Plant pathogen could help track waters polluted with human waste.

The upcoming Copenhagen negotiations will take steps toward an international, climate-stabilizing treaty.

No one would choose to eat polychlorinated biphenyls, or PCBs — yet we unwittingly do. And a new study finds that the cost of their pervasive contamination of our food supply can be elevated blood pressure, a major risk factor for heart disease.

Weather-monitoring stations in the Lower 48 have been logging record daily highs in temperature at twice the pace of record lows. Yet more evidence of climate warming. Many people have pointed to colder than normal winters — or summers — as evidence that global warming is a myth. Climatologists have countered that weather, the meteorological features that we experience at any given hour or day, may show anomalies even as Earth’s overall climate warms. So weather can locally mask the planet’s overall slowly rising fever. Except that any such mask appears to be disappearing throughout most of the United States, according to a new study.