Vol 4 N° 4 [October–December 2006]



p 2 - The future of drylands revisited

p 9 - Nigerian President pledges US$5 billion towards National Science Foundation
p 9 - UNESCO and the BBC bring science to the screen
p 10 - A regional biotechnology centre for India
p 11 - Experts appeal for greater sup-port for sea-level rise research
p 11- National tsunami preparations an absolute priority

p 12 - Badaoui Rouhban on making schools safe in a disaster

p 15 - The very real success of the Avicenna Virtual Campus
p 19 - Students choose life in Kenya

p 24 - Diary
p 24 - New releases

Quick link to Vol. 4 n° 4 (PDF document);
See also ARCHIVES for A World of Science



Greening the deserts

In the 1950s, a sense of great optimism prevailed that we could green the world's deserts. It was believed that techniques like cloud seeding could bring rainfall to dry areas; improved irrigation techniques could boost agricultural production in dry-lands; and selective breeding could create livestock less dependent on water. In short, we thought that poverty in the world's drylands could be reduced through technology. Half a century later, that optimism has been replaced by realism and anxiety. The belief that we can control our climate has given way to concerns about the human impact on the environment, in particular global warming. Current climate scenarios predict that the driest regions of the world will become even drier.

Only last May, a study published in Science indicated that the tropical climate zone was expanding towards both poles. According to the study, which is based on satellite data from 1979 to 2005, the northern and southern hemispheres’ jet streams – fast-flowing winds about 10 km above the Earth’s surface which mark the limits of the tropics – have each moved about 1° of latitude (about 113 km) nearer the poles. ‘If the jet streams move another 2–3° degrees poleward this century, very dry areas like the Sahara Desert could nudge farther towards the poles, perhaps by a few hundred miles,’ predicts co-author John Wallace of the University of Washington (USA).

Despite technological advances in the genetic modification of organisms to make them drought- and pest-resistant, dryland countries are still among the poorest in the world; many also register high population growth.

As we shall see in this issue, the past 50 years have shown us that the ecological and socio-economic situation in drylands is not a simple equation governed by factors such as climate, soil, water and vegetation. Market speculation and enormous price fluctuations on commodities like cotton can affect the income of a rural farmer in a remote village in Mali, in the same way that droughts or floods will affect his or her harvest.

Policy choices also enter into play. Nearly one-fifth of China is desertic. Last February, the government announced an ambitious plan to reclaim 250 000 km2 of desert by 2020 by planting trees and grasses, banning land use in some areas and investing in sustainable energy and efficient water use.

One thing we have learnt over the past 50 years is that, if drylands do not cover the globe, they are nevertheless a global problem. To cite the authors of The Future of Drylands Revisited, ‘dust from central Asia causes health concerns not only in China and Japan but also in North America [and] dust from Africa may be contributing to the decline of coral reefs in the Caribbean.’

W. Erdelen
Assistant Director-General for Natural Sciences

Back to top