Flavio Lehner was a graduate student working with computer models simulating Earth’s climate at the University of Berne in Switzerland when he had a chance to join a research vessel collecting sea temperatures and measuring ocean currents between Greenland and Svalbard, Norway. “As a lifestyle, field work is very agreeable,” Lehner said. “But for me, it was a watershed moment. I had to decide which way to go.” Was it to be a life in the real world of ocean voyages or mathematical abstractions? “They had been measuring ocean currents for 10 years,” Lehner said. “In real-world data collection, you look at one fraction of the Earth for a long time. With models, you can look at the big-picture questions.” Two of those big-picture questions are how much snow will fall on the mountains of the West and how much water will be available for the region’s forests, farms and cities in a world growing warmer as greenhouse gases build up in the atmosphere. Today, Lehner, 35, and his colleagues at the National Center for Atmospheric Research in Boulder are trying to divine answers through a welter of mathematical calculations designed to reflect how the world works. Those equations are linked together in NCAR’s Community Earth System Model, a sort of algorithmic Rube Goldberg machine, which connects a set of algorithms representing the laws of physics that govern the planet – thermodynamics, transfer of radiation and global conservation of momentum and water – and uses them to generate a picture of the future. It takes years to construct such a model, and it is hoped it accurately reflects the world. “The models do have deficiencies, and we work on those,” Lehner said. To view the full article from February 2020 visit the Journal.
