It is not my intention to bother everyone each week with the announcement of
these lectures, but because the response to last week's announcement was so
pronounced and because of this week's subject material is appropriate to the
list, let me mention this week's lecture as well:
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The Evolutionary Biology Lecture of the Week for April 24, 2006 is now
available at:
http://aics-research.com/lotw/
The talks center primarily around evolutionary biology, in all of its
aspects: cosmology, astronomy, planetology, geology, astrobiology,
ecology, ethology, biogeography, phylogenetics and evolutionary
biology itself, and are presented at a professional level, that of one
scientist talking to another. All of the talks were recorded live at
conferences.
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April 24, 2006
Part II: Planetary-scale Patterns
Auditing the Earth: Present Changes,
Future Changes, and Irreversibility
Stuart Pimm, Duke University
35 min.
"Man eats Planet! Two-Fifths Already Gone!"
Stuart Pimm uses this headline as the title to one the chapters in his 2001
book, "The World According to Pimm," and he recapitulates many of the
planetary-scale lessons from that book in this week's lecture.
When talking about this subject, it's easy to slide into alarmist hysteria,
but even under the most rational and calm discussions the numbers are still
staggering. Humanity is clearly transforming the face of the planet. We now use
50 percent of the world's freshwater supply and are consuming 42 percent of the
world's plant growth. Simultaneously, we are destroying the tropical moist
forests of the world, the sites of the world's great biodiversity. Indeed, they
may be gone in as short a period as 20 to 30 years.
The effect that this is having on the planet's biodiversity is that we are
extinquishing animal and plant species 100 to 1000 times faster than the
natural
rate of extinction. Such numbers should make it clear that the human impact
on our planet has been, and continues to be, extreme and detrimental.
Planetary-scale ecology may be rapidly eclipsing economics as the "dismal
science."
Yet even after decades of awareness of our environmental peril, there remains
passionate disagreement over what the problems are and how they should be
remedied. Much of the impasse stems from the fact that the problems are
difficult
to quantify.
How do we assess the impact of habitat loss on various species, when we
haven't even counted them all? And just what factors go into that 42 percent of
biomass that we are hungrily consuming? It is only through an understanding of
the numbers that we will be able to break that impasse and come to agreement.
While it's in Stuart's nature to be an optimist ("unashamedly optimistic" is
how he describes himself), the implications of the numbers he presents are
nonetheless alarming. But without being an optimist, change for the better
probably isn't possible.
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Wirt Atmar
