When scientist Peter Soroye first saw the figures showing estimated bumblebee populations in North America had fallen by nearly 50% in a single generation, he immediately checked the numbers. But these, published in journal Science, were accurate.
Rising temperatures are contributing to drastic declines of bumblebees across Europe and North America at rates “consistent with a mass extinction”, threatening food cultivation, the study concluded. The researchers estimated that Europe’s bumblebee populations fell by 17% between the two periods the study looked at - from 1901 to 1974 and from 2000 to 2014 - while in North America, the figure was 46%.
“We couldn’t believe that the declines were this severe over such a short time period,” said Soroye, lead author of the study and a PhD student at University of Ottawa. “I reckon I must have gone through, like, seven times to double check that everything was right and it was. And so yes, these declines are really drastic. They’re really severe,” he told the Thomson Reuters Foundation by phone.
Declining bee populations have also been linked to heavy pesticide use and habitat loss caused by changes in land use. But Soroye said global warming was exacerbating their plight.
Bumblebees are larger than honeybees, and while they do not produce honey, they are important pollinators.
If the trend continues, nutritious fruits, nuts and many vegetables would have to be substituted by staple crops like rice, corn, and potatoes, leading to an imbalanced diet, the U.N. Food and Agriculture Organization warned in 2019.