Transcript Chapter 15: Climate

Chapter 15: Climate
David Gindra, Sam Freres, Peter Sheehy,Keyu Yan
What is the atmosphere?!?
What is the atmosphere made of?
Early atmosphere: Hydrogen and Helium
Volcanoes: Carbon, Nitrogen, and Sulfur
...but what about Oxygen??
Photosynthesis!
Ga = gigaannum
(1 billion years)
Layers of the Atmosphere
Troposphere: Weather, planes, (people!)
(from Greek tropien, “turn” or “change”)
Stratosphere: Ozone layer
Absorbs UV radiation
Mesosphere: Boring in-between layer
Winds, temperature decreases. (Gravity/planetary waves???)
Thermosphere: Space begins here
Karman line (100 km), ionized gases, auroras, heated by solar energy
Where does heat go?
Albedo
(fig. 15.5)
!
Albedo & The Greenhouse Effect
Albedo: Reflection of the sun’s energy
Different surfaces reflect different amounts
Greenhouse Effect: Holds in energy
Naturally, not a bad thing! (Without it, we’d be dead.)
Different gases cause the Greenhouse Effect:
H2O
CO2
CH4
N2O
(other gases)
Why does it rain?
Latent heat: Energy stored in water vapor
Carries 580 calories of energy per gram
Convection currents: Pressure difference
Warm air rising = low pressure, cool air sinking = high
pressure
Moving air masses cause rain:
Moist air that cools causes rain to fall
What about Minnesota?
Flat because of glaciers, means lower than average
rainfall
What are some other weather patterns?
Jet streams:
Where convection currents meet
Coriolis Effect:
Earth’s rotation causes circular currents
Monsoons: Seasonal rain
Large amounts of the Earth’s population
depend on seasonal rains for agriculture
Fonts: Borders between air masses
Warm or cold; cause local weather
What about hurricanes?
Cyclonic storms:
Swirling winds around low-pressure locations create swirling storms
Hurricanes: tropical cyclones
Warm tropical waters create “hot towers”, destructive over large areas
Tornadoes: terrestrial cyclones
Swirling funnel clouds, destructive in local areas
What about Minnesota?
POLAR VORTEX?!
Natural Climate Variability
● Climates shift on scales of decades, centuries, and
millennia
● There are multiple factors that influence this natural
shift in climate
● There is expanding evidence to help us discern specific
patterns
Ice Cores
● Ice cores tell us about climate history
● Every time it snows, small amounts of air are trapped in
the snow layers
● In cold places, yearly snows accumulate and compress
lower layers into ice, trapping air bubbles
● By drilling deep into ice sheet, they can extract ice cores
from which they collect these air bubble samples and
can show how the atmosphere changed over time
How can we use this information?
Track CO2 variation
Track volcanic eruptions
We can look at isotopes of oxygen
By looking at the proportions of heavier and lighter
isotopes (oxygen atoms), climatologists can reconstruct
temperatures over time
● Vostok Ice Core
● Greenland Ice Sheet
●
●
●
●
Temperature and CO2
● European Project for Ice Coring in Antarctica (EPICA) has produced a
record reaching back over 800,000 years
● Correlation between atmospheric temperatures and CO2 concentrations
Influence of Earth’s movement
● Milankovitch cycles: periodic shifts in the earth’s orbit and tilt
● Earth’s elliptical orbit stretches and shortens in a 100,000 year
cycle
● Axis of rotation changes its angle of tilt in a 40,000-year cycle
● Over a 26,000-year period the axis wobbles like an out-of-balance
spinning top
● Changes the distribution and intensity of sunlight reaching the
earth’s surface
El Niño
● Ocean-atmospheric cycle
● Both the ocean and the atmosphere have regular patterns of
flow, or currents, but these shift from time to time
● Areas of warm water slosh back and forth
● Sloshing in the ocean influences low-pressure areas in the
atmosphere--and winds and rain change as a consequence
● One important example is known as El Niño/Southern
Oscillation, or ENSO
ENSO
● The core of the ENSO system is a huge pool of warm surface water
in the Pacific Ocean that sloshes slowly back and forth between
Indonesia and South America
● This is a huge low-pressure area
● Every 3-5 years, this low pressure near Indonesia shifts eastward
and the mass of warm surface water surges back east across the
Pacific
● Sometimes, between El Nino events, coastal waters become really
cool, and these extremes are called La Niña
● Together this cycle is called ENSO
Effects on us?
● Repercussions in weather
systems across North and
South America
● Intense storms and heavy
rains from California across
the Midwestern states
● La Niña years bring extreme
hot and dry weather to these
same areas
● Floods to the Mississippi
River basin
Anthropogenic Climate Change
Climate change caused or produced by humans
The Idea
● Anthropogenic Climate change is not a new
idea
● First proposed by swedish physicist Svante
Arrhenius in 1895
● pointed directly to climate change caused by
the release of CO2 from coal burning
First Traces
● Anthropogenic climate change was first witnessed
in 1957 at the mauna loa observatory in hawaii
● Initial measurements showed an increase in CO2
levels by 0.5 percent per year
● research continued at the mauna loa observatory
show a trend of increasing CO2 levels in the
atmosphere
Keeling Curve
Initial Research
● Intergovernmental Panel on Climate
Change(IPCC)
● Report released in 2007(AR4)
● 90% chance global climate change is
anthropogenic
● Some changes, Researchers were “virtually
certain” of being anthropogenic
Where does anthropogenic climate change come from?
The world is now warmer than it has been in the last two
millennia
What does that mean?
● Warming, Drying, and Habitat change
● Polar regions are melting causing habitat
destruction for penguins, and poor hunting
conditions for polar bears
● Permafrost melt causes infrastructure to sink
● Predicted half of the world's glaciers will
disappear by
● CO2 absorbed by the ocean lowers the pH and
destroys coral formations
● Sea levels rise due to glacial melt and thermal
expansion of sea water
● Droughts become more frequent, and have already
increased 30% since 1970
● Even a 2 degree celsius rise in temperature could
destroy 20-40% of the amazon rain forest
● As water temperatures rise above 85 degrees
fahrenheit, corals lose their photosynthetic
algae and “bleach”
● Increased atmospheric energy causes storms
to grow and become more damaging
● As sea level rises many cities will flood
● ⅓ of current world population lives in areas
that would flood if Greenland's ice were to
melt
● Most of the world’s wealthiest urban cities
are on coastlines
Envisioning Solutions
1.Political Science—new rules and standards
2. Science—scientific strategies,technologies
or renewable resources
New Standards and Rules
1) 1992,Earth Summit, Rio de Janeiro Brazil
——“sustainable development that doesn’t
destroy opportunities for future generations”
2) 1997, Kyoto, Japan——Kyoto Protocol
Business Groups and NGO
U.S. Policies
I) Ideal policy——a single national standard
II) Policies situations—— various laws
depends on different states —> a jumble of
conflicting local and state rules
i.e. California [what do you think?]
Minnesota—U.S.
I) School bus retrofits and idle reduction
Children face heightened exposure to diesel exhaust from the self-polluting nature of buses, and the
tendency of buses to idle during loading and unloading.
II) Auxiliary power units for long haul trucks
MPCA is using Congestion Mitigation and Air Quality funds to retrofit a minimum of 200 on-road
diesel vehicles from public fleets in 2009.
III) Idling policies and ordinances
Several Minnesota counties and cities have internal idling policies for their transportation fleets, like
Hennepin County.
http://www.pca.state.mn.us/index.php/air/air-quality-and-pollutants/general-air-quality/motor-vehicle-pollution/cleaning-updiesel-engines-in-minnesota.html
Other Regional Initiatives
What can you do? (Personal)
Science
I) Technologies and scientific
strategies/analysis —> wedge analysis
C02 Capture and Storage
II) Renewable resources [chapter 20]
Stabilization Wedges
I) what?(case study)II) why?(case study) III)How(p339)?
still have limitation
Technology—C02 Capture and Storage