I can’t speak for CE, but we at Giving Green have looked a bit into Wren.
Some thing I like about Wren:
They seem to have put some thought and extra effort into picking offsets they think are better than normal.
They have a nice interface and good publicity, so hopefully that will crowd some money into funding good projects.
Some things I don’t like about Wren:
I fundamentally disagree with the idea that measuring a ‘carbon footprint’ and then offsetting this footprint is a meaningful and productive way to fight climate change. People should be doing what they can to reduce their own emissions, and using their donations in the most effective ways possible. Why should the amount of carbon an individual emits be a meaningful marker for how much one should contribute to the fight? This logic only works if offsets are seen as a way to give someone permission to undo the damage of a high-carbon lifestyle. That’s a dangerous perspective, as we need to reduce emissions from all angles, not just increase on one hand and offset on the others. Plus, no offsets are certain enough to really undo a person’s damage. Giving Green recommends that individuals and organizations view offsets simply as a philanthropic contribution to a pro-climate project with an evidence-based approach to reducing emissions, rather than a way to eliminate their contribution to climate change.
Their selection of recommended offsets seems a bit ad-hoc. Sometimes I get the logic of why a certain project is special in the great sea of offset projects, but other times I don’t really see it. There isn’t much information on their selection process or criteria- it all feels relatively non-transparent to me. Maybe someone would lob the same criticisms at Giving Green, but we’ve tried to be as transparent as possible, and when we re-launch our website in a couple of weeks there will be a bunch more documentation on our process and selection criteria.