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Time for Climate Engineering

Time for Climate Engineering

Sunday, 10 April, 2022 - 04:45
Najib Saab
Secretary-General of the Arab Forum for Environment and Development (AFED) and editor-in-chief of Environment & Development magazine

While talk of reducing carbon emissions responsible for climate change continues as if it were a problem for the future, scientists are working to devise solutions for current environmental challenges. Among these are the impacts of rising temperatures on infrastructure, including roads, water, electricity and sewage networks.

The latest report from the Intergovernmental Panel on Climate Change (IPCC) published this week asserts that, even if the world succeeded in achieving the goal of stopping the average rise of temperature at 1.5 degrees Celsius before the end of the century, this global average masks extreme local variations. Beyond talking averages, the world has already begun in recent years to witness recurrence of storms, hurricanes, floods, droughts and heat waves at a scale and frequency not previously known. Meteorologists expect a variation in rise of average local temperatures reaching in some regions, including the Middle East, more than double the global average. In addition to median and average, extreme heat waves are expected to hit the countries of the Middle East at unprecedented levels and for long periods, with the actual temperature in summer exceeding 50 degrees Celsius for weeks, and reaching 60 degrees on some days. Without proactive measures, some countries will become uninhabitable.

Extreme temperatures will necessitate making adjustments to building systems, utility and transportation networks, food production methods, and health care. High temperature is not the only challenge, as climate changes cause frequent floods that happen suddenly, as is the case in some Arab countries. Although extremes are not an everyday occurrence, engineers do not base their designs on averages, but on the tolerability of extremes, such as weight, wind speed, water flow, or temperature.

One of the problems that Arab countries face periodically are torrential rains that flood roads and cause great damage to structures and services, besides disrupting the movement of people and goods. It is noteworthy that some officials do not remember climate change except on these occasions, as they hold it responsible for natural disasters, with the intention of evading accountability. It is true that climate change is behind the increasing frequency and severity of floods, but most of the time the problem precedes this and has nothing to do with it. It goes back to cities and infrastructures being designed in ways unsuitable for the terrain and weather conditions, before it being a climate problem.

Recently, I was invited on a television program to talk about the devastation caused by torrential rains in some Arab cities. I explained that the problem is mainly related to the natural fluctuations of the weather before being an issue of climate change, and thus it often is the result of design faults related to urban planning, roads and infrastructure. In most cases, whether in Alexandria, Hasaka, Amman, Muscat or Dubai, floods are not a novel occurrence. What has changed is that they used to hit hard every ten or twenty years, whereas now they occur every two or three years. However, what makes their damage even greater is that the urban expansion reached areas that were protected in the past, and in many cases structures block the natural courses of torrential rains.

Moreover, the sewage and rainwater collection networks did not develop to keep pace with the urban expansion, so the infrastructure remained insufficient to meet the needs of the superstructures. The biggest problem is that these networks are often designed according to median rain averages, and therefore cannot withstand extreme limits. The other problem of road flooding in cities is that the drainage networks, where they exist, receive waste water and rain water in one pipe, which causes fresh water to be soiled and wasted, in addition to flooding the roads because the volume exceeds the carrying capacity of the network. The solution in countries that suffer from an acute shortage of fresh water, such as Arab countries, is to separate the wastewater network from rain water. Whereas sewage treatment requires complex and expensive processes to purify and reuse, collecting rainwater through an independent network allows it to be used for irrigation and household needs at a low cost. The collected rainwater can also be diverted to aquifers and wells where available. The need for these measures increases as asphalt and cement surfaces cover most of the areas in cities, which prevents rainwater from naturally seeping into the ground. A pioneering initiative in this regard is the “rain harvest network” which Egypt will be introducing as an integral part of all new urban developments.

I read a recent report on experiments being applied in Australia to counter the effects of high temperatures and floods on the roads. Excessive rise in temperature leads to asphalt melting and cracking, which makes it vulnerable to disintegration and erosion when the heat wave is followed by rain and a sudden decrease in temperature. A successful method developed by Australian engineers to address the problem is to pump air and cold water into hot asphalt as it is being spread on the roads, which helps to strengthen and stabilize it, while maintaining its flexibility. It was found that the damage after the hot and rainy season decreased significantly this year on the roads where the new technology was applied. Another experimental solution in Australia is to add small pieces of light-colored ceramic to the asphalt mixture, which reflects the sun’s rays and reduces the heat of the road surface and surrounding areas. In one city, this measure could reduce temperatures by an average of 10 degrees in an area that suffers from the heat island phenomenon, where buildings impede air flow.

These ideas are no more science fiction, as they are becoming real solutions, capable of saving billions in road maintenance bills and the repair of damages caused by high temperatures and torrential rains. A forthright proof is that the additional cost of road maintenance in Africa alone for climate-related reasons is soon expected to exceed $200 billion annually.

Most of the buildings, services and infrastructure in Arab countries today are not commensurate with the fluctuations in weather and the current state of nature. What should we do, then, in order to make them climate-ready?

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