the science behind carbon emissions and climate...
TRANSCRIPT
The science behind carbon emissions The science behind carbon emissions and climate changeand climate change
January 17, 2008
Clinton S. Boyd, PhD
South East Michigan Sustainable Business Forum
What is the difference between weather and climate?What is the difference between weather and climate?
Definition of Climate
o The long-term weather patterns of average temperature and precipitation totals and typical occurrence of climatic extremes for a particular region.
o Changing of the seasons
Definition of Weather
o The current state of the atmosphere at a given time and place in terms of temperature, pressure, precipitation, humidity etc.
o Weather is variable, changing from day to day, and is not related to averages
Time-scale is of importance
Source: NASA
Source: USDA
Source: NASA
Put it all together Put it all together …… Climate is a complex systemClimate is a complex system
The Distinction between Global Warming and Climate ChangeThe Distinction between Global Warming and Climate Change
Climate Change
o The planetary climate system is a self-regulatory system that exists in a quasi-equilibrium state
o Regional climate arises from the interaction of atmospheric chemistry, ocean currents and major geographic features etc.
o Climate is self-adjusting: the “forcing” of climate by a key driver will cause the equilibrium to “see-saw” (show instability) until a new stable equilibrium has been established.
o This process is “climate change”, whereby the Earth’s climatic sub-regions reshuffle in response to the new “status quo”.
o Climate change or shifts in climate have occurred many times over geological history
o This term refers to an increase in the global, mean surface temperature of Earth (refers to temperature of the atmosphere)
o A driver of climate change
Global Warming
So where do carbon emissions fit in So where do carbon emissions fit in ……Take 1Take 1
The role of the atmosphere in regulating the The role of the atmosphere in regulating the planetary climate systemplanetary climate system
Greenhouse Gases and the Greenhouse Effect Greenhouse Gases and the Greenhouse Effect
o Trace gases in the atmosphere that have heat-trapping properties.
o By virtue of their molecular structure, they can collectively absorb and re-radiate infra-red radiation across a wide range of wavelengths, thereby reducing the amount of heat escaping from the atmosphere into space.
Definition of Greenhouse Gases (GHG)
Definition of Greenhouse Effect
o The natural, insulating effect of the atmospheric greenhouse gases, which maintains the Earth’s mean surface temperature
o Natural Greenhouse Effect vs. Anthropogenic (Enhanced) Greenhouse Effect
(Anthropogenic = related to human activities)
o Principal natural GHG: water vapor, carbon dioxide, methane, nitrous oxide, ozone
(in order of relative abundance)
Source: Union of Concerned Scientists (www.ucsusa.org)
To what extent does the greenhouse effect To what extent does the greenhouse effect influence global temperatures and climate?influence global temperatures and climate?
Distance from the sun is a major determinant in planetary Distance from the sun is a major determinant in planetary surface temperaturessurface temperatures
Table: Surface Temperatures of the Moon, Earth, Mars, Table: Surface Temperatures of the Moon, Earth, Mars, and Venus (and Venus (°°C)C)
n/a482n/aVenus
20-63-140Mars
5815-88Earth
(-23)123
107-153-233Moon
DayNightMaximum
MeanMinimum
Source: NASA
Table: Atmospheric Composition of Earth, Moon, Venus and Mars
240-340-63482-2315Mean Surface Temperature (°C)
0<110<1Other
00001.7 ppm
Methane
0.11.670 ppm01Argon
00.130021Oxygen (O2)
1.92.73077Nitrogen (N2)
9895.329600.03Carbon dioxide (CO2)
EARTH (without life)
MARSVENUSMOONEARTHGas (%)
Data: NASA; James Lovelock, Ages of Gaia (1988)
What would the temperature of earth be without the What would the temperature of earth be without the ““natural greenhouse effectnatural greenhouse effect””??
-18°Co The presence of a heat-trapping atmosphere helps stabilize the mean global
temperature, dampening the extremes in minimum and maximum temperatures
o The amount (% volume) of GHG (e.g. carbon dioxide) significantly alters the mean global temperature on Earth
o The dominant gases, nitrogen and oxygen are not GHG, and do not influence temperature
o Thus, less than 2% of the atmosphere is responsible for the natural greenhouse effect
o Of the trace gases, carbon dioxide only makes up 0.03% of the atmosphere
Scientific evidence that trace amounts of greenhouse gases Scientific evidence that trace amounts of greenhouse gases are important are important drivers or drivers or ““forcersforcers”” of climateof climate
Ice cores from Antarctica (Vostok)
280 ppm280 ppm
180 ppm180 ppm
COCO22 Flow: Natural FluctuationsFlow: Natural Fluctuations
o Period covers several cycles of glacial and interglacial periods
The evolving climate change debateThe evolving climate change debate
Part IPart I
o Atmospheric GHG concentrations are increasing
o The mean global temperature is increasing
o Climatic shifts are occurring around the globe
Initial arguments
Atmospheric concentrations of greenhouse gasesAtmospheric concentrations of greenhouse gases
Mean surface temperatureMean surface temperature
Are there signs that the EarthAre there signs that the Earth’’s s climate is changing?climate is changing?
Argentina's Upsala Glacier was once the biggest in South America, but it is now disappearing at a rate of 200 meters per year.
Rhone glacier in Valais, Switzerland: In 2001, the glacier had shrunk by some 2.5km, and its 'snout' had shifted about 450 meters higher up.
Cape Hatteras, North Carolina: changing sea-levels
With rising sea-levels, island nations are shrinking away
Mount Hood, Oregon: disappearing snowcaps
Disappearing polar ice
Source: UNEP
Source: UNEP
o Climate is variable and shifts are naturally occurring phenomena
o Natural vs. Anthropogenic Greenhouse Effect
Current arguments
The evolving climate change debateThe evolving climate change debate
Part IIPart II
If If ““climate variabilityclimate variability”” is a natural process, why then do is a natural process, why then do climatologists belief that human activities are responsible for climatologists belief that human activities are responsible for the the
present climate change?present climate change?
o The tempo and timing of the current climate change is abnormal
o The current “forcing” of the climate cannot be attributed to any known natural, geophysical, or cosmological phenomena, other than a rise in mean global temperature (and its associated “knock-on” effects)
o An increase in the atmospheric concentration of GHG, a key “driver” of climate, can explain the rise in mean global temperature
o The mean global temperature and the atmospheric concentrations of methane and carbon dioxide, both powerful greenhouse gases, have risen substantially since the beginning of the industrial revolution
o The increase in atmospheric GHG can be attributed primarily to the combustion of fossil fuels through human activities.
Natural Greenhouse Effect Natural Greenhouse Effect
versus versus
Enhanced (Anthropogenic) Greenhouse Enhanced (Anthropogenic) Greenhouse EffectEffect
o Natural versus synthetic greenhouse gases
o Global warming potential of each GHG
o Sources and sinks (natural versus anthropogenic)
Table: Some properties of the main greenhouse gases Table: Some properties of the main greenhouse gases
23 900Anthropogenic32000.0320SF6Sulfur hexafluoride
6500Anthropogenic50 0000.0700CF4Perfluoromethane
1300-1400Anthropogenic12.10.1050CHClF2HCFC-22
6200-7100Anthropogenic1020.5030CCl2F2CFC-12
310Natural /Anthropogenic
120311275N2ONitrous oxide
21Natural /Anthropogenic
12.21721700CH4Methane
1Natural /Anthropogenic
variable358 000278 000CO2Carbon dioxide
n/anaturalShort-livedvariablevariableO3Ozone (tropospheric)
n/anaturalShort-livedvariablevariableH2OWater
Global Warming Potential (GWP)
EmissionSource
Atmospheric lifetime (years)
1994 concentration (ppb)
Pre-Industrial concentration (ppb)
Chemical Formula
Greenhouse Gas
1. Data modified from United Nations Environment Programme’s Introduction to Climate Change2. PPB = parts per billion (on the basis of volume)3. The halocarbons CFC-12, HCFC-22 and CF4 are used here to represent the contribution of a multitude of different
synthetic ozone depleting substances and their substitutes4. Emissions sources are either natural, anthropogenic (man-made), or both5. GWP values are for the 100-year time horizon (based on the IPPC Second Assessment Report)
The Carbon CycleThe Carbon Cycle
Source: UNEP
Balance:
Sources = Sinks
Net Gain:
Sources > Sinks
Source: www.pewclimate.org
Source: www.pewclimate.org
Fossil fuel combustion is the main source of COFossil fuel combustion is the main source of CO2 2 emissions emissions throughout the different economic sectors throughout the different economic sectors
So, why all the attention on carbon? Take 2So, why all the attention on carbon? Take 2
o Most GHG are carbon-based
o The principal GHG emissions associated with human activities are carbon-based, CO2 and CH4
CO2 CH4N2O
SF6CHClF2
CF4
CHCl3CCl4 H2OO3
PFCHFC
Source: www.pewclimate.org
Source: www.pewclimate.org
Sources of anthropogenic GHG emissions by sectorSources of anthropogenic GHG emissions by sector
Worldwide USA
Source: www.pewclimate.org
Table: COTable: CO22 intensity for different energy and fuel sourcesintensity for different energy and fuel sources
UnitCO2 Emissions(lbs/unit)
UnitCO2 Emissions(lbs/unit)
Biomass - variableAviation gasoline gallons 18.355 Geothermal Energy - 0Motor gasoline (unleaded) gallons 19.564 Wind - 0Liquified Petroleum Gases gallons 12.805 Photovoltaic and Solar Thermal - 0Kerosone gallons 21.537 Hydropower - 0Jet Fuel gallons 21.095 Tires/Tire-derived fuel short ton 6160Distillate Fuel (#1,2,4 Fuel Oil and Diesel) gallons 22.384 Wood and Wood Waste short ton 3814Petroleum coke gallons 32.397 Muncipal Soild Waste short ton 1999Residual Fuel (#5,6 Fuel Oil) gallons 26.033 Waste-To-Energy - variable
Methane thousand ft3 116.376 Nuclear Energy - 0Landfill gas thousand ft3 variableFlare gas thousand ft3 133.759Natural Gas (Pipeline) thousand ft3 120.593Propane gallons 12.669
Anthracite short ton 3852.16Bituminous short ton 4931.3Subbituminous short ton 3715.9Lignite short ton 2791.6
Renewable SourcesNon-Renewable Sources (Fossil Fuels)
Petroleum Products
Natural Gas and Other Gaseous Fuels
Coal
Other
Modified from: Fuel and Energy Source Codes and Emission Coefficients ( Voluntary Reporting of Greenhouse Gases Program) [Energy Information Agency]
Source: US EPA, 2000
Sources of GHG in United States (1998)Sources of GHG in United States (1998)
Source: US EPA, 2000
Source: US EPA, 2000
Source: US EPA, 2000
Thank you !Thank you !
Senior Scientist
Sustainable Research Group
949 Wealthy SE Suite 205
Grand Rapids, MI 49506
Tel: 616.301.1059
Fax: 616.301.1135
Email: [email protected]
www.sustainableresearchgroup.com
Clinton S. Boyd, PhD