But I'm not talking about issues with the short term (like AGW, which in my hypothetical has already been dealt with) but with the long term. If we decide to maintain our planets climate in a certain state for times that generally exceed natural oscillations (like 30,000+ years) at some point there would be consequences. What that might be I can't say for certain which is why I posed the question.
On the other hand change is natural. By freezing things in one state we may keep certain species around but we also will be preventing the evolution of new ones. Imagine Earth if Deinonychus had become a technologically advanced species and froze things to be like the early Cretaceous.....we wouldn't be here for one thing.
Change and stasis are both 'natural' in that they both occur.
Until we understand how climate works and how it affects ecosystems far better than we do now, and until we can arrive at a rational reason to try to alter the climate, science-based methods for doing so safely and effectively, and fair and just targets for the changes, I'm not at all interested in optional climate change for the sake of change or for the sake of perceived good.
This should not be misunderstood - I think we need to make significant and rapid changes in our behavior so that the current changes in climate can be slowed or possible reduced.
I simply don't want us to 'play' with the climate without superior understanding, adequate reasons, and plans B, C, and D.
Furthermore, I don't want us do anything that gives priority to human considerations.
Humans aren't my favorite species but, even if we were, considering human interests balanced against those of the other species on this planet, I'd opt for the extinction of humanity over signficant damage to the rest of life on this planet.
According to my moral system, we don't have the right to risk or commit some of the climate-altering actions that I think are being considered in this thread. It isn't just our world - we share it with an immense number of other species.