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Complete video at:
http://fora.tv/fora/showthread.php?t=584
Celebrated mathematical physicist John Baez
looks at global warming from an historical
perspective, and details the widespread
ecological damage that may result from rapid
climate change.
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John Baez - "Zooming Out in Time"
The graphs we see these days, John Baez
began, all look vertical--- carbon burning
shooting up, CO2 in the air shooting up,
global temperature shooting up, and
population still shooting up. How can we
understand what really going on? "It's like
trying to understand geology while you're
hanging by your fingernails on a cliff,
scared to death. You think all geology is
vertical."
So, zoom out for some perspective. An Earth
temperature graph for the last 18,000 years
shows that we've built a false sense of
security from 10,000 years of unusually
stable climate. Even so, a "little dent" in
the graph of a drop of only 1 degree Celsius
put Europe in a what's called "the little ice
age" from 1555 to 1850. It ended just when
industrial activity took off, which raises
the question whether it was us that ended it.
Zoom out further still to the last 65 million
years. The temperature graph show several
major features. One is the rapid (every
100,000 years) wide swings of major ice ages.
When they began, 1.35 million years ago, is
when humans mastered fire. But almost all of
the period was much warmer than now, with
ferns growing in Antarctica. "Now it's cold.
What's wrong with a little warming?" Baez
asked.
The problem is that the current warming is
happening too fast.
Studies of 1,500 species in Europe show that
their ranges are moving north at 6 kilometers
a decade, but the climate zones are moving
north at 40 kilometers a decade, faster than
they can keep up. The global temperature is
now the hottest it's been in 120,000 years.
One degree Celsius more and it will be the
hottest since 1.35 million years ago, before
the ice ages. Baez suggested that the
Anthropocene may be characterized mainly by
species such as cockroaches and
raccoons who accommodate well to humans.
Coyotes are now turning up in Manhattan and
Los Angeles. There are expectations that we
could lose one-third of all species by
mid-century, from climate change and other
human causes.
Okay, to think about major extinctions, zoom
out again. Over the last 550 million years
there have been over a dozen mass
extinctions, the worst being the
Permian-Triassic extinction 250 million years
ago, when over half of all life disappeared.
The cause is still uncertain, but one
candidate is the methane clathrates ("methane
ice") on the ocean floor. Since methane is a
far worse greenhouse gas than carbon dioxide,
massive "burps" of the gas could have led to
sudden drastic global heating and thus the
huge die-off of species. Naturally the
methane clathrates are being studied as an
industrial fuel for when the oil runs out in
this century, "which could make our effect on
global warming 10,000 times worse," Baez
noted.
"Zooming out in time is how I calm myself
down after reading the newspapers," Baez
concluded. "A mass extinction is a sad thing,
but life does bounce back, and it gets more
interesting each time. We probably won't kill
off all life on Earth. But even if we do,
there are a hundred billion stars in our
galaxy, and ten billion galaxies in the
observable universe."
--Stewart Brand, The Long Now Foundation
Tags : ecology ice age history co2 emissions environment greenhouse environmental gases graphs charts climate fora tv fora.tv |
