Climate models

Even 50-year-old climate models correctly predicted global warming

In climate science, models are essential tools in trying to understand an uncertain future. But attempts to predict the future are easy targets, and climate change skeptics have long sought to poke holes in past climate change predictions to undermine the credibility of today’s dire warnings. Now a full review of climate models dating back to 1970, most of the findings were, in fact, quite accurate, Scientific reports.

Early climate simulations included relatively few parameters by today’s standards, limited in part by computers of the time. Today, supercomputers can perform trillions of calculations per second and take into account many other complex interactions that influence global climate. But the researchers wanted to assess how well these models of varying vintages and sophistication predicted the future.

Scientists compared actual global temperatures with 17 forecasts of average global temperatures using models developed between 1970 and 2001. The majority of models accurately predicted the 0.9 degree Celsius warming that has occurred since the industrial Revolution. Ten of the models were so accurate that the study found no statistically significant difference between the temperatures they predicted and those that were directly measured.

Some of the older climate predictions have missed the mark not because they apply the physics that drives global warming, whereby so-called greenhouse gases trap heat in the atmosphere and warm the planet, but because they have overestimated or underestimated the amount of greenhouse gases that humans will emit in the coming decades. When the researchers incorporated more accurate greenhouse gas emissions, the model predictions aligned with observed temperatures.

The results come as no surprise to scientists in the field, who have long had faith in the rigor and predictive power of these models. And while the results won’t appeal to skeptics, they underscore just how seriously the dire predictions made by the latest and most advanced models should be taken seriously. The realization that we knew where our climate was heading with such precision for half a century places our decades of inaction in eerie relief.