Transcript Slide 1
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.
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 near surface 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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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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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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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.)
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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 green house gas) that escapes from the ocean, can change climate.
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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 (CO 2 ) • Methane (CH 4 ) • Nitrous Oxide (N 2 O)
THE MAIN SOURCES OF INCREASING CO
2
• Residential energy use • The main source of CO 2 in the home is the burning of oil and natural gas for heating and cooling.
• Automobile exhaust • Transportation is the second largest source of CO 2 in the United States.
THE MAIN SOURCES OF INCREASING CO
2
• Power plants • The generating of electricity is the largest source of CO 2 the United States.
in • Deforestation • The cutting down of trees reduces the capability of the natural environment to remove CO 2 from the atmosphere, effectively raising CO 2 levels.
THE MAIN SOURCES OF INCREASING CH
4
• Landfills • Decomposition of waste in landfills is the largest human related 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 CH
4
• 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 N
2
O
• 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 N 2 O.
THE MAIN SOURCES OF N
2
O
• Fossil Fuels • The combustion of fossil fuels results in the production of N 2 O, but the amount varies depending on the type of fuel, maintenance, and a number of other factors.
• Waste • N 2 O 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. CO 2 not only the greenhouse gas that is is most abundant in human emissions (see graph on this slide), there is a noticeable relationship between the increase of CO 2 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 CO
2
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… • …b y 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!
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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!
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QUIZ
2) Which of the following are all natural causes of climate change?
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!
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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
Many nation’s food supplies have now been saved from drought and flooding due to reduced carbon emissions. Way to go!
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QUIZ
4) Which of the following is NOT a greenhouse gas?
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!
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QUIZ
5) Which of the following is NOT a main source of CO 2 ?
A. Automobiles B. Residential energy use C. Power plants
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 CH 4 ?
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 N 2 O?
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!
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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
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.
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On each slide in this presentation, you will see buttons along the bottom. Each of these buttons serves a unique purpose:
Go to next slide Go to first slide Go to previous slide A link to more information on the World Wide Web
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