GLOBAL WARMING

History of Earth’s Climate

• Earth formed ~4.6 billion years ago• Originally very hot• Sun’s energy output only 70% of

present• Liquid water present ~4.3 billion

years

History of Earth’s Climate

• Life appeared ~3.8 billion years ago• Photosynthesis began 3.5-2.5 billion

years ago– Produced oxygen and removed carbon

dioxide and methane (greenhouse gases)

– Earth went through periods of cooling (“Snowball Earth”) and warming

• Earth began cycles of glacial and interglacial periods ~3 million years ago

What is global warming?

The sun sends out energy as heat and light. This energy comes to our earth during the day time.

Some of the sun’s rays get ‘trapped’ in the atmosphere.

Some of them get reflected back into space.

The ones which get through the atmosphere warm the earth up.

All the time, the earth radiates heat into space, which cools it down. We only really notice this at night, when there is no heating from the sun.

Some of the heat going out is trapped by the atmosphere(carbon dioxide). This is what makes our planet warm enough to live on.

But if too much heat is trapped, our planet will warm up and the climate will change.

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Earth’s Temperature

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How Global Warming Works

Fossil fuels (coal, oil, natural gas)

Carbon Dioxide (CO2)

What is the atmosphere and why does it trap heat?

The atmosphere is the air around the surface of the earth. It is made from a mixture of gases. We need it for animals and plants to survive.

Some of the gases act like a blanket, trapping heat. These gases are called ‘greenhouse gases’.

This is known as the ‘Natural Greenhouse Effect’. Without it, the earth would be much colder.

(the atmosphere is really much thinner than it looks above)

The Sun’s energy passes through the car’s windshield.

This energy (heat) is trapped inside the car and cannot pass back through the windshield, causing the inside of the car to warm up.

Example of the Greenhouse Effect

Why is global warming happening?

Burning of Fossil Fuels

Pollution from coal, natural gas, and oilPollution from coal, natural gas, and oilPollution from coal, natural gas, and oil

• HUMAN ACTIVITIES

• VOLCANIC ERUPTIONS

• DEFORESTATION

DEPLETION OF OZONE LAYER

EFFECTS OF GLOBAL WARMING

• INCREASE IN TEMPERATURE

• RISE IN SEA LEVEL

• STORMS

What’s the proof that global warming is taking place?

Portage Glacier

1914 2004

• Alaska

Photos: NOAA Photo Collection and Gary Braasch – WorldViewOfGlobalWarming.org

Colorado River• Arizona

June 2002 Dec 2003

How is global warming measured?

Ice Core Data

CO2 Measurements Before 1958 - Antarctica

Blowing Up Your World

• 1. How many of you leave your bedroom light on when you are not in the room?

• Turning off lights saves energy and money. The more energy used, the more rivers are dammed or more fossil fuel is burned, causing air pollution and increased levels of carbon dioxide in the atmosphere.

Blowing Up Your World

• How many of you, when you drink a soft drink, throw the container into the garbage?

• Throwing away containers of any kind wastes energy and resources and adds to our waste problem. Many towns are running out of landfill space. 3 pts d

Blowing Up Your World• How many of you use a hairdryer

or other energy-consuming convenience appliance, especially in the morning?

• Hairdryers use a lot of energy. In the morning so much energy demand is put on our grids that power companies have to find other sources of energy just to meet the morning rush hour 2 pts d

Blowing Up Your World• . How many of you, when you go to a

store, get a bag for your purchases, even if you have only one or two small items to carry?

• Making paper and plastic bags uses energy and resources. The bags add to our litter and waste problems, and plastic is not biodegradable. Recycling is not the best answer because collecting and recycling materials requires energy. Instead, carry a reusable cloth bag or a knapsack with you. 3 pts d

Blowing Up Your World

• How many of you eat take-out or cafeteria food that is served in foam or plastic containers?

• Polystyrene and other plastic containers are made from precious petrochemicals, do not decompose in landfills, and release toxic gases when they are burned in incinerators.

10 pts d

Blowing Up Your World

• How many of you use handkerchiefs instead of tissues and use cloth towels instead of paper towels?

• Paper comes from trees. The more of it we use, the more trees that are cut down 2 pts d

So how can each of us slow global warming now?

Because greenhouse gas emissions are tied very closely to our energy consumption, using less fossil fuel based energy puts fewer greenhouse gases into the atmosphere.

This will help slow global warming.

Reduce our consumption of fossil fuels

Mountaintop removal for coal mining near Rawl, West Virginia.

50% of electricity in the United States is produced from coal.

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What’s being done now to reduce our emissions?

Solar Power Wind Power Fuel-Efficiency

What can you do to help solve the problem?

Simple Things To Do

Turn off your computer or the TV when you’re not using it.

Take shorter showers. Heating water uses energy.

Keep rooms cool by closing the blinds, shades, or curtains.

Turn off the lights when you leave a room.

Use compact fluorescent bulbs.

Simple Things To Do

Dress lightly when it’s hot instead of turning up

the air conditioning. Or use a fan.

Dress warmly when it’s cold instead of turning up the heat.

Offer to help your parents keep the air filters on your AC and furnace clean.

Walk short distances instead of asking for a ride in the car.

Plant a tree. Recycle.

Be Bulb Smart—Use CFLs

IncandescentCompact

Fluorescent

500 lbs. of coal

What’s the difference?

•1,430 lbs. CO2 pollution avoided •$30 saved

We humans are thought to be the main cause of global

warming and climate change……..

but we still have the chance to do something about it.

Our take-home message…

Each of us must take steps to protect our Earth's climate.

Presentation by…...

UJWAL

137Z1A0117 GAUTHAM

137Z1A0128Civil 1st year

PRESENTATION BY.......... UJWAL 137Z1AO117

GAUTHAM 137Z1AO128

CIVIL 1ST YEAR

Thank you………..