Passages

 LONG-TERM FORECAST: HOT AND DRY! 

A.

Melting land ice in the Arctic is set to cause a global rise in sea levels, leading to

disastrous effects for both man and wildlife. Many species worldwide are threatened

with extinction, and low-lying islands and landmasses will disappear entirely. But the

havoc wreaked by the effect of greenhouse gases won’t be confined to just too much

water, but the absence of it, as well. In other words, desertification. A decrease in the

total amount of rainfall in arid and semi-arid areas could increase the total area of

drylands worldwide, and thus the total amount of land potentially at risk from

desertification.

B.

Desertification is officially recognised as land degradation in arid, semi-arid and dry

sub-humid areas resulting from various factors including climatic variations and human

activities. This degradation of formerly productive land is a complex process. It involves

multiple causes, and it proceeds at varying rates in different climates. Desertification

may intensify a general climatic trend, or initiate a change in local climate, both leading

towards greater aridity. The more arid conditions associated with desertification

accelerate the depletion of vegetation and soils. Land degradation occurs all over the

world, but it is only referred to as desertification when it takes place in drylands. This is

because these areas are especially prone to more permanent damage as different

areas of degraded land spread and merge together to form desert-like conditions.

Global warming brought about by increasing greenhouse gas levels in the atmosphere

is expected to increase the variability of weather conditions and extreme events. Many

dryland areas face increasingly low and erratic rainfalls, coupled with soil erosion by

wind and the drying-up of water resources through increased regional temperatures.

Deforestation can also reduce rainfall in certain areas, increasing the threat of

desertification. It is not yet possible, despite sophisticated technology, to identify with

an acceptable degree of reliability those parts of the Earth where desertification will

occur. Existing drylands, which cover over 40% of the total land area of the world, most

significantly in Africa and Asia, will probably be most at risk from climate change. These

areas already experience low rainfall, and any that falls is usually in the form of short,

erratic, high-intensity storms. In addition, such areas also suffer from land degradation

due to over-cultivation, overgrazing, deforestation and poor irrigation practices.

D.

It is a misconception that droughts cause desertification. Droughts are common in arid

and semi-arid lands. Well-managed lands can recover from drought when the rains

return. Continued land abuse during droughts, however, increases land degradation.

Nor does desertification occur in linear, easily definable patterns. Deserts advance

erratically, forming patches on their borders. Areas far from natural deserts can

degrade quickly to barren soil, rock, or sand through poor land management. The

presence of a nearby desert has no direct relationship to desertification. Unfortunately,

an area undergoing desertification is brought to public attention only after the process

is well underway. Often little or no data are available to indicate the previous state of

the ecosystem or the rate of degradation. Scientists still question whether

desertification, as a process of global change, is permanent or how and when it can be

halted or reversed.

E.

But desertification will not be limited to the drylands of Africa and Asia. According to the

environmental organisation Greenpeace, the Mediterranean will suffer substantially,

too. If current trends in emissions of greenhouse gases continue, global temperatures

are expected to rise faster over the next century than over any time during the last

10,000 years. Significant uncertainties surround predictions of regional climate

changes, but it is likely that the Mediterranean region will also warm significantly,

increasing the frequency and severity of droughts across the region. As the world

warms, global sea levels will rise as oceans expand and glaciers melt. Around much of

the Mediterranean basin, sea levels could rise by close to 1m by 2100. As a result,

some low-lying coastal areas would be lost through flooding or erosion, while rivers and

coastal aquifers would become saltier. The worst affected areas will be the Nile Delta,

Venice in Italy and Thessaloniki in Greece, two major cities where local subsidence

means that sea levels could rise by at least one-and-a-half times as much as

elsewhere.

F.

The consequences of all this say Greenpeace, are far-reaching, and the picture is a

gloomy one. Livestock production would suffer due to a deterioration in the quality of

rangeland. Yields of grains and other crops could decrease substantially across the

Mediterranean region due to increased frequency of drought. Crop production would be

further threatened by increases in competition for water and the prevalence of pests

and diseases and land loss through desertification and sea-level rise. The combination

of heat and pollution would lead to an upsurge in respiratory illness among urban

populations, while extreme weather events could increase death and injury rates.

Water shortages and damaged infrastructure would increase the risk of cholera and

dysentery, while higher temperatures would increase the incidence of infectious

diseases, such as malaria and dengue fever. Serious social disruption could occur as

millions are forced from their homelands as a result of desertification, poor harvests

and sea-level rise, while international disputes over shared water resources could turn

into conflict.

G.

Future climate change could critically undermine efforts for sustainable development in

the Mediterranean region through its impacts on the environment and social and

economic well-being. While in many respects climate change exacerbates existing

problems instead of creating new ones, the sheer magnitude of the potential problem

means it cannot be ignored. There is some scope for adaptation, but the fact that many

measures would be beneficial irrespective of climate change suggests that radical

changes in our policies and practices will be needed. It is also vital that developed

countries meet their obligations to assist adaptation in developing countries through

access to know-how and financial assistance. Ultimately, however, the long-term

sustainability of the Mediterranean region requires keeping climate change within

tolerable bounds. Current understanding of safe limits points to the need for prompt

international agreement – and action – to make the drastic cuts in emissions of

greenhouse gases required to stabilize atmospheric concentrations of these gases.