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
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
Ice-Albedo Positive Feedback
Temperature increases
Less Ice on Surface
More Solar Energy Absorbed and less Reflected – Albedo lower
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!