Global Warming

Ch. 13 Section 3

• Sunlight enters Earth’s atmosphere• Earth’s surface radiates heat back to the

atmosphere– Some heat escapes– Some heat is trapped by Greenhouse Gases

• Ex: water vapor, carbon dioxide, methane, nitrous oxide

• Trapped heat radiated back to Earth’s surface, warming the air.

• Without this Earth would be too cold to live on• However, too many greenhouse gases can trap

too much heat.

Greenhouse Effect

Greenhouse Effect

Greenhouse Effect

Greenhouse Gases - gases that absorb and radiate heat

• Water vapor• Carbon Dioxide • CFC’s• Methane• Nitrous oxide

• Water vapor and CO2 absorb the most heat in the atmosphere

CO2

• Most is absorbed by the ocean or used by plants during Photosynthesis

• Therefore, CO2 levels fluctuate with the season– Summer = less CO2 ----------------------------------------------

– Winter = more CO2 ------------------------------------------------

• WHY???

CO2 Levels

There has been a significant rise in CO2 in the atmosphere in the last 50 years due to burning fossil fuels

Ice Core Samples

• Can determine the levels of CO2 in the atmosphere thousands of years ago

CO2 and Temperature

• Because CO2 holds more heat than other gases in the atmosphere, scientists think that more CO2 means greater global temperatures

• Therefore…• Burning = more CO2 = Higher temps.

Temp. and CO2 Levels

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Consequences of Global Warming• Birds nesting earlier• Flowering earlier – more allergies• Change weather patters– Droughts and flooding– More hurricanes and typhoons

• Rising sea level– Flooding of coastal areas– Erosion of beaches– Increase in salinity in aquifers

• More mosquitoes that carry diseases

• Agriculture– Most severely effected– Decreased crop yield– Could need more irrigation

• Animals– Shift their geographical range– Reduce the number of zooplankton

Consequences of Global Warming

IPCC

• International Panel on Climate Change– Average global temp. increased by 0.6oC last century– Snow cover and ice have decreased– Global sea level has risen

Kyoto Protocol

• 1997, 160 countries

• Requires countries to reduce CO2 and other greenhouse gas emissions by 5% by 2012

• We did sign, then Bush unsigned us

Ch. 13

Section 1 Objectives

• Explain the difference between weather and climate.

• Identify four factors that determine climate.• Explain why different parts of the Earth have

different climates.• Explain what causes the seasons

Weather vs. Climate

• Weather – what is happening right at that moment– It is cloudy and raining outside

• Climate – the average weather over a long period of time– We live in a hot, dry area

Latitude- distance north or south from the equator

• Determines what type of climate an area has

• The further from the equator the ________ the temperature.

Latitude

• Daylight hours depend on your latitude– Equator = 12 day and 12 night– Close to the poles = all day or all night part of the year

Atmospheric Circulation

• Warm air rises• Cold air sinks• Warm air hold more water vapor• When it cools the water vapor condenses into

precipitation

El Nino

• When warm and cold water masses change location in the Pacific Ocean for a short time

• Causes increased rainfall in the southern US, but causes droughts in Indonesia and Australia

• La Nina – exact opposite• Pacific Decadal Oscillation – a long term El Nino

Topography influences on climate

• Topography is the shape of the earth’s surface

• As elevation increases temperature drops

Solar Maximum and Volcanoes

• Solar Maximum – sun emits more ultraviolet radiation, warming the earth

• Vocanoes – dust and such can block out some of the sun cooling the earth

Seasonal Climate Change

• Seasons change due to the tilting of earth as it goes around the sun.

Section 2 Objectives

• Explain why Earth’s atmosphere is like the glass in a greenhouse.

• Explain why carbon dioxide in the atmosphere appears to be increasing.

• Explain why many scientists think that the Earth’s climate may be becoming increasingly warmer.

• Describe what a warmer Earth might be like.

Ozone layer- are where ozone (three oxygen atoms) is concentrated in the

stratosphere

• Act like sunscreen for the earth

• Block out UV rays that harm genetic material

Chlorofluorocarbons (CFC’s)

• The miracle chemical• 1970’s they were used for– Coolants– Deodarants– Hairspray, etc.

• However, at high elevations CFC’s break apart and the parts destroy and combine with ozone molecules

• 1 CFC molecule can destroy 100,000 ozone molecules

The Hole

• First reported in 1985 over the South pole– Ozone had shrunk by 50 – 98%– Why over south pole?

How it effects humans

• Worse sunburns• More eye cataracts• Immune system repression (UV-B)• More skin cancer

Montreal Protocol - 1987

• Representative of 36 Nations

• Reduce CFC emissions (only) by 35% between 1989 – 2000

• Now signed by 177 countries

• Global Cooperation Does Work!!!

Differences between Global Warming and Ozone depletion

• Different type of radiation:

–Infrared vs. Ultraviolet

• Different effect: –earth warming vs. health problems

• Ozone depletion does not cause global warming directly

• But, it can effect oceans uptake of CO2

Do not confuse them

Skin Cancer

Let’s take a skin cancer quiz!!!

Skin cancer comes in many shapes and sizes

• Things to watch for– Shiny or waxy lump– Firm red lumps– Lump that bleeds and does not heal– Itchy red spot that might be tender (not

eczema)

Overt eyes if squeamish

Squamous cell

• upper skin layer, caused by sunlight and tanning beds, usually curable if treated early, but it can metastasize

Basal cell

• deeper layer of skin, most common form, usually caused by sun and tanning lamps,

Malignant melanoma Worst kind!

• ABCDE rule – A = asymmetry – B = borders – C = color– D = diameter, over 5mm – E = elevation

Risk factors

• Skin type• Sun/tanning exposure

• Freckles

• Family History

How to prevent it

• Sunscreen• Wear hats• Take vitamins (folic acid)• Eat vegetables• Drink Green Tea• Eat Fish• Eat whole grains