UK butterflies declining; spike in one species doesn't negate climate change | Fact check
The claim: Growth in UK butterfly population means climate change isn't happening
A Sept. 15 Instagram post (direct link, archive link) shows British media personality and political commentator Katie Hopkins discussing purported events in the U.K.
"The butterfly population in the UK has exploded − up by 338% − and butterflies are a marker of a very healthy environment," she says. "So now we can all just hope and pray that the next time Extinction Rebellion or Just Stop Oil gather that they are absolutely swarmed by an absolute mass of butterflies leaving them unable to speak or hopefully breathe."
Extinction Rebellion and Just Stop Oil are environmental groups that advocate for government action to stop climate change
The post was liked more than 9,000 times within three weeks.
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Our rating: Partly false
While the population of one species of butterfly increased by 338% between summer 2022 and summer 2023, butterfly populations have declined overall in the U.K. since the 1970s, according to a local butterfly conservation and research organization. Multiple lines of evidence, including geographical changes in butterfly populations, show that climate change is occurring.
UK Butterfly populations have declined since the 1970s
Butterfly populations in the U.K. have declined overall, according to Sophie Hall, spokesperson for the Butterfly Conservation, a U.K. butterfly and moth conservation and research organization.
"In the U.K., long-term trends show that 80% of butterfly species have decreased in abundance or distribution since the 1970s," she said in an email. "On average, U.K. butterflies have lost 6% of their total abundance at monitored sites and 42% of their distribution nationwide over the period 1976-2019."
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Hall told USA TODAY that the population of one specific species of migratory butterfly − Red Admirals − did increase by 338% in the summer of 2023 compared to the summer of 2022, based on the organization's annual citizen science survey. However, that change does not mean that climate change isn't happening.
In fact, the population increase may be due to climate change.
"We believe the increase in Red Admiral numbers could be due to climate change and more of the butterflies ... choosing to overwinter here because of warmer temperatures," Hall said
Data shows human emissions are driving climate change
Global climate change is occurring because of an increase in the concentration of atmospheric greenhouse gases released by human activity. The physical process by which these gases delay the escape of heat into space and warm the planet is well understood and has been verified through observations and experiments.
This warming, which has been detected by multiple independent climate agencies, has already caused sea level rise, an increase in heat wave frequency and melting from ice sheets, glaciers and Arctic sea ice.
U.K. butterflies are also impacted by climate change. While the Red Admiral thrives in warmer temperatures, other species do not.
In general, U.K. butterflies and moths that live in the south and are adapted to warmer conditions have expanded their range northwards, Hall said. Species that thrive in colder, wetter climates have also retreated farther north or higher in elevation to escape warming.
“Changes in the distribution of butterfly species are a clear indicator of the changing climate,” Hall said. “Without action, some species will have nowhere left to go."
USA TODAY reached out to the Instagram user who shared the post for comment but did not immediately receive a response.
Our fact-check sources:
Sophie Hall, Oct. 2, Email exchange with USA TODAY
Butterfly Conservation, 2022, The State of the UK's Butterflies 2022 Report
NASA Vital Signs of the Planet, accessed Oct. 2, Ice sheets
NASA Vital Signs of the Planet, accessed Oct. 2, Arctic Sea Ice Minimum Extent
NASA Vital Signs of the Planet, accessed Oct. 2, Causes
NASA Vital Signs of the Planet, accessed Oct. 2, Carbon dioxide
NASA Vital Signs of the Planet, March 25, 2021, Direct Observations Confirm That Humans Are Throwing Earth's Energy Budget off Balance
The Conversation, July 31, 2020, John Tyndall: the forgotten co-founder of climate science
Australian Government Department of Climate Change, Energy, the Environment and Water, accessed Oct. 2, Understanding climate change
EPA, July 2022, Climate Change Indicators: Heat Waves
Carbon Brief, April 28, 2021, Melting glaciers drove ‘21% of sea level rise’ over past two decades
Butterfly Conservation, accessed Oct. 2, Big Butterfly Count
BBC, Sept. 15, UK butterfly numbers at highest level since 2019
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This article originally appeared on USA TODAY: Claim misleads on climate change, UK butterflies | Fact check
