Birth, life, and death is an endless cycle, both for sentient beings and for phenomena. A human might live a century, an empire seldom makes it for three, and geological ages a hundred times longer stretch back over four billion years. Change is the only constant.
Due to many interlocking causes and conditions we are now at a massive inflection point. That our empire should fall now to a mix of corruption and resource depletion is surprising only in that we've lasted nearly two and a half centuries with only one serious domestic discontinuity. Humans have faced political, economic, and environmental crisis countless times since our species arose.
But the exhumation of carbon which we seem powerless to stop will erect not just the headstone for our empire, but perhaps for our entire species along with the biosphere in which humans evolved.
A new intelligence may arise and progress, as our kind once did, in another fifty or hundred million years. When they dig deep enough, they'll learn of the Anthropocene Thermal Maximum.
The Earth, over four billion years old, has been in a constant state of flux. Volcanoes and asteroids can rearrange things in the geological blink of an eye. Ice ages have come on gone the whole time humans and our ancestors have existed, although the clear record from the Vostok ice cores only go back two thirds of a million years.
Those layers of ice show the Earth literally breathing carbon dioxide in and out, 180 ppm and ice ages at the minimum, and about 280 ppm through the 12,000 year long Holocene which now draws to a close. Two hundred years ago humans almost simultaneously began exhuming carbon a hundred times faster than the Earth was used to and we broke through a food supply constraint with a mix of fossil nitrates and synthetic nitrogen fertilizer. The two century long septupling of our population puts us at the edges of our supply of land, water, sea food, and now our historically safe, pleasant climate is breaking down just as we exhaust the easily accessible liquid fuels.
There is no nice way out of this dilemma; in fact it's quite possible there is no way out at all for our species, and the rest of the biosphere as we know it right along with us.
Mother Nature is going to correct our overgrowth, as she does for every species that gets so far out of line with its environment. The fact that we're self aware and that some of us show individual sparks of brilliance matters not; collectively we're no wiser than the cyanobacteria that first gave this planet its oxygen atmosphere.
We'll struggle against this correction, of course; we're built to survive as individuals, as families, as tribes, and perhaps even as nations. The urge to eat today is strong – humans will consume the seed for next year's crop if they're hungry enough. I have no doubt that, exhausting oil, we'll double down on climate change by using the coal we have left to replace it.
280 ppm is the upper end of normal carbon dioxide levels that our species has known. Today we're at 390 ppm and the overall system has likely gone non-linear. There is a very real possibility that even if a slate wiper of a virus took our whole species over the next few weeks the Earth would continue its current warming trend, duplicating a previous peak, the Paleocene Eocene Thermal Maximum.
Fifty five million years ago, in two separate millennium long spasms, the Earth's oceans exhaled massive amounts of methane clathrates. The average temperature shot up 11F, the oceans acidified, and half of all ocean species went extinct. Tropical species that survived found their way to Arctic waters.
Here is a quote you should read several times until it becomes very, very clear.
During these events – of which the PETM was by far the most severe – around 1,500 to 2,000 gigatons of carbon were released into the ocean/atmosphere system over the course of 1,000 years. This rate of carbon addition almost equals the rate at which carbon is being released into the atmosphere today through human activity.
Human fossil fuel use at the current rate matches the profile for a massive clathrate outgassing. The oceans, warmed by our exhumation of carbon carbon, are starting to respond on their own. We can theorize about bioremediation of clathrate outgassing but the simple truth is that if the largest carbon dioxide emitter per capita can't stir itself to do something about a threat this obvious, nothing will be done.
Here are some things that are already in play.
We're going to hit a wall with the availability of oil first, due to declining returns coupled with dramatically reduced investment due to the economic crisis. We'll come to a similar grim realization with natural gas, but not until we wreck many North American aquifers through shale and coal bed methane production. We'll get interested in conservation but coal will be the only readily available fuel to drive the needed restructuring of our society – a cure that will kill. And no one will give an inch on standard of living.
The Haitian earthquake was entirely natural, but it serves as a good model for outcomes in a world facing climate change and fossil fuel depletion. The homes for a multitude are wrecked, a busy Atlantic hurricane season is bearing down on the region, and we're financially limited in our ability to respond.
Now atop Haiti's misery Pakistan floods, with 10% of the population displaced, while Russia burns. The Russian grain embargo due to losing 20% of their crop has grim implications if conditions in Australia are anything but picture perfect for this year's wheat crop. If this doesn't start tipping over the governments of wheat importing countries it'll be a miracle. I thought this would happen in 2009 but we got lucky on weather and the economic contraction we're experiencing actually helped matters. We're probably not going to be so lucky in 2011.
When climate fails to meet minimums governments fall, or fail completely. Afghanistan and Somalia both face long term drought and remain stubbornly stateless lands. They're going to be joined in this breakdown of order, with humans fleeing and fighting amongst themselves as well as the current tenants of anywhere they might try to migrate. Recall that septupling of population mentioned earlier – the Earth is full.
We aren't going to be getting liquid fuel out of the ground and we're going to find it politically and operationally impossible to produce enough biofuels to project military force the way we have been, even if we had the finances to do so, which we do not. The attempted peacekeeping of the 1990s in Somalia will be a thing of the past as climate change makes such problems more prevalent and fossil fuel depletion makes responding increasingly difficult.
More energetic tropical storms are already here and rising seas are a longer term issue, but these coupled with the right here/right now ocean acidification problem are going to hit overall stability for the human species hard. Half of us live close to the sea and a significant portion of the protein we eat comes from seafood. We're going to get chased right up out of our favorite habitat, quickly by storms, relentlessly by rising water, and the whole reason for being there in the first place, that access to seafood, will become a moot point when ocean acidification crashes the already over fished food chain.
Species come and go, even hominids. Our species passed through a genetic bottleneck about 70,000 years ago which has been attributed to the Toba eruption. Today, if Pakistan and India were to engage in a full throttle nuclear exchange, despite the overall warming trend, we'd face perhaps a decade of nuclear winter similar to the aftereffect of a large eruption. This would swiftly decimate our ranks, perhaps down to as few as that same 10,000 to 15,000 individuals who came through the Toba bottleneck.
Even if it were a 100,000 survivors the path down to zero isn't hard to see. Scattered pockets of humans, most refugees from a modern world which teaches none of the hunting and gathering skills needed day to day, would face terrible difficulties. A bad year of avian flu here, a potent hurricane bearing down on a pocket of unsuspecting survivors there, and pretty soon all that was of homo sapiens would be works that plate tectonics would consume before any successor stirred enough to notice that they were not the first to pass this way.
And the heat will just keep coming, because we've already set positive feedbacks in motion in the Arctic. The finding, interpreting, and reporting of the evidence that we were here at all is a task for some distant future diarist. I hope his kind display more wisdom and kindness than ours has.