(Daily News Scan - DNS English) Combating Smog: Cloud Seeding
Important Points:
In order to keep Delhi and NCR air clean and smog free, a technique called cloud seeding was suggested by Haryana Chief Minister in a letter to Prime Minister.
Delhi’s air quality has deteriorated to alarming levels and despite efforts; pollution level has grown to be hazardous and harmful. Cloud seeding will help in washing away toxic pollutants in the air.
In this DNS we will know about Cloud Seeding and how it can combat pollution.
Cloud seeding is a weather modification technology to artificially create rain. It is a way to artificially create rain. It is also known by other terms like manmade precipitation enhancements, artificial weather modification. It works when there are pre existing clouds in the atmosphere. Rain happens when moisture in the air reaches levels at which no longer it can be held.
Cloud seeding aims to facilitate and accelerates the process by making available chemical nuclei around which condensation takes place. The seeds of rain are the iodides of silver or potassium, dry ice (solid carbon dioxide) or liquid propane. These seeds can be delivered into the clouds by planes or by simply spraying from the grounds.
There are three cloud seeding methods: static, dynamic and hygroscopic. Static cloud seeding involves spreading a chemical like silver iodide into clouds. Silver iodide makes rain clouds more effective at dispensing their water.
Dynamic cloud seeding aims to boost vertical air currents which encourage more water to pass through the clouds translating into more rain. Hygroscopic cloud seeding disperses salts through flares or explosives in the lower portion of the cloud. The salt grows in size as water joins them.
Cloud seeding technique is not new to India and it has been used in Karnataka Andhra Pradesh and Maharashtra to address drought. This technique’s experiment has been carried out by Pune based Indian Institute of Tropical Meteorology. They have been carrying out experiments on this for several years. The experiments have been done in areas around Nagpur, Sholapur, Hyderabad, Ahmedabad, Jodhpur, and recently Varanasi. If we look at the success rate of these experiments in inducing rain it is about 60 -70 percent. It also depends on the local atmospheric conditions, the amount of moisture in the air and cloud characteristics. Some private companies also offer cloud seeding service.
The scientists at IIT –Kanpur had prepared a project to induce artificial rain via cloud seeding method to clear smog in Delhi. In May 2019 Karnataka cabinet had approved a budget of Rs 91 crore for cloud seeding for duration of 2 years. This included 2 aircrafts spraying chemicals on moisture laden clouds to induce rainfall. Hindustan Aeronautics Limited had also partnered with IIT Kanpur and agreed to provide Dornier aircraft and their pilots to provide logistical support to the project.
Cloud seeding technique has been applied and used by various countries around the world. America, Spain, Australia and France have already used this technique. United Arab Emirates used the technique and it let to creation of 52 storms in Abu Dhabi. Also this type of seeding is routine in Russia and other cold countries. In the cold countries it is used to disperse fog at the airports.
Looking forward to the challenges of this technique it is a bit on the costlier side. It involves the process of delivering chemicals into the sky and releasing them into the air by plane which is an expensive process. The chemicals used in this technique might be harmful for the plants, animals and everyone in the environment. Lastly we can also find that it may ultimately change climatic patterns on planet. Cloud seeding is effective but controversial technique with some harmful effects.
