Climate Change Scenario Primer

Introduction

We can’t predict the future, but scenarios allow us to explore possible futures, the assumptions they depend upon, and the courses of action that could bring them about.

This interactive primer explains what climate change scenarios are and how they are connected to socioeconomics, energy and land use, emissions, climate change and climate impacts.

What follows below is a brief summary of each aspect of the Primer. Click below to explore the tool and access much more information and options for further reading.

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This Climate Change Scenario Primer is part of the SENSES Toolkit, which aims to help you understand and communicate climate change scenarios.

Explore an overview of the SENSES Toolkit for Climate Change Adaptation here!

Find out more about the SENSES project and upcoming tools and publications on the SENSES Project website.

What are Climate Change Scenarios?

• Climate change scenarios are a powerful tool for understanding climate change, charting response strategies, and supporting climate policy making.
• Climate change scenarios are not about predicting the future, but come in the form of projections of what can happen or pathways of how to reach certain goals.
• Climate change scenarios are usually used in pairs or larger sets which determine their context and meaning.
• Owing to the nature of climate change, scenario analysis is a common tool in climate change research and its various subfields. Broadly speaking, seven different types of scenarios can be identified:

How are Socioeco­nomic Develop­ment and Climate Change connected?

• Socioeconomic development and climate change are intricately linked, with social and economic activities determining energy and land use determining emissions determining climate forcing and climate change determining climate impacts which in turn affect socioeconomic developments.
• Climate change response strategies fall into mitigation strategies to limit human impact on climate change and adaptation strategies to limit the climate change impact on humans. Mitigation and adaptation scenarios (often also called “pathways”) are used to analyse such response strategies.

Socioeconomic Development

• Socioeconomic scenarios provide a consistent set of assumptions about societal, technical, cultural and economic developments over the 21st century.
• They typically centre around a general narrative about the world’s future augmented by projections of factors like population, economic activity, and urbanisation.
• Socioeconomic scenarios in climate change research are increasingly based on the Shared Socioeconomic Pathways (SSPs) which represent five different futures with widely varying challenges to mitigation and adaptation.

Energy, Land Use and Emissions

• Integrated assessment models (IAMs) are complex models of the energy-land-economy-climate system that use socioeconomic assumptions to produce energy, land use and emissions scenarios.
• IAMs show that the widely varying socioeconomic futures described by the SSPs lead to large variations in energy, land use and emissions in baseline projections without climate policy interventions.
• IAMs are used to derive both baseline projections (What can happen?) as well as pathways oriented to achieving mitigation goals (What should happen?)

(Climate Change) Mitigation

• Representative Concentration Pathways (RCPs) represent different emissions, concentration and radiative forcing projections leading to a large range of global warming levels, from continued warming rising above 4 °C by the year 2100 to limiting warming well below 2 °C as called for in the Paris Agreement.
• When combined with the Socioeconomic Pathways (SSPs) they provide a powerful framework to explore the space of future mitigation pathways in terms of different levels of mitigation stringency and different assumptions about socioeconomic development.
• The mitigation pathway literature developed by the application of integrated assessment modelling comprises a wide variety of mitigation pathways, including pathways with limited technology availability and delays in climate policy in addition to variations in mitigation targets and socioeconomic drivers.

Climate Change

• Climate models are complex systems describing the physical world including its atmosphere, ocean, ice sheets and vegetation. The most comprehensive climate models are called Earth system models.
• Climate models generate projections of future temperature and precipitation based on GHG concentration scenarios.

Climate Impacts

• There is a wide range of sectors considered in climate impact research including impacts related to agriculture, energy, and health.
• Climate impact models use data from climate and socioeconomic scenarios to create impact scenarios.