CO₂ and Methane Rose Sharply in 2007

This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense Fund.

Last week, NOAA released some disheartening numbers: both CO₂ and methane increased sharply last year. Growth rates are increasing (see graph to the right).

The CO₂ numbers weren’t a surprise. A paper with similar findings was published last November by a team that included a NOAA scientist. I wrote a blog post summarizing the study, which analyzed the reasons behind the trend (see Rise of Atmospheric Carbon is Accelerating).

The methane numbers, however, were disturbing. Until this year, methane levels have been essentially unchanged since 1998.

Scientists worry that melting permafrost could release large amounts of methane, setting off a dangerous feedback process. Fortunately, last year’s methane increase doesn’t appear to come from permafrost, though researchers are continuing to watch for signs.

The rise in methane, scientists think, is most likely from "rapidly growing industrialization in Asia and rising wetland emissions in the Arctic and tropics."

These accelerating increases in greenhouse gas pollution are a reminder that we can’t be complacent about global warming. Also, non-CO₂ emissions can’t be ignored. We must reduce all the emissions we can control, and turn these trends around. It’s time to cap emissions!