Paying the price
Those who speak loudest in this world, notably the politicians who have a falsely high opinion
of their importance to the welfare of society, are in the habit of taking a blinkered and short-term
view of the physical world in which they, and we, have to live. Climate is one factor that is
largely ignored on the assumption, perhaps, that there is little or nothing humans can do about
it.
The attitude of governments to climate change has never been attentive, unless a major change,
temporary but real enough, produces a severe drought or a severe flood problem. Yet, as a review
by scientists from a number of universities published in Science for 28 March indicates,
there is such a thing as abrupt climate change that could have drastic effects on human affairs,
and calls for urgent consideration. Policy-makers, claim the authors, should consider expanding
research into abrupt changes, improve the systems available for monitoring them and take actions
designed to enhance the response of ecosystems and economies.
For example, in the 20th century warming in many northern regions occurred in two abrupt steps,
that suggests the juxtapositioning of natural causes and human-induced changes. The temperature
on the Atlantic side of the Arctic in the 1920s rose by 4C or more in places, and during the
following decade the United States suffered extended drought, with a serious effect on agriculture.
An abrupt shift in climate in the Pacific region in 1976–77 triggered oceanic and coastal temperature
changes in the Americas. Low-salinity deep waters affected the seas between Greenland and Europe.
Centuries before, the effects of drought caused the collapse of the Mayan civilisation and the
Akkadian empire. It is considered that human activity may be the impetus that upsets climatic
equilibrium and so produces an abrupt change in climate.
Loss of vegetation by over-exploitation of natural resources reduces the ability of roots to
capture water, and promotes run-off of surface water to streams and oceans; this may produce
a desert. Although most ecological and economic systems are able to adapt to a gradual change,
abrupt changes may cause permanent damage, particularly in systems with a long lifetime or some
immobility. Human activity is liable to prove the last straw in disturbing an equilibrium. For
example, over 10,000 years ago, many large North American mammals, which had been able to survive
previous climate variations during their history, being stressed by yet another abrupt change,
succumbed to the pressure of being hunted relentlessly. The habitat fragmentation induced by
human expansion impeded migration and increased the vulnerability of some ecological systems
previously in equilibrium. If human activities are driving a climatic system towards a threshold
point where disequilibrium occurs, the next century will see abrupt climate change calling for
drastic action.
Effective strategies can be devised to counteract such effects. For instance, in the so-called
Little Ice Age the Viking settlements in Greenland became extinct, while the neighbouring Inuit
culture survived, thanks to a successful strategy.
As the authors of the report comment: "Any future abrupt climate change might have large and
unanticipated impacts. Improved understanding of the processes may increase the lead time for
mitigation and adaptation." Whether our industrialists and economists will try to understand
the situation our children have to face, if we continue to use natural resources at the same
rate as now, is questionable.
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Justus von Liebig was born 200 years ago, on 12 May 1803, in Darmstadt, Germany. He became
engrossed with chemistry at an early age, to the dismay of his teachers, who considered that
he was neglecting his other studies in order to concentrate his attention on his pet subject.
At the age of 15 he was apprenticed to a pharmacist, but soon abandoned that career. His early
studies were at Bonn and Erlangen. Then in 1822 he went to Paris to join the laboratory of Joseph
Gay-Lussac, where he worked on mercury and silver fulminates and a range of cyanates.
