"Readers told us how spring has changed where they live. Our map shows where leaves are sprouting sooner."

"As global warming nudges temperatures higher, memories of the past offer an informal account of how the seasons have changed. A formal account comes from the USA National Phenology Network — phenology is the study of seasonal change — which reports the annual appearance of spring’s first leaves in the contiguous United States since 1981.

Spring is trending earlier across a vast U-shaped area of land stretching from coast to coast, according to my analysis of their data.

Spring’s arrival appears especially accelerated at higher elevations. In parts of California’s Sierra Nevada, for instance, trees that used to sprout leaves in mid-May now tend to do so in early April. The reason is unclear, climatologists told me, but it could be that snow has grown scarcer in the mountains, which allows the ground to absorb more of the sun’s heat, creating a feedback loop."

Harry Stevens reports for the Washington Post March 13, 2024. [2]