Well - I don't know... but I do trust the scientists to carry out research and it isn't surprising they're divided on the verdict because there is only one earth to base an opinion on and it is a very compllcated system.
There are obviously two inflences - natural and man made. I am fairly convinced that man's contirbution is significant but I am equally convinced that nature's inflence on change is dominant. Either way, it makes sense to manage man's influence better so that we reduce our impact on change - but that's an expensive option. But man's contribution could simply be a trigger for change.
That is a problem. The cost of preserving the environment is far too costly to contemplate and it's easier and much cheaper to argue that change is not happening as a result of man's influence - and hence it's not necessary to make any changes in our behaviour.
But, on the contrary, I think it is responsible to make changes in our behaviour where we believe it reduces our impact.
Personallly, I believe that nature is a very finely balanced system. We can't rely on it always behaving the same way in the future. We have been very lucky in the past to have a system that produced generally predictable patterns of weather, temperature, rainfall, humidity, light - in fact everything that allowed us to develop the way we have - but there is evidence of signifiance changes in environment, in different parts of the world over the course of history. Eg. for whatever reason the Gulf Stream has for thousands of years, brought a certain kind of weather to Britain... but it hasn't always been the case, and just because it was true for a long time, doesn't mean to say it always will be in the future.
But the balance may just be changing. This could have been triggered by man upsetting the balance, or it could simply be a result of natural shifts over the long cycle of time - or the combined effect of the two things together. In some ways it doesn't matter which is responsible. If change has been triggered by man - then I am not sure what we can do about it because the trigger has happened - except that we have a responsibility to modify our behavours to minimise our impact. If the change is as a result of nature ... then that's how it is and we just have to adapt, and live with it - but we still have a responsibility to change our behaviour to reduce our impact.
I think of it like a string that resonates at a paricular frequency ... it's fine doing that until something changes and then the string can't resonate at that freqency any more. And, at some particular frequencies, the resonance is turbulant and chaotic. That could be happening now.
Who can predict how much it takes to tip an apparently ordered system, like the earth's weather system, into absolute chaos? - there is no reason why it shouldn't just tip into chaos. But, I believe that nature's tendency is to settle into order when it can. I see chaos is really the indicator of change. Chaos will return to order and pattern again - but it will be different patterns, and a different order, and there may be a lot more unpredictability and chaos before order returns.
The greatest impact will be felt by those communities that are less able to deal with change - the poorer countries, land locked countries, low lying islands and lands ... In the wealthier nations there may be lots of things governments can do to protect their citizens but there is likely to be huge amounts of political and social change as a result.
