Global Warming

Autumn Colours

Despite the deepening effects of climate change, scientists say autumn leaves in North America and Europe are not changing colour later, but they may be becoming duller. “Warmer temperatures in September and October reduce anthocyanin production in leaves, which could mean that fall colours would become less brilliantly red or purple,” said Susanne S. Renner of Washington University in St. Louis. She adds that only if the first frost comes later than it used to, would the brilliant foliage appear later. “The end result is that leaves still start to die after about the same amount of time on the tree as they have in years and even decades past,” Renner said.

Stronger El Niño’s

New research finds that the El Niño ocean warming episodes across the tropical Pacific will become more frequent as the Arctic becomes more ice-free in the warmer decades to come.

Writing in the Journal Nature Communications, lead author Jiping Liu of the University of Albany says that as the ice loss continues in the Arctic to the point that it is ice-free in summer, strong El Niño events will increase by more than a third. Arctic sea ice cover is now about 50% less in summer than a century ago. The rapidly warming Arctic is already altering weather, and the predicted increase in strong El Niños would mean there will be even stronger climate impacts later this century, Liu says.