Discuss with your group:

1. Compare and Contrast Weather and Climate

2. What causes wind?

Chapter 16Global 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

1) Latitude2) Atmospheric Circulation (direction of the

wind)

3) Ocean Circulation4) Topography

Climate Factors

1) Latitude: the distance north or south from the equator impacts a regions climate►What is 0o?

Latitude

Latitude

Greenland at noon in the summer

Dominican Republic Winter Sun

Latitude

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 Factors4) 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?

Chemist Charles Keeling’s CO2 measurements

Why measure here?

CO2 rates rising quickly

1764 --- 276 ppm 1995 --- 360 ppm2010 --- 390 ppm

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 powerplants24% transportation20% industrial

processes14% 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 Changes6) Effects to plants and

animals

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 Issue2) Consequences in Future3) Need behavior changes4) International5) 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 LayerOzone 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 DepletionChlorofluorocarbons

(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 LayerMontreal 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