Climate Change is caused by human emissions; it moves faster or slower partly in response to our rate of emissions, but also because of natural "tipping points" that make the planet take things in its own hands. So, for example, during one of the last great climactic shifts, the planet may have gone from being fairly warm to an ice age in less than ten years; and then the ice age may have ended in a single season! These things are very hard to model, but projections for the future that imagine Climate Change will occur in a gradual and orderly fashion are probably wrong.
