What is an emission scenario?

Emission scenarios

Model calculations of the climate are based on for example emission and radiation scenarios. Emission scenarios are assumptions about future atmospheric levels of greenhouse gasses. They are based on assumptions about the future development of the world’s economy, population growth, globalization, transition to environmentally friendly technology and more. All this affects the level of greenhouse gas emissions, which in turn affects the greenhouse effect. One way of measuring how the greenhouse effect will change in the future is to estimate radiative forcing, which is measured in power per square meter (W/m2). With more greenhouse gases in the atmosphere we get more radiative forcing. Such scenarios are called Representative Concentration Pathways (RCP).

What are Representative Concentration Pathways?

Every RCP-scenario represents a future with different levels of emissions (and radiative forcing). On this platform three scenarios are used: 2.6, 4.5 and 8.5. Read more what they mean in the article “What do different RCPs mean?”. 

 

Apart from RCP scenarios, Shared Socio-economic Pathways (SSPs) are also used in the climate models. These pathways are a separate complementary effort to look at factors such as population, education, economic growth, urbanization and technological development. Theoretically, each SSP can be used alongside the RCPs as long as it goes with the narrative (that will be explained below). While the RCP are used as input to evaluate the level of global warming in the future considered the levels of emissions, the SSPs look at the possibilities of emission reduction. SSPs can be combined with climate impact scenarios (as RCP scenarios) as well as sets of policy assumptions to study for example the interactions between climate change, related climate impacts, vulnerability to these and possible actions. But what are Shared Socio-economic Pathways?

What are Shared Socio-economic Pathways?

These pathways are five scenarios that describes different socio-economic developments used in climate models. The SSPs has been introduced because the climate is changing due to the emission of carbon dioxide, other greenhouse gases and the change of land use. These factors are crucial for further climate development and therefore the climate scenarios need to take these factors into account. The SSPs differ in terms of, among other things, population development, equality, energy use and global carbon dioxide emissions. In all SSPs, the global economy is growing. Read more about the characteristics of the SSPs in the article “What is SSPs? and What is the difference between SSPs and RCPs?”. Frida is working on a figure that we could have here as well (or only in the article). None of the SSPs are more likely than the other but the world can develop in several different ways depending on decisions in a number of different areas, where different paths are possible. All SSPs pose different major challenges for emission reductions and adaptation. However, no actual climate policy is included in these scenarios. Although climate policies can be explored in studies based on the conditions provided by the scenarios, for example to achieve a certain emission reduction.

Learn more about scenarios for climate change

  • What do differents RCP mean?
  • What do SSP mean?
  • What is the difference between RCPs and SSPs?