Is PG & E's Carbon Offsetting Program Supported by Science?

As I update news tonight, I find the following two stories on carbon offsetting:

• Location of Trees Planted to Offset Carbon Emissions Vital to Combat Climate Change
• California Utility Sells Carbon Offsets

The first one says that for planting trees to really have an impact in reducing global warming, you need to plant them in the tropics. Planting trees in the U.S., it claims, does little in the way of climate.

The second one says PG & E is selling its customers carbon offsets, and using revenues to plant trees in California.

Hmmmm....

Granted, the first article cites mechanisms other than just carbon sequestration by which planting trees helps fight global warming. And I'm not so sure the idea that planting trees in temperate regions doesn't affect the climate will hold up, scientifically (frankly, I'd need to read the whole scientific article to get a better sense of how solid their findings are).

But still, the finding is another piece of evidence that we have a ways to go before we get this whole carbon offsetting business - an important piece of the climate pie if done right - nailed down for consumers, businesses, and the planet.