Geology Reference
In-Depth Information
who have the ultimate say about which scientific results appear in the IPCC reports,
which makes its predictions somewhat conservative due to the influence of countries de-
termined to downplay the seriousness of global warming. There are also good scientif-
ic reasons for regarding the IPCC predictions as underestimates. Most of its models do
not incorporate the impacts on climate of living beings such as marine algae and land
vegetation that absorb carbon dioxide from the atmosphere and produce planet cooling
clouds. The loss of these beings in a warming world triggers powerful positive feed-
backs in the direction of further warming, which the IPCC has largely ignored. Nor has
the IPPC considered longer term positive feedbacks on warming from changes to ice
sheet area and sea level rise. All of the above by no means invalidates the work of the
IPPC, but we would be well advised to take its worst-case scenario as the most likely
best case.
Recent observations of the real earth lend support these perceptions of the IPPC pre-
dictions. In 2007, a brief but influential paper published in
Science
showed that observed
sea level rise was 100% greater than predicted by the IPCC for that same year. This res-
ult is important not just because of the catastrophic impacts of sea level rise, but because
(as James Lovelock has pointed out in his latest book) sea level is an excellent measure
of the amount of heat absorbed by the earth—far better than the more usual measure
of globally averaged surface temperature. Sea level responds to global warming in two
ways: through the thermal expansion of the oceans and through the melting of the land-
bound ice in glaciers and ice sheets. The fact that sea level has risen so dramatically
and so far above the IPCC predictions confirms that the earth is warming dangerously,
and suggests that action based at avoiding even the worst-case IPCC scenario will not
help us to avoid severe climate change. The sceptics, of course, suggest that there is
no warming at all. But even the most reasonable of them, such as Nigel Lawson, base
their arguments on global average surface temperature, which is not the best indicator
of warming since runs of relatively cold years (such as 2007 and 2008 in the UK) easily
distract us from the relentless long-term upward temperature trend. Sea level rise is far
more reliable and far less variable.
Additional cause for concern comes through climate models either not considered by
the IPCC, or watered down by the main mass of its more moderate models. In 2006 re-
searchers based at Oxford University harnessed the spare processing capacity of com-
puters owned by members of the general public in order to carry out many more cli-
mate simulations than were considered by the IPCC in its previous report published in
2001—the TAR (Third Assessment Report). The most likely temperature increase for
a doubling of carbon dioxide that came out of these additional simulations was around
3.4°C, somewhat similar to the IPCC predictions, but the shock came when researchers
found a much wider range of outcomes than did the IPCC, with a small number of out-
