Wait, now pollution is preventing global warming? That’s the conclusion of a recent study in the journal Geophysical Research Letters, which says rising temperatures seen in Europe over the last few years result as much from the reduction of air pollution as from the creation of it. The research, which looked at the effects of aerosols on climate, confirms an older concept known as global dimming, and complicates our understanding of how mankind affects the climate.

According to the study, temperatures in Europe have risen over the past 28 years far faster than could be explained by the greenhouse effect alone. After looking at the aerosol concentrations in the atmosphere in six spots, the authors of the paper realized the temperature rise was assisted by more sunlight penetrating the newly pollution free skies. It seems that the stricter pollution standards, adopted in part to slow global warming, may have sped it up.

The idea that pollution may be reflecting some of the sun’s energy is not new. The term global dimming is decades old, and some believed that the reduction in pollution was the cause global warming. But now, with the link between greenhouse gas pollution and global warming firmly established, papers like this one highlight how complex the situation is, and how solutions like simply cutting air pollution may have a range of unintended and counterintuitive consequences.