More intense heat, longer hot spells, increasingly erratic rainfall and prolonged droughts threaten Jordan's already scarce water resources over the coming decades, according to climate projections that paint a sobering picture for the Kingdom.
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What makes the findings particularly striking is that the risk does not hinge on the number of days temperatures will exceed 40 degrees Celsius. Every rise in temperature accelerates water loss through evaporation, and every extension of dry periods leaves soil without rain for longer. Rainfall may also grow more concentrated, with larger volumes falling in a single day and rapidly converting into runoff and flash floods.
The "Country Information Sheet on Jordan" does not project a uniform climatic future for the Kingdom. The severity and nature of the risks vary by location. The Jordan Valley and the southern desert stand out as centres of extreme heat, while the northern Badia region is forecast to experience heavier daily rainfall. The western and northern highlands record the highest rainfall and surface runoff, while the eastern plateau and desert areas are the driest. The Dead Sea region occupies a distinct position in terms of heat, evaporation and water loss.
The findings were released two days ago by the RICAAR initiative of the United Nations Economic and Social Commission for Western Asia (ESCWA). They show that the average number of days per year on which temperatures exceed 40 degrees Celsius stands at around 20 nationally, but rises significantly in some low-lying areas, surpassing 70 days annually.
The paper analyses Jordan's current and future climate by comparing a reference period of 1995 to 2014 with two future windows: 2021 to 2040 and 2041 to 2060. It uses two emissions scenarios, SSP2-4.5 and SSP5-8.5. The first assumes a lower emissions trajectory; the second assumes higher emissions and therefore a substantially greater warming impact.
On rainfall, the paper points to a limited increase in the amounts expected to fall on the wettest days. In the western part of the Kingdom, the projected near-term increase ranges from 0.3 to 0.4 millimetres, while in the central region it reaches around 1.1 millimetres under both emissions scenarios. Parts of the northern desert stand out more sharply: forecasts there suggest the rainfall recorded on the wettest single day could increase by more than 25 percent.
Crucially, the results underline that drought and heavy rainfall are not opposites. A prolonged dry spell may be followed by a large volume of rain in a short period, meaning an increase in rainfall intensity does not necessarily translate into improved water availability.
Drought figures prominently in the findings through the Consecutive Dry Days Index, which measures the longest continuous stretch without significant rainfall. Jordan's average for this period, based on the reference data, already stands at around 121 days per year, reflecting the country's extended dry season. Forecasts indicate these periods could grow longer in parts of the Kingdom under certain scenarios.
The significance of that figure extends beyond an absence of rain. Longer droughts coincide with higher temperatures and sustained evaporative water loss, which means reading drought in isolation from heat gives an incomplete picture of the pressure on the country's resources.
The paper singles out the Dead Sea region as a hotspot for evaporation, attributing this to the combined effect of heat and salinity. A potential increase in evaporation, it warns, could worsen water loss and accelerate the ongoing decline in the Dead Sea's water level, with knock-on effects for ecosystems and coastal infrastructure.
The paper also makes clear that rainfall totals alone are an insufficient measure of usable water. After rain falls, some is lost to evaporation, some seeps into the ground, and some flows across the surface towards valleys, streams and reservoirs. This last component is described as surface runoff.
Surface runoff volumes differ markedly across Jordan. The western highlands, which receive more rainfall, generate higher runoff than the drier eastern plateau. The Kingdom-wide average during the rainy season is around 1.2 millimetres per month in the reference period, rising to more than 4 millimetres per month in the western highlands.
Looking ahead, projections suggest limited near-term changes in runoff, followed by an expected decrease in the central part of the Kingdom in the subsequent period. However, a lower average runoff does not mean a reduced risk of flash floods. Overall seasonal runoff may decline while a single heavy rainfall event over a few hours or one day can still generate large, sudden volumes of water, particularly in the western highlands.
The findings ultimately pose a fundamental question about water conservation and management under climate change. The challenge is not confined to declining rainfall; it encompasses rising temperatures, increased evaporation and shifts in the volume of water reaching valleys and reservoirs after rain falls.
This article was originally written in Arabic by Farah Atiyat for Al Ghad. It was translated into English with AI assistance and edited by Jordan News.
