Here's a NOAA graphic that's been floating around. It's interesting how a little attention to design makes it somehow more attractive. It really doesn't take long to get the gist. Maybe the colors will help people remember it, though. Call it the Quaternary CO2 Hockey Stick or the orange on navy blue curve.

A site called Universe Today uses it to introduce a recent lecture by Mike Mann. I personally think neither well nor badly of Mann; there has been so much noise around the poor fellow that it's pretty much impossible to make a fair judgment without meeting him. But unless you are already caught in the ideological circus, you ought to admit he makes some excellent points which seem true to the scientific rather than the ideological approach to climate change.
“We have to make it clear that the ice sheets are not Republicans or Democrats – they don’t have a political agenda as they disappear,” said Michael Mann, a physicist at Pennsylvania State University, who has been at the recent forefront of climate research. “Certain facts cannot be denied. We have to find a way to steer the conversation to a good faith debate about what we do about the problem, not this bad faith debate about the reality of it.”
So why the bad faith debate? Indeed, why the politicization of the non-political parts of the question?
“If you can politicize something in today’s political environment,” Mann continued, “you can immediately get half the population on your side. Unfortunately the forces of anti-science — those who deny the science — have been very effective in politicizing the framing.”
Yet many people suggest that Mann is at the core of an ideological push to politicize. Who is right? Well, if you have a few years to devote to the problem full time and a scientific bent, you can figure it out for yourself.
Probably, you don't. So you can look to scientific authorities like the National Academy of Sciences, The Royal Society, the AAAS, the AGU, the American Meteorological Society, etc. They pretty much unanimously defer to the IPCC.
Or you can start with the presumption that IPCC is broken. Well, it's been proven not to be flawless: all it took was one unequivocal error about Himalayan glaciers to do that, but I don't think anybody's been proposing it as gospel except as a straw man argument.
You can suggest that an anti-industrial ideology (rather than a scientifically based whole-systems view that comes naturally to someone studying climate) is behind a skewed interpretation of the evidence. You can construct imaginary histories of a vast conspiracy using the methodologies of paranoid movements through history. But you can't account for the support of IPCC from the national academies of all the countries with a substantial research culture without positing that all of science has been dishonest. This is essentially Greg Craven's approach, which I highly recommend to anyone who doesn't have the time to work through the science for themselves.
There's no doubt that we could do a better job of exposition. As someone who has been taught in engineering schools, I found the climate science curriculum even within the universities to be poorly organized and unsatisfactory.(I think it's gotten a bit better since then, and I'm very much looking forward to the release of Ray Pierrehumbert's textbook next month.) I think neither engineers nor scientists understand how much better engineering textbooks are compared to science textbooks. So that we do an even worse job at outreach to the scientifically educated segment of the public is not surprising. But I don't write it off. It's a real and important issue.
On the other hand, the opposition thinks we are swimming in money. We simply don't have the resources to do this. The market for atmospheric and oceanic science textbooks is small. The talent base is stretched thin. And the tradition of exposition is not great.
So admittedly, the whole chain of reasoning is more obscure than one would like. I am trying to do my part to help on this front. But the facts are still the facts, and you really need to start with a very suspicious and hostile point of view to imagine that the key concepts are imaginary. Yet, many people do.
This is the context for Mann's conclusion:
Mann asked for journalists’ help in the future.

“No doubt we are in for a period of months or even years where climate science is likely to be subject to the sort of politically motivated inquisition that we haven’t seen, frankly, since the 1950’s,” he said. “It is necessary and important for the scientific community to do the best it I can to defend itself from this oncoming attack, and frankly, we are entirely reliant on the willingness of the mainstream media to serve in its role as the critical and independent arbiter and not just report the two sides of the so-called debate, but to actually establish what is fact and what is fiction. The scientists will not be successful against the attack that is coming unless the media is serving its role.”
Emphasis added. I will add this. If journalism does not do its job journalism must be replaced.