The next meeting will be Friday, November 6th, at 10.30 am.at our usual location in the Javits room, library 2nd floor. The speaker will be William Jungers, Distinguished Teaching Professor and Chairman of Anatomical Sciences, to talk on Hobbit Biology: Homo floresiensis and Human Evolution
The small-bodied, small-brained, culture-bearing hominins from the Late Pleistocene of Indonesia have been attributed to a new species of our own genus, Homo floresiensis. Known as the "hobbits" in the popular press, these unexpected and controversial fossils have served to challenge our understanding of the human career. Evolving in isolation, they present a unique anatomical package of primitive and human-like features that suggests either very ancient ancestry or"island dwarfing" with multiple reversals. Attempts to dismiss Homo floresiensis as a community of pathological (microcephalic) Asian pygmies are misguided but perhaps predictable.
Dr. Jungers obtained his PhD in 1976 at the University of Michigan. His research is concerned with body size and the functional and biomechanical aspects of musculoskeletal design in living and fossil primates, ranging from giant subfossil lemurs to extinct hominins. Quantitative methods are essential tools in the comparative analysis of form and function and in testing falsifiable hypotheses. The present remains the key to understanding the past. Dr. Jungers is participating in the description, excavation and analysis of the newly discovered fossils from Indonesia, Homo floresiensis (see above). Research also continues in Madagascar. New species continue to be discovered and diagnosed, improved reconstructions of paleo-communities are now available, range extensions of living species have been documented, and life histories are being revealed along with dietary and positional preferences.
Dr. Jungers' subject has recently become more timely with the news of the discovery of a hominid skeleton 4.4 million years old, more than a million years older than the previous record. See:
The new co-chair, Al Carlson, started with announcements.
He was sad to note the passing of Lawrence Slobodkin and Harry Kalish during the preceding month. Obituaries have been emailed out to all faculty and staff from the provost's office.
On a more upbeat note, our speaker of March 2006, Joanna Fowler, was recently awarded the national medal of science by president Obama.
Jean Peden and Manny London of the undergraduate colleges program were introduced and encouraged emeriti to volunteer to teach freshman seminars. These are 1 hour per week of one semester for a section of about 20 students on a subject of your choice. A remuneration of $1200 is available for supplies and travel through your department. Several of our members have done this and found it rewarding. Contact Jean at 632-4378 for more information.
Our main speaker, David Black of Marine Sciences was then introduced to speak on "Global warming: causes, consequences, and what you can do about it.".
Professor Black introduced himself as someone who never grew out of his childhood obsession with mud pies.
For other details of his bio see the May issue of this newsletter (click on archives).
More seriously, he regards himself as a paleo-oceanographer: he studies fossils in marine sediments to shed light on climate history and what it may portend for the future, in particular about the present warming trend.
According to him there are now very few scientists who disagree that global warming is occurring.
Of course there have been times in the past when the earth was distinctly warmer, most recently 125,000 years ago.
And 120 million years ago there was even no ice on the planet at all.
But now there is a large human population, and shortages of fresh water in some areas is what may lead to our first major crisis.
What are the influences on climate? The movement of the tectonic plates causes changing positions of the continents for one, and the uplift of mountain ranges like the Himalayas for another. These and other causes have gotten the earth into a condition where ice ages can occur. For the last 800,000 years these have more or less tracked the so called Milankovitch cycles of variation in the earth's orbit and tilt. During this period also global temperatures have closely tracked the concentration of greenhouse gases, notably carbon dioxide and methane.
How do we know all this since human temperature records hardly go back more than a century? The answer is we use proxies: tree rings, ice cores and marine sediments. Prof Black himself studies forminafera, fossils of animals with shells, in sediment cores taken off the California and Venezuela coasts. These track movements of the intra-tropical convergence zones where the trade winds meet, and also ocean acidification caused by dissolved carbon dioxide. In ice cores, hydrogen and oxygen isotopes depend on temperature and little bubbles in the ice actually preserve samples of prehistoric air.
But about 8000 years ago the carbon dioxide went off the track of the previous Milankovitch cycles, followed later by methane (i.e: much prior to the industrial revolution). It is now thought that this started with the onset of forest clearing and agriculture, particularly rice farming in Asia. Greenhouse gases by now are at levels not seen for at least 650,000 years and rapidly increasing. The concern is that we do not understand all the feedback effects. One serious positive feedback could be the huge quantities of methane hydrate ice held in the thawing permafrost (and the even greater quantities in the sediments of the continental shelves). Methane is a greenhouse gas 25 times more potent than carbon dioxide. Recent research on Greenland ice cores has shown warming events with a very rapid onset, as much as 10 degrees C in as little as 35 years. This suggests that there might be feedback effects that operate less like a smooth change and more like a switch which reaches a threshold for turning on.
One of the first results of all of this will be decreasing supplies of fresh water in some places, particularly third world countries*, but also here. Most of us have heard of the lawsuits engendered by the declining flow of the Colorado river. It is not so generally known that the Ogallala aquifer which underlies the breadbasket in the middle of the country from S. Dakota to Texas consists of fossil water filled by the melting of the last ice age. At the current rate of depletion it will be dry in 25 years. Similarly, the Biscayne aquifer on which the metropolitan populations of South Florida depend will be compromised by a sea level rise of as little as 6 inches. The current estimate for global sea level rise by the end of this century is 1 foot. And if all the ice on Greenland and Antarctica were to melt as in that time 120 million years ago, the sea level would rise by a total of 70 meters!
* The issue of water shortages being the first crisis was confirmed by Maude Barlow (senior advisor on water to the the UN and chair of the Washington-based Food and Water Watch) at the Provost's lecture this month. According to her the aquifer supplying Mumbai will run out this year.
Prof Black ended with an exhortation of all the things we can do to minimize our carbon footprint. But while I am already doing nearly all of these things I do feel a little lonely. The town hall meetings held by our congressman over the summer were besieged by people loudly proclaiming (among other things) that "3000 scientists say global warming is a fraud". And most of them had vehicles (not to mention physiques) much burlier than mine.
In a wider indicator, the US public came dead last of 19 countries in a poll this summer on the priority their government should give to addressing climate change. With 10 points for very high priority and 0 for no priority at all, our citizens could not muster an average of 5 (not much removed from don't know/don't care?). The Chinese people were second from the top with close to 9. See:
Finally, a Pew poll taken this month shows a sharp reduction in the number of people in the US who think there is solid evidence of global warming and that it is a serious problem - now down to 35%, see: http://people-press.org/report/556/global-warming