Hotter temperatures could lead to a "mass extinction" of bumblebees

In the course of just a single human generation, the likelihood of a bumblebee population surviving in a given place has declined by over 30 per cent.

Published: February 7, 2020 at 10:45 am

Bumblebees are drastically declining across Europe and North America due to hotter and more frequent extremes in temperatures, scientists say.

A new study indicates the likelihood of a bumblebee population surviving in a given place has declined by 30 per cent in the course of a single human generation.

The researchers say the rates of decline appear to be “consistent with a mass extinction”.

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Peter Soroye, a PhD student at the University of Ottawa and the study’s lead author, said: “We found that populations were disappearing in areas where the temperatures had gotten hotter.”

He added: “If declines continue at this pace, many of these species could vanish forever within a few decades.”

For the research, which was published in the journal Science, the team used data collected over a 115-year period from 66 different bumblebee species across North America and Europe to develop a model simulating “climate chaos” scenarios.

They were able to see how bumblebee populations have changed over the years by comparing where the insects are now to where they used to be.

Dr Tim Newbold, of the University College London’s Centre for Biodiversity & Environment Research, said: “We were surprised by how much climate change has already caused bumblebee declines.

“Our findings suggest that much larger declines are likely if climate change accelerates in the coming years, showing that we need substantial efforts to reduce climate change if we are to preserve bumblebee diversity.”

Bumblebees play a key role in pollinating crops like tomatoes, squash and berries.

The researchers say their methods could be used to predict extinction risk and identify areas where conservation actions are needed.

Professor Jeremy Kerr, of the University of Ottawa and the study’s senior author, said: “This work also holds out hope by implying ways that we might take the sting out of climate change for these and other organisms by maintaining habitats that offer shelter, like trees, shrubs, or slopes, that could let bumblebees get out of the heat.

“Ultimately, we must address climate change itself and every action we take to reduce emissions will help.”

Reader Q&A: If bees became extinct, what effect would this have on mankind?

Asked by: Adam Young, London

You might think it would just be a question of learning to live without honey, but bees play an incredibly important role in agriculture as pollinators. Cereal crops are wind-pollinated but virtually all fruit and many vegetables are insect-pollinated, overwhelmingly by bees. Without bees, crop yields would fall off dramatically. It’s estimated that one-third of all the food we eat relies on bees for its production. That includes virtually every fruit you might make into jam, but finding something to put on your toast would be the least of your worries.

Over evolutionary timescales, other insects would probably take over the empty ecological niche but in the short term you could expect the apple, orange, coffee, chocolate and rapeseed oil industries to collapse. This wouldn’t be an extinction-level event for humans, but it would cause widespread economic hardship and possibly famine until alternative cultivation systems and crops could be developed.

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