Global Climate Change

Statement: “It has been so hot this summer, must be that global warming”

Goals ► 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 1: 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.

Weather ► State of the atmosphere at any one time in a region ► What is today’s weather like? ► What was the weather like last summer? ► What was the weather on October 21st

Climate Climate: is the long- term average weather conditions in an area ► Seattle, Washington ► Phoenix, Arizona ► San Diego, Calif. ► Portland, Maine

Climate Factors 1) Latitude: the distance north or south from the equator impacts a regions climate ► What is 0 o, 90 o ? ► What is Atlanta’s latitude?

Latitude Latitude influences climate – because the amount of solar energy an area of Earth receives depends on its latitude. More solar energy falls near the equator than the poles.

Latitude Greenland at noon in the summer

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 (caused by Earth’s rotation) ► Westerlies - produced between the 30 and 60 latitudes ► Trade Winds - between 30 N/S and the equator ► Polar Easterlies – from 60 to the poles

Climate Factors 3) Ocean Circulation Patterns: Oceans carry HEAT from the equator or cool waters from the poles ► Surface currents caused by winds and the rotation of the earth.

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

Mountain ranges influence precipitation distribution. Warm air from the Pacific blows east, then hits the mountains and rises. As it rises, it cools which causes it to rain on the western side of the mountains. By the time the air reaches the eastern side of the mountains, it is dry = Rain Shadow Effect

What causes seasonal changes?

Seasons Seasons: caused by the fact that Earth’s axis is tilted at 23.5 o.

Section 1 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 2: 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 20 miles from the beach in NJ? ► How is it possible that you find fossils of Palm Trees in parts of Canada? ► Today, global average temp = 59 o F

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 CO 2 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 CO 2 levels tied closely to temperature

Measuring CO 2 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?

Chemist Charles Keeling’s CO2 measurements Why measure here? CO 2 rates rising quickly ppm ppm ppm

Rising CO 2 Levels ► Never 390 ppm in last 420,000 years (possibly 20 million) ► Continue to rise rapidly ► Most CO 2 in atmosphere is coming from burning fossil fuels like coal, oil and natural gas ► WHAT DOES THAT MEAN FOR THE FUTURE?

Where is the CO 2 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 CO 2

Where is the CO 2 Coming From? Americans = 4.6% of the world’s population, yet 24% of emissions of CO 2 From just U.S. coal burning exceeds 146 other nations with 3/4 th of world population Per capita, Americans release 500 tons yearly

What do these graphs tell you?

What do higher CO 2 levels mean for our future climate?

It’s All About Carbon ► hp?storyId= hp?storyId= hp?storyId=

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 1.4 o C to 5.8 o C (2.5 o F to 10.4 o F) 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

Maple Trees in VT and NH have been producing less and less maple syrup over last few decades.

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. 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. 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 2 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 3: 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 = O 3 ► Good ozone vs. Bad Ozone

The ozone layer is located in the stratosphere.

Ozone Depletion The ozone depletion is largely due to: 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 in refrigerants and aerosols ► 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

Wide Ranging Impacts

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) ►