Climate Change in Libya and Desertification of Jifara Plain
Using Geographical Information System and Remote Sensing Techniques
Dissertation
zur Erlangung des Grades
Doktor der Naturwissenschaften
am Fachbereich Chemie, Pharmazie, Geowissenschaften
der Johannes Gutenberg-Universität
in Mainz
vorgelegt von
عطية محمود محمد طنطاوي
Attia Mahmoud Mohamed El-Tantawi
Geboren am 13. September 1966 in El-Gharbia, Ägypten
Mainz 2005
Dedication
to
Prof. Dr. Dr. h. c. Manfred Domrös
Mrs. Gisela Domrös
as a token of admiration and respect
Summary
The study was arranged to manifest its objectives through preceding it with an introduction.
Particular attention was paid in the second part to detect the physical settings of
the study area, together with an attempt to show the climatic characteristics in Libya. In the
third part, observed temporal and spatial climate change in Libya was investigated through
the trends of temperature, precipitation, relative humidity and cloud amount over the periods
(1946-2000), (1946-1975), and (1976-2000), comparing the results with the global
scales. The forth part detected the natural and human causes of climate change concentrating
on the greenhouse effect. The potential impacts of climate change on Libya were examined
in the fifth chapter. As a case study, desertification of Jifara Plain was studied in
the sixth part. In the seventh chapter, projections and mitigations of climate change and
desertification were discussed. Ultimately, the main results and recommendations of the
study were summarized.
In order to carry through the objectives outlined above, the following methods and
approaches were used: a simple linear regression analysis was computed to detect the
trends of climatic parameters over time; a trend test based on a trend-to-noise-ratio was
applied for detecting linear or non-linear trends; the non-parametric Mann-Kendall test for
trend was used to reveal the behavior of the trends and their significance; PCA was applied
to construct the all-Libya climatic parameters trends; aridity index after Walter-Lieth was
shown for computing humid respectively arid months in Libya; correlation coefficient,
(after Pearson) for detecting the teleconnection between sun spot numbers, NAOI, SOI,
GHGs, and global warming, climate changes in Libya; aridity index, after De Martonne, to
elaborate the trends of aridity in Jifara Plain; Geographical Information System and Remote
Sensing techniques were applied to clarify the illustrations and to monitor desertification
of Jifara Plain using the available satellite images MSS, TM, ETM+ and Shuttle
Radar Topography Mission (SRTM). The results are explained by 88 tables, 96 figures and
10 photos.
Temporal and spatial temperature changes in Libya indicated remarkably different annual
and seasonal trends over the long observation period 1946-2000 and the short observation
periods 1946-1975 and 1976-2000. Trends of mean annual temperature were positive
at all study stations except at one from 1946-2000, negative trends prevailed at most
stations from 1946-1975, while strongly positive trends were computed at all study stations from 1976-2000 corresponding with the global warming trend. Positive trends of mean
minimum temperatures were observed at all reference stations from 1946-2000 and 1976-
2000, while negative trends prevailed at most stations over the period 1946-1975. For
mean maximum temperature, positive trends were shown from 1946-2000 and from 1976-
2000 at most stations, while most trends were negative from 1946-1975. Minimum temperatures
increased at nearly more than twice the rate of maximum temperatures at most
stations. In respect of seasonal temperature, warming mostly occurred in summer and autumn
in contrast to the global observations identifying warming mostly in winter and
spring in both study periods.
Precipitation across Libya is characterized by scanty and sporadically totals, as well as
high intensities and very high spatial and temporal variabilities. From 1946-2000, large
inter-annual and intra-annual variabilities were observed. Positive trends of annual precipitation
totals have been observed from 1946-2000, negative trends from 1976-2000 at most
stations. Variabilities of seasonal precipitation over Libya are more strikingly experienced
from 1976-2000 than from 1951-1975 indicating a growing magnitude of climate change
in more recent times.
Negative trends of mean annual relative humidity were computed at eight stations,
while positive trends prevailed at seven stations from 1946-2000. For the short observation
period 1976-2000, positive trends were computed at most stations. Annual cloud amount
totals decreased at most study stations in Libya over both long and short periods. Remarkably
large spatial variations of climate changes were observed from north to south
over Libya.
Causes of climate change were discussed showing high correlation between temperature
increasing over Libya and CO2 emissions; weakly positive correlation between precipitation
and North Atlantic Oscillation index; negative correlation between temperature
and sunspot numbers; negative correlation between precipitation over Libya and Southern
Oscillation Index. The years 1992 and 1993 were shown as the coldest in the 1990s resulting
from the eruption of Mount Pinatubo, 1991.
Libya is affected by climate change in many ways, in particular, crop production and
food security, water resources, human health, population settlement and biodiversity. But
the effects of climate change depend on its magnitude and the rate with which it occurs.
Jifara Plain, located in northwestern Libya, has been seriously exposed to desertification
as a result of climate change, landforms, overgrazing, over-cultivation and population
growth. Soils have been degraded, vegetation cover disappeared and the groundwater wells
were getting dry in many parts. The effect of desertification on Jifara Plain appears
through reducing soil fertility and crop productivity, leading to long-term declines in agricultural
yields, livestock yields, plant standing biomass, and plant biodiversity. Desertification
has also significant implications on livestock industry and the national economy.
Desertification accelerates migration from rural and nomadic areas to urban areas as the
land cannot support the original inhabitants.
In the absence of major shifts in policy, economic growth, energy prices, and consumer
trends, climate change in Libya and desertification of Jifara Plain are expected to
continue in the future.
Libya cooperated with United Nations and other international organizations. It has
signed and ratified a number of international and regional agreements which effectively
established a policy framework for actions to mitigate climate change and combat desertification.
Libya has implemented several laws and legislative acts, with a number of ancillary
and supplementary rules to regulate. Despite the current efforts and ongoing projects
being undertaken in Libya in the field of climate change and desertification, urgent actions
and projects are needed to mitigate climate change and combat desertification in the near
future.
8. Results and Recommendations
8.1 Results
The present study has revealed a number of results; the following are considered the main:
(1) Libya occupies a part of northern Africa between 20° to 34° N and 10° to 25° E.
(2) Libya’s total population was at 5.3 million in 2001 including more than 500,000 nonnationals,
almost 90 % of them living in the coastal region, and about 10 % live widely
scattered oases in mid- and southern Libya.
(3) Lands of Libya are generally divided into northern coastal plain and high lands, isolated
mountains and depressions in the south. Serir desert in the east, El-Hamada ElHamra
desert in the west are the most obvious geomorphological features in Libya.
(4) Climate of Libya is determined by contrasting Mediterranean and Sahara climates.
More than 95 % is desert. Mean annual temperatures decrease gradually northward, in
contrast to precipitation which decreases southward. Winter is the rainiest season 50-70
% followed by autumn and spring, while no or negligible precipitation occurs in summer.
Climatic regions in Libya are: Arid desert climate (BWh) in mid- and southern
Libya, Steppe climate (BSh) in northern Libya, and Mediterranean climate type (CSa)
in northeastern Libya on Jebal El-Akhdar.
(5) Groundwater is the main water resource in Libya ; it supplies about 88 % of the water
needs. The Great Man-Made River Project is a massive project with four-metersdiameter
pipes and a length of about 4000 km aiming to divert the groundwater from
the southern basins to the coastal areas where about 90 % of Libya’s population has
settled.
(6) Climate change is every deviation from the normal having significance according to
the actual use of statistical tests, while the term trend denotes climate change characterized
by a smooth, monotonic increase or decrease of average values over the period of
record.
(7) It is clearly identified that the 20th century was the warmest century during the past
1,000 years. Trend of the global mean annual temperature was 0.07 °C/decade. Warming
pronouncedly occurred over two periods, 1910-1945 (0.14 °C/decade) and 1976-
2000 (0.17 °C/decade). The bulk of global warming occurred in summer and autumn from 1910-1946, while winter and spring were the governing seasons of global warming
from 1976-2000. Minimum temperatures increased at nearly twice the rate of
maximum temperatures.
(8) Global land precipitation has increased by about 2 % since the beginning of the 20th
century. Though the increase is statistically significant, it is neither spatially nor temporally
uniform. It was relatively stable, or slightly increased from 1900 to the early
1940s, then increased sharply from the mid-1940s to the mid-1950s and has remained
relatively high over most of the land areas except the tropics, where precipitation decreased
to below the 1900–1988 average in the 1970s and 1980s.
(9) Trends of mean annual temperature over Libya were positive at all study stations from
1946-2000 except at one, negative trends prevailed at most stations from 1946-1975,
while strongly positive trends were computed at all study stations from 1976-2000
corresponding with the global warming trend. Positive trends of mean minimum temperatures
were observed at all reference stations over the periods 1946-2000 and 1976-
2000, while negative trends prevailed at most stations from 1946-1975. For mean
maximum temperature, positive trends were computed from 1946-2000 and from 1976-
2000 at most stations, while most trends were negative from 1946-1975. Minimum
temperatures increased at nearly more than twice the rate of maximum temperatures at
most study stations. Negative trends of mean temperature range were computed at most
stations over both periods 1946-2000 and 1976-2000.
(10) Positive trends of extreme minimum temperatures were deduced at all reference
stations from 1946-2000. In contrast, the trends of extreme maximum temperature were
negative or weakly positive at most stations in the same period. Trends of mean
extreme minimum temperature expressed a striking warming from 1976-2000 at all stations,
while positive trends of extreme maximum temperature prevailed at only eight
stations.
(11) For seasonal temperature trends over Libya, warming mostly occurred in summer and
autumn in contrast to the global observations identifying warming mostly in winter and
spring in both periods 1946-2000 and 1976-2000.
(12) The 1990s were the warmest decade over global and Libya, the 1998 was the warmest
year over global, while 1999 was the warmest yeas over Libya in the 20th century.
(13) Most study stations are located in northern Libya and little information was available
for southern parts which must be taken into account to investigate the spatial changes of
temperature over Libya. Remarkably large spatial variations of temperature changes
were observed from north to south over Libya.
(14) Positive trends of annual precipitation totals were observed from 1946-2000, while
negative trends were computed at most stations from 1976-2000. Positive trends of annual
precipitation intensity were elaborated in the long-observation period (1946-2000),
while negative trends prevailed in the short-observation period (1976-2000) at most stations.
Trends of winter and spring precipitation showed positive trends, while and
trends of autumn precipitation were negative at most stations from 1946-2000. Remarkably
large variations were seen among the different seasons over the period 1976
to 2000.
(15) Remarkable variations were observed in distribution of annual precipitation total
changes over Libya. From 1946-2000, precipitation increased over northern Libya,
while it decreased over southern Libya. From 1976-2000, the trends of annual precipitation
total were negative over most Libya indicating decreasing precipitation at most stations.
(16) Negative trends prevailed for mean annual relative humidity at eight stations, while
positive trends were shown at seven stations from 1946-2000. For the short observation
period 1976-2000, positive trends were computed at most stations.
(17) Annual cloud amount totals decreased at most study stations over both periods 1946-
2000 and 1976-2000.
(18) For all-Libya from 1951-2000, positive trends were identified for annual, minimum,
autumn, summer, winter, maximum, and spring temperatures, while negative trends of
extreme maximum temperature and mean annual temperature range were computed.
From 1951-1975, decreasing trends were identified for mean annual, summer, minimum,
autumn and maximum temperatures, while increasing trends were observed for
winter and spring temperatures. From 1976-2000, strongly positive trends were observed
for annual, minimum, summer and autumn temperatures, and positive trends
were computed for winter, maximum and spring temperatures.
(19) From 1951-2000, weakly positive trends of 0.03, 0.03, 0.06 and 0.07 mm/decade prevailed
for annual precipitation total over all-Libya, annual precipitation intensity, winter
precipitation and spring precipitation, respectively. No trend was seen for autumn precipitation.
Trend of annual precipitation over all-Libya was negative of -0.20
mm/decade. From 1976-2000, positive trend occur for winter precipitation at 0.17
mm/decade, while negative trends were computed for annual total, annual intensity,
spring and autumn precipitation.
(20) A positive trend was identified for the annual mean relative humidity over all-Libya
from 1951-2000, a positive trend was computed from 1976-2000, while a negative trend
was seen from 1951-1975.
(21) Annual cloud amount totals decreased over all-Libya in both periods 1951-2000 and
1976-2000.
(22) Natural climate forcing probably increased during the first half of the 20th century,
while since 1951, the changes observed are mostly due to human activities, and some
changes are also reflection are natural variability.
(23) Correlation coefficient was significantly positive (0.27) between global annual temperature
and sunspots number in the 20th century. The effect of sunspots number on
temperature change was higher over the first half of the 20th century (1901-1950) than
over the second one (1951-2000).
(24) There was no correlation between sunspots number and mean annual temperatures
over Libya during the study period 1946-2000.
(25) The Pinatubo eruption was primarily responsible for the 0.8 °C drop in global average
air temperature in 1992. Mean annual temperature in Libya is affected by the eruption
of Mount Pinatubo (15°N-121°E) on 12 June 1991, the years 1992 and 1993 were the
coldest in the 1990s.
(26) High variability of precipitation can partly be explained by changes in atmospheric
circulation, which in turn alter the storm tracks and precipitation distribution.
(27) Correlation coefficient between North Atlantic Oscillation and global mean annual
temperature was weakly positive (0.12) over the 20th century.
(28) Reversed relationship was seen between NAO index and temperatures in Libya.
(29) The relationship between NAO index and annual precipitation totals in Libya are positive
in winter. The effect of NAO decreases eastward.
(30) El-Nino phenomenon is now widely recognized as the recurring cause of major natural
perturbations to the climate system.
(31) There was no correlation between Southern Oscillation Index (SOI) and climate
change over Libya (temperature and precipitation).
(32) Anthropogenic causes of climate change have increased significantly from the 19th
century and have largely increased over the 20th century.
(33) A strong relationship between CO2 concentrations and global warming was observed
in the 20th century, correlation coefficient was significantly positive at 0.78. Correlation
coefficient between methane and global mean annual temperature from 1901-1994 was
positive and significant (0.75).
(34) Total concentration of CO2 has increased in Libya from 1950-2000. The largest contributor
to CO2 emissions is fossil fuel consumption. Correlation coefficient between
CO2 and temperature trends in Libya was significantly positive.
(35) Patterns of landuse and urban heat islands can play a small role of climate change in
settlement centers located in northern Libya.
(36) Libya is vulnerable to climate change because of prevailing arid and semi-arid climates,
recurrent droughts, and inequitable land distribution. High precipitation variabilities
and intensities may cause severe moisture stress on cultivated crops.
(37) Increasing temperature derives also soil erosion and wind speed, which in turn increase
amount of Saharan dust causing health and economic problems. Gibli wind has
drastically effects on Libya.
(38) Crop productions and food security, water resources, human health, population settlement
and biodiversity can be affected by climate change over Libya. But the effects
depend on its magnitude and the rate with which climate change occurs.
(39) As high precipitation variabilities, wheat and barely crops in Libya experience to
greatly changes from year to year in their productions and harvest areas.
(40) Climate change may increase the vulnerability of livestock due to shortage of water
resources, increased salinity, and loss of grazing sites
(41) Changing temperature and precipitation regimes cause change in the water budget. As
a result, irrigation and flood control system, water storage, and hydroelectric installations
as well as for a production systems are seriously affected.
(42) Sandstorms over northwestern Libya dating 29.03.2002 for 12 hours with a speed of
70 km/hour affected human health through charging the air with 387 microgram/m
3
pollutions,
the safe level according to WHO is 120 micrigram/m
3
/day.
(43) In Libya, population and urbanization increased sharply in the second have of the 20th
century, it generated impacts on natural resources and the environment (water resources
and soils) which are very vulnerable to climate change.
(44) Loss of biodiversity is a consequence of climate change at the local and global level,
recurrent drought might decrease the ability of trees to resist pests, several kinds of
animals and plants disappeared.
(45) Among the important consequences resulting from climate change in arid and semiarid
lands, ranks desertification which is diminution or destruction of the biological potential
of land, and can lead ultimately to desert-like conditions.
(46)Jifara Plain, located in northwestern Libya, has experienced to desertification, soil was
degraded, vegetation cover disappeared and groundwater wells were getting dry in
many areas.
(47) Soil degradation is the main aspect of desertification in Jifara Plain; the most dominant
soil-degradation process is wind and water erosion.
(48) Vegetation destruction takes place in Jifara Plain through overgrazing and overcultivation,
both activities being driven by the needs of growing population.
(49) The scarcity of water was aggravated by water level declines and deterioration of water
quality. Water level declined over 1 m/year in some parts and total dissolved solids
increased exceeding 9,000 mg/liter in the last four decades in Jifara Plain. Water deficit
in Jifara Plain was six times from groundwater safe use.
(50) In northwestern Libya, 33,500 ha have been affected by sand dunes movements. In
northern Jifara Plain (758,026.2 ha), the area which covered by sands has increased
from 430,154.6 ha in 1989 to 450,636.3 ha in 2001.
(51) Over 25 % of highly fertile lands have been consumed by the expansion of urban areas
in Libya. The belt-up area of Tripoli increased from 8,011.4 ha in 1966 to 19,236 ha
in 2000.
(52) Desertification of Jifara Plain was caused by: climate change which can accelerate
desertification process through precipitation patterns and Gibli wind; landforms in Jifara
Plain accelerate soil erosion followed by desertification; overgrazing and overcultivation
are being increasingly eroded due to the widening and excessive use of
technical methods; Increasing of population alters the consumption patterns against the
limited natural resources.
(53) The effect of desertification on Jifara Plain appears through reducing soil fertility and
crops productivity, leading to long-term declines in agricultural yields, livestock yields,
plant standing biomass, and plant biodiversity. It has also significant implications on
livestock industry and the national economy. It accelerates migration from rural to urban
settlement areas as the land cannot support the original inhabitants.
(54) In the absence of major shifts in policy, economic growth, energy prices, and consumer
trends, global warming is expected to continue. The mean annual temperature of
all-Libya will be increased about 1 °C from 2000-2050 based on the projection of trend
from 1976-2000 corresponding with the global temperature trend projection. Precipitation
at 10 stations represented a decrease based on 1976-2000 period, while two stations
only declared increasing of precipitation in the first half of 21st century.
(55) Water deficit will be increased in response to the increasing of water demands for
domestic, industrial and agricultural purposes. In Libya, as a whole, water demands will
be increased from 5,579 mill. m3
in 2000 to 8,965 mill. m3
in 2025 followed by water
deficit of 4,735 mill. m3. Approximately half of the deficit water in all Libya will be in
Jifara Plain which is inhabited by more than 50 % of Libya’s total population.
(56) Libya cooperates with the United Nations and international organizations. It has
signed and ratified a number of international and regional agreements which effectively
established a policy framework for actions to mitigate climate change and combat desertification.
Libya has implemented several laws and legislative acts, with a number of
ancillary and supplementary rules to regulate.
(57) In Libya, two nature reserves and five national parks were established in several outstanding
environmental regions, covering a substantial area of 134,000 hectares. Libya
in interested in establishing of the Natural Protectorates in many parts of Jifara plain.
(58) Libya was ranked during the 1960s and 1970s as a world pioneer in the field of desertification
combat. The first use of fixation with petroleum emulsion was in Libya 1961.
125,000 ha have been stabilized by this method, in 1971 oil derivatives has been used to
fix sand dunes named internationally the Libyan method.
(59) Water development projects were also established including steps for the utilization of
surface water; in addition to the construction of thousands of reservoirs and tanks. Sixteen
major dams with an estimated annual storage capacity of 300 mill. m
3 were constructed
and over 100 mill/m
3
are treated annually for agricultural purposes. The Great
Man-Made River project alleviates the pressure on water resources in northern parts of
Libya such as Jifara Plain.
8.2 Recommendations
Despite the current efforts and ongoing projects being undertaken in Libya in the field
of climate change and desertification, urgent actions are needed to mitigate climate change
and combat desertification in the future.
(1) Mitigation of climate change and desertification combat require well-integrated national,
regional and international efforts. Developing countries need international support
in these fields and substantial reductions of greenhouse gases in developed countries
and adaptation strategies are crucial.
(2) Greenhouse gases can be reduced by improving energy efficiency using cleaner energy
sources and technologies and promoting renewable energy in electricity generation
using wind and solar energies.
(3) Sink actions of CO2 can also be carried out through the increase of CO2 absorption
capacity including planting and maintaining suitable types of trees in city center and
along the roads, as well as along the water drains. In addition planting forests using
treated sewage water for their irrigation, which have high biomass as are also an important
sink for carbon dioxide.
(4) The present number of meteorological stations in Libya is inadequate and must be
improved and intensified especially in the southern parts of the country.
(5) Research projects of climate change and desertification and development strategies in
Libya must be set up as soon as possible.
(6) Gathering all the institutions which work in climate change and desertification issues
in order to avoid the quarrel in decisions. Supporting the scientific institutions and institutes
in order to increase the role of researches, education, and training. Monitoring,
analyzing and forecasting variation is of prime importance to climatologists as well as
policy and decision makers.
(7) Adaptation could be impeded in many areas by anticipated rate of climate change,
limited access to technical expertise and wider social and economic circumstances and
policies. Impacts of climate change could seriously undermine efforts for reorientation
the society towards sustainable development.
(8) Sustainable deve lopment strategies must include expected climate change. Subsequently,
national environmental action plans and implementation must incorporate
long-term changes and should put the welfare of people at the center of the development
agenda. More cooperation between people and government is crucial to implement
polices.
(9) Improving and well management of natural resources, especially soil and water, success
will be achieved by the means of an effective and decisive management taking into
account the social and economic circumstances of the inhabitants. Measures to combat
desertification must ultimately be directed toward people, sustaining and improving
their livelihoods.
(10) Expansion of safely cropped areas by introducing crops which are more resistant to
extreme conditions and by improving methods of cultivation and water conservation.
Priority has to given to the quality of agriculture productions which has to be improved,
instead of cultivating more marginal lands. Modern technologies and approaches in agriculture
and water resources management are very important to meet increasing demands
and to alleviate the effects of climate change and desertification.
(11) Discharges from the groundwater aquifer in Jifara Plain should be properly managed
and the rate of the sea water intrusion could also be reduced by investigation and new management policies for optimal use of the freshwater in the aquifer. Improved irrigation
methods, mechanization, fertilization, plant protection and the selection of crops
that use water more efficiently are important for facing desertification.
(12) Conservation of animal and plant varieties will be a series issue, as some nature reserves
and national parks become increasingly inappropriate from climate for the species
they were meant to protect.
(13) Popular awareness of climate change and desertification is crucial to achieve the objectives
and requirements of sustainable development. Citizens should be aware about
the importance of natural resources and not be excusive in using them. Local
knowledge should also be enlisted.
(14) The availability of information base is very important for putting policies and action
plans to mitigate climate change and combat desertification.
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