GLOBAL CLIMATE CHANGE - Mr. Nolan
Name: _________________
GREENHOUSE EFFECT (UV Energy Input vs. IR Energy Output)
Q) What is the Greenhouse Effect?
Solar light energy passes through Earth’s atmosphere. This light energy is known as
ultraviolet (UV) energy. When UV light energy hits the Earth, most of it is converted into
heat energy, known as infrared (IR) energy. Some of this infrared heat energy is
absorbed by Earth’s land and water masses; and some of the IR heat energy is radiated
up from the Earth into the atmosphere.
Greenhouse gases (GHGs) in the atmosphere trap some of the heat energy the Earth
emits and prevents it from radiating out into space. This heat trapping adds more heat
to the lower atmosphere and the Earth’s surface. In fact, without the greenhouse effect,
the average global temperature would be 60oF colder than it is today and there would
be no life on Earth. However, as you add more GHGs, you trap more heat and increase
global temperatures.
You experience all this when you sit in a car on a sunny day with the windows closed.
UV energy hits the dashboard and seats and is converted to IR/heat energy. These
materials radiate heat, causing the interior of the car to get warmer. Some of the heat
escapes through the glass and metal, but some is also trapped inside the car.
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GREENHOUSE GASES
The major greehouse gases (ranked in order of global heat trapping impact) are:
#1) Water vapor
#2) Carbon dioxide
#3) Methane
As the graph below shows, atmospheric concentrations of human-source greenhouse
gases have increased enormously during the last 150 years since the industrial
revolution when humans began burning fossil fuels like coal, oil, gasoline, and natural
gas (methane).
BURNING FOSSIL FUELS GENERATE CARBON DIOXIDE
What are fossil fuels made of?
And, why does burning them release carbon dioxide?
Here’s a balanced formula for combustion of coal: 2(C10H2) + 2102 --> 2H20 + 20CO2
The common chemical formula for gasoline is C8H18. Burning it gives you:
C8H18 + 12.5 O2 ---> 9 H2O + 8 CO2
Natural gas (methane) for gas stoves and furnaces:
CH4 + O2 --> CO2 + H2O (unbalanced reaction)
Heating oil is very similar to diesel fuel. Heating oil's chemical formula is between
C14H30 and C20H42.
And why does burning fossil fuels release carbon dioxide (CO2)?
 It’s just like breaking down C6H12O6 into CO2 and H20 during cellular respiration.
 Break bonds of bigger molecules to get the energy. The by-products are smaller
molecules made up of the same atoms.
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RECENT GLOBAL WARMING
As the concentration of greenhouse gases (GHGs) in the atmosphere increases, they
prevent more IR heat energy from escaping into space. It is something like having a
thicker blanket covering you. As the graph below shows, over 100 years, Earth has
experienced a correlated global average temperature increase or approximately 1.4oF.
The rate of warming is increasing. In fact, 11 of the warmest years in recorded history
have occurred in the past 13 years.
REGIONAL VARIATIONS IN WARMING
As shown in the figure below from Accuweather, not all regions warm the same. For
example, the poles are warming faster than the equator. Central Canada is warming
faster than other regions. Southern Africa and Argentina have even cooled slightly.
Variations have numerous causes, ranging from air and ocean currents, and impacts of
forests. This figure compares September 2009 with the average for the period 19511980 by region.
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POPULATION CHANGE & THE CLIMATE CRISIS
What happens when you have: 1) a rapidly increasing human population
…and 2) every year each individual releases more GHG emissions?
Answer: Global GHG emissions increase every year due to: (1) rapid population
increase, and (2) annual increases in per capita GHG emissions. (“per capita”
means per person)
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POPULATION STATISTICS
World Population in 1900 = 1.6 billion
World Population in 2008 = 6.7 billion (FYI: US Population = 305 million)
World Population estimate for 2050 = 9.3 billion
The world population has grown significantly in the 20th century and is projected to
grow exponentially in the 21st century mostly in the developing regions.
Population growth is simply due to a reduced death rate relative to birth rate.
The three main causes of the reduced death rate are:
 Increased food production and distribution
 Improved public health
 Improved medical technology
Q) What are main implications of population growth?
 More people consuming more fossil fuels per person = more GHG emissions.
 Decreasing availability of adequate food, water, safe shelter, and income.
Why is Human Population Growth So Catastrophic?
“At the root of all the converging crises of the World Problematique is the issue of human
overpopulation. Each of the global problems we face today is the result of too many people using
too much of our planet's finite, non-renewable resources and filling its waste repositories of land,
water and air to overflowing. The true danger posed by our exploding population is not our absolute
numbers but the inability of our environment to cope with so many of us doing what we do.
“It is becoming clearer every day, as crises like global warming, water, soil and food depletion,
biodiversity loss and the degradation of our oceans constantly worsen, that the human situation is
not sustainable. Bringing about a sustainable balance between ourselves and the planet we
depend on will require us, in very short order, to reduce our population, our level of activity, or both.
http://www.paulchefurka.ca/Population.html
Deforestation & Desertification
Starvation
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WHO IS PRODUCING ALL THESE GREENHOUSE GASES?
Americans burn far more green house gases per capita than people of other nations.
 Annually Americans produce 20 tons CO2 per capita
 Most Europeans produce <10 tons
 Chinese produce 4 tons
 India per capita is 1 ton.
As China and India are developing rapidly, so is their energy production. Total
emissions from China have just surpassed that of the U.S. As India develops, and has
an enormous, predominantly rural, population explosion, its total emissions may also
surpass the US in the more distant future.
http://rainforests.mongabay.com/09-carbon_emissions.htm
Still, on a per capita basis, the Chinese and Indians release far fewer GHG’s than
Americans. They individually hold far less responsibility for global warming than you do.
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