Geography and population
The الجماهيرية العربية الليبيةn Arab Jamahiriya has a total
area of about 1.76 million km². It is bordered in the east by مصر and Sudan,
on the south by Chad and Niger, in the west by الجزائر and Tunisia, and in
the north by the Mediterranean Sea. Four physiographic regions can be distinguished:
the Coastal Plains, that run along
the الجماهيرية العربية الليبيةn coast and vary in width;
the Northern Mountains, that run
close to the coastal plains and include the Jabal Nafusah in the west and
the Jabal al Akhdar in the east;
the Internal Depressions, that cover
the centre of الجماهيرية العربية الليبية and include several oases.
the Southern and Western Mountains.
About 95 % of the country is desert.
The cultivable area was estimated at 3.80 million ha, which is only slightly
over 2 % of the total area. In 1987, the total cultivated area was estimated
at 2.28 million ha, or 60 % of the cultivable area, of which 1.93 million
ha consisted of annual crops and 0.35 million ha consisted of permanent crops.
The total population is about 5.4 million
(1995) of which 14 % is rural. The annual demographic growth rate was 4. 1%
between 1980-91. The average population density is 3 inhabitants/km², but
varies between 50 inhabitants/km³ in the northern regions of Tripolitania
and Cyrenaica to less than 1 inhabitant/km³ elsewhere. Agriculture contributes
less than 5% to GDP, although it provides employment for approximately 13
% of the active population.
Climate and water resources
The climatic conditions are influenced
by the Mediterranean sea to the north and the Sahara desert to the south,
resulting in an abrupt transition from one kind of weather to another. The
following broad climatic divisions can be made:
the Mediterranean coastal strip with dry summers and relatively
the Jabal Natusah and Jabal Akhdar highlands experiencing a plateau
climate with higher rainfall and humidity and low winter temperatures, including
snow on the hills;
moving southwards to the interior, pre-desert and desert climatic
conditions prevail, with torrid temperatures and large daily thermal amplitudes.
Rain is rare and irregular and diminishes progressively towards zero.
The average annual rainfall is 26 mm,
with more than 100 mm/year over only 7% of the land surface. The highest rainfall
occurs in the northern Tripoli region (Jabal Nafusah and Jifarah Plain) and
in the northern Benghazi region (Jabal al Akhdar) - these two areas being
the only ones where the average annual rainfall exceeds the minimum value
(250-300 mm) considered necessary to sustain rainfed agriculture. Rainfall
occurs during the winter months, but great variability is observed over space
and time (year to year).
The total mean annual runoff calculated
or measured at the entrance of the wadis in the plains is estimated at 200
million m³/year, but part of it either evaporates or contributes to the recharge
of the aquifers. Therefore the surface water resources are roughly estimated
at 100 million m³/year. Sixteen dams, with a total storage capacity of 387
million m³ and with an expected average annual volume of water controlled
in the order of 60 million m³, had been constructed by 1991. Additional dams
are planned, to achieve a total storage capacity of 686 million m³. This difference
between the average annual runoff and the storage capacity of the dams is
so that the runoff water of exceptionally wet years can be stored.
Currently, aquifers are only recharged
only in the northern regions, namely in the northwestern zone, Jabal Nafusah
and Jifarah Plain, and in the north-eastern zone, Jabal al Akhdar. Renewable
groundwater resources are estimated at 800 to 1 000 million m³/year, but part
(perhaps 50%) now flows out either to the sea or to evaporative areas (sabkhas).
Not all the renewable groundwater can be abstracted without affecting the
environment, because of the deterioration of water quality by saline water
encroachment. For this reason, the safe yield has been estimated at 500 million
m³/year. South of the 29th parallel, an important development of Palaeozoic
and Mesozoic continental sandstone enabled water to be stored safely during
the long period of the late Quaternary, before the climate turned extremely
arid. Most water used in الجماهيرية العربية الليبية comes from these huge fossil reserves.
Through the Great Manmade River Project
about 2 km³/year of fossil water is expected to be transported from the desert
to the coastal areas, mainly for irrigation but part will be used for the
water supply of the major cities.
The map below shows the ecological zones, as shown on the
FAO global map of ecological zones produced as part of the FRA 2000. Please refer
to FRA Working Paper 20 for
further information on the Global Ecological Zone map.