Before the introduction of agriculture our hunter gatherer ancestors had the habit of burning large tracts of open plain to drive animals before them, hopefully off a cliff where they could be skinned and butchered.
That burning probably marked the true beginning of the Anthropocene, an era, if not an epoch, characterized by the changes we’ve introduced to the geology and more recently even the geography of the planet.
Burning the fields changed the behavior of animals and the growing patterns of plants and trees. It changed the albedo of the Earth itself and the movement of the winds above it.
Beavers dam trees and ruminants paw through the snow to get at the grasses underneath. But when we began farming our treatment of land and rivers was an organized and systemic change to the environment. Now we have 800,000 dams built and 33% of habitable land is under the plough. The reservoirs behind the dams have a different albedo than the land they covered and the humidity also changes the wind patterns around it. And the land ploughed under every spring is dark and heat absorbing while the crops at summer’s end are usually lighter in color and are certainly absorbing CO2.
So I don’t think there’s any question that we have changed the climate throughout pre-history and history. I would put the beginning of the Anthropocene at somewhere between 50,000 and 13,000 BCE. And of course it continues today and has grown stronger, with roads, pollutions and emissions of CO2, with jet contrails, canals, megacities and deforestation.
The question is, will our impacts on the environment (including the climate) end in tears?
As regular readers probably already suspect, I’m more optimistic than many others who have looked at this topic. (I studied anthropology during my brief sojourn at the university and have retained a very real interest in it since. I’m not an expert but I have followed closely their explanations.)
It is my conviction that in some areas we are already past the period of our peak influence on the environment and in others that we are approaching that peak.
Specifically, we seem to have reached a peak of how much land we are using for agriculture–the worthy world organizations don’t predict that we will be taking more land for farming.
Also, residential use of land is being concentrated in the large cities of the world, with greater percentages of the population living in urban environments and smaller percentages in rural–and both trends and human desire for advancement make it look as though that will continue.
As we make progress in the developing world, deforestation should slacken–especially if we realize that biofuels are not really a force for good–because those living in the developing world will gain access to electricity and fuels with higher caloric density than dung or branches.
As for climate–well, that is the topic of the millenium to date, and it receives a lot of attention. I’m a Lukewarmer. I think atmospheric sensitivity is lower than many activists and a majority of scientists (although the tide seems to be turning and low sensitivity is becoming more acceptable as a forecast).
But I’m still concerned. Even a low sensitivity of our atmosphere to concentrations of CO2 leave us vulnerable to what will happen in the next fifty years.
I’ve spent a year detailing why on the other blog I maintain, where I forecast (and show my work) that human consumption of energy will be six times as great as in 2010 by the year 2075. That’s why the blog is names 3,000 quads–that’s how much energy I think the world will burn in 2075, compared to the 523 we used in 2010.
Even a very low sensitivity of the atmosphere will not allow us to ignore the effects of that amount of energy. Worse, because other forecasts are much lower (the DOE thinks it will be less than a thousand, although they didn’t update their forecast last year…) we are not putting the infrastructure in place to allow the energy to be provided by anything other than mountains of coal. And that’s the real threat to us.
But the scope of the threat is not at a planet-busting level. As I’ve written before, it may produce a wetter and wilder world–but it will still be recognizable and both life and civilization will go on. So will development, and when population peaks right before the end of the century, no less an august body than the IPCC also predicts that our emissions will begin to decline. We are definitely not talking the end of the world here.
And that’s when this conversation will get interesting. When population has not only stabilized but achieved a decent level of income and access to technology–when 80% of the population lives in cities and much of the planet has returned to nature–what then will we decide to do with our planet?