Geology Reference
In-Depth Information
tually Gaia would probably settle into a new hot state, bearable for her, but immensely
dangerous and uncomfortable for us.
Perhaps we can at least be mildly grateful that another potential negative feedback
has recently come to light. In a warming world, hurricanes could become far more
powerful and destructive than ever before, as Katrina so grimly demonstrated. But
strangely enough, the new super-hurricanes could set off a negative feedback that could
take some of the heat out of climate change. Scientists analysing images from the
SeaStar satellite watched in amazement as each of thirteen hurricanes crossing the At-
lantic from 1998 to 2001 stirred up nutrients from the sediments below that fed phyto-
plankton blooms on the ocean surface for up to three weeks after each hurricane had
passed. By removing carbon dioxide from the air and seeding clouds the phytoplankton
blooms must have cooled the Earth, but as yet no one knows by how much. Unlike glob-
al dimming, here is a negative feedback with no strings attached, but, even if it turns out
to be important, we still have no excuse for destroying Gaia's wild places or for extract-
ing ever-increasing amounts of minerals from her already ravaged crust.
There is a remarkably solid consensus amongst climate scientists about the very real
dangers of climate change. But it would be unfair to end this rapid overview without
mentioning the criticisms of the small band of climate sceptics who have argued that the
observed warming is due to natural variability in the activities of the sun and volcanic
emissions. It is true that these important effects account for about 40% of the observed
variation, but we now know that they have helped to cool rather than warm the planet
during the last quarter century, and are unable to account for the 0.6°C warming trend
of the last 30 years. So the sceptics have been forced to accept that warming is happen-
ing, even though most are paid, in one way or another, by the oil industry, including
ExxonMobil, a major funder. The sceptics have shifted their ground from denial to ar-
guing for the lower end predictions of the IPCC, which more or less favour business
as usual. One key sceptic, the infamous Bjorn Lomborg, rightly points out that combat-
ing climate change will cost trillions of dollars, but he suggests that this huge sum of
money would be better spent on dealing with AIDS and on bringing water and sanit-
ation to the poor of the global South rather than on climate change, which to him is a
minor problem. But according to Stephen Schneider, one of the world's leading climate
scientists, the trillions of dollars required to tackle climate change now don't add up to
much in relation to the amount of wealth generated by a growing global economy, nor
to the much higher costs of dealing with the consequences in the future. He points out
that acting now to avert climate change would have no significant negative effect on our
future wealth.
Perhaps the sceptics should consider what happened during the Eocene period some
55 million years ago, when the Earth warmed by 5°C in the tropics and 8°C in the tem-
