Climate change should be easily proved - although its seemingly not as easy as one would expect, as the scientific facts can show warming and cooling. Hence, they have had to call it climate change, rather than last decade's global warming.
What can't be proved is that its manmade. We've had major climate shifts before, and the ancients didn't drive 5l V8 Range Rovers. Personally, I think its likely it is, but it cannot be proven. Its well known that the BBC have had this agenda for decades, and they were caught out.
Remember, it has not been proven yet that smoking causes cancer. Personally I think its likely it can, but it cannot be proven. And some of the most healthy people I know have smoked. And many people I know who are cancer survivors have never really smoked. But the NHS and BBC will categorically say it does.
Still, if the climate is manmade, and nature is unable to recover, I have the ideal cure when I'm in power.