I'm sure many years ago if someone called offering to invest in solar energy or wind turbines it would of be laughed at, but now these renewable energy sources could be are future and is now considered a commodity.
Not at all from companies that had proper backing (verified), had management that could be 'verified' (ie, not crappy management bios that say 'has 10 years working in the industry for some of the biggest players), had proper websites that gave investors A LOT of verified information about the company (lawyers used, accountants employed, that sort of thing). And so on.
Folks, it's not the carbon credit market we're warning people about, that is legit, no doubt about that. Rather it's the fly by night operators who use the market to target the naive and foolish into parting with their money, and PART with it they will as so many investors have found out at their peril.