Transcript Ch 20 - Climate Change

20
Global Climate Change
Climate Change Terminology

Greenhouse Gas


Positive Feedback Loop


Change in some condition triggers a response that intensifies the
changed condition
Infrared Radiation


Gas that absorbs infrared radiation
Radiation that has a wavelength that is longer than that of visible
light, but shorter than that of radio waves
Greenhouse Effect

Increase of heat in a system where energy enters (often as light),
is absorbed as heat, and released sometime later
Climate Change (not global warming)

Refers to the recent and ongoing rise in global
average temperature near Earth's surface
 caused
(mostly) by increasing concentrations of
greenhouse gases in the atm.
 significant change in climate lasting for an extended
period of time
 includes major changes in:
 Temperature
 Precipitation
 Wind
patterns
 Occurring over several decades or longer
Greenhouse gases

Greenhouse gases act like a blanket around Earth,
trapping energy in the atmosphere and causing it to
warm
Increased concentration of CO2
 Burning
fossil fuels in cars, industry and homes
 Deforestation
 Burning of forests
 Industrialization
This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides
evidence that atmospheric CO2 has increased since the Industrial Revolution. (Source: NOAA)
Greenhouse
Effect
What we know
CO2 accounts for
60% of increased
heat retention
Radiative Forces
Capacity of gas to
affect energy
entering and leaving
the atm
Introduction to Climate Change

Certain facts about climate are not in dispute

What we Know
 CO2
has the ability to trap heat
 Methane, Nitrous oxides, CFC’s tropospheric ozone can
also trap heat
 demonstrated
in the mid-19th century
 CO2 ability to capture infrared energy scientific basis of many
instruments flown by NASA

Based on the knowledge above the following can be assumed

Increased levels of greenhouse gases must cause the Earth to warm in
response
What we know

Sea level rise
Last 100 years rose ~6.7 inches
 Last 10 years, rose ~12 inches


Global temperature rise
 All
major global surface temp reconstructions show that
Earth has warmed since 1880.
 Most of this warming has occurred since the 1970s
 the 20 warmest years having occurred since 1981
 and with all 10 of the warmest years occurring in the
past 12 years
What we know
Sciences evidence

Warming oceans
 Oceans
have absorbed much of this increased heat,
with the top 2,300 feet of ocean showing warming of
0.3020F since 1969

Shrinking ice sheets
 Greenland

& Antarctic ice sheets have decreased
Data from NASA's show
 Greenland
lost 36-60 cubic miles of ice/year from 2002 - 2006
 Antarctica lost 36 cubic miles of ice/year 2002-2005.

Declining Arctic sea ice / Glacial retreat /
Extreme events / Ocean acidification
Pollutants That Cool the Atmosphere

Atmospheric Aerosols - “ Aerosol Effect”
 Both
human and natural sources
 Sulfur can remain in troposphere for weeks or months
 Sulfur-laden haze in the atm reflects infrared radiation

Complicates models of climate change
 Negative
feedback loop
 occurs
when the result of a process influences the operation
of the process itself in such a way as to reduce changes
 One
of the many complications that affects modeling
climate change
Climate Models

Climate affected by:
 winds,

clouds & ocean currents
Advanced models can project future warming events
 Do
there best to factor in all known data
 Models
are only as good as the data
 Models have limitations
Effects of Global Climate Change Melting Ice & Rising Sea Levels

IPCC – International Panel on Climate Change
 Projects
sea-level rise of 18-59 cm by 2100
 Projects temp to rise1.8 to 4.0ºC by 210

Sea level rise - 2 ways
 Thermal
 matter
 Melting

Expansion
changes in volume in response to a change in temp
of land ice
Melting has positive feedback
 Increased
melting decreases ice, which decreases
albedo leading to further warming
(Albedo – Reflections from the a white surface)
Melting Ice & Rising Sea Levels

Thermal expansion


Melting of glaciers and polar ice caps


Large ice formations, like glaciers and the polar ice caps, naturally melt
back a bit each summer.
Melting of surface ice


When water heats up, it expands
massive ice sheets that cover Greenland and Antarctica to melt at an
accelerated pace
Consequences



Seawater reaches farther inland
destructive erosion, flooding of wetlands, contamination of aquifers &
agricultural soils
lost habitat for fish, birds, and plants
Case-In-Point
Impacts in Fragile Areas

Eskimo Inuit live traditional life
 Alaska
& Canada
 Dictated by freezing climate

Climate change is altering their existence
 Wildlife
displaced
 Reduced snow cover & shorter ice seasons
 Thawing of permafrost
 soil

at or below the freezing
World-wide, permafrost contains huge amounts of dissolved carbon

The amount of carbon sequestered in permafrost is 4x the carbon that
has been released to the atmosphere due to human activities in modern
time
Effects of Global Climate ChangeChanging Precipitation Patterns

Some areas will get more water, some areas will
have greater droughts
Effects on Organisms - Coral Reefs

Coral reefs can be bleached due to increase in water
temperature & increase in pH (Acidic)
 Affects
coral symbiotes & makes them more susceptible
to diseases
Effects of Global Climate ChangeEffects on Organisms

Zooplankton in parts of California Current have
decreased by 80% since 1951
 Affecting
entire food chain

Species have shifted their geographic range

Migrating birds are returning to summer homes
earlier

Ecosystems at greatest risk of species loss

coral reefs, mountain ecosystems, coastal wetlands,
tundra, and polar spas
Effect on Organisms - Vegetation
Effects on Agriculture

Difficult to anticipate
 Productivity
may increase in some areas & decrease in
others

Rise in sea level will inundate flood plains & river
valleys

Effect on pests is unknown

Warmer temperatures will decrease soil moisture requiring more irrigation

Location where certain crops can be grown may
have to change
Effects of Global Climate Change

Extreme weather
 More
Wildfire in California
 More extreme hurricanes
International Implications of Climate
Change

Developed vs. Developing countries
 Differing
self-interests
 Differing ability to meet the challenges of climate change
Dealing with Global Climate Change
Two ways to manage climate change

Mitigation:
 Limiting
greenhouse gas emissions Locate/invent
alternative fuels to fossil fuels
 Increase
efficiency of cars and trucks
 Carbon Capture and Storage
 Plant and Maintain trees to naturally sequester carbon

Adaptation:
 Learning
to live with environmental changes & societal
consequences brought about by global climate change
 Move
inland (Rising sea levels)
 Construct dikes and levees
 Adapt to shifting agricultural zones
Relationship Between
Mitigation & Adaptation
International Efforts to Reduce
Greenhouse Gas Emission

Kyoto Protocol
 Legally
binding
 Provides operational rules on reducing greenhouse
gases
 By 2010, 183 countries had ratified it
 US



 It
has not sign it. The reason being…..
It did not require developing countries to make emission reductions
It would seriously harm the economy of the United States
Clinton signed it but the senate and house did not
will be difficult to implement without US backing
 EPA is taking it upon itself to define laws associated with CO2
reduction in US
Those that agree the climate is
changing due to human influence

97% of Scientists
 NASA
(Environment protection agency) – of course
 NIH (National Institute of Health)
 EPA
Skeptics

Modeling system are flawed
 They
do not take into account many factors
 Can not predict the future

Do not have enough good recorded temp data
 This
could be just part of a large weather cycle that has
not recorded (We have not been around long enough to
record temp over thousands of years)
 Aren't temperature changes natural?

Can't we wait and fix the climate if things get
really bad
Interesting things on-line

You tube: Climate change way over simplified
(but very interesting to think about)

http://www.upworthy.com/one-guy-with-a-marker-just-madethe-global-warming-debate-completely-obsolete-7
As always know your source – all info is bias in one
direction or the other. Do your best to get raw (not
manipulated) data.