Greenhouse Effect and Climate Change

THE GREENHOUSE
EFFECT AND THE

CHANGING CLIMATE

The Natural Greenhouse Effect→ This is without

human intervention

▪ The atmosphere acts like the glass in a

greenhouse

▪ Sunlight streams from the Sun into the

Earthʼs atmosphere to heat the Earth

▪ As heat radiates from the Earthʼs surface

it can do 1 of 2 things.
▪

Escape into space

▪

Be absorbed by gases that are present in the
atmosphere

The Enhanced Greenhouse Effect

•The enhanced greenhouse effect works in the same way as the natural greenhouse effect

•The only difference is that there are more gases in the atmosphere to allow absorption of
solar radiation

•More gases are present in atmosphere due to human emissions

•Gases being emitted:

•***Water vapor

•***CO2

•Nitrous Oxides

•CFCʼs…Remember those?

•Methane…decomposition

•***Water vapor and CO2 absorb the MOST heat

•BUT…without the Greenhouse Effect the Earthʼs average temperature would be around 4⁰F

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Water Vapor

■

Water Vapor is the most abundant greenhouse gas in the atmosphere

■

The Good about Water Vapor

–When enough exists in the atmosphere it condenses (gas to liquid) to become a
cloud

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Which reflects sunlight

■

The Bad about Water Vapor

–As temperature rises more groundwater evaporates, warm air can hold more
water.

■

Meaning more water is evaporated since itʼs warm air and it can hold more.

–Allows for absorption of thermal Infrared radiation

■

A hard gas to measure accurately worldwide

Carbon dioxide

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Began rising with the onset of
Industrial Revolution

■

First started monitoring in 1958

–Showed fluctuating levels
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High levels in spring and winter,
lower levels in summer and
autumn

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Why?
–Photosynthesis

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Levels never decrease from year to year

Nitrous oxides

■

Remember that Nitrogen is a natural cycle
that Earth has always had

Began rising with the onset of Industrial
Revolution

Continued rise in concentrations due to
high fertilizer use in agriculture

Sources: power plants, nylon production,
vehicle emissions, nitric acid production

Chlorofluorocarbons—CFCʼs

•At the surface of the Earth, in the troposphere, they are stable, harmless and happy
little molecules

•However when they start moving up in altitudes

•They break apart due to the UV radiation becoming stronger

•These broken down CFC molecules then react and destroy ozone molecules.

•A by-product of breaking CFCʼs apart is Atomic Chlorine Gas

•We have done away with CFC production however they are still in the atmosphere and
we have also created new chemicals that are doing the same thing as CFCʼs

•Carbon tetrafluoride

•Sulfur hexafluoride

•Hydrofluorocarbons (HFCʼs)

CFCʼs and the Ozone Layer

•The use of CFCʼs were in the 1970ʼs found to be linked to the shrinking ozone layer

•Most call it the “Ozone Hole”, it is not a literal hole

•Think of it more along the lines of thinning

•A study in 1985 in Nature Magazine reported that the ozone layer over the Antarctic
had thinned somewhere between 50-98%

•These signs were noticed in 1979

•This “Hole” changes size throughout the year due to air movements

Methane

■

Very effective absorber of solar
radiation

■

Methane is a natural process

–

It is also influenced by humans

■

Released from low oxygen
environments (areas covered in water)

–

Swamps or rice fields

■

Humans are demanding more rice,
beef, natural gas and coal

–

All of these resources emit
concentrations of methane

Natural Climate Change

Volcanic Eruptions

■when volcanoes erupt they give off more
than just lava

–volcanic ash...particulate matter

–sulfur dioxide
■mixes with water vapor and dust to
block the sunlight

■Volcanic winters

–after large eruptions of volcanoes the
reaction with sulfur dioxide can cool
the immediate area and the planet
(due to wind)

Ocean Currents

■slight shifts in ocean
currents and their
temperatures change the
temperatures of
neighboring land masses

■What type of heat transfer
would cause this change
in currents?

Earthʼs Orbital Change

■remember nutation?

–earthʼs wobble?

■slight changes can cause the angle of the sunlight to vary

–which changes average temperature and seasons

El Niño and La Niña

■El Niño– climate event in which
warm equatorial waters replace
cold off-shore waters

■Caused by a reversal of direction
in global winds

■Impacts:

–Dry places become wet

–Wet areas become dry

–Can cause flooding one place
and drought in another

–Can destroy crops and
reduce fishing

El Nino

Take a look at the image, what effect is most

concerning to you?

■La Niña– climate event in which colder than normal water stretches across the
equatorial South Pacific

■Caused by intensified global winds

■Water moves faster across equator and does not get as warm

■Impacts:

–Can greatly increase precipitation for places that are normally wet
■Ex. Northwest U.S.

La Nina

How often do El Niño events occur?

■On average, every 2 to 10 years

■Lasts for 12 to 18 months

■Since this is naturally occurring, should we be concerned that these cycles seem to
be lasting longer?

Man Made Climate

Change

Greenhouse Gases

■

Remember all previously mentioned greenhouse gases are contributors to
Global Warming and the Climate Change we are currently facing

Industrialization

■

The wide scale rise of industry in countries or regions

–

The Industrial Revolution of the 1800ʼs

–

Machine technology
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Tractors, automobiles, electricity

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Contributes to the enhanced greenhouse effect

Heat Islands

■

an urban area or metropolitan area that is
significantly warmer than its surrounding
rural areas due to human activities

–Development and expansion of cities
and urban areas

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More concrete and buildings add darker
colors to Earthʼs surface

–Dark colors absorb solar radiation
■

Increasing temperatures

Deforestation

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Clearing or cleared land from forests to something of a “non-forest” use

–Like farms, ranches, urban housing development

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Most deforestation occurs in tropical rainforests

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Deforestation can lead to industrialization and development of heat islands

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Can lead to higher levels of carbon dioxide and lower levels of oxygen

–Disrupts photosynthesis process

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Removing green areas and replacing it with urban concrete

–Going from reflection to absorption of solar radiation

GLOBAL WARMING

CAUSES

-Greenhouse Gases

-Industrialization

-Heat Islands

-Deforestation

EFFECTS OF GLOBAL

WARMING

Or effects of something happening

Evidence that “Something” is happening

• Ice cores

• Inside ice Carbon is stored that can be measured to find the levels

• Ice Melt

• Due to higher temperatures than normal

• Sea level Rise

• Due to ice melt

• Coral Reef Bleaching

• Due to pollution of the oceans

• Acid Shock

• Rapid pH change that kills off fish/aquatic species

Greenlandʼs Ice Melt

Consequences we are Facing

• Melting Ice and Rising Sea Levels

• As temperatures rise the glaciers and ice covering the

poles will start to melt (this is already happening) which
places more water into the oceans

• Flooding due to this excess water
• Beach erosion (think NC Outer Banksʼ coastline)
• Changing of salinity in the oceans

•How much salt will be in the water?

Consequences we are Facing

• Global Weather Changes

• Warmer oceans will lead to more storms (Katrina, Sandy)
• Severe changes in regional rainfall amounts

•Droughts or Floods

• Extreme temperatures

•Really Cold winters

•Really Warm summers

HOW WE CAN HELP

…and what we have already done

The Environmental Movement

• The Environmental Protection Agency

•Est. 1970

•Holds businesses, states, cities, people accountable for actions of pollution

• Clean Air Act

•Car emissions regulations

•Reduced factory emissions

• Kyoto Protocol

•Holds the Developed countries accountable for their emissions into the
atmosphere

•Stated that emissions must be below certain percentages

Further Help

■

Montreal Protocol

–Requires participating countries to eliminate CFC use and production

■

Countries are enacting their own laws to hold cities and industries accountable

■

Some countries are using trade agreements to make other countries more
accountable for emissions

Helping with Alternative Energies

■

Remember Nuclear, Hydroelectric, Tidal energies?

–They are green, and reduce emissions of many greenhouse gases

■

Solar Energy

–Passive—Open windows and blinds to allow room or home to naturally heat your
space

–Active—Using solar panels wired into your power-grid to power your homeʼs
electrical needs

Simple Methods to help

■

Recycle

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Car-pool

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Install solar panels

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Plant trees