A long-term study conducted in Colorado has revealed a dramatic decline in flying insect populations, even in remote, relatively undisturbed areas. Over two decades, researchers recorded a 72% drop in insect abundance. This decline is closely linked to rising summer temperatures. The findings suggest that climate change—not just human land use—is driving these losses.
The research, conducted by Keith Sockman, associate professor of biology at the University of North Carolina at Chapel Hill, quantified flying insect abundance across 15 seasons between 2004 and 2024 in a subalpine meadow. This site has 38 years of weather data and minimal direct human impact. The study found an average annual decline of 6.6%, amounting to a 72.4% reduction over the 20-year period.
Sockman explained, “Insects have a unique position in the biodiversity crisis. This is due to the ecological services they provide, such as nutrient cycling and pollination. They are vulnerable to environmental change. Insects are necessary for terrestrial and freshwater ecosystems to function.”
Implications for Ecosystems
While many studies focus on insect declines in human-altered landscapes, this research highlights losses in relatively pristine environments, suggesting that climate change is a key driver. “Mountains host disproportionately high numbers of locally adapted endemic species, including insects. The status of mountains as biodiversity hotspots may be in jeopardy if these declines reflect broader trends,” Sockman said.
The findings underscore the urgent need for comprehensive monitoring of insect populations across diverse landscapes and add to the growing evidence that climate change threatens global biodiversity. Even ecosystems far from direct human impact are not immune, raising concerns about the health of pollinator networks, nutrient cycling, and overall ecosystem resilience.