The climate's changing conditions and temperature has affected the areas where bumblebees can thrive. It has narrowed down the sites bumblebees pollinate in North America and Europe, a new study published Thursday.

Scientists said warming temperatures are causing bees to scale down their travels to as much as 190 miles, according to New York Times. It suggests that, more than pesticides, climate change has made the bees' habitats less than hospitable.

"The bees are losing range on their southern margin and failing to pick up territory at the northern margin - so their habitat range is shrinking," said Leif Richardson of the University of Vermont, who is one of the study's authors, via BBC.

"They just aren't colonizing new areas and establishing new populations fast enough to track rapid human-caused climate change," said Jeremy Kerr, another author from the University of Ottawa, via Time Magazine. "Impacts are large and they are underway. They are not just something to worry about at some vague, future time." 

The scientists studied over 420,000 records of observations conducted from 1901 to 2010 among 67 species of bumblebees. Since the 1970s, the researchers have noted that bees have been slowly dying in the southern ranges of Europe and North America.

In order to survive, the scientists suggest humans should help by assisting the bees during migration. Some expert, however, do not agree with this.

"There seem to be some interesting level of variation in bumblebee species' response to changes in climatic conditions, something that isn't discussed in the paper," said Nathalie Pettorelli of the Zoological Society of London, via the BBC report. "This level of inter-specific variability might be important to consider when thinking about mitigation strategies, as one solution might not fit all."

The study was published in Science Magazine.