Desertification

Issue since the 70’sBasis of UN conference in 1977

(UNCOD)Aim to eradicate it by 2000!!Since viewed as one of most

pressing issues affecting human kind

Desertification

“Land degradation in arid, semi-arid and dry sub-humid areas, resulting

from various factors including climatic variability and human

activities”

UNEP 1992

Desertification

“An acute process that occurs at rates several orders of magnitude faster than purely climatically driven land

responses.”

Thornes, 1996

Land

“terrestrial bio-productive system that comprises the soil, vegetation, other biota and ecological and hydrological

processes that operate within the system”

Land Degradation

“reduction or loss of the biological or economic productivity caused by land use change, from a physical process, or a combination of the

two”

Problems

Adopting a definitionTaken 20 yearsHuman influenceConditionsCauseProcesses

Causes

Triggered by changes in climate and socio-economic boundary conditions of dryland systems

Enters +ve feedback of over exploitation of the land

Results in land degradation and disruption of local economies

Dryland characteristics

High incident radiationhigh seasonal temperature variationslow humiditystrong windsintense and sporadic rainfalli.e. a delicate hydrological balance

Triggers

Overgrazingdeforestationprecarious agricultureuncertain rainfallriver floodingdepletion of surface waterdepletion of ground water

That is:

Anything that unbalances dryland systems

In the long termIncludes expansion of settlement at

the cost of cultivatable land

Extent

Determined by: rainfall patterns soil morphology soil pedology vegetation land use

Water

A main limiting factor re production and settlement

A fundamental cause of Desn

Areas have potential for water development

lack integrated water management policy

Areas of research

Assess the nature and extent of the problem

Identify physical processesIdentify remedial actionsInvestigate the reln to other

environmental problemsThe human dimension

The Human Dimension

Scientists seen in a -ve light because of:

1) Speed of research relative to societal problems

2) Nature of scientific findings3) Manner in which scientific research

develops

Science and Society

No instant solutionsTime periodsReln between drought and

desertification

Nature of findings

Desn complex and multifacetedDiversity of drylandsSolutions non transferableScientists viewed as not doing

anything

Nature of Research

Findings not definite and finaliterative developmentnew sources of data, new

technology, more research results in paradigm shift

Scientist’s Role

Establish and retain clarityMonitoringUnderstand scalesSystem recovery

Solutions

Need involvement of everybody farmers, pastoralists, national resource

users, international, governments etcTraditional science not producing

resultsNeed community action and

indigenous knowledge

Namibia

824 000 km2

Driest country of Sahel34% arid, 58% semi-arid, 8% sub-

humid1.6 million popn

No perennial rivers47% land owned by white, commercial

farmers48% communal farmers, 90% of popn

SDP - Summer Desertification Programme use of natural resources, changes,

solutionsCBNRM - Sustainable Animal and

Range Development Programme livestock and communal farming

NAPCOD - Namibian Programme to Combat Desertification Ministries, NGO, community workshops

All fairly successfulAll had community participation and

local knowledgeConstrained at national levelNeed overall planning. Policy and

legislative framework

Europe

Tertiary - climate transition to summer drought

Evolved under stress of changing geological and climatic conditions

Holocene - consolidated dry periodsN-S aridity gradient getting steeper

last 5000 years