Cause and Effect: Human Activity and Global Warming

Scientists often perform investigations to find the cause of an existing problem or change.  For example, upon observing that 1/3 of the students of MS 88 do not eat their lunch on Fridays, a student can perform a study to find out why these students at MS 88 leave their square-shaped pizza untouched.   Scientists also perform investigations to find the effect of an existing problem or change.  For example, a student can perform a study to determine what happens when the students of MS 88 do not eat lunch on Fridays.

---

A cause and effect relationship is when one event or characteristic results in another.  Scientists attempt to understand and explain cause and effect relationships so that they can help prepare the world for future events and conditions, while searching for immediate solutions to prevent/reduce/address current problems and conditions.

Scientists often use the transitional "signal" words and phrases to indicate cause and effect relationships. You can explain a cause and effect relationship using these words and phrases, and/or identify cause and effect relationships written by other scientists upon spotting these words and phrases in published scientific studies.

---

As scientists, we make observations, and then allow those observations to inspire scientific questions. Consequently, these fascinating questions drive us to investigate for answers.  One observation scientists have noted worldwide is the dramatic increase in carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere over the past 50 years.  What is the cause of this change?  What is the effect of this change?  You might ask?

Well, lets first take it back to the basic composition and function of the Earth's atmosphere.  The Earth's atmosphere is made up of a mixture of gases-- mostly Nitrogen, Oxygen, water vapor (the gas state of water)-- which is held in place by Earth's gravity.  The atmosphere acts like a blanket for the Earth, keeping it nice and warm, while protecting it from the Sun's harmful ultraviolet rays.  

---

The greenhouse effect is the process that traps heat in the Earth's atmosphere by which solar energy is both absorbed by Earth and re-radiated (bounced back) in all directions.  This process is called the greenhouse effect because the Earth's atmosphere is essentially behaving, well, you guessed it: like a greenhouse!

The recent increase in carbon dioxide, methane, and nitrous oxide (also known as "greenhouse gases") in the Earth's atmosphere has a similar effect of adding more mass to a blanket: more heat gets trapped underneath, and the temperature rises. This phenomena of rising temperatures in the Earth's atmosphere due to the increase in greenhouse gases is called global warming.  But what is the cause of the increase in these greenhouse gases?  Here is what the students of MS 88 concluded upon examining a series of images and captions from an article published by NASA:

• “People want corn and corn products faster and cheaper.  As a result, more chemical fertilizers are used, which give off nitrous oxide.  Therefore, there is an increase in nitrous oxide in the Earth’s atmosphere.”
• “People around the world love McDonalds.  Consequently, the amount of livestock increases, which produce more methane gas.  As a result, there is an increase in methane gas in the Earth’s atmosphere.”
• "People buy more and waste more.  Therefore, landfills are packed, giving off a ton of methane gas.  This leads to an increase in methane gas in the Earth’s atmosphere.”
• “People love to drive big, fancy cars.  That is why more gasoline is burned, putting more carbon dioxide in the atmosphere.  Therefore, there is an increase in carbon dioxide in the Earth’s atmosphere.”
• “People use and waste a lot of paper products.  Therefore, more forests, which usually absorb carbon dioxide from the atmosphere, are cut down.  As a result, there is an increase in carbon dioxide lingering in the Earth’s atmosphere.”
• “People love their electronic gadgets.  Consequently, more fossil fuels are burned to provide electricity.  Therefore, there is an increase in carbon dioxide in the Earth’s atmosphere.”

Note the different transitional "signal" words.  Also, note the common word beginning each cause... people!  Human activity is by far the largest cause of global warming.  Learn more about how mankind is changing the Earth's climate here: http://climate.nasa.gov/causes. 

But what are the effects of the increase in carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere?  What is the effect of global warming? Check out a video by NASA to learn more about both the causes and effects of global warming:

To learn more about what other scientists are observing and predicting to be the effects of global warming, check out the following websites:

• http://environment.nationalgeographic.com/environment/global-warming/gw-effects/
  
• http://planetsave.com/2009/06/07/global-warming-effects-and-causes-a-top-10-list/
  
• http://www.climatehotmap.org/global-warming-effects/
• http://timeforchange.org/cause-and-effect-for-global-warming

Homework: Read at least two of the articles above.  Then write 3 different effects of the increase in carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere.  Make sure to use the transitional cause and effect "signal" words (above), and write in complete sentences.  Use the example sentences to help get you started.  Remember, we are discussing EFFECTS this time, not causes.

• "The result of the increase in carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere is ________________."
• As a result of the increase in carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere, __________________."
• "The effect of the increase in carbon dioxide, methane, and nitrous oxide in the Earth's atmosphere is. _______________."
• "One effect of global warming due to the increase in greenhouse gases is ____________."