"Animals do roughly the opposite which make the system work."

Crikey - is it really that simple?

Actually, no. PDQ's oversimplification of the ecology and ecosystems of the planet and how they've been affected by anthropogenic climate change is typical of how deniers work. In part I blame this communication failure on scientists who need to understand the opposition has been in the business of sourcing, processing, selling and marketing for years; scientists are not known for their marketing prowess. To the more gullible members of society conditioned to see the claims of businesses and their cohorts as being indisputable fact and unlikely to question what they're told, it comes as natural to be distrustful of people who are not trying to sell them anything, or telling them things which threaten to burst their cosy consumerist bubble (made of straw).

In truth it's far more complicated (but understandable) than the deniers make out. PDQ's cut-n-paste explanations of respiration and photosynthesis are largely irrelevant out of content, which they are in this case. Saying something like "An increase in carbon dioxide causes an increase in plant growth" is utterly ridiculous. An increase in 'Tomogrow' liquid fertiliser will result in an increase in plant growth too.

As for the biosphere being a system constantly seeking equilibrium though various mechanisms that might be true, but human activity has altered the variables within that system and the effects are at best unknown and at worst positively disastrous. All the sub-systems within the planet-wide ecosystem are interconnected; change one and they all change. Problem is, we don't know to what degree and how. These systems are incredibly finely balanced and we don't fully understand how declines in species diversity and evolution will effect the biosphere. We know one thing though that the fossil record is unambiguous about: climate change radically alters ecosystems sometimes in very short spaces of time and this will effect all life living in that ecosystem in one way or another.

So the choice is to do feck all and hope we're wrong, or change the way we are doing things and if we're wrong the worse that will happen is the loss of rich people's toys, some lifestyle changes for all of us and the fact we will be living more harmoniously within the ecosystems and ecologies we are part of and if we're wrong, no harm done after a period of re-adjustment.

Not a choice really, is it?