A climate model simulation of the Early Eocene period roughly 50 million years ago returned temperatures that were too high compared to evidence in the geologic record, suggesting that the model may also project unrealistically high temperatures for the future.

The Arctic Ocean is likely to have its first ice-free summer before 2050, according to an analysis of simulations from more than 40 different climate models. How frequently the sea ice vanishes in the summer depends on the rate of greenhouse gas emissions in the future.

As temperatures warm across much of the globe, how often will people be threatened by extreme heat and extreme air pollution happening at the same time?

Scientists at the National Center for Atmospheric Research (NCAR) have used an ensemble of multiple climate model runs to simulate conditions along potential routes for the MOSAiC polar expedition, using today’s conditions in the “new Arctic.” The results suggest that thinner sea ice may carry the ship farther than would be expected compared to historical conditions and the sea ice around the ship may melt earlier than the 12-month goal. Of the 30 model runs analyzed in the new study, five (17%) showed melt-out in less than a year.

The American Meteorological Society has created a new national award in honor of NCAR senior scientist Warren Washington, a pioneer in the development of computer models of Earth's climate.