assignment 6

BE SURE TO READ ALL DIRECTIONS!!!!

Adapted from Glencoe online learning website:

The Earth's atmosphere is a complex, dynamic system. Weather conditions affect everything from how we travel on a daily basis to the food that can be produced worldwide each year. For millions of years of Earth history, natural cycles of warming and cooling affected Earth organisms in important ways, about which scientists can only speculate. But what about human impact on the atmosphere? Do humans play a role in climate change? Natural atmospheric cycles have occurred for millions of years. Is it possible that human activities over the last 250 years could significantly impact such an established, large, and complicated system?

The Industrial Revolution, which began in Great Britain in the mid-1700s was a watershed event in human interaction with the atmosphere. As fossil fuels were burned in increasingly greater amounts, the amount of carbon dioxide released into the atmosphere rose significantly. Industrialization and population growth continue today. At what cost? While the topic is hotly debated in the scientific community, scientists agree on several points. Atmospheric concentration of carbon dioxide and other greenhouse gases is increasing at an unprecedented rate, there is a direct connection between the concentration of carbon dioxide in Earth's atmosphere and the average surface temperature, and the average temperature at the Earth's surface currently is increasing. However, there is great debate on how much is a result of human activity. Throughout Earth's history, climate change has been driven by natural processes and events rather than by human activity. Is that still the case?

This will count as a quiz grade for the fourth quarter. Be sure to complete all three parts.

(Scoring Rubric)

You will be posting your answer to PART III to this discussion. Remember your web ettiquette and the fact that you are anonymous to each other, but not me.

PART I: Answer the following questions about Global Climate Change using the resources below:

1. The greenhouse effect is a natural atmospheric process that has a tremendous impact on Earth. Describe this process, including what causes it, the factors that influence it, and how it affects Earth.
2. Identify the major greenhouse gases found in Earth's atmosphere.
3. While the term greenhouse effect often has a negative connotation when used in the media, the process is crucial to life on Earth. Explain why.
4. Compare the levels of atmospheric carbon dioxide just prior to the beginning of the industrial age in the mid-1700s and in 2004.
5. Changes in the concentration of greenhouse gases can cause changes in Earth's average surface temperature. What other natural factors or events also can cause long-term changes in surface temperature?
6. How long have consistent weather measurements been collected and recorded throughout the United States?
7. Atmospheric composition and conditions are different today than at other times in Earth's history. What types of things do scientists examine to learn what the atmosphere was like hundreds, thousands, or even hundreds of thousands of years in the past? Specifically, explain how a history of climate can be reconstructed from an ice core.
8. Analysis of air pockets in glacial ice show that an abrupt climate change took place about 12,000 years ago. The discovery of this period, named Younger Dryas, has changed scientific thinking about the length of time required for global climate change. Describe the Younger Dryas period, including how it could be related to a past global warming trend.

Resources

The Web sites given here will help you answer questions about global climate change and how it is measured. The information you gather will help you form an opinion about the level of importance of human activities to the current global warming trend.

http://www.ncdc.noaa.gov/oa/climate/globalwarming.html

Visit this site to find answers to frequently asked questions about global warming. Questions include "Is the climate warming?" and "Can observed changes be explained by natural variability?" Links within the answers provide graphed data and additional related information.

http://news.bbc.co.uk/2/hi/6321351.stm

The article at this site explains the process of global warming, and describes specific human activities that are altering the composition of Earth's atmosphere.

http://www.ncdc.noaa.gov/paleo/abrupt/index.html

The paleoclimate record shows that rapid and dramatic climate changes have occurred throughout Earth's history. Visit this site to learn what scientists know and don't know about what caused these changes, as well as how Earth's climate was affected by them.

http://www.whoi.edu/main/climate-ocean

Click on the Global Warming links and read another perspective.

http://www.gcrio.org/CONSEQUENCES/winter96/geoclimate.html

The article at this site explains how scientists use a wide variety of information to understand past climate change and predict future trends. Graphs showing estimates of mean surface air temperature, as recently as the last 1000 years and as distant as the last 100 million years, are provided.

http://www.weathernotebook.org/transcripts/1999/10/20.html

This site explains how Earth's climate changed abruptly during a period in Earth's history known as the Younger Dryas. The article found here relates long-term global warming to possible rapid cooling of the climate.

http://www.gisp2.sr.unh.edu/GISP2/MoreInfo/Ice_Cores_Past.html

The article at this Web site explains how scientists use ice cores to learn how Earth's climate has changed over the last 200,000 years.

http://weather.nmsu.edu/USClimat.htm

This site gives a chronology that outlines the history of weather data collection in the United States.

http://www.cbsnews.com/stories/2003/09/23/tech/main574644.shtml

The article at this site addresses changes in global climate that began 8000 years ago. Visit this site to learn about a new theory connecting the development of farmlands in Asia and Europe to increases in atmospheric CO2 and methane thousands of years ago.

PART II: Analyze the graphs

Scientists collect data about global change through both direct and indirect measurements. Graphed data often shows trends and patterns that can help researchers evaluate past changes in climate and make predictions about future climate changes. Study each of the six graphs shown at the Web sites listed below, then write a brief analysis of the data shown by each graph. Your analysis should include a description of the variables shown on the graph and a summary of any trends or patterns you observe.

Graphs to analyze

# 1

http://www.ncdc.noaa.gov/img/climate/globalwarming/sio-mlgr.gif

Carbon dioxide concentration, as measured at Mauna Loa, Hawaii, from 1955 to the present

#2

http://www.ncdc.noaa.gov/oa/climate/carbondiox.html

Atmospheric concentration of carbon dioxide and methane and Antarctic temperature, from 420,000 years ago until prior to the Industrial Revolution

#3

http://www.ncdc.noaa.gov/oa/climate/globtemp.html

Global surface mean temperature anomalies from 1880 to the present

#4

http://www.ngdc.noaa.gov/paleo/ei/ei_reconsa.html

Reconstructed annual northern hemisphere mean temperature from 1400 to 2000

#5

http://www.gcrio.org/CONSEQUENCES/winter96/article1-fig5.html

Estimate of Earth's mean surface temperature for the last 800,000 years

#6

http://www.ncdc.noaa.gov/img/climate/globalwarming/ipcc14.gif

Arctic sea ice extent anomalies from 1973 to 2000

PART III: State your opinion

Finally, write your opinion which answers the following question: "Is human activity responsible for the current global warming trend affecting the Earth?" Your written opinion does not need to be lengthy, but should include details from your research that support your point of view. POST it below and respond to two other posts, then defend your opinion during the ensuing discussion with your classmates and teacher, using FACTS from the reading materials.