Discuss with your group: 1. Compare and Contrast Weather and Climate 2 Discuss with your group: 1. Compare and Contrast Weather and Climate 2. What causes wind?
Chapter 16 Global Climate Change
Statement: “It has been so hot this summer, must be that global warming”
Goals for Chapter 16 What is climate? What factors determine climate? What causes seasonal changes? What is the ozone layer and how is it being altered? Describe how human actions are changing the make up of the Earth’s atmosphere and what are the potential consequence of that.
Section: Climate and Seasons GOALS: Explain the difference between weather and climate. Identify four factors that determine climate. Explain why different parts of the Earth have different climates. Explain what causes seasons.
Why is our climate the way it is?
Weather State of the atmosphere at any one time in a region
Climate Climate: is the long-term average weather conditions in an area
4 Factors that determine Climate Latitude Atmospheric Circulation (direction of the wind) Ocean Circulation Topography
Climate Factors Latitude: the distance north or south from the equator impacts a regions climate What is 0o?
Latitude
Latitude Greenland at noon in the summer
Latitude Dominican Republic Winter Sun
Climate Factors 2) Atmospheric Circulation: the direction the wind comes from impacts climate Which way generally does wind blow across the U.S.?
Atmospheric Circulation Prevailing Winds: winds that blow predominantly in one direction Westerlies Trade Winds Polar Easterlies
Climate Factors 3) Ocean Circulation Patterns: Oceans carry heat from the equator or cool waters from the poles Surface currents caused by winds
Climate Factors 3) Ocean Circulation Patterns: Oceans carry heat from the equator or cool waters from the poles Surface currents caused by winds
Ocean Currents
Ocean Currents
Climate Factors 4) Topography: the shape of the land influences climate greatly Mountains can impact temperature and precipitation patterns
Topography: Where do you think it snows the most in the U.S.?
Can it snow near the equator?
Topography
What causes seasonal changes?
When do we get the most direct sunlight? Noon Sunlight
When do we get the most indirect sunlight? Noon sunlight
When is the daylight hours longest and the shortest? December 21st at 7 PM EST: WHY DOES IT LOOK LIKE THIS
What time of year is this? How do you know?
What 2 days of the year does it look like this: equal day and not all around the globe?
Seasons Seasons: caused by the fact that Earth’s axis is tilted at 23.5o.
Section Review Explain the difference between weather and climate. Identify four factors that determine climate. Explain why different parts of the Earth have different climates. Explain what causes seasons.
Section : Global Warming GOALS: Explain how the greenhouse effect works Describe why carbon dioxide is important in the atmosphere, but why scientists find it troubling that levels are rising Analyze what a warmer world might look like DO NOT CONFUSE OZONE DEPLETION WITH GLOBAL WARMING!!!
Has Earth’s Climate Always Been Like Today’s? How is it possible that you can find shark teeth far from the ocean inland? How is it possible that you find fossils of Palm Trees in parts of Canada? Today, global average temp = 59oF
Has Earth’s Climate Always Been Like Today’s? Over past 4.7 billion years climate has changed by Volcanic eruptions Changes in solar output Continents moving Meteorites Natural variations in CO2 Some changes slow, some quickly
Why does a greenhouse stay warm in the winter? Why does the inside of the car heat up quickly on a sunny day?
Greenhouse Effect Naturally occurring process in the atmosphere where gases trap in heat. Like a blanket covering planet Known about for over a century Without it Earth would be COLD
Greenhouse Gases Major greenhouse gases include Carbon Dioxide Water Vapor Methane CFCs All act to trap in heat
Greenhouse Effect
We know from the past that CO2 levels tied closely to temperature
We know from the past that CO2 levels tied closely to temperature
Measuring CO2 Since 1958 in Mauna Loa Hawaii What does this data show? What trends does it show? Why does it go up and down each year?
CO2 rates rising quickly 1764 --- 276 ppm 1995 --- 360 ppm 2010 --- 390 ppm Chemist Charles Keeling’s CO2 measurements Why measure here?
Rising CO2 Levels Most CO2 in atmosphere is coming from burning fossil fuels like coal, oil and natural gas Never 390 ppm in last 420,000 years (possibly 20 million) Continue to rise rapidly WHAT DOES THAT MEAN FOR THE FUTURE?
Where is the CO2 Coming From? 42% Coal powerplants 24% transportation 20% industrial processes 14% residential and commercial usages Exhale, drive, turn on light, burn log in fire 1 gallon of gas burned equals 20 pounds of CO2
Where is the CO2 Coming From? 4.6% of the world’s population, yet 24% of emissions of CO2 From just U.S. coal burning exceeds 146 other nations with 3/4th of world population Per capita yearly 500 tons
What do these graphs tell you?
What do higher CO2 levels mean for our future climate?
It’s All About Carbon http://www.npr.org/templates/story/story.php?storyId=9943298
Global Warming Earth’s global average temperature continues to rise due to the increase in greenhouse gases in the atmosphere
Global Warming Earth’s global average temperature continues to rise due to the increase in greenhouse gases in the atmosphere
How Can You Predict The Future? Very Complex Computer Models Those models are saying… It is likely that the world will warm 1.4oC to 5.8oC (2.5oF to 10.4oF) between 2000 and 2100
Why Care? I would like a warmer winter, and I Love Beach Weather
WHY CARE? It’s not like I can do anything. Plus, I Love my car. Some potential benefits of global warming
Consequences of a Warmer Earth 1) A Grand Experiment With Potentially Major Changes 2) Melting Ice = Higher Seas 3) Change in Weather Patterns 4) Human Health Problems 5) Agriculture Changes 6) Effects to plants and animals
Both photos show Sperry Glacier in Montana’s Glacier National Park Both photos show Sperry Glacier in Montana’s Glacier National Park. Top: 1913: Bottom: 2008
Many major cities in the world are below, near or just above sea level.
Florida after sea level rise of 5 meters
Impacts on Organisms Habitats shift, usually toward the poles or to higher altitudes. Migrations start earlier in the spring. Loss of ice makes hunting seals difficult for polar bears
Impacts on the Oceans An increase in ocean temperature is associated with a process called coral bleaching. Changes in ocean acidity, resulting from an increase in dissolved carbon dioxide, can harm organisms.
Reducing Risks
Improve Efficiency of Cars
International Agreements What make Global Warming a difficult issue for political leaders to deal with? 1) Complex Issue 2) Consequences in Future 3) Need behavior changes 4) International 5) Wealth Companies
International Agreements Why are international agreements needed? What makes them hard to negotiate? What differences exist between the developed and developing countries?
Kyoto Protocol 1997 International Treaty accepted by 160 countries to limit CO2 pollution 1990 levels by 2012 U.S. did not ratify New treaties trying to negotiate
Global Warming: What does the future hold?
Section Review Explain how the greenhouse effect works Describe why carbon dioxide is important in the atmosphere, but why scientists find it troubling that levels are rising Analyze what a warmer world might look like DO NOT CONFUSE OZONE DEPLETION WITH GLOBAL WARMING!!! (What are some similarities/differences)
Agree or Disagree Developed countries should help countries with tropical rain forests so those poorer countries can afford to leave their forests intact. Carbon dioxide is a naturally occurring molecule and rising levels in our atmosphere should not be worried about.
Section : The Ozone Shield GOALS: Explain how the ozone layer shields the Earth from harmful radiation. Describe how CFCs are damaging the ozone layer. What are impacts for a thinner ozone layer.
Why is the atmosphere important?
Ozone Layer Ozone Layer: An area of the stratosphere with high concentrations of ozone gas Acts like a sun screen blocking out UV rays Ozone = O3 Good ozone vs. Bad Ozone
Ozone Depletion Chlorofluorocarbons (CFCs) Man-made chemical “Miracle Chemical” Damages the ozone layer Takes a LONG time to get to ozone layer and destroys many ozone molecules
CFCs Used for decades Each CFC molecule can destroy 100,000 ozone molecules over decades
Ozone Hole Antarctic Ozone Levels
Impacts of Thinning Ozone Layer Damage to skin cells (including skin cancers) Damage to eyes UV Light damages DNA Kills phytoplankton (single-celled organisms) which are the base of most ocean food chains UV light damages crops
Protecting the Ozone Layer Montreal Protocol: international agreement in 1987 to phase out CFC usage Second conference in 1992 in Copenhagen WHY WILL IT STILL BE A PROBLEM FOR MANY MORE DECADES?
Section Review Explain how the ozone layer shields the Earth from harmful radiation. Describe how CFCs are damaging the ozone layer. What are impacts for a thinner ozone layer. DO NOT CONFUSE OZONE DEPLETION WITH GLOBAL WARMING!!! (What are some similarities/differences) http://www.youtube.com/watch?v=qUfVMogIdr8