Lecture of the Week: Part II: Planetary-scale Patterns

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. (requires QCShow Player)

"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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