Tag: planet

In the wake of the World Summit on Sustainable Development in Johannesburg, South Africa, there’s been a lot of talk about how to balance human needs with the health of the planet. Ecologists have been trying to measure the impact of humans on the environment for a number of years, with some sobering results. The Great Lakes Radio Consortium’s Daniel Grossman went to the New York Botanical Garden recently to gauge mankind’s ecological footprint:

Transcript

In the wake of the World Summit on Sustainable Development in Johannesburg, South
Africa, there’s been a lot of talk about how to balance human needs with the health of the
planet. Ecologists have been trying to measure the impact of humans on the environment
for a number of years, with some sobering results. The Great Lake Radio Consortium’s Daniel Grossman went to the New
York Botanical Garden recently to gauge mankind’s ecological footprint.

[Rain forest sounds, misters, tinkling of water, rain falling on leaves]

To get a good sense of the impact humans are having on earth, you could travel for weeks
on intercontinental plane flights, river boats and desert jeeps. Or, as Columbia University
biologist, Stuart Pimm suggested, visit a botanical garden. There, under the glass and
ironwork of a conservatory, Pimm says you can see a resource that humans are
over-using – Earth’s most important resource, its plant-life.

“We’re sitting in the rain forest here at the New York Botanical Society. And it’s a riot of
green.”

Professor Pimm says here beneath the misters in the Tropical Rain Forest Gallery is a
good place to start a whirlwind tour of Earth’s greenery. The air is heavy with moisture
and sweet-smelling.

“Rain forests are some of the most productive parts of the planet. They grow extremely
quickly and they are therefore generating a lot of biological production.”

What Pimm calls biological production most of us know as plant growth. Biologists say
all this green growth in tropical forests and elsewhere on Earth is the foundation upon
which all life rests.

“Everything in our lives is dependent upon biological productivity – everything that we
eat, everything that our domestic animals eat.”

And everything that every other animal eats as well. In a recent book, Pimm painstakingly
tallies up how much biological productivity we use. He starts with the rain forest. In the
last 50 years, loggers and settlers have cut down 3 million square miles of lush tropical
forests. Much was cut down for subsistence agriculture, a purpose Pimm says it serves
poorly.

“Although the tropical forest looks rich and productive, it is a very special place. And
when you chop that forest down the areas that replace it often become very, very much
less productive.”

[Sound of walking around conservatory]

Pimm speaks of the toll on greenery of cities and roads and of land converted to farming
in temperate regions such as the U.S. Midwest. Then, trekking along the botanical
garden’s gravel paths, he leaves behind the tropical mists and steps into the dry heat of a
Southwestern desert. Deserts and other dry lands are not very productive, but they
account for a substantial fraction of Earth’s land surface. Most of it is grazed by flocks of
sheep, goats, camels and cattle, often causing severe damage to vegetation. When these
uses are added to the other impacts of humanity on earth’s bounty, the results are
surprisingly large.

“What silence has shown is that we are taking 2/5ths of the biological production on land,
a third from the oceans. And that of the world’s fresh water supply, we’re taking half.”

[Fade out sound of conservatory. Fade up sound of Texas frogs.]

[Sound of plane engines]

Frogs and toads croak out a spring mating ritual in a concrete drainage ditch. Nearby, a
pilot practices maneuvers in a small plane occasionally drowning out the amphibian
serenade. Living in culverts, sharing the night with droning engines, these wild animals
are never completely free of human influences. From his Stanford University office,
Professor Peter Vitousek says wherever you look, the din of human activities is
interrupting and crowding out other species. Vitousek made one of the first attempts to
tally the impact of people on plant productivity in 1985.

[Frogs fade out in time for Vitousek’s act]

“The message to me was that we are already having a huge impact on all the other species
because of our use of the production of Earth and the land surface of Earth. That’s not
something that our models predict for some time in the future or something that we’re
guessing at on the basis of fairly weak information. It’s something that we’re clearly
doing now. That’s already happening.”

Many ecologists say this conclusion is beyond doubt. What they can’t say is whether
human domination of so much of nature’s output is good or bad. University of Minnesota
Professor David Tilman says as a member of the human race himself, he appreciates the
comforts in clothing, shelter and food our lifestyles buy us. And he acknowledges that the
survival of our own species is probably not imperiled – at least for the moment – by the
destruction of others. Still, he wonders if someday we’ll regret today’s resource intensive
practices.

“I think the more relevant question to me is, ‘Are we doing this wisely?’ ‘Are we wisely
appropriating the resources of the world?’ So, my concern is that we live in a balanced
way – a way that is sustainable through generations – that we leave our children and
grandchildren the same kind of world that we have.”

An expert on the impacts of agriculture, Tilman says we’re using up more resources than
can be replaced. He says if we don’t grapple with these important issues now, by the time
the human population reaches eight to ten billion or so people later this century, it might
be too difficult for us to do enough to save the planet’s life as we know it today.

For the Great Lakes Radio Consortium, I’m Daniel Grossman.