One apparent result of a changing climate is that spring seems to be starting earlier than in the past. Yet, it has been hard to substantiate this claim. There has been little actual evidence–other than anecdotes–to prove this assertion either way.
Now, researchers have used “old television footage of outdoor sporting events” to get real data on “how early trees and other plants are leafing out.”
Using TV footage of the Tour de Flanders cycling race–an event that has been run in early spring in Belgium since 1913–“researchers watched more than 200 hours of video for races from 1981 to 2016.” From this old video, the researchers compiled “observations of leaf-out and flowering of 46 individual trees and shrubs” which could be specifically identified in the 1981-2016 footage.
Based on the observations, there has been “surprisingly strong advances in the timing of tree leaf-out and flowering.” In the 1980’s, trees had almost never flowered or leafed-out by the time of the race; in contrast, by the period 2006 to 2016, the probability of the trees flowering had increased 67%. This change was most strongly related to higher temperatures from January to March.
Yes, spring is starting sooner than in the past.
Read the article (Katie Langin, Science, July 3, 2018).