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RSPCB-JSO & JEE-OZONE LAYER (Importance, Depletion, Effects and Protection of Ozone Layer)

The ozone layer is the part of the Earth's atmosphere which contains relatively high concentrations of ozone gas, which is an inorganic molecule with the chemical formula O3. Ozone is a pale blue gas with a pungent (chlorine-like) smell. Though relatively high, the concentration in this layer is still small in comparison to other gases in the stratosphere.

 

The Ozone layer absorbs most of the ultraviolet radiation reaching the earth from the sun. Ozone Layer in the atmosphere is thicker over the poles than over the equator.

 

How is Ozone created?

 

When the sun's rays split oxygen molecules into single atoms, Ozone is created in the atmosphere. These single atoms combine with nearby oxygen to form a three-oxygen molecule — Ozone.

 

Who discovered the Ozone Layer?

 

The Ozone Layer was discovered by the French physicists Charles Fabry and Henri Buisson in 1913.

 

Why is Ozone Layer important?

 

Ozone protects the Earth from harmful ultraviolet (UV) rays from the Sun. Without the Ozone layer in the atmosphere, life on Earth would be very difficult. Plants cannot live and grow in heavy ultraviolet radiation, nor can the planktons that serve as food for most of the ocean life. With a weakening of the Ozone Layer shield, humans would be more susceptible to skin cancer, cataracts and impaired immune systems.

 

Is Ozone harmful?

 

Ozone can both protect and harm the Earth — it all depends on where it resides. For instance, if Ozone is present in the stratosphere of the atmosphere, it will act as a shield. However, if it is in the troposphere (about 10 km from the Earth's surface), Ozone is harmful. It is a pollutant that can cause damage to lung tissues and plants. Hence, an upset in the ozone balance can have serious consequences.

 

Disruption of Ozone Balance in the atmosphere

 

Since the 1970s scientists have observed human activities to be disrupting the ozone balance. Production of chlorine-containing chemicals, such as chlorofluorocarbons (CFCs), have added to depletion of the Ozone Layer.

 

What is 'Ozone Layer depletion'?

 

Chemicals containing chlorine and bromine atoms are released in the atmosphere through human activities. These chemicals combine with certain weather conditions to cause reactions in the Ozone Layer, leading to ozone molecules getting destroyed. Depletion of the Ozone Layer occurs globally, but the severe depletion of the Ozone Layer over the Antarctic is often referred to as the 'Ozone Hole'. Increased depletion has recently started occurring over the Arctic as well.

 

When is World Ozone Day?

 

International Day for the Preservation of the Ozone Layer is observed on September 16 every year.

 

Montreal Protocol on Ozone Layer depletion

 

Montreal Protocol is a multilateral environmental agreement that regulates the production and consumption of ozone-depleting substances (ODS). It was adopted on September 15, 1987. The Parties to the Montreal Protocol reached agreement at their 28th Meeting of the Parties on 15 October 2016 in Kigali, Rwanda, to phase-down hydrofluorocarbons (HFCs). Countries agreed to add HFCs to the list of controlled substances, and approved a timeline for their gradual reduction by 80-85 per cent by the late 2040s.

 

RSPCB-JSO RSPCB-JEE

RSPCB - JSO & JEE I Chapter - Global Warming : Environmental General Knowledge

Q: What is global warming?

A: Here's a simple definition of global warming. (And yes, it's really happening.) Over the past 50 years, the average global temperature has increased at the fastest rate in recorded history. And experts see the trend is accelerating: All but one of the 16 hottest years in NASA’s 134-year record have occurred since 2000

Climate change deniers have argued that there has been a “pause” or a “slowdown” in rising global temperatures, but several recent studies, including a paper published in the journal Science, have disproved this claim. And scientists say that unless we curb global-warming emissions, average U.S. temperatures could increase by up to 10 degrees Fahrenheit over the next century.

Q: What causes global warming?

A: Global warming occurs when carbon dioxide (CO2) and other air pollutants and greenhouse gases collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface. Normally, this radiation would escape into space—but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. That's what's known as the greenhouse effect.

Q: How is global warming linked to extreme weather?

A: Scientists agree that the earth’s rising temperatures are fueling longer and hotter heat waves, more frequent droughts, heavier rainfall, and more powerful hurricanes. In 2015, for example, scientists said that an ongoing drought in California—the state’s worst water shortage in 1,200 years—had been intensified by 15 percent to 20 percent by global warming. They also said the odds of similar droughts happening in the future had roughly doubled over the past century. And in 2016, the National Academies of Science, Engineering, and Medicine announced that it’s now possible to confidently attribute certain weather events, like some heat waves, directly to climate change. 

Q: What are the other effects of global warming?

A: Each year, scientists learn more about the consequences of global warming, and many agree that environmental, economic, and health consequences are likely to occur if current trends continue. Here’s just a smattering of what we can look forward to:

·       Melting glaciers, early snowmelt, and severe droughts will cause more dramatic water shortages and increase the risk of wildfires in the American West.

·       Rising sea levels will lead to coastal flooding on the Eastern Seaboard, especially in Florida, and in other areas such as the Gulf of Mexico.

·       Forests, farms, and cities will face troublesome new pests, heat waves, heavy downpours, and increased flooding. All those factors will damage or destroy agriculture and fisheries.

·       Disruption of habitats such as coral reefs and Alpine meadows could drive many plant and animal species to extinction.

·       Allergies, asthma, and infectious disease outbreaks will become more common due to increased growth of pollen-producing ragweed, higher levels of air pollution, and the spread of conditions favorable to pathogens and mosquitoes.