A new study reveals that increasing carbon dioxide emissions are shrinking populations of larger bees, including bumblebees and carpenter bees, while smaller pollinators may benefit. High CO2 reduces protein in pollen and alters nectar chemistry, making it harder for big bees to survive and reproduce. The research, conducted across 25 sites in Pakistan but globally relevant, found that large-bodied pollinators like Xylocopa and Amegilla are especially vulnerable. Large bees are critical for pollination because they carry more pollen and travel farther than smaller species. Many flowers have evolved to rely on specific bee sizes for effective reproduction. The study suggests that protecting habitats, creating wildlife corridors, planting bee-friendly trees, and reducing competition from introduced honey bees can help large pollinators adapt to rising emissions. Reducing global greenhouse gas emissions remains the most direct way to address this threat. The findings add to growing evidence that climate change disrupts ecosystems in ways that cascade through food webs and agricultural systems, reinforcing the urgency of decarbonization efforts.
