Understanding the Four Climate Scenarios: Exploring the Future of Our Planet

Climate change has become one of the most pressing concerns of the 21st century, posing an unprecedented challenge to humanity’s future. To understand the range of possible futures that our planet may face, it’s essential to examine different climate scenarios. In this blog post, we will discuss four key climate scenarios that help us understand potential outcomes and provide insights for developing effective climate policies.  These are demanded by both the TCFD and the EU CSRD, so it’s critical to get it right. The scenarios are based on the Representative Concentration Pathways (RCPs) used by the Intergovernmental Panel on Climate Change (IPCC).

RCP 2.6: The Best-Case Scenario

RCP 2.6, often referred to as the best-case scenario, assumes that we can successfully implement and maintain aggressive climate change mitigation measures. This scenario envisions a future in which global greenhouse gas (GHG) emissions peak before 2020 and decline significantly thereafter. By the end of the century, emissions are expected to reach near-zero or even become negative, meaning that more GHGs are removed from the atmosphere than emitted.

Key features of RCP 2.6 include:

• Rapid transition to renewable energy sources and improvements in energy efficiency
• Widespread adoption of carbon capture and storage (CCS) technologies
• Changes in land use and agricultural practices to minimise GHG emissions
• Large-scale afforestation and reforestation efforts

Under RCP 2.6, global warming is projected to be limited to 1.5°C to 2°C above pre-industrial levels by 2100, thus avoiding the worst consequences of climate change. Although this scenario may seem optimistic, it emphasises the importance of immediate, ambitious action to reduce emissions and mitigate climate change.

RCP 4.5: The Moderate Mitigation Scenario

RCP 4.5 represents a world where we take moderate action to reduce GHG emissions, resulting in a stabilisation of atmospheric concentrations by the end of the century. This scenario assumes that a combination of policy, technological advancements, and market-based solutions will help to reduce emissions, albeit more slowly than in RCP 2.6.

Key features of RCP 4.5 include:

• Gradual decarbonisation of the energy sector, with increased use of renewable energy and nuclear power
• Implementation of energy efficiency measures across various sectors
• Moderate adoption of CCS technologies and other emission reduction strategies
• Some changes in land use and agricultural practices to curb emissions

In this scenario, global warming is projected to reach 2.4°C to 3°C above pre-industrial levels by 2100. While the impacts of climate change would still be substantial, they would be less severe than in the worst-case scenarios.

RCP 6.0: The Slower Mitigation Scenario

RCP 6.0 is a scenario in which GHG emissions peak around 2080, followed by a slow decline. This pathway represents a future where efforts to mitigate climate change are made, but at a more sluggish pace than in RCP 4.5.

Key features of RCP 6.0 include:

• Slow and uneven transition to renewable energy sources, with continued reliance on fossil fuels
• Limited improvements in energy efficiency across various sectors
• Minimal adoption of CCS technologies and other emission reduction strategies
• Fewer changes in land use and agricultural practices, leading to higher emissions

Under RCP 6.0, global warming is projected to reach 3°C to 4°C above pre-industrial levels by 2100. This scenario would result in more severe consequences of climate change, including more frequent and intense extreme weather events, loss of biodiversity, and significant impacts on global food and water resources.

RCP 8.5: The Worst-Case Scenario

RCP 8.5 is often referred to as the worst-case or “business-as-usual” scenario, in which no significant efforts are made to mitigate climate change. This pathway envisions a future with high population growth, increased reliance on fossil fuels, and little progress in energy efficiency or emission reduction technologies.

Key features of RCP 8.5 include:

• Continued dependence on fossil fuels, particularly coal, with minimal transition to renewable energy sources
• Lack of significant improvements in energy efficiency across various sectors
• No meaningful adoption of CCS technologies or other emission reduction strategies
• Increased deforestation and land-use changes that exacerbate GHG emissions

Under RCP 8.5, global warming is projected to reach 4°C to 6°C above pre-industrial levels by 2100. This scenario would have catastrophic consequences for the planet, including more frequent and severe extreme weather events, massive loss of biodiversity, widespread food and water shortages, and the displacement of millions of people due to rising sea levels and climate-related disasters.

Summary

Understanding these four climate scenarios allows us to better comprehend the possible futures we face depending on the actions we take to mitigate climate change. By examining the potential consequences of each scenario, policymakers and citizens alike can make informed decisions about the necessary steps to create a more sustainable and resilient world.

It is crucial to recognise that the future is not predetermined, and we have the power to influence which climate scenario becomes our reality. While RCP 2.6 may seem challenging to achieve, it represents the best chance we have to avoid the most severe impacts of climate change. To create a more sustainable and just future, we must prioritise immediate, ambitious action to reduce GHG emissions, invest in clean energy, and implement effective climate adaptation strategies.