The world's forests are taking longer than expected to recover from increasingly frequent droughts, meaning their ability to store climate-changing carbon dioxide is smaller than previously thought, Utah University researchers said on Thursday.

If forests are absorbing less carbon dioxide, then the effects of climate change will be worse than past models had predicted, the Utah study published in the journal Science said.

Droughts take their toll on forests. Credit:Erin Jonasson

"This really matters because in the future droughts are expected to increase in frequency and severity due to climate change," William Anderegg, the study's lead author, said in a statement.

"Some forests could be in a race to recover before the next drought strikes."