New global climate calculations show faster warming

New calculations of how the world’s climate is changing confirm that the volume of greenhouse gas emissions makes a difference. They also show that warming is taking place at a faster rate than suggested by previous calculations. SMHI has now carried out the first calculations using the new version of the global climate model EC-Earth.

After several years of development, researchers at SMHI’s Rossby Centre have now carried out the first calculations using the latest version of the global climate model EC-Earth. These calculations show how the climate is changing up until the year 2100, the end of this century. They are based on assumptions about future societal developments and volumes of greenhouse gas emissions.

“The latest climate calculations confirm that greenhouse gas emission volumes make a difference,” says Ralf Döscher, who leads SMHI’s climate modelling unit, the Rossby Centre. “They also show that warming is occurring at a faster rate than suggested by previous calculations.”

Graphics showing temperature anomaly until year 2100 compared to preindustrial time, 1850-1890
The new calculations produced using the global climate model EC-Earth (CMIP6, unbroken lines) show how much the average global temperature rises with various societal developments involving different greenhouse gas emission volumes. The new calculations clearly show that warming is happening at a faster rate than previously calculated (comparison between dotted and unbroken lines in each colour). The green curve represents a sustainable society that follows the actions of the Paris Agreement. The purple curve represents a society that continues to be driven by fossil fuel use and that has not reduced emissions or taken other actions to limit the amount of atmospheric greenhouse gases. The dotted lines show the average values for corresponding calculations based on the RCP scenarios (CMIP5), as used in the climate research carried out in recent years. Enlarge Image

Investigating more rapid changes

The researchers are now investigating why the new calculations show a faster rate of climate change than previously suggested.

“Several models have produced similar results, indicating that warming is taking place at a faster rate, and this confirms the urgency of working to reduce emissions,” Ralf continues.

The biggest change can be seen in the far north, with temperatures in the Arctic rising much faster than the global average. This is affecting sea ice, which is reduced in all scenarios.

“If we follow the medium or highest emission pathways in the future, the Arctic sea ice will disappear completely during the summer,” says Torben Koenigk, Head of the Global Modelling Unit at SMHI’s Rossby Centre. “If we succeed in limiting warming, less ice will melt in the Arctic and, in particular, the local temperature increase in the Arctic will be less.”

The first step towards a complete climate service

The climate calculations are currently being analysed by researchers at the Rossby Centre, comparing them with calculations from other research teams who have carried out equivalent climate calculations within the CMIP6 international collaboration, where calculations from around thirty different climate models are being coordinated and compiled in a joint open database.

In future, it will be possible to interpret these climate calculations using a regional climate model, giving more detailed data about how the climate is changing in Sweden.

“Once the regional processing is complete, we will have sufficiently detailed data to present a climate service that can be used when making societal adaptations in line with a changed climate, for example,” adds Ralf. “In the meantime, it is best to continue using the data published via our climate services at”

The calculations also form the basis for new research that will be presented in scientific articles, and that will be evaluated in the next major climate report by the UN’s Intergovernmental Panel on Climate Change (IPCC) – AR6 – to be published in 2021-2022.

Data is already openly available in SMHI’s ESGF data node, where other researchers can download and use the material.