[ad_1]
TORONTO —
Researchers studying climate change at McGill University say they have projected a more precise window of when the Earth will likely cross “dangerous warming levels,” with their new threshold set at 2027-2042 – 25 years earlier than previous mdelling.
The study, published in “Climate Dynamics,” uses historical data that reduces prediction uncertainties by about 50 per cent compared with the current modelling being used by the Intergovernmental Panel on Climate Change (IPCC).
What are climate models?
Climate models are mathematical simulations that calculate projections dependent on the variables or factors that can affect the Earth’s climate – such as atmosphere, ocean, land surface and the sun, the study release says.
“Climate skeptics have argued that global warming projections are unreliable because they depend on faulty supercomputer models. While these criticisms are unwarranted, they underscore the need for independent and different approaches to predicting future warming,” study co-author and professor in the Dept. of Atmospheric and Oceanic Sciences at McGill Bruno Tremblay said in the release.
The study says that wide ranges in overall temperature projections in past climate models make it difficult to pinpoint outcomes.
Using an example of atmospheric carbon dioxide levels to demonstrate the pitfalls of current modelling – the study pointed out that if atmospheric C02 concentrations are doubled, the IPCC modelling program would predict a temperature rise spanning anywhere from 1.9 to 4.5 degree Celsius, “a vast range covering moderate climate changes on the lower end and catastrophic ones on the other.”
A new approach
The researchers’ new approach centres around historical climate data to project the Earth’s temperature, rather than the “theoretical relationships” currently calculated by modelling used by the IPCC.
“Our approach allows climate sensitivity and its uncertainty to be estimated from direct observations with few assumptions,” says study co-author Raphael Hebert, in the release.
For the study, researchers used their new modelling approach to project the Earth’s temperature to the year 2100. Their results found that the threshold for dangerous warming levels – 1.5 degree Celsius and higher – will likely be crossed between 2027 and 2042.
This window is much narrower than the IPCC’s modelling that puts the window between now and 2052.
The study also found that the expected warming was a little lower, by about 10 to 15 per cent, but that their findings about “very likely warming ranges” using their new modelling matched up with the IPCC’s numbers.
“Now that governments have finally decided to act on climate change, we must avoid situations where leaders can claim that even the weakest policies can avert dangerous consequences,” says co-author Shaun Lovejoy, a professor in the Physics Department at McGill University in the release.
“With our new climate model and its next generation improvements, there’s less wiggle room.”
[ad_2]
Source link
