Instead of using climate models coded in Fortran in the 1960s and 70s, MIT decided that there was no saving the ancient code and to start from scratch.
MIT professors Raffaele Ferrari and Noelle Eckley submitted their Bringing Computation to the Climate Challenge proposal as part of MIT’s Climate Grand Challenges (CGC). Out of 100 submissions, MIT chose five projects to fund and support, one of which is Ferrari and Selin’s.
CLIMA made the choice that old climate models, many of which were built 50 years ago and coded in Fortran, had to be abandoned if there was going to be any progress toward better climate models. Ferrari realized that “traditional climate models are in a language (MIT) students can’t even read.”
The language that CLiMA chose is Julia, which another CLiMA researcher described as a serious challenge “because Julia hadn’t been used on such a big science project before.”
Ferrari said that Julia was a good choice, leading to the current situation in which the team has built what it describe as a digital twin of the Earth that can simulate global climate conditions. Current models have low resolution with the smallest being the 100-200 kilometer scale. Small-scale weather processes, like rainfall, sea ice and cloud cover, simply can’t be accurately predicted.
CLiMA’s model is able to include small-scale climate elements but global precision isn’t the end goal. “We want to take this large-scale model and create what we call an ’emulator’ that is only predicting a set of variables of interest, but it’s been trained on the large-scale model,” said Ferrari.