Forests are one of the planet’s most important buffers against climate change. They absorb carbon dioxide, slow the accumulation of greenhouse gases in the atmosphere, and buy time for everything else.

The climate models used to project future warming rely heavily on forests continuing to do that job.

However, a new study suggests those models are significantly overestimating how much carbon forests will actually absorb.

This is because the models haven’t caught up with a recent and uncomfortable ecological discovery: warming temperatures are slowing tree growth, even as more carbon is available.

The study was led by Brendan Clark, a postdoctoral researcher at Cornell University,

Clark built a statistical model of future tree growth and carbon storage and compared it with one of the most widely used land surface models in climate science. The gap between the two was striking.