The Retreating Edge
The Anthropocene, with the threat of 'global warming' or more precisely climate change imminent one thing that is often not mentioned is how long this period might last.
What does the future hold for us? We will will most likely keep pumping out CO2 until we run out of easy stuff to burn, in the case of 'easily' extractable petroleum, 50-100 years and coal resources another couple of hundred years after that.
CO2 Levels and Glaciation
The result is quite likely to be a 1000 year super-interglacial period of at of unusually warm climate. Some deserts might actually bloom again, depending on which way the Gulf Stream points but we will lose much productive farmland and many coastal areas. The earth's atmosphere will rid itself of the carbon eventually but the carbon pumped into it will override the effects of our current astronomical cycle (1000 more years of warming followed by 22,000 years of cooling). Human intervention has made the current cycle unlike any others in the past 1 million years.
All of our known history from the beginnings of agriculture to the advent of civilization(s) has taken place in the interglacial period of the past 12,000 years. We are in an ice age (or climate decline) that has been going on for 10 million years or so. Precisely put we are living in the Holocene epoch of the quatenary period of the Cenozoic era. Some have called it the Anthropocene because of mankinds collective efforts which have had, for the first time, an effect on current climate cycles.
Temperature Changes
We are in the middle of an ice age or rather in the middle of an interglacial period in the middle of an ice age. We are well past the post glacial optimum which occurred 5-7000 years ago, more or less near the beginnings of agriculture and the first cultures which led to civilizations. The next glacial advance is due in about 11,000 years, all that CO2 may buy us another 1000 years of a 'false climatic optimum' before the glaciers come again but come again they will.
Why? Well given the current understanding of the planets natural history to date that seems to be how it works. We live in the 3rd major episode of glaciation for our planet in the past 1 billion years. The previous ones were:
-Pre-Cambrian 700 million years ago
-Permo-Carboniferous 300 million years ago
-Late Cenozoic last 10 million years
Glaciation cycles seem to correspond in a stochastic fashion to 1-eccentricity in the earths orbit 2-the precession of the equinoxes 3-cyclical axial wobble (tilt) Simply stated:
-eccentricity
-precession
-tilt
There is almost certainly a solar component that contributes substantially to the cycle. But essentialy it is a long frequency cycle that extends deep into geologic time and we haven't been around long enough for accurate longterm observation of the sun.
When the earths orbit is a long ellipse and summer sweeps out the most distant quadrant of the ellipse the orbit is said to be more eccentric and accumulated snows are less likely to melt in the summer or snow can accumulate and turn into glacial ice creating feedback loop which causes more snow to fall and stick.
Antarctic Glaciers
A probable precondition seems to be landmasses near the poles for the ice to accumulate on, increasing the albedo of the poles and reinforcing the cycle. Currently with continental drift we have two large continents near the poles, Greenland and Antarctica, both covered with ice. In the first glaciation (Pre-Cambrian) the super-continent Pangaea had a spur that extended into the Antarctic, in the second (Permo-Carboniferous) the continent of Laurasia had a large arctic component.
Laurasia:
In the current age we seem to alternate back and forth between a southern hemisphere ice age, which we have now and a northern hemisphere ice age which is pending. This is due to axial tilt and precession components, with continents in the right place for this kind of oscillation to create extended periods of glaciation.
The cycles run in 22,000 40,000 and 100,000 yrs punctuated by mini-ice ages (300, 2800, 4500, 12,000 yrs ago to illustrate a few examples). Three of these within the realm of rcorded history. Some of the tales of disruption, migration, famine and war that were written down from those periods do not make pleasant reading.
If you follow the archaeology when the climate starts changing in your neighborhood, its time to change your habits, move, die or fall victim to someone else. When land and water resources go from marginal to sub-marginal humans begin to move for economic reasons that equate to life or death.
Some of the peoples affected by this oscillation have already started to move. In the news you can see actions of the Janjeweed militias against settled inhabitants of the Sahel which has been drying out slowly since the post glacial optimum. Call it what you will the Sahel region is already the scene of the opening sequence of conflicts over a growing scarcity food, water resources and land. These conflicts will expand there and in other regions.
Inevitably it is bad decisions and and the inability of social institutions to adapt that kill the most people. Even if we in the industrialized world develop more efficient technologies unless we create social financial institutions which allow more flexible adaptation and implementation worldwide we run the risk of developing a 'Festung Europa or a Festung America' outlook designed to keep out the displaced multitudes who will be forced to move in search of new livelihoods and survival.
Extent of Last Advance in N. America
The problem is not with our stars but with our manufacturing, but with us, our institutions and our philosophy of technology, waste and the inclination of governments and business to load shift burdens of cleanup compliance and insurance onto taxpayers.
Notionally it could be construed as a social component because bad decisions and an inability to change is what will kill people. In addition to the more technologies we also need to create, on an international level, the social institutions which will allow us to adapt more flexibly and minimize the impact of imminent change on global populations. Planning in advance instead of waiting to long can save a lot of time and money. Its also one advantage we have over the rest of the animal kingdom.
Is this the Cause Celebre of the 21st and not just a Celebrity cause? If the students of today take the obvious lessons of the pending future to heart and study the useful and necessary disciplines to build the technologies and business that will give us a future. 1000 years of summer is not all that long.
