Climate change and intensified farming have already reduced insect biodiversity across large parts of the globe. Insects are widespread and influential, with many species common in tropical regions. Scientists emphasize urgent action to protect natural habitats, curb the expansion of high-intensity farming, and cut greenhouse gas emissions to mitigate climate change.
“The interaction between historical warming rates and intensive land use is linked to a 49% drop in insect abundance and a 27% decline in species richness in some regions,” notes a study led by experts from the Center for Biodiversity and Environmental Studies at University College London (UCL).
The study, published in Nature, is the first to describe how the combination of rising temperatures and changing land use is driving large-scale losses of insects worldwide.
Results show a notable pattern: where natural habitat remains plentiful, insect abundance and richness fall by modest margins of 5% to 7%. In contrast, reductions reach 61% to 63% in areas with limited natural habitat.
“Our results indicate that insect biodiversity benefits from climate change mitigation, habitat conservation within landscapes, and reductions in farming intensity,” researchers caution.
Vulnerable to human pressures
Reductions in insect abundance and richness are especially pronounced in tropical regions. Positive responses to climate change are rarer in non-tropical natural habitats.
“High availability of nearby natural habitats reduces losses in insect abundance and richness often tied to farming and warming, but mainly in low-density farming systems,” researchers stress.
Charlie Outhwaite, a lead author, notes that many insects are highly sensitive to human pressure, a factor tied to worsening climate change and farmland expansion.
Outhwaite highlights the urgency of protecting natural habitats, limiting the spread of intensive agriculture, and reducing pollutant emissions.
Why protect insects? Their declines affect local ecosystems and can threaten human health and food safety, especially through pollinator losses.
“Our findings may only reflect the tip of the iceberg; other regions could show greater biodiversity losses,” Outhwaite warns. The researchers analyzed a large dataset on insect abundance and richness across nearly 20,000 species and over a quarter of a million records.
p
The team compared biodiversity in areas with different farming intensities and varying historical climate warming.
p
Natural habitat loss buffers
In places with high-intensity farming and significant warming, insect numbers were 49% lower than in most natural habitats without warming, while species richness was 29% lower.
“Tropical regions show the strongest declines in biodiversity linked to land use and climate change,” the study notes.
In regions with low-intensity farming and notable warming, proximity to natural habitats buffered losses: when 75% of land was natural habitat, insect abundance fell by only 7%, compared with a 63% drop where natural habitat covered only 25% of the landscape.
One explanation is that many insects rely on plant shade during hot days, so the loss of natural habitat makes them more vulnerable to heat.
Yet researchers caution that the problem may be even more severe. Biodiversity declines caused by human activity could be greater in areas with a long history of land use, and pollution or other factors may amplify impacts.
p
Tim Newbold, another lead author, comments on the environmental costs of high-intensity farming as the world tries to meet growing food demands.
The danger of agricultural expansion
Pollinating insects appear especially vulnerable to farming expansion, with estimates suggesting they are more than 70% less abundant in dense farmland than in wild areas, according to Newbold.
Researchers advocate careful farmland management and conservation of natural habitats near farms, arguing these actions could help vital insects continue to thrive.
Peter McCann, co-first author, urges further study of the importance of insects for ecosystems and human well-being, aiming to address these threats before many species are lost.
Researchers from the UCL Center for Biodiversity and Environmental Studies emphasize the role of humans in shaping biodiversity, including efforts around the IUCN Red List and the broader links between land use and disease risks.
Reference: Nature study, cited as a key piece in ongoing biodiversity research.
End of report.
Environment department contact: contact information removed for this rewrite.