UC Berkeley researchers found that climate change models made since the early 1970s were accurate in predicting today’s climate, according to a recent study.
The look-back study, which was conducted by campus scientists, as well as researchers from the Massachusetts Institute of Technology and NASA focused on evaluating the accuracy of climate change models from the past. Scientists examined 17 particular models between 1970 and the late 2000s.
According to lead author and campus doctoral candidate Zeke Hausfather, 10 of 17 models accurately predicted what climate conditions would be like today, while four projected too much change and three projected too little. Hausfather added that the aim of the study was to show that prior climate change models did not overestimate the impacts of greenhouse gas production.
“There’s been a common argument made by skeptics in many places that climate models overestimate warming, which is made with very little support,” Hausfather said. “We wanted to go back to the early climate models that were published, look at those forecasts and compare them to what we see today.”
In order to evaluate the models’ accuracy, researchers looked at factors, including how well the models were able to predict changes in temperature and overall greenhouse gas emissions.
One challenge with older predictions was the fact that many models struggled to estimate how much greenhouse gas would be emitted by humans over the next 30 years, according to Hausfather. He added that researchers accounted for this obstacle by looking at the change in temperature in relation to the amount of greenhouse gases emitted.
Hausfather said it was remarkable that climate change models from the 1970s were able to precisely show a model of the climate today, given their limited information.
“This is impressive for climate models in the early 1970s since the idea of global warming didn’t have much recognition yet and a lot of scientists, based on limited records, believed that the Earth is cooling,” Hausfather said.
While this type of research, according to the study, will lend significant credibility to both past and current climate change models, Hausfather and his coauthors plan to examine models of climate change at a more regional level — along with ocean heat models to further gauge the accuracy of past studies.
One potential obstacle in future studies is that many of the models were stored as physical copies rather than digital, according to Hausfather.
“We have to pore through countless scientific journals and magazines to find that data,” Hausfather said.