Maximum Sustainable Thermodynamic Footprint of Humanity
Discussion
Paul Chefurka:
"The number suggested by the Thermodynamic Footprint or Fossil Fuel analysis isn’t very helpful either – even a population of one billion people without fossil fuels had already gone into overshoot.
That leaves us with four estimates: two at 35 million, one of 10 million, and one of 7 million.
The central number of 35 million people is confirmed by two analyses using different data and assumptions. My conclusion is that this is probably the absolutely largest human population that could be considered sustainable. The realistic but similarly unachievable number is probably more in line with the bottom two estimates, somewhere below 10 million.
I think the lowest two estimates (Fowler 2008, and Fowler 2009) are as unrealistically high as all the others in this case, primarily because human intelligence and problem-solving ability makes our destructive impact on biodiversity a foregone conclusion. After all, we drove other species to extinction 40,000 years ago, when our total population was estimated to be under 1 million.
So, what can we do with this information? It’s obvious that we will not (and probably cannot) voluntarily reduce our population by 99.5% to 99.9%. Even an involuntary reduction of this magnitude would involve enormous suffering and a very uncertain outcome. It’s close enough to zero that if Mother Nature blinked, we’d be gone.
In fact, the analysis suggests that Homo sapiens is an inherently unsustainable species. This outcome seems virtually guaranteed by our neocortex, by the very intelligence that has enabled our rise to unprecedented dominance over our planet’s biosphere. Is intelligence an evolutionary blind alley? From the singular perspective of our own species, it quite probably is. If we are to find some greater meaning or deeper future for intelligence in the universe, we may be forced to look beyond ourselves and adopt a cosmic, rather than a human, perspective."
(http://paulchefurka.ca/Sustainability.html)
Research Reports
Paul Chefurka:
"The Ecological Assessments
As a species, human beings share much in common with other large mammals. We breathe, eat, move around to find food and mates, socialize, reproduce and die like all other mammalian species. Our intellec tand culture, those qualities that make us uniquely human, are recent additions to our essential primate nature, at least in evolutionary terms.
Consequently it makes sense to compare our species’ performance to that of other, similar species – species that we know for sure are sustainable. I was fortunate to find the work of American marine biologist Dr. Charles W. Fowler, who has a deep interest in sustainability and the ecological conundrum posed by human beings. The following two assessments are drawn from Dr. Fowler’s work.
First assessment
In 2003, Dr. Fowler and Larry Hobbs co-wrote a paper titled, “Is humanity sustainable?” that was published by the Royal Society. In it, they compared a variety of ecological measures across 31 species including humans. The measures included biomass consumption, energy consumption, CO2 production, geographical range size, and population size.
It should come as no great surprise that in most ofthe comparisons humans had far greater impact than other species, even to a 99%confidence level. The only measure inwhich we matched other species was in the consumption of biomass (i.e. food).
When it came to population size, Fowler and Hobbs foundthat there are over two orders of magnitude more humans than one would expectbased on a comparison to other species – 190 times more, in fact. Similarly, our CO2 emissions outdid otherspecies by a factor of 215.
Based on this research, Dr. Fowler concluded that there are about 200 times too many humans on the planet. This brings up an estimate for a sustainable population of 35 million people.
This is the same as the upper bound established above by examining hunter-gatherer population densities. The similarity of the results is not too surprising, since the hunter-gatherers of 50,000 years ago were about as close to “naked apes” as humans have been in recent history.
Second assessment
In 2008, five years after the publication cited above, Dr. Fowler wrote another paper entitled “Maximizing biodiversity, information and sustainability." In this paper he examined the sustainability question from the point of view of maximizing biodiversity. In other words, what is the largest human population that would not reduce planetary biodiversity?
This is, of course, a very stringent test, and one that we probably failed early in our history by extirpating mega-fauna in the wake of our migrations across a number of continents.
In this paper, Dr. Fowler compared 96 different species, and again analyzed them in terms of population, CO2 emissions and consumption patterns.
This time, when the strict test of biodiversity retention was applied, the results were truly shocking, even to me. According to this measure, humans have overpopulated the Earth by almost 700 times. In order to preserve maximum biodiversity on Earth, the human population may be no more than 10 million people – each with the consumption of a Paleolithic hunter-forager."