The Threat to The Planet: Our Precarious State

Some time ago I managed to find myself on the general mailing list of Dr James Hansen and nobody calls him--Jim is top scientist at NASA's Goddard Space Institute. I`m quite happy to be on this list as I receive regular updates on Jim's work, amazing how he manages to write so many articles and do his scientific work. I think we should all thank him for this; taking the science to the people is a difficult but important taks in today's world. As Carl Sagan said, science is as a candle in the dark, and if we ever needed a guiding light it is now!

The Threat to The Planet

A review of our situation through 3 recent books; The Weather Makers, Field Notes From Catastrophe and An Inconvenient Truth.

The first thing to say is that this 4 page review for "The New York Review" is available to download here and is well worth the time.

1. Species extinction and the extreme nature of anthropogenic climate change.

"If we continue along this path a large fraction of specieson earth, as many
as 50% or more , may become extinct"

2. Sea level rise and its potential effects.

Business as usuall scenarios lead to predictions of more than 5 degrees of warming; last time temperature where this warm was 3 million years ago and sea levels where eighty feet higher!

"The earths history reveals cases in which sea levels, once ice sheets begin to
collapse , rose one meter every twenty years for centuries"

"The area if greenland in which summer melting takes place has increased more
than 50% in the last twenty-five years."

3. The moral obligation upon the US to act.


4. The opportunities that this offers and the rate of progress that is possible purely on current technologies.

"The US is still only half as efficient in its energy usage as Western-Europe i.e the US emmits twice as much per unit GNP"

5. The importance of car efficiencies and powerplants having carbon capture and storage compatibility.

"The Californian legislature has passed a regulation requiring a 30% reduction in automobile greenhouse gas emmissions by 2016. If addopted nationwide this regulation would save more than 150 billon dollars in oil imports"

6. The threat of positive feedbacks or vicious cycles that threan to increase the rate of climate change.


7. The continuing poor state of the media and the perpetual search for balance. We need someone to say the earth is flat for everyone who says it is round.


8. Possible policies to address climate change.


9. The impact of 'An Inconveneint Truth' a modern day 'Silent Spring' ?

"Al Gore may have done for global warming what Silent Spring did for pesticides.
He will be attacked, but the public will have the information needed to
distinguish our long term needs from short-term special interests"

Some significant points:

It had previously been my belief that species extinctions would largely be due to barriers to 'migration' such as mountain ranges, oceans, cities etc. It turns out that a far more fundamental cause of extinction may begin to kick in soon, particularly under business as usual scenarios.

"Studies of more than a thousand species if plants, animals and
insects...found an average migration rate...[poleward] of 4 miles per
decade fro the second half of the twentieth century"

This doesn't seem to disastrous--the wildlife is following the thermal regime. But:

"During the past thirty years isotherms have been moving poleward at the rate of about 35 miles per decade"

This mismatch doesn't effect extinction rates whilst the distance that isotherms have moved is relatively small in comparison to the range of various habitats but as climate change accelerates and continues over time there will be huge numbers of extinctions simply because species cant relocate rapidly enough.

"If human beings follow a Business-as-usual course...the eventual effects of climate change may be comparable to those at the time of mass extinctions [such as at the CT boundary when the dinosaurs died out]."

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