As evolution is a slow process it is a presumption that the rate of physical change moves at the same pace as the rate of change of the environment in which an animal lives or has the evolutionary tools to survive a cataclysmic event.
Darwin's observation of the finches of the Galapagos Islands has substantiated the former whilst the eradication of all the large reptiles and the dominance of small animals, mammals in particular is proof of the latter.
Our species is now on the threshold of another cataclysmic event, one in which we have had a starring role as producer and now as lead actor. We have caused so much damage to the environment it will change at a rate that excludes us from keeping up with it and challenges our ability even to respond with defensive measures such as renewable energy sources.
It took the best part of five hundred thousand years for our antecedents to get up off their knuckles and just walk on their hind legs. This may sound like a long time but the dinosaurs dominated this planet for millions of years before their reign came to an end.
It has taken just two hundred years for us chatty apes to extract sufficient mineral wealth from the ground to permanently change the climate and we may well be the only species to inhabit this planet that has actually managed to eradicate itself purely by its own actions.
After that gloomy statement, do we humans have a future?
I think there are two futures available to us. We can wrestle with the challenges we have presented for ourselves or we consider the possibility of venturing away from this planet entirely and seek out somewhere else to live and exploit.
To leave seems inappropriate, a little like going to a friend's house for a party, trashing the place then not helping to clean up afterwards.
It is certainly the work of fiction, as colonising another planet in our solar system alone will take centuries.
Meanwhile we have to live on this planet and use what resources are available to us more responsibly than we have done so up to now and assume we are tied to this planet. This will lead to adapting to a climate that will remain in a state if flux for at least a century. In that time the established weather and climate models will fall by the wayside as a new climate slowly emerges. While that is taking place, the changing climate will affect our ability to grow crops and rear livestock. I think it is also inevitable that annual migrations will have to change as traditional feeding and watering points will no longer be able to nourish a species on the move. This will have a major impact on the entire food chain. With an imbalance in the food chain there will inevitably be a migration of all animals that used to rely on that food chain; and in this is man. The economic impacts of nations on the move will be devastating and will lead to armed conflict. In Iraq the war revolves around the supply of oil, in years to come the struggle will focus on the control of water and other natural resources, perhaps even woodland.
What the preceding text does not consider is the opportunity for Mother Nature to stick her spanner in the works. We are overdue a pandemic similar to that which struck after WW1. With the frequency of travel made possible by advances in aeronautical engineering over the last hundred years or so it is now possible to get to just about any point on the planet in under 24 hours. This does of course mean that a mutating virus could become entrenched within a matter of hours and have a major impact on world populations within a couple of weeks.
Frightening stuff and at the moment the stuff of science fiction; but for how long?