Scientists and other concerned about global warming have, in my opinion, not done a good job people trying to get the message across.
In particular, they often present arguments about warming that has occurred during the last century or so, showing alarmingly steep graphs of global temperature rises. In very few cases will you be shown what preceded the recent temperature changes, over a much longer period of centuries or millennia.
I have tried to point this out here in this blog -- see The rattlesnake;s rattle (part 2)— and included a few illustrations that I was able to patch together back then (in 2010).
Well, I recently came across 2500 Years of European Climate Variability and Human Susceptibility (PDF) in which some European scientists present tree ring–based reconstructions of central European summer precipitation and temperature variability over the past 2500 years.
To expound on my point, let’s look at the following chart from the above paper:
I’d consider any trends that emerge from studying natural phenomena over several millennia are more likely to be meaningful than supposed trends obtained from results of measurements made only in the last century or so.
I have added a green ellipse around the part that is often used when discussing global warming, and I’d say that the accusation can be made, with quite some justification, that basing global warming arguments over such a restricted period (the art that’s circled, a handful of decades) is not very convincing science.
But if you consider the entire scope of this chart, it becomes much “safer” to argue that there indeed has been a sudden and significant rise in temperature during the last half century.
That’s what I was trying to get at in earlier bog posts, via my not-so-good analogy of the rattlesnake with its tail steeply raised giving us a warning that we cannot afford to ignore:
By the way, you’ll probably be fascinated by The Season of the Witch: Climate-Change and Witch-Hunt Through the Ages