The beauty of a graph

Last week I wrote about how one image can say more than a thousand words, and this in the context of history. But it's also applicable in other sciences, and it's a great way to communicate science to a greater public.

Take for instance the famous and unjustly criticised "Hockey Stick" graphportrayingthe recent global warming of the Earth. In its current formfirst developedby Mann, Bradley & Hughes, it recently got a cool upgrade. Marcott and colleagues wrotean article inScience(8 March 2013), showing research into the how temperatures in the last 11300 years varied against the average.

(Note: if you are of the belief that global warming is a hoax and we are all duped by whatever brooding kind of evil scientists, please stop reading now. Don't bother to continue, and don't comment either. Read first through John Cook's amazing website Skeptical Science, including rebuttals of any possible and imagined counterargument, and then come back to this article. I can wait.)

Although the article was rather full of calculations, blogger ImaGeo(Tom Yulsman)from Discoverblogs luckily found the following gem hidden in the supplementary material, and got the lead author to comment on it, too.



This is not only seriousscience, it is cool. ImaGeocalled it "Art of the Antropocene: The Scythe", and he's right. It's no longer a nice little hockey stick, but cuts right to the bone of the problem: the recent global warming is happening a lot faster than any other warming in the past 11300 years.

The researchers gathered 73 different datasets based on fossils of tiny organisms in the sea floor. But with each dataset comes uncertainty. In order to obtaina meaningful result that could be studied, the researchers let each of the 73 datasets vary within its margin of error, and that 1000 times. Each colour in the graph is one of those simulations (corresponding with a global temperature),in atechnique called Monte Carlo simulation.

The result, plotted against the average global temperature shows that recent global warming, in absolute numbers not unprecedented, is happening at breakneck speeds. While contemplating the beauty of this graph, do keep in mind that uncomfortable message...