The document discusses global warming and ozone layer depletion caused by human activities, primarily through greenhouse gas emissions and ozone-depleting substances. It outlines the effects of these environmental issues, including rising temperatures, severe weather events, health risks, and ecological impacts. Furthermore, it offers prevention methods such as reducing energy consumption, using renewable energy, and avoiding ozone-depleting substances.

1. VIVEKANANDHA
ARTS AND SCIENCE COLLEGE FOR WOMEN
Veerachipalayam-637 303,Sankagiri,Salem Dt, Tamilnadu,India.
Affiliated to Periyar University Salem ; recognised under section 2(f)&12(b) of the UGC act,1956
DEPARTMENT OF MICROBIOLOGY
SUBJECT: ENVIRONMENTAL MICROBIOLOGY
TITLE : GLOBAL WARMING, OZONE LAYER DEPLETION
SUBJECT INCHARGE :
Dr.MYTHILI RAVICHANDRAN
Head Of The Department
Department of Microbiology
VIAAS , Sankagiri .
SUBMITTED BY :
SWATHI NATRAJAN
III B.sc Microbiology
Department of Microbiology
VIAAS , Sankagiri .

2. GLOBAL WARMING

3. INTRODUCTION
• Global warming is the increase in the Earth’s average
temperature due to the rising concentration of
greenhouse gases in the atmosphere.
• The main cause of global warming is human activity,
such as burning fossil fuels for energy, transportation,
and industrial activity.

4. CAUSES
• Global warming results from the increasing concentration of
carbon dioxide (CO2) and other greenhouse gases that trap
heat in the earth’s atmosphere.
• This trapped energy comes from incoming solar radiation
absorbed by the earth’s surface and re-radiated back into the
atmosphere as infrared energy.

5. • Though natural cycles and fluctuations have caused the
planet’s climate to change continually over the last
800,000 years, it is human activity that has driven our
current era of global warming.
• In particular, our burning of fossil fuels.such as coal, oil,
gasoline, and natural gas has led to the greenhouse effect.
• In the United States, the largest source of greenhouse
gases is transportation, followed closely by electricity
production and industrial activity.

6. Burning fossil fuels
When coal and gas are burned to create electricity or power vehicles,
carbon dioxide is released into the atmosphere.
Deforestation
When trees and forests are cleared or thinned, the carbon they store
is released into the atmosphere as carbon dioxide. Deforestation is
responsible for about 25% of global greenhouse gas emissions.
Greenhouse gas emissions
Carbon dioxide, methane, and nitrous oxide are greenhouse gases
that trap heat in the atmosphere, causing the Earth’s surface
temperature to rise. Concentrations of these gases are higher than
they’ve been in the last 800,000 years.

7. EFFECTS OF GLOBAL WARMING
Rising temperatures
As greenhouse gas concentrations increase, so does the
global surface temperature.
Sea level rise
The global average sea level has risen by about 7.9 inches
since 1901.
More severe storms
Climate change can increase the frequency and intensity of
extreme weather events like heat waves, droughts, and
floods.

8. Loss of species
Changing ecosystems can influence the geographic ranges of
many plant and animal species
Soil degradation
Climate change can cause erosion, decline in organic matter,
salinization, soil biodiversity loss, landslides, and
desertification.
Health risks
Climate change can worsen air and water quality, increase
the spread of certain diseases, and affect the food we eat.

9. Coral reef death
Many coral reefs are dying, which threatens the
thousands of species of fish and other organisms that
live there.
Global warming can release long-buried microbes,
which can cause outbreaks

10. PREVENTION
Reduce energy consumption
Use energy-efficient appliances, turn off lights and
electronics when not in use, and insulate homes.
Use renewable energy
Invest in solar panels or renewable energy credits to
support clean energy production.
Conserve water
Take shorter showers, fix leaks, and use water-
efficient appliances.

11. Reduce meat consumption
Choose plant-based diets, which tend to have lower
carbon footprints.
Use public transport or carpool
Reduce reliance on fossil fuels by using public transport,
walking, or biking.
Recycle and compost
Properly dispose of waste to reduce landfill emissions

12. OZONE LAYER DEPLETION

13. INTRODUCTION
• The ozone layer is the common term for the high
concentration of ozone that is found in the
stratosphere around 15–30km above the earth’s
surface.
• It covers the entire planet and protects life on earth by
absorbing harmful ultraviolet-B (UV-B) radiation from
the sun.

15. OZONE LAYER DEPLETION
Ozone layer depletion is the gradual thinning of the earth’s
ozone layer in the upper atmosphere caused due to the
release of chemical compounds containing gaseous
bromine or chlorine from industries or other human
activities.
• Some compounds release chlorine and bromine on
exposure to high ultraviolet light, which then contributes
to ozone layer depletion. Such compounds are known as
Ozone Depleting Substances (ODS).

16. • The ozone-depleting substances that contain
chlorine include chlorofluorocarbon, carbon
tetrachloride, hydrochlorofluorocarbons, and
methyl chloroform.
• Whereas, the ozone-depleting substances that
contain bromine are halons, methyl bromide, and
hydro bromofluorocarbons.

18. CAUSES OF OZONE LAYER DEPLETION
Chlorofluorocarbons
Chlorofluorocarbons or CFCs are the main cause of ozone layer
depletion. These are released by solvents, spray aerosols, refrigerators,
air-conditioners, etc.
The molecules of chlorofluorocarbons in the stratosphere are broken
down by ultraviolet radiations and release chlorine atoms. These
atoms react with ozone and destroy it.
Unregulated Rocket Launches
• Researches say that the unregulated launching of rockets results in
much more depletion of the ozone layer than the CFCs do. If not
controlled, this might result in a huge loss of the ozone layer by the
year 2050.

19. Nitrogenous Compounds
The nitrogenous compounds such as NO2, NO, N2O are
highly responsible for the depletion of the ozone layer.
Natural Causes
The ozone layer has been found to be depleted by certain
natural processes such as Sun-spots and stratospheric
winds. But it does not cause more than 1-2% of the
ozone layer depletion.
• The volcanic eruptions are also responsible for the
depletion of the ozone layer.

20. EFFECTS OF OZONE LAYER DEPLETION
Effects on Human Health
Humans will be directly exposed to the harmful
ultraviolet radiation of the sun due to the depletion of the
ozone layer. This might result in serious health issues
among humans, such as skin diseases, cancer, sunburns,
cataract, quick ageing and weak immune system.
Effects on Animals
• Direct exposure to ultraviolet radiations leads to skin
and eye cancer in animals.

21. Effects on the Environment
Strong ultraviolet rays may lead to minimal growth,
flowering and photosynthesis in plants. The forests also
have to bear the harmful effects of the ultraviolet rays.
Effects on Marine Life
• Planktons are greatly affected by the exposure to
harmful ultraviolet rays. These are higher in the
aquatic food chain. If the planktons are destroyed, the
organisms present in the food chain are also affected.

22. PREVENTION
Avoid ozone-depleting substances
Avoid using products that contain ozone-depleting
substances (ODSs) like CFCs, halogenated hydrocarbons,
methyl bromide, and nitrous oxide.
Use eco-friendly products
Use eco-friendly cleaning products and buy local
products. Reduce vehicle use
Minimize the use of cars and use public transportation, a
bicycle, or walk instead.

23. Maintain air conditioners
Regularly inspect and maintain air conditioners to
prevent refrigerant leakage. When servicing, recover and
recycle refrigerants instead of venting them into the
atmosphere.
Use renewable energy
Use renewable sources of energy.Reuse and recycle:
Reuse and recycle

24. THANK YOU