Climate Models Were Always Right on Global Warming
There are many people across the United States of America – as well as the world – who do not believe the argument for climate change, with many arguing that climate models are over-predicting how fast Earth is heating up.
With startling regularity, the claim continues to be argued that there is proof that climate change is not happening as fast as the experts claim. These claims are usually based on individual examples of data that may have been misinterpreted, even though over the years multiple studies have re-examined different climate models and continue to conclude that they are still working well.
A recent study has extensively investigated all global climate models that were released between the 1970s and 2007, which includes the ones that were used in the Intergovernmental Panel on Climate Change’s first three reports.
Lead study author Zeke Hausfather is a climate scientist at the University of California in Berkeley and has also worked alongside Tristan Abbott and Henri Drake – scientists from Massachusetts Institute of Technology – and Gavin Schmidt who is a scientist at NASA. Hausfather comments:
“It’s always a sign that you’re onto a good project when your first thought is, “Why hasn’t anyone done this before?” No one has really gone back and gathered all of the old model predictions that were in the literature, in part because climate models have changed a lot.”
Obviously many of these original models have become archaic with newer models replacing them. Yet even with advancing technology helping to make clearer projections, most of the early models had got their predictions of how warm the Earth would increase by right. In fact out of 17 models, only three were found not to be accurate.
However the latest study focuses on an often ignored, yet crucially important point regarding how climate models work. Each model has worked on the projections of future greenhouse gas emissions, which in turn predicts the level of warming expected.
But predicting most things can be difficult, especially when you try to predict carbon emissions, as there are many factors to take into consideration such as population growth and changes made within the energy landscape as well as economic shifts – all human factors making a difference to the natural world.
It was also suggested that in the past several of the models that had been criticized were actually pretty accurate as the simulation of the connection between greenhouse gases and temperatures were correct but the expectations regarding carbon emissions in the future were different to the emissions that were eventually created.
Basically, if scientists had entered the correct levels of greenhouse gas emissions when first creating the models, we would have seen the exact levels of future warming that they predicted.
During the 1980s James Hansen, a researcher for NASA, created a climate model that would eventually lead to him giving a congressional testimony on the threat of climate change. His testimony helped highlight climate change awareness throughout the world however due to his model over predicting warming by around 50% disbelievers were able to use his words as proof of global warming not being a real threat, due to their belief that scientists were prone to over exaggerate the facts.
Alongside his colleagues, Hausfather was quick to point out that the problem with his model was not the physics but the fact there was an assumption that there would be higher methane and chlorofluorocarbon emissions – both of which are dominant greenhouse gases – than there actually was.
One of the reasons for this over-projection was the fact that the model did not allow room for the impact the Montreal Protocol would have. The Montreal Protocol was a global agreement to phase out chlorofluorocarbons in an attempt to protect the ozone layer and potentially repairing the damage that was already caused.
As Hausfather said, “If you went back and reran that model with the actual levels of CO2 in the atmosphere and methane and chlorofluorocarbons, you would have gotten a value that was indistinguishable from the warming that we’ve actually observed.”
Even with these issues addressed there are still many obstacles for the next climate models such as making sure that all assumptions regarding greenhouse gas emissions in the future are accurate.
There will also be a need to look at specific physical processes on Earth that are difficult to understand, including clouds which have always been hard to represent, even though many scientists think they will be an important influence in regards to climate change. And as each model gets more and more detailed, the emphasis on making sure these details are improved upon will be significant.
In summary, the latest study implies that conclusions from previous models have been accurate for many years when it comes to global warming.
As Hausfather said, “they haven’t been overestimating warming, but at the same time it isn’t warming faster than we thought. It’s pretty much warming just as we thought it would.”
Sandra Hart is a Contributing Editor at The National Digest based in the United Kingdom. You can reach her at inquiries@thenationaldigest.com.