Newscientist just released a good series of articles as a result of the recent IPCC abstract that humans are 90%-ish likely to be the cause of global warming.

http://environment.newscientist.com/channel/earth/dn11462

For those worried about the ecological problems with releasing the CO2 gases into the atmosphere. Lake Nyos contains about 300 million m3 of CO2, and recharges at a rate of 300,000 m3 per year.

http://www.icbe.com/carbondatabase/CO2volumecalculation.asp

The US emits about 3 trillion m3 of CO2 per year.

The total amount of co2 in the lake is quite large, but the release of this CO2 is fairly small in the grand scheme of things. And not all of it needs to be released, just enough so that a similar release won't happen in the future.