Life on the Ledge is Over
What happens when we wreck the platform on which civilization is built?
Take a look at the right half of the chart below, which shows the estimated average temperatures on earth from one million years ago to the present. The rightmost box shows the temperatures during the last 20,000 years; the box to its left shows the period from one million years before the present until 20,000 years before the present.
What do you notice?
Here’s what I notice about the last million years. The average global temperature has bounced around pretty wildly. It has only rarely been as warm on our planet as it is now, and usually not for very long. It also seems that the global temperature stopped fluctuating so much about 12,000 years ago, at the beginning of what we call the Holocene period.
The earth’s climate has been unusually stable for the entirety of the Holocene period. As scientist James Hansen wrote, we’ve become used to strange conditions: “it’s our relatively static experience of climate that is actually exceptional.”
