This would be a much bigger issue if Gore was still VP, or senator, or held any kind of elected (or appointed, I suppose) office that allowed him to alter or directly influence the environmental policy of the US. As it is, it may make one rather sceptical about his actual devotion to the cause he espouses, but I don't see how it's any more improper than companies lobbying for the laws they want, or other high-profile people without elected office lobbying for their pet cause. Nobody cares about Cheney's ties to Haliburton *now*, it was when he was VP that it was considered a conflict of interest.