First, it is abundantly clear that there is a sharp warming trend, since about 1950 or 1970. So, for example, tropical and middle latitude glaciers are melting rapidly (the familiar example of Mt. Kilimanjaro, where a 12,000-year-old glacier is expected to be gone in 10 years, is only one example).
Second, it is abundantly clear that CO2 has increased substantially (from 280 ppm to 380 ppm in less than a century). I gather that the physics of atmospheric warming have been known since the 19th century, and an increase of CO2 should produce a predictable amount of warming, one that is in agreement with what is now observed. (Of course, the reality is far more complicated, because in the real world, it's not just CO2, it's also cloud cover, particulate matter, and the great complexity of the oceans and their circulation. Etc.)
But there are things that do not make sense to me about this issue, things that I've tried to find out about. One, is the present warm spell really unprecedented in modern times? There were high temperatures and bad droughts in the 1930s, at least in North America. I've tried in vain to get a clear discussion about what was going on in the Arctic in that period. Now, we hear about "drunken trees" that lean at funny angles because the permafrost is melting. Has this ever happened before? What was the Arctic Ocean ice doing in those days? I have the vague impression it was in retreat in those days. The best source of information about global warming (from the point of view supporting human-caused warming) is realclimate.org. They don't seem to say anything about the 1930s. So one thing I would definitely examine is the historical temperature record, what does it really say? Premodern temperature records might be more interesting still. I get the impression that 7500 years ago was warmer than the present. Do they know why?
Another thing that does not make sense to me is the role of the Sun in climate change. We are told that the Sun's output changes very little (0.1%) from decade to decade, and that this can only explain a relatively small portion of climate change. (The scientists also say that the Sun's output has not increased in the last decade or two while global warming is at its greatest.) But I've read for years that the Little Ice Age may have been due to the Maunder Minimum (when the Sun had hardly any sunspots; when the Sun has more sunspots, it puts out more energy). It would be valuable to get a clear story on this.
My hunch is that ocean circulation patterns were different enough to cause the warm decade globally. Intriguingly, though, El Ninos were weak in the 1930s, and El Nino years (like 1998) are usually the warmest years.
Indicates Maunder Minimum irradiance was lower by 0.37% (minimum) to 1.23% (maximum) -- a lot more than 0.1%.
Good post, my main concern in this study is that they seem to ignore the recent announcement that Mars is experiencing warming as well.
As a reasonably informed poster, don't you agree that it is ludicrous not to examine the temperature effects on other planets (especially our nearest neighbor) when trying to asses what contributes to global warming?
Mars in this case would appear to represent a reasonable 'control' subject - where human induced warming is minimal or non-existent? (I say minimal because those Mars rovers sure resembled SUV's, and God knows those are just evil global warming contributors).
Second, I still haven't seen any data which would indicate that CO2 has increased in any systemic way. 380 is definitely higher than 280, but like I said, it could be as a result of any number of things which would normalize the levels to a much more stable mean. That data point by itself does not constitute evidence, but if there is more data I'll be happy to have a look at it.
I'm not questioning anyone's motive here, or claiming that anything is being misrepresented. I'm only saying that based upon statistics, the data point does not contain the information that people are attributing to it. It may be one point in a broader set of data which can lead to that conclusion, but by itself it does not.
At it's core though, the problem that seems to be emerging to me is that we are trying to take very sparse data which support a certain trend, and use it to draw a conclusion of a scale so massive that it can't be supported. It's like trying to support a stone roof with toothpick thickness pillars. It can in fact be done, but you need a lot of them... more than I have seen so far.
At the same time, (and as you pointed out), they seem to be simply ignoring all the data which may contradict the trend they have pronounced. Correlation records of sunspot with warming trends and evidence of past glacial melting are two which even I can pick off the top of my head.
I'm really committed to keeping an open mind here, but it's already difficult to keep from seeing the kinds of philosophical errors which the left has so frequently proven guilty of in the past. I'm setting it aside for now, but if this is all the data that's out there then,the left's desire to redesign society to match their model is looking like the cause of much of the hyperbole.