This is metabolism of carbon dioxide as it occurs in humans. Most 'animal' respiration at the cellular level happens similarly. Not the point where humans could transfuse animals due to genetic differences but in similar in mechanism.
This is not an option to realize as a 'cause' to Human Induced Global Warming. This is life. This is reality. The 'insult' to Earth started NOT with the increase in human numbers but with the 'consumerism' of habits of those humans. Primarily first world humans, whom know better than to continue to exploit the planet and other people. The First World would like to 'look down' at the rest of the world as a superior society. When it comes right down to it, we are human and very vulnerable and given the 'ungodly' pursuit of the First World nations I would hardly call them civilized or moral.
Living with Earth morally is at issue and what that means. Science counts. Sound science comes to know the intimacy of Earth. If you will God's creation. Where religion and science depart company is way what that is truthful is primarily in the fundamental practices which exists back in the day before longevity of humans was nearly guaranteed through modern medicine.
To compare the relevance of what is appreciated by the questionably First World USA White House, the only aspect of science Dick Cheney is interested in is whether or not his defibrillator will work when needed. A far cry from humanity so much as narcissism.
That narcissism is not his alone to appreciate, it transends many aspects of current business of the world. Personally, I have little to know appreciation for 'carbon credits/trading.' It isn't realistic over TRUE regulation of carbon dioxide emissions. Carbon Credits is a 'bone' tossed to desperate scientists that want to garner the assistance of business and the so inclined in governments. Carbon trading has not to date proven to be useful. Even the Bush White House as recently as this week was noted as saying the EU was not doing enough. I agree in that Carbon Trading is not truely an answer so much as just another power grab to ignore the truth of science and therefore ignoring the 'real' answer for the sustained growth of human populations.