Atmospheric and Climate Change Chapter 13

13-1 Climate and Climate Change Objectives 1.Explain the difference between weather and climate. 2.Identify four factors that determine climate. 3.Explain why different parts of the earth have different climates. 4.Explain what causes the seasons.

What Factors determine climate? Climate-long term prevailing weather (state of the atmosphere) Determined by: Latitude, atmospheric conditions, circulation patterns, oceanic patterns, local geography, solar activity, and volcanic activity.

 Latitude –Distance from the equator measured in degrees north or south of the equator –Strong influence  Determines amount of sunlight th –More sunlight at the equator vs. the poles

 Atmospheric circulation –Warm air rises, cold air sinks –Warm air holds more moisture –Heat differences cause winds

 Global Circulation Patterns –Patterns are disrupted at the equator  Cool air rises at the equator and is forced to the poles  Air condenses and 30 degrees N and S  Air sinks, causes water to evaporate from land  Flows back to the poles or equator

 Prevailing winds (westerlies) –Blow from one direction most of the year –Trade winds at 30 degrees N and S

 Ocean Circulation patterns –Hold vast amounts of heat –Currents redistribute heat –Cold and warm currents

–El Nino – Southern Oscillation  Short-term periodic change in the location of warm and cold currents in the Pacific ocean  Winds in west Pacific become stronger and push warm water eastward  Causes drought in Indonesia and Australia

 New El Nino Event New El Nino Event New El Nino Event  Fox News Report on El Nino Fox News Report on El Nino Fox News Report on El Nino

–La Nina -  Water in the Pacific is colder than usual

 Topography –Mountain ranges

 Other influences –Solar activity  Increase UV and energy from the sun –Volcanic activity  Releases gases (SO 2 )and dust into the atmosphere which affects weather

 Seasonal Changes –Tilt on Earth’s axis

13-2 Ozone Shield Objectives 1.Explain how the ozone layer shields the Earth from much of the sun’s harmful radiation. 2.Explain how chlorofluorocarbons damage the ozone layer. 3.Explain the process by which the ozone hole forms. 4.Describe the damaging effects of ultraviolet radiation. 5.Explain why the threat to the ozone layer is still continuing today.

Ozone Shield  Ozone layer – –O3–O3–O3–O3 –Absorbs UV – protects DNA of all living things

Chemicals that cause Ozone depletion –CFC’s (chlorofluorocarbons) damages ozone  Stable at surface but reacts in atmosphere  destroys ozone molecules

Ozone hole  Thinning of atmospheric ozone that occurs at the poles –First report in 1985, but noticed in 1970’s

–Chlorine reacts with ozone and destroys it  Forms in polar stratospheric clouds –Can’t be replaced by ground level ozone

  Current data Current data

 Affects –Increased UV radiation  Damages DNA  Cancer  Weaker immune system

 Kills phytoplankton  Harms amphibians, marine life, and plants

 Protection of Ozone –International agreements (Montreal Protocol) to eliminate CFC use (1987, 1992,…)  US pledged to ban all substances by 2000 –Did we do it??  Level is going down

 It will be years before affects of programs can be measured because CFCs stay active for years

  Video

13-3 Global Warming Objectives 1.Explain why Earth’s atmosphere is like the glass in a greenhouse. 2.Explain why carbon dioxide in the atmosphere appears to be increasing. 3.Explain why many scientists think that the Earth’s climate may be becoming increasingly warmer. 4.Describe what a warmer Earth might be like.

Greenhouse affect  Traps sun energy  Major greenhouse gases (absorb and radiate heat): Water vapor, CO 2, CFCs, methane, and nitrous oxides

 Keeling –Started measuring CO 2 levels  1958 – 314 ppm  2000 – 368 ppm  ppm  ppm –Increased use of fossil fuels –Levels have normal seasonal fluctuations

–Increase of CO 2 could cause a global rise in temperature (global warming)  Glaciers and poles melt –Sea level rise

 Affects –Increase of global temperature –Rise of sea level  Loss of coastline –Agriculture  Droughts or too much rain

 Some scientists believe that the warming is part of natural climatic variability –What is the evidence ?

Consequences of a Warmer Earth These things could happen rather caused by nature or man….  Melting of ice and sea level rise  Global weather patterns change  Human health problems  Agriculture  Plants and animals

How do we reduce the risk?  Reforestation  Reduce dependence of on fossil fuels  Reduce use of harmful chemicals  International agreements - –Kyoto Protocol

  MoroccoThe Kyoto Protocol is an international agreement linked to the United Nations Framework Convention on Climate Change, which commits its Parties by setting internationally binding emission reduction targets.   Recognizing that developed countries are principally responsible for the current high levels of GHG emissions in the atmosphere as a result of more than 150 years of industrial activity, the Protocol places a heavier burden on developed nations under the principle of "common but differentiated responsibilities."   The Kyoto Protocol was adopted in Kyoto, Japan, on 11 December 1997 and entered into force on 16 February The detailed rules for the implementation of the Protocol were adopted at COP 7 in Marrakesh,, in 2001, and are referred to as the "Marrakesh Accords." Its first commitment period started in 2008 and ended in 2012.

Under the Protocol, countries must meet their targets primarily through national measures. However, the Protocol also offers them an additional means to meet their targets by way of three market-based mechanisms International Emissions Trading Clean Development Mechanism (CDM) Joint implementation (JI)