CLIM 101: Global Warming: Weather, Climate and Society

Carbon Footprint, Energy UseCarbon Footprint, Energy Use

Lecture 17, 2 Nov 2010

Evidence for Evidence for Human-induced Human-induced

Changes in GHGsChanges in GHGs(Overwhelmingly (Overwhelmingly

convincing!)convincing!)

※Rate of increase of GHG is largest in 10,000 years

Carbon CycleCarbon Cycle

Fossil fuel burning

also subduction, metamorphosis, and volcanism

Carbon CycleCarbon Cycle

Total known fossil fuel deposits: 4500 Gt

Are there changes in the efficiency Are there changes in the efficiency of the land and/or ocean sinks for CO2 ? of the land and/or ocean sinks for CO2 ?

Fossil fuel burning

Decay and burning of live

biomass

Photosynthesis

Solution

Fraction of the CO2 emitted by human activities Fraction of the CO2 emitted by human activities which remains in the atmosphere which remains in the atmosphere

airborne fraction = atm / (fossil fuel + cement + land use emissions)

COCO22 in the Atmosphere in the Atmosphere

CO2 Concentration Remained in the ATM.

What are the implications for global What are the implications for global warming?warming?

• Residence time of CO2 in the atmosphere is difficult to interpret.

• Roughly 10% of the carbon in the fossil fuel reservoir has been burned so far and at the current rate it will take us 500 years to burn the rest of it.

• Most of the carbon in the fossil fuel reservoir is in the form of coal.

• Burning all known coal deposits would add to the atmosphere-ocean reservoir a mass of carbon roughly equivalent to 5 x the carbon presently in the atmosphere and 8 x the pre-industrial level.

• The true size of the fossil fuel reservoir may be larger but it’s hard to say by how much because we don’t know how much oil shale and methane hydrates we will be able to utilize.

• Were it not for the biosphere, and especially the marine biosphere, most of the Earth’s carbon would be in the form of atmospheric CO2 as it is on Venus.

Global COGlobal CO22 Emissions Emissions• In 2005, global emissions were 27 billion

tons of CO2

• Per capita, emission (27/6.7 billions) = 4 tons/per capita/yr

• US emissions = 20 tons/per capita/yr

What is 4 tons of COWhat is 4 tons of CO22 per person per per person per year?year?

• Drive 10,000 miles per year with a car that gives 30 miles per gallon.

• Fly 10,000 passenger miles per year.

• 300 KWH per month of electricity from coal fired plant.

• 600 KWH per month of electricity from natural gas fired plant.

(my house: 580 KWH in Mar. 2008; 380 KWH in Mar. 2009)

The present concentration is

380 parts per million (ppm): fraction of molecules

380 CO2 molecules for each million air molecules

0.38 CO2 molecules for each thousand air molecules

0.038% of the air molecules are CO2

0.00038

equivalent to 38 cents per $1000

Has increased from 315 ppm in 1958 to 380 ppm today

Unit of measurement of Unit of measurement of Atmospheric COAtmospheric CO22 Concentration Concentration

Atmospheric Carbon Dioxide (COAtmospheric Carbon Dioxide (CO22))At Mauna Loa, HawaiiAt Mauna Loa, Hawaii

Metric tons of carbon (1 metric ton = 2200 lb)

note that we only count the mass of carbon atom in CO2

If M is molecular weight

M(C) = 12

M(O) = 32

M(CO2) = 44

M(C)/M(CO2) = 12/44 = 0.27

CO2 = 20 tons per capita/yr C = 20X0.27 = 5.4 tons per capita/yr

For reference, consumption of energy and products by the average American results in the emission of ~5.4 tons of carbon (tC) per year.

US population is slightly more than 300 million.

Hence, the US emissions are ~1600 MtC (megatons; millions of tons of carbon per year), or 1.6 about GtC (gigatons; billions of tons of carbon)

The US accounts for 22% of the World current emissions, so the total global annual emission is roughly 1.6/0.22 = 7.2 GtC = 27 GtCO2

Unit of measurement of Carbon Unit of measurement of Carbon EmissionEmission

To convert ppm to GtC, multiply 380 ppm by

the mass of the atmosphere (5.12 x 1015 Gt)

and by M(C)/M(air molecules) = 12/29 = 0.414

(380 x 10-6 ) x (5.12 x 1015 Gt) x 0.414 = 806 GtC

Hence each year carbon emissions due to human activities are equivalent to 7.2/806 or nearly 1% of the mass of carbon currently residing in the atmosphere.

There is a small additional mass of carbon in the atmosphere in the form of methane.

How does 7.2 GtC compare with the How does 7.2 GtC compare with the amount that’s already in the amount that’s already in the

atmosphere?atmosphere?

Distribution of regional GHG emissionsDistribution of regional GHG emissions in in 20042004

per capita, over the population of different countrygroupings

• All Kyoto gases including those from land-use• The percentages in the bars indicate a region’s share in global GHG emissions• EIT Annex I: Eastern Europe• Europe Annex II & M&T: Western Europe• JANZ: Japan, Australia, New Zealand.• Middle East• Latin America & the Caribbean• Non-Annex I East Asia• South Asia• North America: Canada, United States of America.• Other non-Annex I: past Soviet Union• Africa.

46% 54%

• 5% of the world’s population (North America) emits 19.4%, while 30.3% (Non-Annex I South Asia) emits 13.1%.

Which countries are emitting the most

greenhouse gases?

Per capita emissions

Total emissions QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

US Energy Consumption by Energy Source, 2004-US Energy Consumption by Energy Source, 2004-20082008

US Primary Energy Consumption by Source & US Primary Energy Consumption by Source & Sector, 2007Sector, 2007

US COUS CO22 Emissions by Fuel & Sector, 2006 Emissions by Fuel & Sector, 2006

How much do different activities contribute?

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are needed to see this picture.

Natural Gas Petroleum

Coal/ Coke Electricity Total

Residential 237.5 89.2 0.6 870.6 1,197.9Commercial 154.1 45.3 6.3 837.3 1,043.0

Industrial 394.8 419.9 186.2 651.5 1,652.4Transportation

33.2 1,975.5 0.0 4.7 2,013.4Total 819.6 2,529.9 193.1 2,364.1 5,906.7

US 2006 Carbon Dioxide Emission Sources by use US 2006 Carbon Dioxide Emission Sources by use Sector Sector

(Millions of Metric Tons)

(5906.7+1233.9)

1062.6

(1062.6+171.3)

US GHGs Emissions, 2006US GHGs Emissions, 2006

World list: All countries >1,000 MMT CO2

or All regions >2,000 MMT CO2

by 2006 

Source: US DOE Energy Information Administration (EIA)

World COWorld CO22 Emissions Emissions

Primary Energy Consumption 2006 (US)Primary Energy Consumption 2006 (US)

Renewable Renewable EnergyEnergy

Solar

Wind

Water

Biomass

Geothermal

Hydrogen & Fuel Cells

Wind PowerWind Power

Recent US Trends: Recent US Trends: EncouragingEncouraging

• 9% drop in US emissions in past 2 years

(Recession; High gasoline price; Efficiency; Non-carbon energy)

• Wind farms, Solar power plants rapidly increasing

• Corporations concerned about risk, public opinion

• EPA ready to regulate Carbon under the Clean Air Act

(Supreme court, 2007); ”A glorious mess”

Center of Ocean-Land-Atmosphere studies

Greenhouse Gas Emission TargetsGreenhouse Gas Emission Targets

IPCC: 25% below the 1990 level by 2020

IPCC: 80% below the 1990 level by 2050

New York: 10% below the 1990 level by 2020

Vermont: 25% below the 1990 level by 2012

Virginia: 0% below the 2000 level by 2025

Waxman-Markey:17% below the 2005 level by 2020

Boxer-Kerry : 20% below the 2005 level by 2020

Greenhouse Gas (GHG) Emissions (India)Greenhouse Gas (GHG) Emissions (India)Sharma et. al (2008); PM Council (2008)Sharma et. al (2008); PM Council (2008)

• GHG (1994) = CO2 (63%) + CH4 (33%) + N2O (4%) = CO2Eq

• GHG = CO2Eq unit: Million Metric Tons (Mt)

• Rate of Increase 2000-2004 (GHG): 4.2% per year

Year 1990 1994 2000 2004 2020

GHG 998 1228 1484 1748 3000

Greenhouse Gas (GHG) Emissions (India)Greenhouse Gas (GHG) Emissions (India)Sharma et. al (2008); PM Council (2008)Sharma et. al (2008); PM Council (2008)

• 2004: CO2: 1.02 tons/person; Pop = 1079.7 million; Total CO2 = 1101.3 Mt; GHG = (CO2/.63) = 1748 Mt

• 2004 GHG emissions = 1.62 tons per person

• 1994: Pop: 914 million;Total CO2 = 793.5 Mt; GHG 1228 Mt (3% of global)

• 1993 GHG emissions = 1.34 tons/person

• 1994 - 2004: CO2 increase: 3.34% per year; GHG: 1.34 to 1.62 tons per capita

Global Carbon Dioxide (Global Carbon Dioxide (CO2) Emissions ) Emissions (2004)(2004)

CO2 (Gt)Population

(millions)Tons per person

World 27.1 6365.0 4.25

USA 5.9 293.7 20.01

India 1.1 1079.7 1.02

China 4.7 1296.2 3.60

Unit: Billion Metric Tons (Gt)

(PM Council, 2008)

2020: Projections for 2020: Projections for CO2Emissions Emissions (India, USA)(India, USA)

• USA: 20% below 2004; 4.7Gt; (4.7/338.4M) ~ 14 tons/person

• India: 72% above 2004; 3Gt; (3/1332M) ~ 2.3 tons/person

• USA: 50% below 2004: 2.9Gt; (2.9/404M) ~7.2 tons/person

• India: 2% increase 2020-2050; 5.4Gt; (5.4/1620M) ~ 3.3 tons/person

3% increase 2020-2050; 7.3Gt; (7.3/1620M) ~ 4.5 tons/person

2050: Projections for CO2 Emissions (India, USA)

• “Polluter must pay”(We (US) are the biggest polluters but we also have the biggest guns.)

• Those who have contributed the least to global warming will suffer the most and the earliest.

• Poor countries would like to improve the quality of life of their people (consume more energy).

• Sustainable developement in a changing climate is challenged by population growth and exetreme poverty.

Ethics of Global WarmingEthics of Global Warming

Impacts Hit the Poor Impacts Hit the Poor HardestHardest

• 30 to 200 million people at risk of hunger with temperature rises of 2 to 3°C.

• 0.7 to 4.4 billion people will experience growing water shortages with a rise of 2°C.

Yields across Africa and Western Asia may fall by 15% to 35%

THANK YOU!THANK YOU!

ANY QUESTIONS? ANY QUESTIONS?