Chapters 7, 18.1, 19.1-3 Climate, Biodiversity, and Global Climate Change.

Chapters 7, 18.1, 19.1-3Chapters 7, 18.1, 19.1-3

Climate, Climate, Biodiversity, and Biodiversity, and Global Climate Global Climate

ChangeChange

What is climate?What is climate?• Climate: an area’s general pattern of atmospheric

conditions over periods of at least 3 decades to thousands of years• weather averaged over a long period of time, i.e.

Seattle is always rainy.• Able to generalize about the conditions of a

particular area• Conditions determine what organisms can live there

• Weather: a set of physical conditions of the lower atmosphere such as temperature, precipitation, humidity, wind speed, cloud cover and other factors in a period of hours or days.• what is happening outside right now.

Factors that Factors that Influence ClimateInfluence Climate• Climate is affected by the distribution of

heat and precipitation. This is affected by:• sunlight• Air circulation• the rotation of the earth• ocean currents

• Over time, patterns of global air circulation and ocean currents distribute heat and precipitation unevenly between the tropics and other parts of the world.

Atmospheric Atmospheric CompositionComposition• What is the atmosphere made

of?• several layers

• troposphere, stratosphere, mesosphere, thermosphere, exosphere

• most important for us...the troposphere and stratosphere

• air is more dense closer to earths surface than in the upper layers of atmosphere (gravity pulls molecules toward earth)• Atmospheric pressure

the tropospherethe troposphere• 70-80% of earth’s air mass is

found here

• Dense layer closest to earth’s surface, where all weather occurs

• extends about 11 miles above sea level

• 99% of the air in this layer consists of nitrogen (78%) and oxygen (21%).

• The rest is water vapor (varies with humidity), argon (.93%), carbon dioxide (.039%), and trace amounts of dust, soot, methane (CH4), ozone (O3), and nitrous oxide (N2O).

the stratospherethe stratosphere• “our global sunscreen”

• extends 17-31 miles above the earth’s surface

• composition similar to troposphere, with much less water vapor and much higher ozone

• ozone layer (11-16 miles above sea level)

• keeps 95% of the sun’s harmful UV radiation from reaching earth

• stratospheric ozone produced when oxygen molecules interact with UV radiation from the sun

• 3 O2 + UV ----> 2 O3

• Global Climate is determined by two major factors.

1. global air circulation in the atmosphere• This is influenced by…

• Unequal heating of the earth’s surface (sunlight)

• Atmospheric convection currents (air circulation)

• The rotation of the Earth (wind)

2. ocean currents distributing heat in the ocean

Air Circulation Air Circulation Influenced By: Influenced By:

Uneven HeatingUneven Heating• at the equator the

sun strikes the earth directly causing the air to heat more• causes tropical

regions to be hot and humid

• Less atmosphere for the sunlight to pass through which results in more sunlight per square meter

• leads to increased evaporation of moisture from forests, grasslands, and water bodies---this results in more precipitation

Air Circulation Air Circulation Influenced By: Influenced By:

Uneven HeatingUneven Heating• at the poles the

sunlight strikes indirectly, causing the heat to disperse• causes the polar

regions to be cooler

• Sunlight is more spread out over a larger area

• More atmosphere to pass through to reach the surface (less energy per sq. meter)

• the regions in between the equator and poles are temperate, generally having warm and cool temperatures

Air Circulation Air Circulation Influenced By: Influenced By: Atmospheric Atmospheric

Convection CurrentsConvection Currents• Uneven heating of the earth’s surface drives the circulation of the air• Air properties…

• Less dense air rises, dense air sinks• “warm air rises”—less dense

• Warm air has a higher capacity for water vapor• “humid summer”

• heat from the sun evaporates ocean water and transfers heat from ocean to atmosphere• creates giant cyclical convection cells that

circulate air, heat, and moisture (hadley and polar cells)

Air Circulation Air Circulation Influenced By: Influenced By: Atmospheric Atmospheric

Convection CurrentsConvection Currents• Large atmospheric convection currents called “cells”

• Hadley Cells located near the equator• Located between 0 and 30 degrees N and S

• Polar Cells located near the poles• Located between 60 and 90 degrees N and S

• In between these two cells is an area of air circulation by neighboring cells, causes a wide range of warm and cold air currents. • Where we see influence of the seasons most as

the earth tilts. (this is where we live)

How convection cells How convection cells form…form…• Hadley Cells…

• At the tropics (near the equator) the warming of humid air causes it to rise.

• As the air rises it cools, which produces a constant flowing of air upward. The cooling causes condensation then precipitation.

• As the air moves upward into the troposphere, the air cools and dries out. It is then displaced horizontally by warmer, moister air from below.

• The cool, dry air sinks at about 30 degrees latitude North and South, and as it sinks it warms as it approaches the surface.

• The air then moves back toward the equator, where it replaces the rising air, completing the cycle.

Equator30

degrees

latitude

Deserts

Tropical Rainforest

s

Air Circulation Influenced Air Circulation Influenced By: Atmospheric By: Atmospheric

Convection CurrentsConvection Currents• The place where the two Hadley cells meet at

the equator is called the intertropical convergence zone (ITCZ).

• Varies with the tilt of the earth, an area where earth receives its most intense sunlight.

• Polar Cells are formed similar to Hadley Cells.

• Warm air rises near 60 degrees and sinks at the poles near 90 degrees. This results in the polar areas being very cold and dry.

• Also helping with atmospheric circulation is surface albedo.

• the reflectivity of a surface (higher in poles with snow and ice)

• Global Climate is determined by two major factors.

1. global air circulation in the atmosphere• This is influenced by…

• Unequal heating of the earth’s surface (sunlight)

• Atmospheric convection currents (air circulation)

• The rotation of the Earth (wind)

2. ocean currents distributing heat in the ocean

Air Circulation Air Circulation Influenced By: Rotation Influenced By: Rotation

of the Earthof the Earth• as the earth spins, the equator moves faster than the regions to the north and south

• this causes heated air masses in the atmosphere to rise and move north or south to cooler areas. This influences global wind patterns.

• prevailing winds: major surface winds that blow continuously to help distribute heat and moisture, also to drive ocean currents.

• Caused by the Coriolis Effect…a deflection in an object’s path as the earth rotates.

Air Circulation Influenced Air Circulation Influenced By: Rotation of the EarthBy: Rotation of the Earth• The prevailing winds are created due to

the Coriolis effect and atmospheric convection currents.

• As the earth spins, deflected convection currents cause the tradewinds, westerlies, and easterlies (prevailing winds).

• Wind moves faster at equator and blows toward equator

• Wind moves slower toward poles and blows away from equator.

Climate Influenced By: Ocean Currents

• driven by the prevailing winds and the earth’s rotation, the earths major ocean currents help redistribute heat from the sun

• influence climate and vegetation near coasts

• warm and cold currents circulate around continents

• Clockwise in Northern Hemisphere

• Counterclockwise in Southern Hemisphere

Climate Influenced by: Ocean Currents

• Tropical waters are warm (more sunlight)

• This warm water expands and rises, which allows water to flow away from the equator

• Shallow warm currents

• As the current moves away from the equator the water cools and sinks

• Deeper cold currents

Biomes• The differences in the amount of sunlight, air circulation,

prevailing winds and ocean currents lead to the development of different terrestrial biomes around the world.

• Deserts• Tropical desert (Sahara)• Temperate desert (Sonoran, AZ)• Cold desert (Gobi)

• Grasslands• Savanna• Temperate Grassland (prairie)• Chaparral• Tundra

• Forests• Tropical Rainforest• Temperate Deciduous Forest• Taiga (Coniferous Forest)

Climatogram

How much do you spew (CO2)?1. What impact is this family having on global carbon

dioxide emissions? Include total lbs in your answer.

(what you calculated is only 1/3 of their emissions) Think about the explanation of their lifestyle as well.

2. Less than 11,000 lbs is a good number for CO2 emissions.

What could be done to reduce their emissions? What would they need to change as part of their lifestyle? Try to alter your scenario to decrease the emissions as much as you can.

Or…what is this family doing to have low CO2 emissions? What is the biggest part of their lifestyle that allows them to do this?

3. Are the changes you are suggesting reasonable? Or is the lifestyle this family is living realistic for everyone? Explain.

• What is climate change?

• What do you believe is causing climate change?

• Is this something we can fix? Why or why not?

• What do you think are some of the effects we could see because of a changing climate?

Climate Change• What is Global Climate Change?

• Refers to long-term changes in any aspects of the earth’s climate, especially temperature and precipitation

• Global Warming: warming of the earth’s lower atmosphere (troposphere), oceans and landmasses because of increase in the concentrations of greenhouse gases.

• Results in climate change.

Historical Climate Trends• Climate has been influenced by sun’s output of energy,

meteorite impacts, changes in earth’s orbit, air circulation patterns and human activity historically.

• Earth has had cyclical patterns of warming and cooling (glacial and interglacial periods)

• Historical temperature trends measured through…• radioactive isotopes in fossils and ocean

sediments; ice cores with bubbles of preserved air; • pollen and tree rings; and • historical temperature data collected since 1861.

• Shows general changes in temperature which in turn affect climate (not completely exact)

Global temperature graphs

• Since temperature data has been recorded 9 of the 10 hottest years on record occurred between 2000-2009

• Globally, temperatures have increased on average 1.8 degrees Fahrenheit (through 2009)

• Not evenly distributed around the globe…some areas significantly warmer and others cooler. Some areas had no change.

http://www.climatecentral.org/videos/web_features/nasa-finds-2011-ninth-warmest-year-on-record

Factors Contributing to Climate Change

• Greenhouse Effect• Warming of the lower atmosphere by

trapping solar energy, which greenhouse gases help radiate back to earth’s surface

• Greenhouse gases: water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone (O3) in troposphere.

• The earth would be a cold, frozen place without this process

Greenhouse Effect

Greenhouse Gases

• Natural Sources• Volcanic eruptions (CO2)• decomposition (CH4 and CO2)• digestion (CH4)• denitrification (N2O) • evaporation (H2O)

• Anthropogenic (Human) Sources• Burning of fossil fuels (CO2 and N2O)• deforestation (CO2, CH4 and N2O)• agriculture (CH4 and N2O)• landfills (CH4) • industry (all of the above)

Human Impacts• Emission of fossil fuels used in industry and to generate

electricity

• Emits carbon dioxide (coal burning)

• As countries become more developed the more emissions they have

• Deforestation

• Clearing forests eliminate a resource that removes CO2 from the atmosphere

• Agriculture

• Emission of methane from livestock (CH4)

• Use of nitrogen fertilizer (nitrous oxides)

Factors that affect global warming• CO2 emissions

• Burning of fossil fuels adds CO2 to the atmosphere

• Concentration of CO2 rose from 285ppm in 1850 to 398ppm in 2010.

• 450ppm seems to be the “tipping point”, optimal level is around 350ppm

• Largest emitters of CO2 are China, US, EU, Indonesia, Russia, Japan, India

• US (19%) and China (21%) account for half of the greenhouse gas emissions.

Factors that affect global warming

• Oceans

• Absorb CO2 from the atmosphere, helps to moderate surface temperature

• Estimated to remove 25-30% of CO2 emitted into the atmosphere

• As air temperature warms so does ocean temperature

• Reduces the ability to absorb CO2

• Increases acidity as CO2 absorption increases

Intergovernmental Panel on Climate Change (IPCC)

• 2500+ climate scientists from more than 130 countries produce this consensus report on climate change at the request of the UN and World Meteorological Organization

• Their findings include…• Earths lower atmosphere is warming due to

increased concentrations of carbon dioxide• This is due to human activities, which is

changing the earth’s climate

• If greenhouse gas concentration increases, Earth likely to experience rapid atmospheric warming and climate disruption• Likely disrupt food and water supplies,

ecosystem services, and flood low-lying areas

2007 IPCC Report• Latest report that includes effects on ecosystems

and biodiversity. Next report will be published in March 2014.

• Summary of Major Findings.

• Between 1906 and 2005 global surface temperature has risen just over one degree F (most since 1980)

• Annual greenhouse gas emissions from human activities rose 70% between 1970-2009

• Glaciers are melting and floating sea ice is shrinking.

• Average sea level rose by about 7 inches

2007 IPCC Technical Paper

• This report was published explaining impacts on biodiversity and ecosystems as a result of climate change.

• It also outlines the impacts on humans via food sources, living areas and socio-economic challenges.

• Look through the report, facts, diagrams and summaries.

• Highlight any common themes among the effects (generalities) that you see.

• What are the impacts on humans, biodiversity and ecosystems as our climate warms up?

• Make a list (from your highlighting) of the most common effects from climate change that we could see.

Effects of Climate Change

• Most historic climate changes took place over several thousand years.

• We are now facing a rapid increase in the average temperature of the lower atmosphere in this century. (climate disruption)

Effects of Climate Change

• Severe Drought

• Caused by decreased rainfall

• Growth of trees and other plants declines, reducing amount of CO2 taken from atmosphere

• Wildfires increase

• Declining streamflows and less available surface water, water shortages

• Ice and Snow Melt

• Climate change most severe in polar regions (poles warm faster than other areas)

• Arctic sea ice disappearing faster than projected

• Mountain glaciers slowly melting and disappearing

• Major source of water for rivers

• Melting Permafrost

• As this melts releases large amounts of CH4 and CO2 into atmosphere

• Creates positive feedback loop with continued global warming.

• Rising Sea Levels

• Predicted to rise 3-6.5 feet by the end of the century, currently they have risen about 9 inches since 1870.

• Due to melting ice, and expansion of water as it warms

• Cause disruption of coastal estuaries, wetlands and coral reefs; flooding of lowlands, coastal cities and islands; saltwater contamination of groundwater.

• A sea level rise of just 1.6 feet is estimated to affect 150 million people.

• Extreme Weather

• Severe droughts and heat waves

• Crop damage

• Increased flooding, heavy rain or snowfall

• Increase in hurricanes and tropical storms

• Biodiversity

• Loss of biodiversity due to disruption of ecosystems

• Most vulnerable are coral reefs, wetlands, tundra, mountaintops

• Warmer climate increases populations of fungi and insects that damage trees and plants

• Agriculture

• Production will drop in some areas, especially those that need specific temperatures/rainfall

• Production might increase in some areas with favorable temperatures

• Health

• Increase in death an illnesses with heat waves

• Increase in pollen, insects, toxic molds and other microbes (asthma, allergies)

• Mosquito-borne diseases more prevalent (malaria, yellow fever, dengue fever)

• Displacement from home (environmental refugees)

Solutions to Slow Climate Change

• Slow and prevent greenhouse gas emissions

• Improve energy efficiency from all sources

• Shift to renewable energy sources

• Decrease/stop deforestation, plant more trees

• Sustainable agriculture

• Carbon sequestration

• Removing carbon from atmosphere and storing it elsewhere

• Global tree planting effort

• Restoring wetlands

• Plant fast-growing plants which could be used as biofuel

• Carbon capture and storage

• Global treaties, initiatives, or legislation

• Montreal Protocol (1987): international treaty that restricts the use of chemicals that deplete the ozone layer.

• Kyoto Protocol: 187 countries ratified this agreement to limit greenhouse gas emissions to below 1990 levels by 2012. Affects limitations in developed countries only.

• The US never ratified this agreement due to exemptions for developing countries, but it was signed symbolically by the Clinton Administration

• Clean Air Act: CO2, CH4 and N2O are listed as pollutants and should be subject to regulation

• Carbon/Energy Taxes

• Cap and Trade Emissions