oa The Impacts of Anthropogenic and Climate Change Forcings on Water Resources Demands and Availability in Jordan in the Near Future

Abstract

The present paper evaluates the composite risk of anthropogenic and climate change on the future water status in Jordan during the period 2030–2050. The projected water status in the country is evaluated based on the more likely population growth and climate change scenarios. The most likely figure for the population of Jordan, excluding refugees from neighboring countries, in 2040 would be ∼15 million people. Given this likely projection, though conservative, annual water needs for the domestic sector alone are expected to be between 700 and 800 million m³, with the current level of water consumption. A rise in near surface air temperature by 2 °C and a drop in total precipitation by 15%, as projected by most Global Circulation Models, would diminish renewable water resources in the mountainous region by ∼ < /AσΣETHιγηλιγητ>25–40%, being more severe as aridity increases.

1. Introduction

There is almost a consensus among earth scientists that the buildup of greenhouse gases in the atmosphere is leading to a global warming. Documented evidence suggests that global temperature observed over continental and marine regions has been rising for the past several decades (IPCC, 2007). The increased air temperature will intensify the hydrological cycle due to increased water vapor release into the atmosphere. Recent unprecedented severe meteorological events such as large scale torrential rains in many parts of the world and the recurrent tropical cyclones invading the southern parts of the Arabian Sea could be cited as a strong evidence of a global climate change. A climate change towards warmer conditions is expected to increase precipitation over the Arabian Peninsula due to the northward extension of the Monsoon Trough which will enhance the Red Sea Trough during the transitional periods, Fall and Spring.

There is almost a consensus among most GCM that a global warming will be most severe in the eastern Mediterranean, with a significant drop in precipitation and a large temperature rise (Zhang et al., 2005; IPCC, 2007; Kelley et al., 2012). Model results suggest that near surface air temperature will increase by 2–3.5 °C following an equivalent doubling of Carbon Dioxide in the atmosphere (Kelley et al., 2012). The projections for precipitation amount, its temporal distribution and variability are not as certain. Due to the northward retreat of the polar front during the winter months, however, the eastern Mediterranean is expected to experience less cyclogenic activities, and as such less winter storms, leading to a precipitation decline (Schulz et al., 2008). It is also projected that the timing and frequency of precipitation in this region will be more erratic, less frequent but more intense. Statistical evidence show a strong reduction in the number of rainy days with precipitation in excess of one mm day-1.

Population growth adds another negative dimension to the water crisis. This includes more water demands for the domestic, agricultural, tourism, and industrial sectors. Additionally, increased population causes severe deterioration to surface and underground water quality through large scale land use changes, release of large volumes of waste, gaseous and liquid effluents and solid waste disposal. It is clear that anthropogenic and natural forcings work hand in hand to adversely impact Jordan's limited water resources. As such, two operational questions need to be answered:

1- What is the near future water needs in the country?,

2- What is the water availability for the near future following a climate change?

Answering these two questions adequately is essential for a better assessment of the relative impacts of climate change and population growth on water availability, demands, and stress during the near future. This projection can be used to minimize the potential risks of the projected climate change and population growth.

2. Current water availability in jordan

Around 70% of precipitation in Jordan falls in the winter months, December through February, due mainly to cyclogenic activities; the other 30% fall in the transitional periods. Average annual precipitation in the country ranges from a ∼600 mm in a small enclave in northwestern Jordan to less than 5 mm near the Saudi borders (Fig. 1). Additionally, this area receives large quantities of solar radiation year around due to persistently clear skies triggered by large scale subsidence. The combination of scanty precipitation along with a large global radiation enhances direct evaporation and substantially limits blue water availability. The average annual renewable water resources in Jordan are estimated at about 800–850 million cubic meters (M m³) (Ministry of Water and Irrigation, Jordan, 2015).

There is observational evidence that precipitation in the country is declining; Fig. 2 shows a time series of precipitation in two stations, one in northern Jordan during the period, 1945 through 2005, and the other one in central Jordan, Rabbah in the Karak Plateau. Both linear regression and Mann-Kendall non-parametric tests reveal that annual precipitation in all stations in the country is declining.

3. Future population

The population of Jordan experienced a large growth during the past 60 years due to natural growth and as a result of political conflicts. The population of the country, however, swelled by about 20 times during the past 60 years. The invasion of Iraq caused a mass movement of Iraqis towards Jordan. The current civil war in Syria paints another unpleasant, in fact very gloomy, portrait of the population dynamics in Jordan, with current population close to 11 million people.

The population growth was paralleled by a similar increase in irrigated agriculture. The area of irrigated lands in the Jordan Valley increased from ∼15 thousand hectares in the early 1960's to ∼38 thousand hectares in 2011. Likewise, irrigated agriculture in the desert region increased from virtually nil in the early 1970's to ∼17 thousand hectares in 2008 (Ministry of Water and Irrigation, 2012). The substantial increase in the irrigated agricultural land caused further demands on freshwater. The availability of irrigation water will shrink in the near future, however, because of growing demands on this resource from other sectors, mainly the domestic sector. The future water status in the country would indeed look quite bleak should population growth continues unabated and a climate change towards warmer and/or drier conditions prevail in the near future.

4. Future Water Needs

Official figures provided by the Ministry of Water and Irrigation, Jordan (2015) indicated that current domestic freshwater supply is ∼150 liters per person/day, which gives a total annual freshwater need of 370 M m³. Nowadays, with only 7.5 million inhabitants (excluding fresh refugees), most households in Jordan receive a specified amount of water during the summer months, and domestic water is supplied once (few hours) per week. Renewable water resources in the country were not enough to meet the water demands, and as such non-renewable fossil freshwater resources have been intensively exploited during the past several decades. These measures have caused steady drop in the level of underground aquifers and resulted in poor water quality. The Dissi Project, conveying fossil water is expected to provide freshwater for several decades before it dries up completely.

Projections based on future population growth scenarios indicate that annual domestic water needs alone will range from a minimum of 550 M m³ to a value close to 1100 M m³ by 2050. A more likely figure would probably be between 700–800 M m³. Thus, renewable freshwater resources of the entire country will barely meet domestic water needs even without a climate change.

Currently, the agricultural sector accounts for about 65% of total freshwater consumed in Jordan (MWI, 2015). Paradoxically, the amount of water allocated for irrigation must drop in the near future because of demands by relatively more needy sectors, the domestic one in

particular. Based on population growth alone, it is obvious that the future water status in the country looks quite bleak even without a climate change. Should the climate of the eastern Mediterranean become warmer and/or drier or both, the country will face a serious, probably tragic, freshwater dilemma in the very near future which will ultimately lead to economic, social and political unrest. The anticipated climate change will seriously influence the future water crisis in Jordan.

5. Projected climate change impact

A climate change in the eastern Mediterranean will impact water resources in at least three ways: 1) reduces blue water availability due to increase direct evaporation from soils, 2) intensifies irrigation water demands, and 3) increases evaporation losses from dams and open water canals. The impact of climate change on the available water resources in Jordan is investigated using a water balance model with a temporal resolution of one day. The model is run over the mountainous areas of Jordan where around 65% to 70% of blue water is generated (Oroud, 2015). A detailed description of the model is presented elsewhere (Oroud, 2008; 2011). Figure 4 shows the linkage between annual blue water availability and annual precipitation as calculated by the daily model. Conservative calculations show that a 2 °C temperature increase along with a 15% reduction in precipitation decreases water availability, on average, by ∼ 25%–40% depending on the level of aridity, being more sever as in more arid regions. This means that renewable water resources in the country following a warmer, drier climate will probably be between 500–650 M m³ by 2050. This conclusion is commensurate with those presented by other investigators (e.g., IPCCk 2007; Margane et al. 2008; Suppan et al. 2008; Giorgi and Lionello, 2008; Kelley et al., 2012).

Irrigation water needs under current climate conditions and following a climate change were simulated for the Jordan Valley using a spatially distributed daily model. Following a climate change, the irrigation water needs will increase by around 15%. This is equivalent to 40 to 50 M m³ of extra irrigation water needed to maintain the irrigation water demands in the Jordan Valley at the current land use regime.

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