We covered this topic before on WUWT, but it showed up again in this week’s AGU highlights. Given the attention to the recent Arctic sea ice low and quick turnaround, I thought it would be appropriate to mention again.
The Arctic has been losing sea ice as Earth’s climate warms, and some studies have suggested that the Arctic could reach a tipping point, beyond which ice would not recover even if global temperatures cool down again. However, a new study by Armour et al. using a state-of-the-art atmosphere-ocean global climate model finds no evidence of such irreversibility. In their simulations, the researchers increase atmospheric carbon dioxide levels until Arctic sea ice disappears year-round and then watch what happens as global temperatures are brought back down. They find that sea ice steadily recovers as global temperatures drop. An implication of this result is that future sea ice loss will occur only as long as global temperatures continue to rise.