a framework for climate model developers and users to systematically compare and evaluate different climate models.
CMIP results are integral to the Intergovernmental Panel on Climate Change (IPCC) assessment reports, which synthesize scientific knowledge on climate change to inform policymakers and the public.
Decoding future scenarios: what are RCPs and SSPs?
Representative Concentration Pathways (RCPs) and Shared Socio-economic Pathways (SSPs) are like roadmaps for how different choices today can lead to vastly different climate futures.
RCPs are scenarios that describe different trajectories for greenhouse gas concentrations in the atmosphere, based on varying levels of human activity. Developed for the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, RCPs are used as inputs in climate models to help scientists project future climate conditions.
There are four main RCPs, each representing a different greenhouse gas concentration trajectory:
RCP2.6: A scenario where strong mitigation leads greenhouse gas emissions to peak early and then decline, resulting in low greenhouse gas concentrations.
RCP4.5: An intermediate scenario where emissions stabilize before mid-century and then decline, resulting in moderate greenhouse gas concentrations.
RCP6.0: Another intermediate scenario with emissions stabilizing by the end of the century, resulting in slightly higher greenhouse gas concentrations.
RCP8.5: A high-emission scenario where emissions continue to rise throughout the century, resulting in increasing greenhouse gas concentrations.
Meanwhile, SSPs are scenarios that describe different socio-economic futures and their implications for greenhouse gas emissions and climate change. Developed to complement the RCPs, SSPs consider factors like population growth, economic development, technological progress and environmental policies.
There are five SSPs, each representing a different socio-economic world:
SSP1 (Sustainability): A world that focuses on sustainability and reducing inequalities, leading to lower emissions.
SSP2 (Middle of the Road): A world with moderate socio-economic trends, continuing current development patterns.
SSP3 (Regional Rivalry): A fragmented world with high challenges to both mitigation and adaptation due to regional conflicts and slow economic growth.
SSP4 (Inequality): A world with significant inequalities, leading to high challenges to adaptation but low challenges to mitigation.
SSP5 (Fossil-fueled Development): A world with rapid economic growth driven by fossil fuels, leading to high emissions.
While RCPs help scientists explore how different emissions concentrations will affect the climate, SSPs allow researchers to map out how societal changes including population, education, and government policies can affect levels of climate change.
Within each SSP group, there can be multiple scenarios that lead to different RCPs. That’s why climate projections are often labeled with both names. For example, SSP2-4.5 represents the “Middle of the Road” scenario that has led to an RCP4.5 with moderate greenhouse gas concentration.
Making sense of climate projection numbers for our region
The Climate Project uses data from ClimateData.ca to highlight projections for the Saugeen Ojibway Nation Territory and Bruce, Grey, and Huron counties.
ClimateData.ca uses three SSP scenarios that span a wide range of possible future climates:
Less warming (SSP1-2.6)
Moderate warming (SSP2-4.5)
More warming (SSP5-8.5)
Understanding climate models isn’t just about graphs and simulations—it’s about grasping how our choices today can shape our future tomorrow. By diving into the data, we can empower ourselves to make informed decisions that can combat climate change head-on.
Dr. Stephanie Keating is the Director, Environment@NII at the Nuclear Innovation Institute.
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