Carbon offsets as favors

Favors aren't necessary. They're just added bonus if you can afford them

A favor is a thank you to the guest for coming. Don't donate instead of giving them something. If you do this don't call it a favor.

Bragging about donating to charity is tacky.

Grace I like it! Wouldn't call it a favor but nice to do especially given the venue and your environmental values. You could just write in the program or put on your website that you are offsetting the environmental impact of the wedding. Favors aren't necessary as others said.

It's a nice gesture to want to donate, but if you want to donate, then just do it privately for a few reasons.

It's not a favor to your guests.

Announcing it publicly like that comes across as "hey look at what a good person I am because I donated to a charity" and that can be really off-putting to some people.

Not all charities are created equal. There are some charities that have recently come under fire for inappropriately spending donated funds. If people don't agree with the charity you've chosen, it can make things pretty awkward.

You all are awesome! Thanks for the advise!

Just donate privately. No one needs a favor.

But pick your charity responsibly; look for ratings on line and make a good choice.