What is the Greenhouse Effect?

What is the CarbonCycle?

How is the temperature of the Earth maintained?

Greenhouse effect

Our atmospheric gases trap and return a major portion of the heat radiating

from the Earth.

It is a natural, necessary process.

3.1

The Earth’s Energy Balance

Data in watts

3.4

The infrared spectrum for CO2

Wavenumber (m–1) = 1______wavelength (m)

Climate Forcing/FeedbackHow does Earth stay Comfortable for Us?

• Gaia Hypothesis– Biological and Physical Processes Produce

Homeostasis

• Negative is Good – Feedback control

• Positive is Bad – Oscillate out of control

http://www.southtexascollege.edu/nilsson/4_GB_Lecture_figs_f/4_GB_16_Homeostasis_Fig_f/Homeostasis_TempControl.GIF

http://apollo.lsc.vsc.edu/classes/met130/notes/chapter16/graphics/neg_feed.free.gifEdited DEH

http://apollo.lsc.vsc.edu/classes/met130/notes/chapter16/graphics/pos_feed.free.gif

Ice-Albedo Positive Feedback

Temperature increases

Less Ice on Surface

More Solar Energy Absorbed and less Reflected – Albedo lower

The carbon cycle

3.5

3.5

CO2 emission sources by end use:

Ways to reduce CO2 Emissions

• Where is the Biggest Target?

• Where are the Easy Targets?

Ways to reduce CO2 EmissionsPower Sector

• Energy Efficiency – use less• Switch from Coal to Natural Gas -50% red.• Renewable Energy

– Solar electric– Solar Thermal– Wind – driven by solar heating of earth– Hydropower – related to solar– BioFuels – solar energy capture

• Plant based

• Algae based

Combined Heat and Power

• Use “waste heat”

• 90-95% total efficiency 1/3 the CO2

• Over 200 College and University systems– Yale 60 Megawatt– Electricity– Steam and hot water

How do scientists study climate?

• Collect data, historical and paleo-

• Consider physical mechanisms at work

• Develop models and test them

• Limitations of science– Can’t prove a positive– Eliminate possibilities– What remains is accepted

Why is there still a ?

• Correlation does not PROVE Causation

• Climate Models (GCM’s) Still Imperfect– Cloud Impacts Undertain

• Wishful Thinking

3.9

Climate Models are used to predict annual global mean surface temperatures.

Blue bands = predicted temperature range using natural processes

Pink bands = temperature range including human influence

Black line= observed temperature

Test Models with Historical Data

3.9

Models can also be used to predict future global temperatures.

Black line = data for the 20th century

Other lines = projected 21st century temperatures based on different socioeconomic assumptions

Limitations of Models

• Assume linear change

• Assume same mechanisms of climate continue to function

• Role of clouds not known with certainty

• Polar Vortex Collapse

• Gulf Stream (Thermo-haline circulation)

• Air Transport in Troposphere– Convection cell position

Kyoto Protocol – 1997 Conference

• Intergovernmental Panel on Climate Change (IPCC) certified the scientific basis of the greenhouse effect.

• Kyoto Protocol established goals to stabilize and reduce atmospheric greenhouse gases.

• Emission targets set to reduce emissions of six greenhouse gases from 1990 levels.

(CO2, CH4, NO, HFCs, PFCs, and SF6)

• Trading of emission credits allowed.

3.11

The Kyoto mechanisms

• Emissions trading – known as “the carbon market" 

• Clean development mechanism (CDM)– Polluters can reduce emissions in developing

countries and get credit.

• Joint implementation (JI). – Eg. USA could buy forests in Brazil and get

credit for carbon sinks

The Kyoto mechanisms

• Registry System – Record transactions

• Annual Reports

• Compliance System

• Adaptation Fund– Money to help poor countries adapt to Climate

Change

Where are we today? (2009)

• Copenhagen Meeting– Kyoto expires in 2012– Kyoto goals not met– US, China, India, and Australia never signed

– Need to move forward with new agreement– Can the US-China-India- and Australia join?

• Meeting begins with real optimism!

Fairness?

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