Scientists have been making projections of future global warming using powerful supercomputers for decades. But how accurate are these predictions? Modern climate models consider complicated interactions between millions of variables. They do this by solving a system of equations that attempt to capture the effects of the atmosphere, ocean, ice, land surface and the sun on the Earth’s climate. While the projections all agree that the Earth is approaching key thresholds for dangerous warming, the details of when and how this will happen differ greatly.
Now, researchers Shaun Lovejoy and Roman Procyk from McGill University and Raphael Hebert from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) hope to change all that. Building on an approach pioneered by Nobel prize winner Klaus Hasselmann, they have developed a new way to measure climate change more accurately and precisely. Their new projections are based on equations that combine the planet's energy balance and slow and fast atmospheric processes called “scaling”. This breakthrough opens new avenues of research on future and past climates on Earth, including ice ages. The new model can even be used to make precise regional temperature projections. By comparing their projections to the conventional ones used by Intergovernmental Panel on Climate Change, the researchers found that the new model gives overall support to the IPCC projections but with some significant differences. While the new model projects a crossing of the key thresholds for dangerous warming a bit later, the time frame for crossing it is much narrower. According to the researchers, there is a 50% chance of exceeding the 1.5 C threshold by 2040.
Original Publication:
Roman Procyk, Shaun Lovejoy, Raphael Hébert: The fractional energy balance equation for climate projections through 2100, Earth System Dynamics (2022). DOI: https://doi.org/10.5194/esd-13-81-2022