As temperatures rise with global warming, many plants are blooming earlier than normal. In cities, which have many dark roofs and asphalt roads that retain heat, the effect is even more pronounced. But one researcher says it’s not just heat that’s causing the problem.

Night streetlights

Ffrench-Constant: “What we found is that some species of tree are budding, bursting their buds, up to a week earlier in brightly lit areas.”

That’s researcher Richard Ffrench-Constant of the University of Exeter.

He studied how street lights affect when plants bloom, and found the shift has far-reaching consequences.

Ffrench-Constant: “For example, some moths, they lay their eggs on oak trees, and they time the hatching of their eggs to correspond exactly to the time of bud-burst.”

But now the moths are out of sync with early budding trees, so fewer are hatching. That creates a problem for songbirds who depend on moths to feed their babies.

But Ffrench-Constant says there are solutions to light pollution.

Ffrench-Constant: “If we can understand exactly which frequencies of light it is that cause this advance in bud-burst, then we should be able to make environmentally-friendly lighting.”

The impacts of climate change in urban ecosystems are complex, but converting to lights that do not mimic nature would help take light out of the equation.

Reporting credit: Analeah Rosen/ChavoBart Digital Media.
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A regular contributor to Yale Climate Connections since 2012, David Appell, Ph.D., is a freelance writer living in Salem, Oregon, specializing in the physical sciences, technology, and the environment. His...