I love financial engineering stuff like this that leaks out into more 'real world'/physical things (being not a finance professional). DDG has purchased so much carbon footprint offsetting whatevers that it's 'carbon negative'... it is... funding (in carbon allowance) 'carbon positive' companies? I'm (hopefully) obviously joking - you can plant lots of trees without saying 'its ok to burn more coal now' - but it's fun to think about isn't it.