Scientists have investigated Earth’s past climate using ice cores, fossils, sediments, and chemical isotopes. They now have a considerable amount of evidence that tells the story of Earth’s past climate, and there have definitely been changes before man ever appeared. Scientists have also found that many climate changes over the last 2-3 million years are closely correlated to astronomical processes and some in the really ancient past (billions of years ago) as well.
Climate change and global warming is currently a widely discussed topic. There are some questions on the degree of natural versus man-made causes. Developing an understanding of the astronomical causes of past climate change (before man) can help with understanding the current situation and why most scientists think there is evidence that the current trends are man-made and worth reacting to vs. natural processes that are out of our control.
View the following resources for background information:
- http://www.bgs.ac.uk/discoveringGeology/climateChange/general/causes.html (Links to an external site.) – Investigations here on Earth
- http://www.kcvs.ca/martin/astro/au/unit1/33/chp3_3.html (Links to an external site.) – General overview
- http://www.soest.hawaii.edu/mguidry/Unnamed_Site_2/Chapter%202/Chapter2A.html (Links to an external site.) – Solar fluctuations
- http://www.soest.hawaii.edu/mguidry/Unnamed_Site_2/Chapter%202/Chapter2A2.html (Links to an external site.) – Orbital fluctuations
Requirements and Format:
Initial Post: Prepare at least a 200-word initial post on the discussion board on one of the following topics using logical, scientific reasoning and make sure you cite appropriately when using outside sources. Your initial post is due by Thursday at 11:59 p.m. ET
Topic 1: In general, what in Earth’s past has caused climate change? Specifically, what astronomical factors have contributed to climate change over Earth’s last 2 million years?
Topic 2: What is different about the present-day situation compared to climate change before man? Assuming Earth’s warming is abnormal at present, how much and what is due to man in comparison to the natural forces?
Topic 3: Scientists think that environments were similar on Mars, Earth, and Venus at one point early in the solar system’s history. Now, Venus has a “run-away” greenhouse effect and Mars has very little greenhouse effect. Do you think Earth is in danger of becoming more Venusian or Martian like in the future? Compare the climates of the 3 planets and use data to support your opinion
Reply Post: Respond to at least two other students’ posts on the discussion board. At least one of your responses must be different than your initial question and response. Your reply should be substantive and thoughtful, prompting conversation on the discussion board; however, please remember to keep your response(s) professional in the classroom. Your response should cover two or more of the following areas:
- Elaborate using additional facts or details (make sure you cite appropriately)
- Further relate the topic to concepts from this week’s lesson
- Provide an alternate perspective, or ask questions related to the information in the post