". . . nor can anyone prove anything".
Not so; Descartes proved that he existed, "I think, therefore I am".
I will quote from the book "the problems with Philosophy" by Bertrand Russell.p7. Descartes ... invented ... the method of systematic doubt
.. he would not believe anything which he did not see quite clearly and distinctly to be true.
... by applying this method he gradually became convinced that the only existence of which he could be quite certain of was his own.
p8. Cognito, ergo sum
But some care is needed in using Descartes' argument ... (it) says rather more than strictly certain ... it does not of itself involve that more or less permanent person who we call 'I' ... etc.
So, according to the esteemed Mr Russell there are flaws with that statement, as indeed there are flaws in all statements and all scientific research. But that doesn't mean the results are false. They may well be true, just not proven. Proof is not as easy as many of us assume.
I am happy to choose my directions based upon my best guess, if I wait for indisputable proof then I will never act. This is what concerns me about any debate, including the global warming debate; many people want 100% certainty. It does not exist. And so that lack of certainty can be used to "do nothing". I have no problem if a decision is made by an individual and the conclusion is different to mine, but to say, "I will wait until it is proved" is not a wise option to my mind and it is often employed by those who have a vested interest in the status quo. For example car manufacturers on this issue &/or suppliers & manufacturers of cigarettes and alcohol on public health, the policy of having 4 large domestic banks etc. Only time can tell the answer of course.
To act ethically we must make our own decision based upon our best efforts. By making our own decision we can then take responsibility for the outcome of our decisions. This is not a perfect approach but is an ethical one. I know there is a fear of being wrong that sometimes makes us hesitate in making decisions, and caution has a useful purpose. But I am not going to pass the buck and blame others, I see the responsibility of my actions rests with me, not with a group of politicians or a group of scientists or even my children. My actions are my responsibility. To me, this is acting ethically. And yes, others will have different actions and as long as their actions are considered, then they are acting in accordance with their own ethics. My ethics are not your ethics, ethics are not absolute right and wrongs; ethics is about values, how they work, what they mean but not the setting of values.
Seriously, do we want to wait for the politicians to tell us what to do? Between vested financial interests and politicians I reckon our individual futures just don't figure much.
It is my perception - maybe not yours, that is OK - that there is increasing pollution, and heat is one of the pollutants. So, I am trying to do my bit to reduce my footprint on this earth. I accept there will never be absolute proof. Personally I don't give a damn about the absolute proof, never ending statistics, pretty graphs and pie charts, the countless studies and figures ... it makes simple common sense to me that we are burning more fuel every year, cutting down more trees, glaciers are melting, air-conditioners sales are growing, it doesn't snow where it used to when I was a boy etc. It is pretty hot standing in the middle of a main road and yet cool under a few trees. Today we have more roads and fewer trees, so it seems logical (but unproven) that it is hotter and that is not good for our long term viability. This sort of observation is enough for me. Maybe not for others, I understand that but I only ask that we all look around and ask the question "Is it warmer today than it was twenty years ago?". It certainly isn't cooler in my experience and as Descartes said "he would not believe anything which he did not see quite clearly and distinctly to be true.", well, I am experiencing the increased pollutants and warming quite clearly in my own experience.
Life and existence is not about certainty, but about our best guess. I've made my best guess.