Tu quoque (/tuːˈkwoʊkwiː/;Latin for "you, too" or "you, also") or the appeal to hypocrisy is an informal logical fallacy that intends to discredit the opponent's position by asserting the opponent's failure to act consistently in accordance with that position. It attempts to show that a criticism or objection applies equally to the person making it. This attempts to dismiss opponent's position based on criticism of the opponent's inconsistency and not the position presented. It is a special case of ad hominem fallacy, which is a category of fallacies in which a claim or argument is rejected on the basis of fact about the person presenting or supporting the claim or argument. To clarify, although the person being attacked might indeed be acting inconsistently or hypocritically, such behavior does not invalidate the position presented.
If you truly believe in environmentalism, instead of debating with me, you should be out there helping the cause.
Presumably, Speaker 1's intent was only to argue the benefits of environmentalism, not to assert his own personal moral standing. Attacking the speaker's actions therefore does not address his argument.
Your argument against consumerism is invalid because you own a computer, cell phone, or other luxuries.
Regardless of whether Speaker 2 believes Speaker 1 is personally acting in accordance with his beliefs, this is not in itself an argument against the validity of those beliefs.