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After my post several weeks ago on former museum director J. Willis Stovall’s dire warnings about the impacts of human activity on the environment, I decided to do a little informal polling of our current museum curators to ask about what impacts of climate change they have seen during their research.
In the past few years, a downturn in frog populations has gotten considerable news coverage. A contagious fungus known as chytrid is largely to blame for this, and the fungus itself has been directly tied to climate change. (http://news.nationalgeographic.com/news/2008/04/080401-frog-fungus.html).
Dr. Caldwell pointed out that although she has been working with frogs in the Amazon for more than 20 years, the consequences of climate change take place over larger time spans, so the amount of measurable change that can be seen over 20 years can seem small.
Nevertheless, changes are occurring, and many species are, without a doubt, sliding along the path to extinction. Caldwell points to a review paper published in The Annual Review of Ecology, Evolution, and Systematics in 2006 summarizing 866 research papers that document how climate change has caused such things as changes in breeding cycles, mis-matches between when certain caterpillars emerge and when bird parents are trying to find them to feed their young, etc.
And that was in 2006!
“If the average public understood how many species are being lost, it would scare them to death,” said Laurie Vitt.
BUT, he added – and here is where my search for information about climate change became a discussion about something else entirely – climate change is just a symptom, not the cause of these extinctions. Climate change is just one part of a much larger problem that includes habitat loss, overuse of natural resources (such as fisheries) and pollution. All of these are symptoms caused by one thing: overpopulation by humans.
Some scientists refer to human overpopulation as “the Elephant in the Room” when it comes to environmental change. We struggle with cutting fossil fuel use, making better use of our resources, curbing pollution. But behind all of these massive global problems is one humongous, and growing, cause. There are, according to the U.S. Census Bureau’s World Population Clock, 6,869,198,668 people on the planet today, with the number, of course, rising steadily. Improvements in health care and technologies that allow for the automation of farming and production of other necessities caused the population growth rate to skyrocket since the beginning of the Industrial Age. Resources on the earth, however, are finite. Any biologist will tell you that when a population begins to outgrow the rate at which its resources can be renewed, nasty things begin to happen.
“We’re like bacteria in a Petri dish,” Caldwell explains. “As the bacteria multiplies, it uses up its food resources (the agar in the dish) and waste builds up, eventually leading to the death of all the bacteria.”
Many resources on our planet are renewable, of course. So the Petri dish analogy is not exactly correct. We can continue to grow food, though for how long we can produce enough to feed the ever-increasing number of hungry mouths is a question up for debate. More immediate than the question of feeding everyone is the issue of crowding – an issue which is much more immediately pressing (if you’ll pardon the pun), and not just for humans, but for all the other species with which we share the planet. As humans use up more space, other species get crowded into less, and the space available may not be adequate for their needs.
Habitat loss is actually the gravest concern facing many species today. “Species end up in fragmented habitats because we cut big chunks out for housing or highways,” Vitt explained. “Tiger salamanders, right here in Oklahoma, are a good example. Tiger salamanders breed in temporary ponds, but they don’t live there. They live elsewhere. A manmade pasture or road that goes in between where they live and breed interrupts their ability to get to and from the water for breeding.”
So What about a few tiger salamanders? There are plenty of folks who can and do make this argument. To misquote Hamlet: “Who is the tiger salamander to us or we to the tiger salamander that we should mourn for it?”
“All organisms are parts of complex ecosystems,” Vitt warned. “All the species interactions maintain the ecosystem over time. The mix, the complexity, helps to protect the whole.”
Think about the bacteria that live in our intestines. There are millions of bacteria in there, and hundreds of species that do all sorts of things – many which scientists don’t begin to understand yet. But their relative numbers remain pretty constant. If you’ve ever had the misfortune to suffer the very unpleasant consequences of the overgrowth of some of that bacteria…. well, it’s not nice. All the bacteria work together, somehow each helping to keep the others’ numbers in check. Scientists don’t really understand yet how and why these bacteria interact, but one thing is certain, you don’t just randomly do away with some of them and not expect consequences to the community at large.
Mass extinction is a cyclical truth on our planet. Five such extinctions have occurred over the history of the Earth. The greatest of these happened at the end of the Permian Period, when some 90% of all organisms were wiped out. The sad truth is that huge extinctions are likely to occur again. According to Dr. Caldwell, some scientists are saying that we have already entered the “sixth Great Extinction.” Some say the crash is inevitable – that it could take place within my lifetime… or that of my ten-year-old son.
Of course, humans are not bacteria.We have the unique ability to THINK. We are the only species that has the capacity to consider the future. We can observe, cogitate, make predictions based on our observations, and then make plans and take action accordingly. If we have the will to do so.
In a letter to BioScience, the journal of the American Institute of Biological Sciences in December, 1969, our museum’s current director, Michael A. Mares – then a doctoral student at the University of Texas at Austin – wrote:
The public must be made aware of the precarious ecological position in which over-population and technology have placed us. Without the intelligent support of laymen, attempts to institute reforms to meet this crisis are doomed to failure. How many colleges and universities offer even a basic course in human ecology available to all students? What is the percentage of future high school biology teachers acquainted with the rudiments of their own species’ ecology? The answers, I believe, are tragic.
In the very near future, we, as biologists, will know why the pillars of our natural environment crumbled, bringing down the temple of our synthetic surroundings. But to know then will not be enough, just as to know now is not enough. In an attempt to be constructive rather than merely critical, the following is suggested. It is known that delaying the age at which a woman first gives birth slows down population growth. It seems feasible that a series of cash rewards could be paid to a couple for delaying the birth of their first child.… Beyond this point a system of deductions for two children and penalties for more than two could be imposed….These methods and activities may cost us two precious commodities, time and money, but we must ask, how much is an environment worth?
The idea of limiting our population growth is controversial, particularly in a country in which personal freedoms are so central to our idea of who we are. But Dr. Mares’ warning and proposal, along with the earlier warning by Dr. Stovall, and added to the voices of the many scientists who are currently speaking up about “the Elephant in the Room,” does warrant some consideration and discussion. As thinking, planning organisms, dependent upon our ecosystem… how should we proceed?