The Scale of Change Over Time

(or “The difference between rust and fire”)

Randall Munroe has given us a great way to look at climate change over a somewhat-deep-time perspective.  (Remember, I’m an anthropologist, so 20,000 years is trifling – it’s next to nothing in geologic time, and only about one-tenth of the time since the first Homo sapiens evolved in Africa.) Today’s XKCD walks the viewer through a very nice scale model of the 20 millennia since the last glacial maximum, with some key events from the geological, archaeological and even linguistic record.  I’ll admit I haven’t taken the time to fact-check his placement of these events, but the ones I’m familiar with seem to be in about the right place (tragic extinctions of saber-toothed cats and Pokemon, I’m less certain about).  Scrolling through 500-year chunks of time, and reading the events therein, leaves one with a clear sense of just how out-of-the-ordinary the change over the last 500 years – and especially the last 100 years – has actually been.

It’s good to see that the associated explainxkcd has not yet descended into a flame war (as of 11am PDT on 12 September 02016).  Clear, popular and provocative explorations often attract the attention of professional climate-denier trolls – this even happened to me once, gentle readers, despite the fact that I have “dozens of loyal fans… baker’s dozens… they come in 13s.” Remember, when there is over 97% scientific consensus on something, it is about as close to proven as science can reasonably get.

As Randall Munroe had pointed out previously, the difference between the effects of regular corrosion and a car fire is simply a question of how fast the oxidization is happening.

When it comes to climate change, extinctions and far too many other phenomena, the difference between Anthropocene changes and natural background rates of change are roughly on that scale of difference.  It’s time to be in emergency response mode if we are to have any hope of saving what’s left.