what is the greenhouse effect? what is the carbon cycle? how is the temperature of the earth...
TRANSCRIPT
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!