Climate Change and Ozone Loss

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Climate Change and Ozone Loss
G. Tyler Millers Living in the Environment 14th
Edition Chapter 21
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Key Concepts

• Changes in Earths climate over time

• Factors affecting climate

• Possible effects of global warming

• Adapting to climate change

• Human impacts on the ozone layer

• Protecting and restoring the ozone layer

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Section 21-1 and 21-2 Key Ideas

• How has the Earths temperature changed in the
  past?
• How do scientists study past climate changes?
• What role do the natural greenhouse effect play
  in Earths temperature?
• What are the major greenhouse gases?

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Past Climate Changes

• CLIMATE VERSUS WEATHER...what is the difference?
• Temperature and climate have been changing
  throughout Earths history.
• Earth 4.6 billion years

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Past Climate Change

• 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

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Past Climate Variations

• Glacial and interglacial periods over last
  900,000 years
• Last glacial period ended 12,000 years ago
• With each temperature change were changes in sea
  level and precipitation patterns.

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Past Climate Changes

• Past globaltemperatures

• Recent trends in global temperatures

Todays global average temp 59oF, 15oC
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Studying Past Climates

• Geologic records and atmospheric measurements
  provide a wealth of information about past
  temperature and climate.
• Ice Cores
• Lake Sediment
• Past 200-300 records
• CO2 levels since 1958

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Studying Past Climates
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Greenhouse Gases

• Certain gases in the atmosphere absorb heat and
  warm the lower atmosphere.
• Greenhouse effect
• Energy from the sun warms the earth. Some of that
  energy is radiated as heat and trapped in the
  atmosphere by clouds, water vapor and other gases.

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Greenhouse Gases
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Greenhouse Gases

• Water Vapor
• Carbon Dioxide
• Methane (CH4)
• CFCs
• CO2 levels gathered from ice data closely reflect
  changes in temperature.
• 1764 --- 276 ppm
• 1995 --- 360 ppm

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The Greenhouse Effect

• Greenhouse effect

• Greenhouse gases(Refer to Table 21-1 p. 464)

Fig. 6-14 p. 110
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Section 1 and 2 Review

• How has the Earths temperature changed in the
  past?
• How do scientists study past climate changes?
• What role do the natural greenhouse effect play
  in Earths temperature?
• What are the major greenhouse gases?

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Section 3 Climate Change and Human Activities
Key Ideas

• How have human activities affected concentrations
  of greenhouse gases in the troposphere?
• What role does the U.S. play in greenhouse gas
  emissions?
• Is the troposphere warming?
• What are some visible warning signals coming from
  glaciers?

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Humans and Greenhouse Gases

• Burning Fossil Fuels
• Clearing and burning forests and grasslands
• Raising large numbers of livestock
• Large rice production
• Using inorganic fertilizers
• All these activities have greatly increased CO2,
  CH4 and nitrous oxide (N2O)

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CO2 levels appear to be highest in last 160,000
years
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Humans and Carbon Dioxide

• 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

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U.S. and Greenhouse Gases

• 4.6 of the worlds 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
• Also large CH4

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Is the troposphere warming?

• There is considerable and mounting evidence that
  the troposphere is warming quickly
• Rate of change
• IPCC found
• 1) 20th Century warmest in past 1,000 years

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Is the troposphere warming?

• 2) Since 1861 global avg. temp increase 0.80C or
  1.40F (mostly post 1980)
• 3) 16 of the warmest years on record occurred
  since 1980 (hottest 1998 followed by 2001 and
  2003)
• 4) Glaciers around world melting quickly and
  poles warming more pronounced
• 5) Global sea levels rose 4-8 inches during 20th
  Century and continue to rise.

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Is the troposphere warming?

• Few skeptics still exist, most just argue it is
  not human caused warming
• Global warming versus Global climate change---
  what is the difference?
• Do NOT confuse it with ozone depletion

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Warning Signals From Glaciers

• The worlds floating ice and land-based ice is
  slowly melting, reflecting less incoming solar
  energy and warming the troposphere further.
• Largest Glaciers Greenland and Antarctica
• Floating Ice Arctic Ocean

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Warning Signals From Glaciers

• Due to wind currents poles will warm more quickly
  than mid-latitudes.
• Arctic Ocean free of ice summer 2050???
• Albedo reflectivity of different surfaces

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1979
2003 shrunk by 9
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Albedo of different surfaces
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Warning Signals From Glaciers

• Positive Feedback more ice melting more
  warming more ice melting.
• Melting floating ice has little impact on sea
  level rise (WHY?)
• Fresher water in ocean, what are the
  consequences?

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Warning Signals From Glaciers

• Greenland melting
• Sea level rise 7m or 23 feet
• 3oC (5oF) would melt entire continent over next
  several centuries
• Warming has become more evident in polar regions
  like Alaska
• Permafrost melting (a positive feedback)

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Warning Signals From Glaciers

• Mount Kilimanjaro glacier free in 15 years?
• 80 of South American glaciers gone also in 15
  years?
• Less fresh water sources
• Tourism loss
• Any good impacts?

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Riggs Glacier Alaska
Glacier National Park, Montana 1913 and 2005
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Section 4 Climate Models Looking Into The Future
Key Ideas

• How do scientists model changes in the earths
  temperature and climate?
• IPCC consensus about future changes in earths
  temperature.
• Why should we be concerned about a warmer earth?

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Projecting Future Changes in Earths Climate

• Climate models

• Apparent influence of human activities

• Could be natural changes

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Climate models

• Scientists have developed complex mathematical
  models of the earths climate system.
• Inputs
• Solar energy
• Earths land
• Ice
• Greenhouse gases
• Clouds, winds, water vapor

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IPCC Reports Best Science

• IPCC (Intergovernmental Panel on Climate Change)
• 1990, 1995, 2001 and now 2007 reports
• Three Major Finding From 2001
• 1) Latest climate models closely match changes
  since 1850

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IPCC Reports Best Science

• 2) There is strong evidence that most of the
  warming observed over the last 50 years is
  attributable to human activities.
• 3) It is likely that the world will warm 1.4oC to
  5.8oC (2.5oF to 10.4oF) between 2000 and 2100

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Why Be Concerned?

• RAPID changes give little time for humans and
  other species time to adapt to changes.
• Fastest change during the last 1,000 years
• Water resources and precipitation changes
• Ocean currents
• Agriculture

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Why be concerned?

• Flooding
• Extreme Weather
• Changes to world biomes
• Diseases may spread
• Displaced nations
• A threat to the worlds economy and stability?

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Section 5 Factors Affecting the Earths
Temperature

• Can oceans store more carbon dioxide and heat?
• How might changes in cloud cover affect the
  tropospheres temperature?
• What impact does air pollution have on
  temperature?
• Can photosynthesis be stimulated thus storing
  more carbon dioxide?

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Factors Affecting the Earths Temperature
Positive (amplify) vs. Negative (dampen)
Feedbacks, Give example of both types

• Changes in solar output

• Changes in Earths albedo

• Moderating effect of oceans

• Clouds and water vapor

• Air pollution

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Ocean Storage of CO2 and Heat

• Ocean currents act to redistribute heat arriving
  at equator moving it north.
• Example Gulf Stream
• Deep ocean currents not well understood.

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Ocean Storage of CO2 and Heat

• Evidence has shown that ocean currents have
  shifted and even stopped during times in the
  past.
• Effect of salinity levels (cold, salty water more
  dense)
• Day After Tomorrow movie effectmore Hollywood
  than science

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Ocean Storage of CO2 and Heat

• Oceans also act to trap about 29 of CO2 released
  into the atmosphere as part of global carbon
  cycle.

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Cloud Cover

• Warmer Troposphere
• More Evaporation
• More Clouds
• WARMER OR COOLER?
• Why might it be a
• positive feedback?
• Why might it be a
• negative feedback?

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Cloud Cover

• Day versus Night Impacts
• Thick clouds versus thin clouds
• High clouds versus Low clouds
• Latent heat release during cloud formation

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Air Pollution

• Soot and other pollutants can warm or cool the
  troposphere.
• Complex interactions between air pollutants and
  their location in the atmosphere may warm or cool
  the troposphere.
• Solar dimming effect

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Photosynthesis

• More CO2
• More Plant Growth
• Less CO2 in atmosphere
• Right?
• Or is this temporary?
• Young vs. Old Plants
• Once dead
• Summer versus Winter

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Methane Gas

• Warmer air release more methane caught up in
• Bogs and wetlands
• Permafrost in tundra
• CH4 is a more powerful greenhouse gas than CO2

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Section 5 Review

• Can oceans store more carbon dioxide and heat?
• How might changes in cloud cover affect the
  tropospheres temperature?
• What impact does air pollution have on
  temperature?
• Can photosynthesis be stimulated thus storing
  more carbon dioxide?

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Permafrost
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Section 6 Some Possible Effects of a Warmer World

• What are some possible effects of a warmer
  troposphere?
• Ecosystem changes
• Agricultural changes
• Rising Sea Level
• Project presentations1) Agriculture, water
  resources, forests, biodiversity, sea level,
  weather extremes, human population, human health.

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Some Possible Effects of a Warmer World
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Possible Benefits from a Warmer Atmosphere

• Less severe winters
• More precipitation in some dry areas
• Less precipitation in some wet areas
• Increased food production in some areas
• Expanded population and ranges of some species

Refer to Fig. 21-13 p. 476
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Section 7 Dealing with the Threat of Climate
Change

• What are our best options?
• What can be done to reduce the threat?
• What about storing carbon dioxide (carbon
  sequestration)?
• How can government play a role in reducing
  impacts?
• What is carbon trading?
• What are the costs of not acting?

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Dealing with the Threat of Climate Change

• There is little disagreement that our planet is
  warming, where most disagreement lies is in what
  to do about it.
• 1) Are economic costs of reducing greenhouse
  gases higher than benefits?

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Dealing with the Threat of Climate Change

• 2) Developed or developing countries, how should
  take responsibility?
• 3) Voluntary cuts or mandatory laws?
• Arguments transcend politics, economics,
  scientific, cultural.

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Solutions Dealing with the Threat of Climate
Change
Options

• Do nothing

• Do more research

• Act now to reduce risks

• Precautionary principle

Fig. 21-17 p. 479
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What can be done?

• Improve energy efficiency
• Reduce fossil fuel use
• Renewable energy sources
• Reduce population growth
• Reduce deforestation
• Carbon sequestration

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Removing CO2 from the Atmosphere
Fig. 21-18 p. 480
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How can the government help

• Tax emissions (carbon tax)
• Increase subsidies for energy efficiency and
  renewable energy
• Cut subsidies for fossil fuels
• Help induce technology transfer

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Emissions Trading

• Buying and selling carbon credits on the open
  marketplace.
• CAP and Trade System
• Set a nationwide goal and allow markets to decide
  how to reach the goal.

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Acting Later May Cost More

• It is likely to cost us less to help slow and
  adapt to global climate change today than deal
  with effects later.
• Costs versus Benefits

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Section 8 What is being Done?

• Kyoto Protocol What is it? What are the problems
  with it?
• What are some other countries, states, businesses
  doing?
• What can we do to prepare for warming?
• Why is global warming such an Inconvenient
  Truth

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Reducing Greenhouse Gas Emissions

• Kyoto Treaty (1997)

• U.S. withdraws from Kyoto Treaty (2001)

• Other reductions in CO2

Refer to Fig. 21-18 p. 483
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Kyoto Protocol

• December 1997 2,200 delegates from 161 nations
• 39 Developed countries cut greenhouse gas
  emissions 5.2 below 1990 by 2012
• Developed countries no cuts until later

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Kyoto Protocol

• Kyoto would only be a first start (5.2 below
  1990 is not much)
• Ratified by more than 120 nations.
• Pres. Bush withdraws in 2001

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Kyoto Protocol

• Several ideas floated, but no real negotiations.
• Next steps????

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What some are already doing

• Some countries, companies, U.S. states and cities
  are beginning to make voluntary cuts
• Great Britain went below 1990 levels and aims to
  cut by 60 by 2050
• BP has met goals of Kyoto

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What some are already doing
Why are some states, cities, or even countries
acting alone a waste when it comes to global
warming?
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How to prepare for warming

• Humans need to adapt lifestyles to fit warming
  already built in.
• Conservation of water
• Moving from coastal zones
• Expand wildlife preserves toward poles
• Preparing for expanded disease areas
• Recreational, agriculture shifts
• Insurance industry beginning to prepare.

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Why is climate change so difficult of a problem

• An Inconvenient Truth
• Long term issue (political system short term)
• Consequences in future
• Slow change on human time scale
• Uncertainty built up by industries
• Changing lifestyles
• International issue
• Hopelessness

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Section 8 Review

• Kyoto Protocol What is it? What are the problems
  with it?
• What are some other countries, states, businesses
  doing?
• What can we do to prepare for warming?
• Why is global warming such an Inconvenient
  Truth

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