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CAUSES, EFFECTS, AND THE HUMAN
IMPACT
By: Amanda Shepherd
A brief introduction to the
science behind global warming,
potential impacts of a warming
Earth, and what humans can do
to decrease their contribution to
a warming climate.
Click Here to Continue
WHAT YOU SHOULD EXPECT TO
LEARN FROM THIS ACTIVITY:
In this presentation, you will learn the following:
THE CAUSES OF
GLOBAL WARMING
THE POSSIBLE EFFECTS
OF GLOBAL WARMING
HOW TO REDUCE YOUR
IMPACT ON THE
ENVIRONMENT
“IMAGINIFF…”
Imagine that you are a world leader, with the power to
decide whether or not hundreds of countries throughout the
world are going to endure drought, famine, flooding, and,
thus, an incredible loss of livelihood. Would you spend the
money necessary to stop this tragedy or just sit idly by?
☼ WHAT IS GLOBAL WARMING? ☼
WHAT IS GLOBAL WARMING?
Global warming is
an “increase in the
average temperature
of the Earth’s nearsurface air and
oceans in recent
decades and its
projected
continuation”.
(Wikipedia)
WHAT CAUSES CLIMATE CHANGE?
There are two categories of climate change drivers:
1. Natural
2. Man-made
(Anthropogenic)
NATURAL CAUSES OF CLIMATE CHANGE
CLICK ON A PICTURE TO FIND OUT WHAT
NATURAL FORCES CAN DRIVE CLIMATE CHANGE!
Okay, I’ve looked at each
of the natural causes!
NATURAL CAUSES OF CLIMATE CHANGE:
SOLAR OUTPUT
Most of the time, the energy that the sun radiates is considered
constant. However, this is not entirely accurate. The output of the
sun does change over time, and
many scientists believe that the
sunspot cycle may be linked to
climatic change.
REMEMBER: Sunspots are huge magnetic
storms on the sun’s surface that are cooler than
the surrounding surface, and thus appear as
darker areas.
For more information on each topic,
please follow the yellow “i” button
at the bottom of the slide!
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TO THE PREVIOUS SLIDE!
NATURAL CAUSES OF CLIMATE CHANGE:
CONTINENTAL DRIFT
As plates move, they change the
position of the continents and the
oceans. This shift causes changes
in physical geography (mountain
building, change in landmass
size, etc.), global wind patterns,
and ocean currents, all of which
have an effect on climate.
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TO THE PREVIOUS SLIDE!
NATURAL CAUSES OF CLIMATE CHANGE:
VOLCANOES
During a volcanic eruption, a large
amount of gases and particles are
put into the air, including water
vapor, sulfur dioxide, dust, and ash.
These gases and particles can block
some incoming solar radiation,
resulting in a cooling of the
climate. While this cooling tends
to be short-term, it is still a
significant contributor to climate
change.
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TO THE PREVIOUS SLIDE!
NATURAL CAUSES OF CLIMATE CHANGE:
ORBITAL CHANGES
As you should recall, the
Milankovitch theory is a theory that
desribes changes in Earth’s orbital
characteristics and how these
changes may affect climate.
Changes in Earth’s orbit affect the
amount of incoming solar radiation,
resulting in a change in climate.
(For a review of the Milankovitch theory,
please follow the
button; it will provide
a link to a further explanation of this
theory.)
CLICK HERE TO RETURN
TO THE PREVIOUS SLIDE!
NATURAL CAUSES OF CLIMATE CHANGE:
OCEAN CURRENTS
Ocean currents are a major transporter of heat. As ocean currents
change (due to plate motion or other causes) or slow down (due to
temperature and salinity changes), the heat transport also changes.
This, along with
water vapor
(which is a greenhouse gas) that
escapes from the
ocean, can
change climate.
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TO THE PREVIOUS SLIDE!
NATURAL CAUSES OF CLIMATE CHANGE:
While natural causes of climate change are numerous, the scientific
consensus is that none of these are responsible for the present
warming of the Earth. Instead, emissions of greenhouse gases from
humans is the likely driver of the recent warming of the planet.
HUMAN CAUSES OF CLIMATE CHANGE
THE GREENHOUSE EFFECT
The sun radiates energy, which enters the Earth’s atmosphere and
some of which is absorbed by the Earth’s surface. When the Earth
radiates this energy back into the atmosphere, some of the heat is
absorbed by gases in the
atmosphere, known as
greenhouse gases. As the
concentration of these
gases increase, less heat
is able to escape from the
Earth, resulting in a net
warming effect.
(For a short animation of the
greenhouse effect, click on the
yellow “i” button below!)
HUMAN CAUSES OF CLIMATE CHANGE
Increasing concentrations of greenhouse gases:
• Carbon Dioxide (CO2)
• Methane (CH4)
• Nitrous Oxide (N2O)
THE MAIN SOURCES OF INCREASING CO2
• Residential energy use
• The main source of CO2 in
the home is the burning of oil
and natural gas for heating
and cooling.
• Automobile exhaust
• Transportation is the
second largest source of CO2
in the United States.
THE MAIN SOURCES OF INCREASING CO2
• Power plants
• The generating of electricity
is the largest source of CO2 in
the United States.
• Deforestation
• The cutting down of trees
reduces the capability of the
natural environment to remove
CO2 from the atmosphere,
effectively raising CO2 levels.
THE MAIN SOURCES OF INCREASING CH4
• Landfills
• Decomposition of waste in
landfills is the largest humanrelated source of methane in
the United States.
• Fossil Fuels
• Methane escapes during the
processes associated with
preparing natural gas and
crude oil for residential and
commercial use.
THE MAIN SOURCES OF INCREASING CH4
• Agriculture
• Animals such as cattle and sheep produce large amounts of
methane as part of their digestive processes. It is also produced
during the decomposition of manure.
THE MAIN SOURCES OF N2O
• Agriculture
• The addition of fertilizers to soil, as well as the production of
nitrogen-fixing crops and other farming practices, adds additional
nitrogen to the soil, which is able to be converted to N2O.
THE MAIN SOURCES OF N2O
• Fossil Fuels
• The combustion of fossil fuels
results in the production of N2O,
but the amount varies depending
on the type of fuel, maintenance,
and a number of other factors.
• Waste
• N2O can be produced during the
nitrification and denitrification of
nitrogen present in both livestock
and human waste.
SO…WHAT’S THE MAIN CONTRIBUTOR TO
GLOBAL WARMING?
Well, that is actually a pretty well agreed-upon conclusion: when it
comes to human-induced global warming, greenhouse gases,
especially carbon dioxide, are thought to play the biggest role. CO2 is
not only the greenhouse gas that
is most abundant in human
emissions (see graph on this
slide), there is a noticeable
relationship between the
increase of CO2 in the
atmosphere and the increase
in temperature of the past
several decades, as shown in
the graphs on the next slide.
SO…WHAT’S THE MAIN CONTRIBUTOR TO
GLOBAL WARMING?
Temperature
CO2
WARMER “COLD” DAYS AND NIGHTS
As the temperature increases, areas will experience less cold
extremes. This means that the coldest day of the year will be warmer
than usual. In some areas this will be temporarily beneficial, as it
will mean increased crop yields in colder environments and a
reduction in mortality from cold exposure. It will also decrease the
demand for heating. However, this will also result in more suitable
conditions for insect outbreaks in many areas.
WARMER “HOT” DAYS AND NIGHTS
As the temperature increases, areas will experience warmer extremes.
This means that the hottest day of the year will also be warmer than
usual. In some areas this will mean decreased crop yields in warmer
environments. It will also increase the demand for cooling.
CHANGES IN PRECIPITATION
As the global temperature increases,
this will cause a change in precipitation
patterns and amounts. There will be an
increased number of flooding events
and also an increase in drought, which
will exacerbate the already large
problem of famine in many nations.
SEA LEVEL RISE
The rise of sea level is a concern
that is raised by many people in
the scientific community. As
temperatures rise, the ice caps
will continue to melt and add
influxes of fresh water to the
oceans. This will result in a
global rise of sea level, which
will displace populations and
place rising pressure on coastal
areas as more people have to
evacuate their homes and find
refuge further inland.
HEAT WAVES
Heat waves are also a risk of increasing global temperatures. Heat
waves will increase the risk of heat-related mortality, or the number
of deaths due to extreme heat. This will also increase the number of
wildfires, especially in areas experiencing drought.
DECREASED SNOWPACK
As rising temperatures cause melting of snow and ice throughout the
world, the reduction of summer melt flows will lead to increased
competition for already overly stretched water resources.
REDUCE YOUR CARBON FOOTPRINT!
What IS a Carbon Footprint?
A Carbon Footprint is “a measure
of the impact human activities
have on the environment in terms
of the amount of greenhouse
gases produced, measured in units
of carbon dioxide”*.
* http://www.carbonfootprint.com/carbon_footprint.html
HOW DO I REDUCE MY FOOTPRINT?!?
• Recycle
• By recycling, you cut down on your
waste and your consumption of new
products.
• Avoid items with unnecessary packaging
• Items that are overly packaged require
more energy in production and also take
up more space in landfills. Avoid these
items! Examples: 12-packs of soda,
bottled water (drink from the tap
instead), snack size bags, etc.
HOW DO I REDUCE MY FOOTPRINT?!?
• Drive Less
• The less that you drive, the less
fuel that you use and the less carbon
you put into the atmosphere. Try
walking, riding a bike, or using
public transportation instead!
• Switch Light bulbs
• By changing your light bulbs to
compact fluorescents you can save
energy and money!
HOW DO I REDUCE MY FOOTPRINT?!?
• Turn the Heat DOWN!!!
• And, while you’re at it, the air conditioner,
too! Simply turning down the thermostat in
the winter and turning it up in the summer
can save a lot of energy…and money, too!
• Warm Up the Water Heater…
• …by using a jacket. Wrap an
insulating jacket (these are made
for this exact purpose…don’t just
use an old blanket!) around your
water heater to help keep it warm
and reduce unnecessary loss of heat.
HOW DO I REDUCE MY FOOTPRINT?!?
• Eat Less Meat
• As you might recall from earlier in this
activity, cattle and other livestock produce a
lot of gas. By cutting back on our
consumption of meat, we can help reduce the
demand for such large numbers of livestock.
• Buy Local Products
• For one, local products don’t have to travel
as far. For another, they are more likely to
come from small, local farms and gardens
instead of large, industrial size plots.
HOW DO I REDUCE MY FOOTPRINT?!?
• Wash Less
• Okay, so no one wants you to be
dirty, but only run your washing
machine and dishwasher when they
are full so that you get as much use of
the water and energy as possible!
• Turn It Off!
• When you are done using
appliances, turn them off and unplug
them, if at all possible. And
remember to switch off the lights
when you leave a room.
Let’s begin your quest to help save the planet
(or, at least, the human race). See what you
can accomplish along the way!
CLICK HERE TO BEGIN
QUIZ
1) Global warming is a(n):
A. Increase in temperature that will likely continue
in the future.
B. Increase in temperature that will stop in the very
near future.
C. Decrease in temperature that will likely continue
in the future.
D. Decrease in temperature that will likely stop in
the very near future.
By supporting the use of alternative energy, you’ve
significantly cut down on your use of fossil fuels!
Click Here to Return to the Question
QUIZ
2) Which of the following are all natural causes of
climate change?
A. Volcanoes, tornadoes, solar output, and tsunamis
B. Thunderstorms, earthquakes, and volcanoes
C. Increasing levels of carbon dioxide, methane,
and nitrous oxide
D. Volcanoes, ocean currents, solar output, orbital
changes, and continental drift
You’ve now switched to a largely solar-powered home.
You’re doing an awesome job!
Click Here to Return to the Question
QUIZ
3) The net warming effect of the Earth’s surface due to rising
levels of certain gases in the atmosphere is known as the
A. Greenhouse problem
B. Greenhouse cause
C. Greenhouse effect
D. Greenhouse question
Many nation’s food supplies have now been saved from drought
and flooding due to reduced carbon emissions. Way to go!
Click Here to Return to the Question
QUIZ
4) Which of the following is NOT a greenhouse gas?
A. Carbon monoxide
B. Carbon dioxide
C. Nitrous oxide
D. Methane
By growing your own fruits and vegetables, you’ve reduced
your dependence on overly packaged and transported goods!
Click Here to Return to the Question
QUIZ
5) Which of the following is NOT a main source of CO2?
A. Automobiles
B. Residential energy use
C. Power plants
D. Breathing
You’ve become a master recycler and in doing so have
helped save numerous trees from being cut down!
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QUIZ
6) Which of the following is NOT a main source of CH4?
A. Fossil fuels
B. Deforestation
C. Landfills
D. Agriculture
By switching to a vegetarian, or at least mostly meatless, diet,
you have helped reduce the demand for large cattle farms.
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QUIZ
7) Which of the following is NOT a main source of N2O?
A. Agriculture
B. Waste
C. Mining
D. Fossil fuels
A number of species rely on an ever-dwindling water supply.
By decreasing warming, you’ve helped them survive!
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QUIZ
8) Which of the following is the MAIN contributor to
the recent warming of the Earth, according to the
majority of scientists?
A. Movement of tectonic plates
B. Human emissions of greenhouse gases
C. Volcanic activity
D. Change in ocean currents
As people like you continue to take steps to reduce their carbon
output, warming slows and the ice caps retain their hold on the poles!
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QUIZ
9) Which of the following is NOT a likely effect of
global warming?
A. Colder warm days and nights
B. Changes in precipitation
C. A rise in sea level
D. Decreased snowpack
You have lowered your carbon footprint significantly. If everyone did
the same, we might be able to save the coral reefs,
which
are currently suffering from warming waters!
Click Here to Return to the Question
QUIZ
10) Which of the following is NOT a way to reduce
your carbon footprint?
A. Drive less
B. Use compact fluorescent light bulbs
C. Turn off appliances
D. Eat more meat
You are an inspiration! Just remember: We really DO have
the whole world in our hands and we must take steps to
ensure it is habitable for our future generations.
Click Here to Return to the Question
On each slide in this presentation, you will see
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