Tropical climates - The Global Climate System: Patterns, Processes, and Teleconnections - page 75

of media. The relative roles of climate variability and human impacts on the
environment in this type of setting led to many articles and professional papers.
It is an argument still not totally resolved and the United Nations recognizes both
in its definition of desertification. The definition adopted by the 1992 United
Nations Conference on Environment and Development states that desertification
is land degradation in arid, semiarid and dry subhumid areas resulting from
various factors including climate variations and human activities. The essay by
Michael Glantz (Section 1.3 ) provides a lucid analysis of the roles of climate and
human activities in such events. Although desertification occurs outside of the
tropics, it is certainly of enormous concern within the tropical realm.
At the Earth Summit (the UN Conference on Environment and Development,
or UNCED) in Rio de Janeiro in 1992, delegates called on the UN General
Assembly to establish an Intergovernmental Negotiating Committee to prepare,
by June 1994, a convention to combat desertification, particularly in Africa. In
December 1992, the General Assembly agreed and adopted the resolution. This
led to the formation of the United Nations Convention to Combat Desertification
(UNCCD) in 1996.
The Conference of Parties, the Convention's supreme governing body, held its
first session in October 1997 in Rome, Italy, when the UNCCD stated, ''The
Convention aims to promote effective action through innovative local programs
and supportive international partnerships. The treaty acknowledges that the
struggle to protect drylands will be a long one - there will be no quick fix.
This is because the causes of desertification are many and complex, ranging
from international trade patterns to unsustainable land management practices.
Real and difficult changes will have to be made, both at the international and the
local levels.'' (www.unccd.int)
It is evident that there is no ''quick fix'', for in a UN publication (The UNCCD
After 10 Years) Kofi Annan, the UN Secretary-General, writes ''Current esti-
mates are that the livelihoods of more than one billion people are at risk from
desertification, and that, as a consequence, 135 million people may be in danger
of being driven from their land ...Indeed, recognizing the urgent need to address
the far-reaching implications of this problem, the UN General Assembly has
declared 2006 the International Year of Deserts and Desertification.'' For
some countries, such as the People's Republic of China, it drew the attention
of national policy makers toward arid lands research and helped to elevate such
research to a sustained national priority.
There is no agreement on where desertification can take place. Many
researchers identify arid, semiarid, and sometimes subhumid regions as the
areas in which desertification can occur or where the risks of desertification
are highest. Others assert that desertification can only occur along the desert
fringes. Following Le Hou´rou ( 1975 ), some researchers suggest that desertifi-
cation can occur only in the 50-300 mm isohyet zone. This interesting statement
suggests that the role of climate is of high significance.