Overlooked pollutants cause 15% of global warming but are ignored by climate treaties

A new study in Science finds that carbon monoxide, volatile organic compounds, and black carbon indirectly cause about 15% of human-driven global warming. Unlike CO2, these pollutants trigger atmospheric reactions that create more greenhouse gases or extend their lifetime. None of them are covered by the Kyoto Protocol or most national climate pledges. The paper's authors, including a former State Department climate advisor, argue the science is now strong enough to include these indirect warming agents in international climate accounting. But political resistance remains high, and the study notes that quantifying emissions from specific sources is still incomplete. The finding adds pressure to expand what counts in climate targets.