To your points regarding skepticism:

A) True, our time on earth has been relatively recent, but I do not think that precludes the possibility (probability) that man has had an active role in influencing the levels of carbon dioxide in the atmosphere. Big geologic events can happen relatively quickly: remember the prevailing theory concerning the mass extinction of dinosaurs is an impact from an asteroid, which would have also occurred in a blink of the geologic record — and I think the rapid displacement of carbon from the subsurface into the atmosphere via the Industrial Revolution and recent history would certainly qualify as a large-scale event, geologically.

B) How do we know it is caused by man? Again, I would enter into evidence the large-scale displacement of carbon from the earth into the atmosphere during the Industrial Revolution. This, coupled with ice core data showing trends in atmospheric conditions and earth temperatures over the past 800,000 years is relevant. Ice core records have shown cyclical fluctuations in earth temperatures and carbon dioxide levels over time (glacial and interglacial cycles) — fluctuations than can be explained by slight variations in the earth’s orbit (e.g., “Milankovitch cycles” — or slight changes in the earth’s axial tilt). However, ice core data also show that carbon dioxide levels have been steadily rising since the Industrial Revolution, rising well beyond the regular cyclical rhythms recorded prior to then, and are currently 40 % higher than levels ever recorded prior to that point in time. So I would argue that we DO have good data — 800,000 years of data, in fact, upon which these conclusions are based. If you graph the temperature & carbon dioxide level cycles from the past 800,000 years, the rhythm looks a little like the earth’s EKG — and the sudden, off-the-charts rise in carbon dioxide over the past few centuries looks like a huge heart attack. Why are scientists so worried? Because they know the very strong correlation between carbon dioxide and earth temperatures. If carbon dioxide levels are showing an unprecedented rise, temperature is sure to follow. And we don’t have any record for how bad it’s going to get.

As for your complaints about the certitude of climate change believers: 1) I think you’re right, there is certainly some hypocrisy between the beliefs and behaviors of this audience. Call it an addiction to the status quo, or well-informed futility, I’m not sure. This movement is going to take more than lightbulbs for sure. It will take DIvestment in fossil fuels and INvestment in alternative energy. 2) Regarding your second complaint, I’m not sure what you are saying here — maybe you are trying to draw a comparison between ancient earth-is-flat believers and those of us who are convinced of the scientific basis for climate change? I would argue that the comparison is rather unfair, considering the disparity in the amount of information evaluated by these two groups. And I think it’s rather convenient to assume that some new scientific discovery is just around the bend, ready to render climate change as ridiculous as a flat earth. But that’s just my opinion.