When one looks back through changes in the environment in the past it has indeed change and dramatically. However, the speed of the current change and that those changes can be directly attributed to human activities means even George Bush has come to accept it is human activities that are the underlying cause.astropete wrote:hi all heres my two pence worth, global climate change is it caused by humans,or is it natural, concider the mt st hellens eruption a few years ago, it spewed out millions of tons of Co, Co2 in one day than what man does in a year, and thats only one volcano, the planet has hundreds. we live on an active planet and as such changes are the norm. dont forget plants were the biggest poluters, ages ago the gas they released into the atmosphere was pure poison, Oxygen. so i belive that the planet is changing as it always has been. i personly fear the depleating Ozone layer that to me is the bigger threat, and as the previous thread states this is an astromical reply, the earth after all is part of the suns family.
What is so surprising about the current impacts is the speed with which the changes are taking place. Thinks like Mt St Helens are well within the capabilities of the planet to maintain stability. It might be a lot of CO2 released but it s a single event and such events are not uncommon.
My own opinion is that it is actually now too late to do much about what we have done. Evidence suggests we have now put enough change into the environment that we have broken the mechanisms maintaining the equilibrium (e.g. the frozen hydrocarbons in the sea are now starting to boil-off - temp has risen enough to start the process which is resulting in a dramatic release of greenhouse gasses (more effective gasses than CO2) which will cause positive feedback, temp rising -> more frozen hydrocarbons being boiled off -> more temp rise, etc. We should be taking dramatic action to minimize the impact but vast damage has already been done. However, those who have taken the responsibility to act (the politicians) are just letting the human race down. They will jet half way round the world and back (with their entourage of advisers, security teams, etc.) and them let self interest get in the way of achieving anything.
One aspect that does reassure me though is that when the human race is gone, the planet will recover and find a new equilibrium and other species will start to evolve to take over. Thus, whilst we might devastate our planet we will not destroy it - just ourselves. And one might ask if such a stupid and warlike species deserves to survive. Maybe we have just "failed the test".