Soils as Driver and Victim of Climate Change in Egypt
137
Therefore the irrigation requirements were increased with an average of 3.28 and
6.68% for the total cultivated area of the studied orchards. In the worse scenario of
increasing temperatures +2 °C, and decreasing precipitation by 10%, the irrigation
requirements will be increased by 8.69% [146].
In coastal Bangladesh, climate change poses a major soil salinization risk. Across
41 monitoring stations, the annual median projected change in soil salinity is 39%
by 2050. Above the median, 25% of all stations have projected changes of 51%
or higher [147]. In Egypt, It is widely assumed that SLR will increase saltwater
intrusion processes in coastal aquifers. The simulations show that the effect of the
global sea level rise in the period from the year 1990 up to 2100 appears clearly
through the coastal topography with relatively low-level elevation adjacent to the
coast [148]. A shift of the interface is expected up to the year 2100 by a maximum
of 43 km covering an area of 1980 km
2 according to scenario RCP2.6 (2.6 °C),
and by a maximum of 57 km covering an area of 2870 km
2 according to scenario
RCP8.5 (8.5 °C). Overexploitation of groundwater leads to an increase in salinity
concentration up to 5000 mg/l and covers about 10% of the Nile Delta area.
4.3 Impact of Rainfall Scenarios on Soils
With climate change, more frequent extreme precipitation and drought events are
projected [149] which may have greater impacts on ecosystem dynamics than the
singular or combined effects of rising CO 2 and temperature [150]. This increase
in the frequency of extreme events may exacerbate the rate and susceptibility to
accelerated erosion, salinization, and other degradation processes, leading to further
carbon losses.
The potential impact of climate changes on soil erosion could be enhanced by
higher precipitation, especially intensive rainfalls and thunderstorms, may result in an
increased rate of erosion and higher surface runoff. Increased rainfall could increase
atmospheric N deposition to soils, may promote soil disturbances, flooding, and subsidence which changes in wetland and waterlogged habitats and also enhance soil
erosion, potentially leading to the pollution of surface waters. Significant increases
in rainfall will lead to increases in leaching, loss of nutrients and increasing acidification, depending on the buffering pools existing in soils. The direction of change
towards increased leaching or increased evaporation will depend on the extent to
which rainfall and temperature change and consequent changes to land use and its
management. In either case, the situation could lead to important changes in soils
[120].
On the other hand, low precipitation generally reduces the rate of water erosion,
but it may intensify wind erosion. Increased droughts will increase the likelihood
of shrink-swell in clay soils, and disturbance to building foundations and increased
soil temperature may also exacerbate chemical attack to foundations to engineered
structures based on clay caps (e.g., in contaminated landfills), with the likelihood of
increased leachate generation and release of landfill gases [112].
137
Therefore the irrigation requirements were increased with an average of 3.28 and
6.68% for the total cultivated area of the studied orchards. In the worse scenario of
increasing temperatures +2 °C, and decreasing precipitation by 10%, the irrigation
requirements will be increased by 8.69% [146].
In coastal Bangladesh, climate change poses a major soil salinization risk. Across
41 monitoring stations, the annual median projected change in soil salinity is 39%
by 2050. Above the median, 25% of all stations have projected changes of 51%
or higher [147]. In Egypt, It is widely assumed that SLR will increase saltwater
intrusion processes in coastal aquifers. The simulations show that the effect of the
global sea level rise in the period from the year 1990 up to 2100 appears clearly
through the coastal topography with relatively low-level elevation adjacent to the
coast [148]. A shift of the interface is expected up to the year 2100 by a maximum
of 43 km covering an area of 1980 km
2 according to scenario RCP2.6 (2.6 °C),
and by a maximum of 57 km covering an area of 2870 km
2 according to scenario
RCP8.5 (8.5 °C). Overexploitation of groundwater leads to an increase in salinity
concentration up to 5000 mg/l and covers about 10% of the Nile Delta area.
4.3 Impact of Rainfall Scenarios on Soils
With climate change, more frequent extreme precipitation and drought events are
projected [149] which may have greater impacts on ecosystem dynamics than the
singular or combined effects of rising CO 2 and temperature [150]. This increase
in the frequency of extreme events may exacerbate the rate and susceptibility to
accelerated erosion, salinization, and other degradation processes, leading to further
carbon losses.
The potential impact of climate changes on soil erosion could be enhanced by
higher precipitation, especially intensive rainfalls and thunderstorms, may result in an
increased rate of erosion and higher surface runoff. Increased rainfall could increase
atmospheric N deposition to soils, may promote soil disturbances, flooding, and subsidence which changes in wetland and waterlogged habitats and also enhance soil
erosion, potentially leading to the pollution of surface waters. Significant increases
in rainfall will lead to increases in leaching, loss of nutrients and increasing acidification, depending on the buffering pools existing in soils. The direction of change
towards increased leaching or increased evaporation will depend on the extent to
which rainfall and temperature change and consequent changes to land use and its
management. In either case, the situation could lead to important changes in soils
[120].
On the other hand, low precipitation generally reduces the rate of water erosion,
but it may intensify wind erosion. Increased droughts will increase the likelihood
of shrink-swell in clay soils, and disturbance to building foundations and increased
soil temperature may also exacerbate chemical attack to foundations to engineered
structures based on clay caps (e.g., in contaminated landfills), with the likelihood of
increased leachate generation and release of landfill gases [112].