A presentation on

Ozone Layer Depletion

andGlobal Warming

Presented by:

Rama Khadka

Before we start some question …..– Have you ever felt the sun's intensity ripping through your skin on

a hot afternoon?– Why it is not too cold at night when there is no sun in the sky??– What is the concentration of carbondioxide in atmosphere now??– What is the annual temperature increase in the earth???– What in the annual temperature increase in Nepal????– Why there is a change like this…..

Ozone Layer depletion

What is Ozone?

Ozone is a natural gas composed of three atoms of oxygen. Its chemical symbol is O3. It is blue in color and has a strong odour. Normal oxygen (O2), which we breathe, has two oxygen atoms and is colorless and odorless. Environmental scientists have classified O3 into two: Good Ozone and Bad Ozone.

Good Ozone – Good ozone (also called Stratospheric Ozone) occurs naturally in

the upper Stratosphere. The stratosphere is the layer of space 6 to 30 miles above the earth's surface.

Where does good Ozone come from?– When UV light strikes (Oxygen) O2 molecules, they split into two

individual O atoms — O and O. When one of the O atoms combine with O2 molecule, ozone (O3) is created.

Even though Ozone is only a small part of the gases in this layer, it plays a vital role because it shields us from the sun's harmful UV rays. It is called Good Ozone, for obvious reasons—because it protects humans, life and animals on earth.

Bad Ozone – Bad Ozone is also known as Tropospheric Ozone, or ground level

ozone. This gas is found in the troposphere, the layer that forms the immediate atmosphere.

Where does bad ozone come from?– Each time there is a reaction of chemicals such as those found in

cars, power plants and factory emissions, in the presence of sunlight (UV light) Bad Ozone is created, so it can be said that Bad Ozone does not exist naturally. Bad ozone contaminates (dirties) the air and contributes to what we typically experience as "smog”

The Ozone Layer– This is simply a layer in the stratosphere containing a relatively high

concentration of ozone.

What is Ozone Depletion?

– Ozone layer depletion, is simply the wearing out (reduction) of the amount of ozone in the stratosphere. Ozone depletion has been pinned down to one major human activity as its cause.

– Industries that manufacture things like insulating foams, solvents, soaps, cooling things like Air Conditioners, Refrigerators and ‘Take-Away’ containers use something called chlorofluorocarbons (CFCs). These substances are heavier than air, but over time, (2-5years) they are carried high into the stratosphere by wind action.

– Scientific evidence indicates that stratospheric ozone is being destroyed by a group of manufactured chemicals, containing chlorine and/or bromine. These chemicals are called "ozone-depleting substances" (ODS).

– ODS are very stable, nontoxic and environmentally safe in the lower atmosphere, which is why they became so popular in the first place. However, their very stability allows them to float up, intact, to the stratosphere.

– The main ODS are chlorofluorocarbons (CFCs), hydrochlorofluorcarbons (HCFCs), carbon tetrachloride and methyl chloroform. Halons (brominated fluorocarbons) also play a large role.

– Their application is quite limited. But the problem with halons is they can destroy up to 10 times as much ozone as CFCs can. For this reason, halons are the most serious ozone-depleting group of chemicals.

Health and environmental effect of ozone layer depletion

Reductions in stratospheric ozone levels will lead to higher levels of UVB reaching the Earth's surface.Effect on human Laboratory and epidemiological studies demonstrate that UVB

causes nonmelanoma skin cancer and plays a major role in malignant melanoma development.

In addition, UVB has been linked to cataracts -- a clouding of the eye’s lens.

Effect on plants Plant growth, as well as its physiological and developmental processes are all affected

negatively.

These include the way plants form, timing of development and growth, distribution of plant nutrients and metabolism, etc.

Effect on biochemical cycles Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical

cycles, thus altering both sources and sinks of greenhouse and chemically-important trace gases e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS) and possibly other gases, including ozone.

Effect on marine Ecosystem Scientists have demonstrated a direct reduction in phytoplankton

production due to ozone depletion-related increases in UVB. Phytoplankton form the foundation of aquatic food webs. One

study has indicated a 6-12% reduction in the marginal ice zone. Solar UVB radiation has been found to cause damage to early

developmental stages of fish, shrimp, crab, amphibians and other animals. The most severe effects are decreased reproductive capacity and impaired larval development.

Effect on materials Synthetic polymers, naturally occurring biopolymers, as well as

some other materials of commercial interest are adversely affected by solar UV radiation.

Today's materials are somewhat protected from UVB by special additives. Therefore, any increase in solar UVB levels will therefore accelerate their breakdown.

Protecting Ozone layerHere are five ways in which we can contribute to protecting the ozone layer and our precious Earth:

Limit private vehicle drivingUse eco-friendly household cleaning productsAvoid using pesticidesDeveloping stringent regulations for rocket launchesBanning the use of dangerous nitrous oxide

Global warming

Greenhouse effect – In a simple term the greenhouse effect can be defined as a

blanket around the earth. – A layer of greenhouse gases – primarily water vapor, and

including much smaller amounts of carbon dioxide, methane and nitrous oxide – acts as a thermal blanket for the Earth, absorbing heat and warming the surface to a life-supporting average of 59 degrees Fahrenheit (15 degrees Celsius).

Greenhouse Gases– Greenhouse gases are those that absorb and emit infrared radiation in the

wavelength range emitted by Earth. In order, the most abundant greenhouse gases in Earth's atmosphere are:

– Water vapor (H2O)– Carbon dioxide (CO2)– Methane (CH4)– Nitrous oxide (N2O)– Ozone (O3)– Chlorofluorocarbons (CFCs)

Let us remember our evolution

And we have changed

To

But during this revolution we have changed many other things also like

– Have produced a 40% increase in the atmospheric concentration of carbon dioxide.

– The concentration of carbon dioxide reach from 280 ppm in 1750 to 400 ppm in 2015.

– Which result from the Strengthening of the greenhouse effect through human activities is known as the enhanced or anthropogenic greenhouse effect.

– When fossil fuels - coal, oil and natural gas - are burnt they release CO2 into the atmosphere. Because of this the layer of greenhouse gas is getting thicker, which is in turn making the Earth warmer.

– The global average (land and ocean) surface temperature shows a warming of 0.85 [0.65 to 1.06] °C in the period 1880 to 2012, based on multiple independently produced datasets.

– Global Warming is the increase of Earth's average surface temperature due to effect of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation, which trap heat that would otherwise escape from Earth.

– According to the International Energy Agency the power sector is responsible for 37% of all man-made Carbon Dioxide (CO2) emissions. It creates about 23 billion tons of CO2 emissions per year – in excess of 700 tons a second.

– In turn, this CO2 continues to heat up our planet which poses an unprecedented threat to us and the environment.

– So, generating electricity through the burning of fossil fuels, in particular carbon-heavy coal, has a greater impact on the atmosphere than any other single human activity.

Effects of climate change

– Rising Seas--- inundation of fresh water marshlands (the everglades), low-lying cities, and islands with seawater.

– Changes in rainfall patterns --- droughts and fires in some areas, flooding in other areas.

– Increased likelihood of extreme events--- such as flooding, hurricanes, etc.

– Melting of the ice caps --- loss of habitat near the poles. Polar bears are now thought to be greatly endangered by the shortening of their feeding season due to dwindling ice packs.

– Melting glaciers - significant melting of old glaciers is already observed.

– Widespread vanishing of animal populations --- following widespread habitat loss.

– Spread of disease --- migration of diseases such as malaria to new, now warmer, regions.

– Bleaching of Coral Reefs due to warming seas and acidification due to carbonic acid formation --- One third of coral reefs now appear to have been severely damaged by warming seas.

– Loss of Plankton due to warming seas --- Which is a foundation of aquatic food web.

In short the single but threatening effect of global warming is Climate change.

In context of Nepal– Nepal is responsible for 0.025 % of global carbon emission

– And has been listed as a fourth vulnerable country due to climate change.

– As the average annual temperature is increasing by 1.5 °C .

– Frequent news on headline like changed rain pattern, floods, drought, vanishing of apple orchids from Mustang village, tree line shifting etc. are now common.

– In short there is an enough evidence of effects of climate change in Nepal too.

What we have done so far???– Many actions were taken in the past few years as mitigation and

adaptation for the global warming and climate change after The United Nations Framework Convention on Climate Change (UNFCCC) in 1992.

– The main current international agreement on combating climate change is the Kyoto Protocol, which came into force on 16 February 2005.

– For countries in the EU, this involves a commitment to reducing carbon emissions by 12.5% by 2012. While the protocol is binding, it isn't compulsory for countries to actually sign up, and, notably, several large counties including the US haven't committed to signing up to the scheme as yet, despite growing international pressure.

– But the scenario have been changed the existing and possible effects of climate change can be very dangerous for the human being.

– So a concrete action with the climate justice for the developing countries like Nepal is MUST.

– Most recently, a UN conference in Bali reached a deadlock after the US refused to support a follow-up deal to Kyoto, which would have seen countries have to reduce carbon emissions by up to 40% by 2020.

– For our future, the Conference of parties (COP) 21 is on its way in Paris and the world is expecting a new climate treaty as a drastic awareness have been seen among the population around the world.

Only one planet No plan B…..

References– http://

www.nmsea.org/Curriculum/Primer/Global_Warming/fossil_fuels_and_global_warming.htm

– http://www.nrdc.org/globalwarming/

– https://en.wikipedia.org/wiki/Global_warming

– https://en.wikipedia.org/wiki/Ozone_depletion

– http://environment.nationalgeographic.com/environment/global-warming/ozone-depletion-overview/