Transcript Climate and Biodiversity

Climate, Biodiversity, and Global
Climate Change
Chapters 7, 18.1, 19.1-3
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 Influence
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 Composition
• 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 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 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 Influenced By:
Uneven 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 Influenced By:
Uneven 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 Influenced By:
Atmospheric Convection 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 Influenced By:
Atmospheric Convection 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 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.
Deserts
30
degrees
latitude
Tropical
Rainforests
Equator
Air Circulation Influenced By:
Atmospheric Convection 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 Influenced By: Rotation
of 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 By: 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-2011ninth-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