Life on the Ledge is Over
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.”
I like to think of the last 12,000 years of the graph as a ledge — a nice, flat surface upon which we’ve built, well, everything.
During the last 12,000 years, humans — a species that had already been around for about 200,000 years — started to thrive like never before. We created an entirely new way of living. We populated every corner of the earth during this period, invented agriculture, established cities, created governments, and built monuments. Eventually we split the atom, cracked the code of DNA, and learned how to leave the planet.
In short, the entire history of human civilization is perched on that ledge of relatively stable temperatures. The ledge provided the conditions in which we and our companion species — wheat, cows, corn, rice, sheep, horses, soybeans, etc. — could thrive. The only world we’ve known since we left behind our hunter-gatherer origins has been on the ledge.
Imagine everything that humans have built sitting on that flat, stable surface.
Within that 12,000 years of stability, there were some small fluctuations that showed us how significant climate change could be for human societies. Can you see on the graph above the changes about 400 years ago, where the temperature declined a bit?
Maybe not. Here’s a more zoomed-in view:
This small fluctuation is what we now call the “Little Ice Age,” a period of several hundred years during which the global temperature declined a bit but temperatures in some regions declined more significantly. In Europe, the Little Ice Age was been linked with social disorder (increased anti-Semitism, witch hunts), famine, and war. There was civil war in China and Japan, and there were awful winters in North America that starved some of the first European colonists. You can read about it all in this terrifying book.
You can probably see where this is going. We built human civilization on this ledge, in conditions that happened to be perfect for the civilization we’ve built. Even small fluctuations in the climate caused massive disruptions in society.
Now, what we built on the ledge is breaking the ledge.
Now look again at the right side of the zoomed-in graph.
The line explodes upward, especially steeply since 1950. This is, of course, man-made climate change, zooming up toward and past one degree of added heat from the fossil fuels we’ve burnt.
We’ve already shot out of the range that humanity has enjoyed over the last 12 millennia. We are almost certain to hit 1.5 degrees; we’re quite likely to add another degree after that.
The universe gifted humanity with an uncommonly stable and hospitable climate on which we could build our civilization. The ways in which we chose to build that civilization are destroying the hospitable climate on which civilization has always counted.
This doesn’t mean that human civilization is over. We seem to be doing enough to avoid the most catastrophic outcomes of climate change. But it probably means that maintaining a comfortable civilization is going to get harder, in some parts of the world a lot harder.
We’ll need to prepare. There’s no time to bury our heads in the sand or blame each other. The ledge is crumbling. We’ll need to construct a new platform on which we can build a civilization.
We’ll need to be ready for more chaos, more uncertainty, and more tragedy. These are probably unavoidable. Life off the ledge will be messier, and we’ll have to devote lots of resources to cleaning up those messes. Getting well-off people in less-messy parts of the world to share their resources with people in messier parts of the world will be one of the great social-justice challenges of the next century.
We’ll need to get creative. In many ways, our species’ cleverness has gotten us into this mess. After all, we’re the only animals who figured out how to burn fossil fuels, turning them into light and strength and speed. The biggest technological advances for most of our history — the light bulb, the automobile, the radio, etc. — made life measurably better for people. Maybe the most important technologies of the near future will just keep life from getting too much worse.
We’ll have to rethink the way that we interact with the other life on our planet. Even if we stopped warming the climate today (and we won’t), we have made the planet inhospitable for many of our fellow residents. We’ll need to learn how to share with other species, and explore how to live within our limits. This will be difficult — we, like all species, are programmed to take as much as we can for ourselves. It may be that our future and the future of our companions on the earth depend on whether we can transcend this drive.
Basically, living off of the ledge will mean that we’ll have to do a lot of things differently. It will be scary and uncertain and painful, but it may also be an opportunity for humans to figure out better ways to live. Only time will tell.