Dr. Yujie He’s paper “Radiocarbon constraints imply reduced carbon uptake by soils during the 21st century” was published in Science Magazine this week. Yujie conducted this analysis while she was a postdoctoral scholar at UC Irvine in the Department of Earth System Science. In her analysis, Yujie developed a reduced complexity model of soil dynamics for each earth system model that contributed simulations to the carbon-climate feedback experiment in the 5th Coupled Model Intercomparison Project (CMIP5). She then used the reduced complexity models to simulate radiocarbon levels in the soils. Comparing the models with observations from 157 measurement sites, Yujie found that the models underestimated the mean age of soil carbon, on average, by about a factor of 6. When she adjusted the reduced complexity models to bring them into agreement with the radiocarbon observations, the rate of soil carbon uptake decreased by about 40%. This suggests that soil carbon accumulation rates may be lower than previous estimates, and that as a consequence more fossil fuel carbon may accumulate in the atmosphere during the 21st century than previously thought. The paper was covered by the Washington Post and The Guardian.