As governments seek innovative ways to boost rainfall, technologies such as cloud seeding may come to the fore, experts say
If every cloud had a silver lining, drought may be less of an economic drain
Threading through clouds, often with shaky turbulence and occasional thunder, 71-year-old pilot Gary Walker burns the flares on his plane’s wings, releasing chemicals as he flies.
“It can be very rough as you get close to some of those clouds,” he admits.
Mr Walker, the chief executive of the Texas-based aviation company SOAR, carries out an increasingly popular - and in some cases, controversial - effort to chemically impregnate clouds to increase rainfall.
Drought has over the past decade wrought economic havoc from the United States to China and beyond, and impacted food prices worldwide.
According to a report by Oxford University, sub-Saharan Africa also faces many challenges, and is the only region where the risks of inadequate water supply and sanitation are rising. North Africa has the greatest percentage of population at risk of water scarcity.
Assessing the risks of water security, the study stresses that investment in better water services, reducing drought or improving flood defences would also “support economic growth and social well-being”.
For example, the researchers’ simulation model looked at the cumulative effect of drought on national economies between 1980 and 2012. In the case of Malawi, it showed that a 50 per cent reduction in the effect of drought led to a 20 per cent higher per capita GDP at the end of the simulation. The same reduction in the drought effect in Brazil led to a 7 per cent higher per capita GDP over the same period.
According to the UN Food and Agriculture Organisation (UNFAO), on north-eastern Nigeria border with Chad and Cameroon, the sub-Saharan Lake Chad Basin, which is the main source of water in the region, between 1963 and 2013 lost 90 per cent of its water mass, with a huge impact on the population.
The extreme US great grain belt drought of 2012, meanwhile, pushed up world food prices, exerting pressure on the cost of living and affecting food security, UNFAO says. It estimates that US retail food prices increased between 3 and 4 per cent in 2013.
In the same year, south-western China’s agricultural industries were also critically affected by drought, having lost approximately 2 billion yuan (Dh1.16bn).
The wide range of economic effects hit numerous sectors, meaning the actual costs are becoming harder to assess, the UNFAO points out.
“The web of impacts may become so widespread that it is often difficult to determine accurate financial estimates of damages.”
To cope with searing global temperatures, protracted droughts and chronic water shortages, some countries are turning to “cloud seeding”, which aims to boost rainfall in dry areas, according to the Thompson Reuters Foundation.
As temperatures continue to rise, largely as a result of climate change - 2016 was the hottest year on record, according to the World Meteorological Organisation (WMO) – more nations are expected to explore ways to boost rainfall.
The Arabian Gulf, with its large swaths of golden desert, is already one of the hottest places on Earth. The mercury in Kuwait last year soared to 54°C, according to the WMO.
In the UAE, officials at the National Centre of Meteorology and Seismology (NCMS) say cloud seeding efforts here are working.
Considered a leader in “rain enhancement”, the nation now uses six specialised aircraft for seeding flights. It has experienced an increase in rainfall of about 10 to 15 per cent in polluted air and 30 to 35 per cent in clean air, officials say.
Omar Al Yazidi, the director of research and development at the NCMS, believes science shows cloud seeding is safe for the environment and the public. He thinks such efforts will only grow in popularity.
In 2015, the centre began offering US$5 million in grant money via its Research Program for Rain Enhancement Science to researchers working on water security challenges.
“The global water shortage is worsening in many parts of the world, so the demand for fresh water is increasing. Cloud seeding could be one of the methods that can contribute to alleviating the water problem,” says Linda Zou, a professor at the Khalifa University of Science and Technology and one of three winners of the first round of funding.
In August, The National reported that officials hosted a series of meetings with leading UK researchers working on climatology and meteorology as part of its summer 2017 European roadshow during the month.
Following a meeting with one of the awardees of the programme’s second cycle, Professor Giles Harrison of the University of Reading, the team visited the European Centre For Medium Weather Forecasts, the European Space Agency and Imperial College.
Prof Harrison’s project, Electrical aspects of rain generation, is based on the natural occurrence of electrical charges and their potential to modify water droplets even when clouds are not charged to the extent that leads to thunderstorms.
This project will investigate the electrical properties of clouds through theoretical and experimental work, firstly to model the growth of charged drops to raindrops, and secondly to measure and modify charges using balloons and aircraft.
“Understanding the role of electric charge in the generation of rain could boost precipitation levels without the use of artificial chemicals,” said Prof Harrison.
“The UAE Research Programme for Rain Enhancement Science has already played a major role in allowing international science networks to flourish and identify new frontiers in cloud seeding science and technology.”
The basic process, however, is hardly new, Reuters points out. First trialled in the United States around the Second World War, it is now discreetly used in more than 50 countries, from Mali to India and Puerto Rico.
China, however, has the biggest cloud-seeding operation, which it utilises not only to increase rainfall but also to avoid hailstorms that can devastate farm crops.
Beijing also turned to cloud seeding in the build-up to the 2008 Summer Olympics, to try to avoid rain during its spectacular opening ceremony.
While the success of cloud seeding efforts remains in question, commercial use of the technology is growing. US and European companies are testing unmanned drones to seed clouds, and promising rain-free wedding ceremonies by “bursting” clouds ahead of the big day.
Still, the technology cannot do much to tease rain from a cloud-free sky, experts warn.
“In extreme heat or drought conditions there are no clouds. Nobody can make clouds,” says Roelof Bruintjes, a senior scientist who works on weather modification for the US National Center for Atmospheric Research.
Rather, the idea of cloud seeding is to make rain form more efficiently inside clouds so more water comes down,
To seed a cloud, pilots introduce a chemical agent, commonly silver iodide. It draws moisture to itself, allowing the cloud’s water vapour to condense into droplets and produce rain, according to the WMO.
Does the process work? “There are still a lot of unknowns and a lot more research to be done,” says Deon Terblanche, the WMO’s director of research.
“But ... if it can be done successfully it will have huge benefits, especially in water-
The amounts of silver iodide used for most cloud seeding are too small to hurt the environment or public health, and do not present any significant risk, he says.
The WMO is carrying out a global review of knowledge on cloud seeding, with the aim of preparing official advice and a comprehensive database of projects as the number of countries seeking to invest in the technology rises, Mr Terblanche says.
That investment cannot come too soon for many. As Mr Bruintjes points out: “Water is the basic sustenance of life.
“If there is no water, there is no life.”