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- A new study published in journal Nature found that Ocean release naturally produced short-lived halogens like chlorine, bromine and iodine which contribute to 8-10 % cooling of this planet.
- By 2100, there is a possibility that this cooling could increase to 18-31 %.
- Oceans perform variety of functions for wellbeing of this planet which includes absorbing carbon dioxide, moderating the climate and cooling the planet.
- Substantial impact of short-lived halogens, with a lifetime of less than six months in the atmosphere, in cooling the planet can’t be ignored as climate models for future prediction do not account for these.
- The name halogen is derived from words having Greek roots -
- Hal - salt and
- gen - to produce
- These are non-metallic elements which constitute Group 17 (Group VIIa) of the periodic table.
- These elements include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) etc.
- These elements produce sodium salts of similar properties for instance – NaCl (common table salt).
Reasons for Halogen release by Ocean
- Naturally released by Oceans.
- Human activities may accelerate it –
- Pollutants like ozone are deposited on the ocean due to increased anthropogenic activities.
- It makes hard for ocean to dissolve halogens as they become insoluble.
- These halogens are forced out of sea water and released into the atmosphere.
Study and findings
- Initially study was focussed on to find out the depletion of ozone in the troposphere by Halogens.
- They considered solar radiation emitted by the sun and Earth’s terrestrial radiation to find out global radiative balance across pre-industrial, present-day and future climates.
- Ozone is a greenhouse gas which contributes to warming.
- It was found that short-lived halogens from oceans reduce warming by depleting ozone.
- They also studied the methane and water vapors too but it was observed that halogens destroy hydroxyl radicals and increase the lifespan of this methane greenhouse
- Also the similar effect was seen on water vapours.
- Formation of cooling aerosols was also declined by halogen.
- However these halogens destroy ozone leading to an overall net cooling effect on climate.
- These halogen emissions are found more in polar regions.
Must Read Article:
Global Warming in Indian context
WMO report on state of Climate
Halogens. Released from oceans, are found to have a cooling effect on climate. They do so by -
1. Decreasing the concentration of Methane.
2. Increasing the rate of Ozone depletion.
3. Reducing the formation of cooling aerosols
How many of the statements given above is/are correct?
A. Only one
B. Only two
C. All three