Today, Lucian at the Planet TV Show (disclosure: I wrote the theme song) eschewed his usually funny-techie-robot focus in favour of the most cogent explanation of global climate change that I've seen so far. Here's the transcript:
According to the math, we cannot know for certain how close we are to the point of no return, until it is too late. So if you are looking for absolute proof, you will not get it unless you are willing to sacrifice everything. Because, you cannot have absolute confirmation that a catastrophic change is occurring—until it has begun and cannot be stopped.
[...] Even if our contribution of CO2 is not the main reason for climate change, it is still important that we reduce and eventually eliminate the release of CO2 from fossil fuels. If we are close to the tipping point, then any small amount of increase may be the amount that pushes us over the edge. By the same token, if we are close to the tipping point, then any small decrease will take us that much further from the edge of a catastrophic shift in climate.
[...] Global warming does not pose a threat to the Earth. Nor does it pose a threat to life on this planet. Both the Earth and life on the planet will survive the effects of global warming and catastrophic climate change. What is in danger is us.
I wrote something very similar in a letter to the editor in a local newspaper more than 12 years ago. It makes me a bit sad for the point to have to be made still.