No, cloud seeding didn’t drown Dubai

Abstract of this article appeared in The Times of India

A warming Arabian Sea means cities around it, Dubai to Mumbai, are vulnerable to extreme weather. But what’s more extreme is that govts and companies are trying to fix the weather using tech

The unprecedented flood in Dubai on April 19 has ignited much-needed discussion on weather modification and geo-engineering. Theories on what caused the extreme rainfall include cloud seeding, global warming and poor drainage systems. So, what did cause the rain?

It was not cloud seeding:

Cloud seeding’s an old weather-modification tech that induces rainfall by spraying chemicals such as silver iodide and common salt into clouds to make nuclei, around which the cloud’s moisture can condense, and form droplets. When sufficient droplets coalesce, they become heavy and fall as rain. It’s crucial to understand that cloud seeding cannot create rain from a clear sky-it needs clouds with sufficient moisture. Therefore, cloud seeding is generally used where clouds form, but it does not rain. Similarly, cloud seeding cannot create more rain than what is already in the cloud.

The storm system that caused flooding in Dubai was too big to be influenced by six or seven cloud-seeding aeroplanes that UAE’s weather body NCM flew, days prior. This weather system had massive amounts of moisture and affected thousands of square kilometers, causing heavy rainfall over UAE, Oman, Bahrain, Qatar, and Saudi Arabia. Oman’s Mahda got more rain than Dubai, and suffered maximum loss of life as well.

It was not unexpected eithen NCM had warned about “unsettled weather conditions” and advised people to work from home. In a nutshell, such an intense downpour over such a vast area cannot happen through cloud seeding. Even if there had been cloud seeding, it would have only marginally affected the intensity of rainfall.

But a warming planet:

Weather reports clearly show the downpour was caused by a combination of a low-pressure weather system over the region, and an anticyclone over Arabian Sea. The anticyclone pushed a massive amount of moisture into the area, which caused heavy rain. But tell-tale signs of global warming are replete in this episode.

Arabian Sea is warming at one of the fastest rates. Its surface temperature has increased by 1.2°C to 1.4°C in the last four decades. Surface warming has increased the evaporation rate, increasing water vapour in the atmosphere. Simultaneously, a warmer atmosphere, again due to global warming, can hold more moisture, and dump it as extreme rainfall. This is the precise mechanism through which extreme rainfall and cyclones have increased over Arabian Peninsula and western India.

Dubai was hit by extreme rainfall in Feb too. In fact, an equally ferocious storm lashed Dubai on March 8, 2016. The trend is evident – cities around Arabian Sea, including Mumbai, will increasingly be hit by extreme rainfall and cyclones, as global warming intensifies. A warming planet will spare none, not even the wealthiest sheikhdom.

‘Fixing’ weather is a tricky slope:

The chatter on cloud seeding, thought misinformed, shows the public’s apprehension about such tech. Now is when to discuss them more vigorously, because such tech are becoming real and big, and can potentially harm the planet and cause conflict between countries.

Weather modification is being carried out worldwide without any international oversight.

Take cloud seeding, used in over 50 countries, including large-scale application in US, China and UAE. China plans to bring 5.5m sq km, an area equivalent to 1.5 India’s, under a weather modification programme by 2025. What will be its impact on neighbouring countries, and global climate?

Geo-engineering tech is developing rapidly. Solar radiation modification – a group of technologies to deliberately reflect sunlight into space to cool the planet is being seriously explored as a solution to climate crisis. It includes injecting sulphur droplets into stratosphere, spraying salty water into clouds over oceans, and scattering glass over polar ice to reflect sunlight into space. Some scientists are adding nutrients to the ocean to stimulate phytoplankton growth, to suck atmospheric CO₂. Private companies, too, have entered this business. A Silicon Valley-backed start-up launched nearly 50 sulphur-filled balloons from Mexico into stratosphere to reflect sunlight. This company now plans to sell “cooling credits” for such launches.

Plus, there’s no oversight:

All these tech advances are being developed and tested without domestic or international regulations. International conventions (London Convention on Prevention of Marine Pollution, Convention on Biological Diversity and Vienna Convention on Protection of Ozone Layer) prohibit geo-engineering. But these have been ignored. A few nations attempt at UN’s Environment Assembly to regulate or ban geo-engineering also failed.

But this ostrich-like attitude won’t solve the problem. At least 20 countries and many more corporations have the financial muscle to send planes into stratosphere and spray sulphur particles. Who will stop them? A multilateral framework to govern geo-engineering and large-scale weather modifications is the need of the hour; something that merits open and transparent discussion with the public.