IONA, Nova Scotia — A century ago, the flaming fall foliage in Nova Scotia would have long faded by early November. But today, some of the hills are still as nubbly with color as an aunt’s embroidered pillow.

Climate change is responsible, scientists say. As the seasonal change creeps later into the year, not only here but all across the northern United States and Canada, the glorious colors will last longer, they predict — a rare instance where global warming is giving us something to look forward to.

“If climate change makes eastern North America drier, then autumn colors will be spectacular, as they are on the Canadian Shield in dry summers, especially the red maples,” said Root Gorelick, a biology professor at Carleton University in Ottawa. The Canadian Shield is a broad ring of forests and ancient bedrock that extends hundreds of miles from the shores of Hudson Bay.

Over the very long term, the warming planet may have a negative effect on fall foliage, but even then any adverse impact is uncertain. It is not just an aesthetic question, but an economic one as well: The changing colors drive billions of dollars in “leaf peeping” tourism in Canada and the United States.