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Data on plant leafing and blooming in the US show spring arrived 20 days early for much of the country’s south this year, with the impact of climate change illustrated in new maps from the National Phenology Network.
The network, which is led by and receives funding from the US Geological Survey, facilitates observation of plant and animal life cycles. It built the maps using Spring Leaf and Bloom Indices, climate change indicators that use volunteers’ observations of leafing and blooming by temperature-sensitive flowering plants native to North America.
Combined with heat and temperature data, researchers at the network were able to compare leafing and blooming conditions in 2017 to long-term historical averages across the US. The results showed spring arriving two to three weeks ahead of schedule in much of the southern half of the country, with plants in Washington DC turning green a full 22 days early.
Jake Weltzin, the USGS ecologist who serves as executive director of the NPN, said the early onset of spring “poses significant challenges for planning and managing important issues that affect our economy and our society”.
Among other harmful impacts of significantly early spring, the resulting early blooming of flowers can disrupt plants’ synchronisation with the annual arrival of the birds and insects that pollinate them, according to the USGS.
The NPN data and maps also track with a study published in the October edition of the journal Ecosphere that showed climate change is pushing the arrival of spring earlier in the year across the US national park system.
Global surface temperatures were also the hottest on record for the third year in a row in 2016. Last week the US Senate approved President Donald Trump’s choice to head the country’s Environmental Protection Agency, Scott Pruitt, who in his previous role as Oklahoma’s attorney general repeatedly sued the agency and described himself as a “leading advocate against the EPA’s activist agenda”.