The dangerous global warming threshold is likely to be crossed between 2027 and 2042. In a study published in Climate Dynamics, scientists at McGill University have taken a new and broader approach to predict the Earth’s temperature in the future.
Scientists have predicted future global warming using climate models for decades. These models play an important role in understanding the Earth’s climate and its likely changes. But how accurate are they?
Climate models are mathematical modeling of various factors that interact to influence the Earth’s climate. While they are based on the best understanding of existing Earth systems, uncertainties remain when it comes to predicting the future.
“Climate skeptics have argued that global warming predictions are unreliable because they depend on faulty supercomputer models. While these criticisms are unfounded, they highlight the need for independent and different approaches to predicting future warming, ”says co-author Bruno Tremblay, a professor in the Department of Atmospheric and Oceanic Sciences at McGill University.
Until now, the wide range of total temperature forecasts has made it difficult to determine the results for different mitigation scenarios accurately. For example, if the concentration of carbon dioxide in the atmosphere doubles, general circulation models (GCMs) used by the Intergovernmental Panel on Climate Change (IPCC) predict a highly likely increase in global average temperature between 1.9 and 4.5 ° C. This range is too wide.
“Our new approach to predicting Earth’s temperature is based on historical climate data, rather than theoretical relationships that are not fully captured in GCM. Our approach provides an estimate of climate sensitivity and uncertainty based on direct observations with small assumptions, ”explains study co-author Raphael Hebert, a former research fellow at McGill University.
In the Climate Dynamics study, scientists presented a new Scaling Climate Response Function (SCRF) model to predict Earth’s temperature up to 2100. It reduces forecast uncertainty by about half compared to the approach currently used by the IPCC based on historical data. Analyzing the results, the researchers found that the dangerous warming threshold (+ 1.5°C) is likely to be exceeded between 2027 and 2042. This is a much narrower window than all previous estimates.