Science: Every June, US climate scientists descend upon Breckenridge, Colorado, to kick the tires on the nation's foremost academic global climate model. Some years there is added pressure, as scientists try to tune up the Community Climate System Model (CCSM) for simulations that will feed into the next report of the Intergovernmental Panel on Climate Change (IPCC). This is one of those years, and scientists are more worried than usual.

The question is whether they can meet a 1 October deadline for completing a critical part of their increasingly complex simulation of the interplay of Earth's atmosphere, oceans, land, and ice. "We're all very nervous," says atmospheric modeler Philip Rasch, who works remotely for the National Center for Atmospheric Research (NCAR) in nearby Boulder and who oversees the atmospheric component of the model. A big reason for the concern is the budget cuts that have affected the center, which hosts and manages CCSM.