Nitrogen emerges as the latest climate-change threat

By Robert S. Boyd | McClatchy Newspapers

WASHINGTON — Scientists are raising alarms about yet another threat to Earth's climate and human well-being. This time it's nitrogen, a common element essential to all life.

For years, people have been bombarded with warnings about the harmful effects of carbon — especially in the form of carbon dioxide (CO2), a greenhouse gas widely blamed for global warming.

Now, it's becoming clear that human activities, such as driving cars and raising crops, also are boosting nitrogen to dangerous levels — polluting air and water and damaging human health.