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Climate Change, and the Scientific Process. Let ’ s review last week: sometimes Venus, Earth and Mars are called the Goldilocks planets. Compare these Three:. Let ’ s look at atmosphere more carefully:. Venus Carbon Dioxide: 96% Nitrogen: 3.5%. Earth Nitrogen: 78% Oxygen: 21 %
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Climate Change, and the Scientific Process Let’s review last week: sometimes Venus, Earth and Mars are called the Goldilocks planets
Compare these Three: Let’s look at atmosphere more carefully:
Venus Carbon Dioxide: 96% Nitrogen: 3.5% Earth Nitrogen: 78% Oxygen: 21 % Argon: 0.9% Water: > 1% Carbon Dioxide: 0.004% * Mars Carbon Dioxide: 95% Nitrogen: 3% Argon: 2%
How did Venus get so hot? A planet with an atmosphere Solar radiation comes in The greenhouse gases reradiate. Some of the energy goes towards the surface. Planetary radiation goes out, but gets absorbed Greenhouse gases Planetary surface
In class, or lab exercise: Greenhouse effect Go to http://phet.colorado.edu/en/simulation/greenhouse
How do greenhouse gases naturally get into the atmosphere? Water: evaporation CO2: vaporization of rocks, release from volcanos, vaporization of biotic material (like fossil fuels), respiration Methane: release from earth, biology (bacteria, cows, rice)
2. Comets hitting the young earth brought water, water vapor and carbon dioxide.
3. Earth developed an oxygen atmosphere from plant life What is happening to the atmosphere today?
Report on Global Climate Change –IPCC 2013* “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased .” * Intergovernmental Panel on Climate Change: A total of 209 Lead Authors and 50 Review Editors from 39 countries and more than 600 Contributing Authors from 32 countries contributed to the preparation
Articles published in peer review journals support idea that this is happening, and that it is caused by humans Peer review, or refereed: article has been anonymously approved by another expert in the field before publication
Global warming: a look at the data These temperatures are derived from different methods
Class exercise with Mauna Loa (top of volcano in Hawaii) data: Plotting some data on the CO2 concentration in the atmosphere Date CO2 (ppm) Each team will plot one year’s worth of CO2 data
Group # ______ 395 394 393 392 391 390 389 388 387 386 385 384 CO2 Concentration (ppm) 383 382 381 380 379 378 377 376 375 July July July July July July July 2006 2007 2008 2009 2010 2011 2012 2005
Summary of effects: Shrinking ice sheets Sea level rise Declining arctic ice Global temperature rise Melting glaciers Warming oceans
What can we do to reverse this? Currently, 30% of both the US House and Senate are on record as denying climate change, or its importance. Solution requires many nations to address the problem: China in particular
What can we do… • Buy more fuel efficient cars and trucks, do less driving, do more car pooling, use CFL (compact fluorescent) light bulbs, use solar cooker… • Develop Solar power on homes • Burn less coal (which creates much of our electricity) • Develop alternative energy: wind, nuclear • What are your ideas?
Take away message: Earth’s temperature is increasing because carbon dioxide concentration is increasing. All evidence is that this is caused by human activity. Lecture tutorial, Greenhouse effect