Quick recap

• What is albedo? What role does it have in helping to control climate?

• This February was the second coldest Winter on record in parts of the north east United States. How can climate change be real then?

Albedo

• Ability to reflect light– Ice reflects about 80%– Water absorbs about

80%

• Albedo increases during glacial periods and decreases when melting occurs.

Oceans

• Remove ~30% of excess CO2 from atm.

• Increased CO2 in the atmosphere means increased CO2 in oceans.– Recall from earlier

chapters this increases Carbonic Acid (H2CO3) in oceans.

• Oceans have the ability to store and absorb heat in deep ocean– Delayed due to warming– Heat returns to atm and

ends with warming temperatures.

Quick Recap

• People often confuse greenhouse gases, their association with climate change and ozone depletion. Discuss with your neighbor what each is and whether they are all connected or not.

Quick Recap• Greenhouse effect– Greenhouse gases in the

troposphere trap solar radiation (IR) heat in the troposphere.

– WITHOUT TROPOSPHERIC COOLING EARTH WOULD BE ABOUT 0OF AVERAGE

• Climate change– Alterations to climate

patterns (precipitation, temperature, prolonged rainy/dry seasons)

– Nonanthropogenic:• Cyclic variation in

temperatures and levels of atmospheric gases.

– Anthropogenic• Human activity (primary

use of fossil fuels) is increasing concentration of GHG in the troposphere.

Greenhouse GasesGas (time in ATM) Source Relative Warming Potential

CO2 (50-120 yrs) Burning F.F. plant burning + deforestation

1

CH4 (12-18 yrs) Natural leaks, cattle, coal 23

N2O (114-120 yrs) Fertilizers, F.F, livestock waste, industry

296

CFC (11-20 yrs) Air conditioning/ refrigerator coolants, plastic foams

900-8300

HFC (10-400 yrs) “ “ 13-12700

Halons Fire Extinguishers 5500

CCl4 Cleaning Solvents 1400

SF6 Insulation + power lines 23900

Ability to trap heat

Ways to measure changes in climate

• C-14 samples in ice and remains.

• Plankton and isotopes from ocean.

• Glacial ice cores– Sulfur dioxide and

carbon samples

• Tree rings– Indicate dry/wet years– Cold vs warm

• Coral isotopes– C-14 in shells – Thickness of shells and

CaCO3

• Historic records• Temperature

measurements.

How is carbon getting from reservoirs back into the atmosphere?

What has happened since the industrial revolution.

Potential impact of Climate change

• Flooding of coastal areas

Glacial melt

Ocean acidification

Spread of infectious disease

Droughts

Ways to reduce the impact ..

Changes in transportation• Increase CAFÉ standards– Increased MPG of cars

Changes in transportation

• Alternative fuels– Electric vehicles• may only change nonpoint source to point source

pollution

– Fuel cells– Hybrids

• Catalytic converter– In cars to reduce amount of HC, CO and Nox in

atmosphere

Changes in Industry

• Electrostatic Precipitators and Scrubbers

Other ways to help

• Government taxes on carbon emission.• Create cap and trade programs.• Switch to cleaner energies• Legislation• International treaties

1992 Earth Summit

• Rio de Janeiro • 106 nations approved framework on Climate

Change• 2 principles:– Scientific uncertainty must no be used to avoid

Precautionary Principle– Industrialized nations must take lead

• Reduction in GHG emission by 5.2 % below 1990 levels by 2000

GHG + CLIMATECHANGE

1992 Earth Summit

• 2nd component was the Convention on Biological Diversity– As UN focused on preventing climate change they

also focused on the prevention of global loss in biodiversity and prevention of species eradication

Kyoto Accord / Protocol

• Voluntary effort to reduce GHG emissions by 5.2% below 1990 levels by 2012

• No requirements on developing countries• Emission trading (carbon market)• Clean development mechanism– Create reduction programs which offset emission credits

• Joint implementation– Transfer of credit of one country to another with

emission reduction commitment by another

GHG + CLIMATECHANGE

The Ozone Hole

Seasonal thinning of Ozone Layer • Ozone hole is over Antarctica• Greatest depletion end of August- beginning

of November

So how have we remedied the hole?

• Montreal Protocol– Treaty to cut CFC by 2000– Also halt the production of CFC– Very effective and have seen a drastic increase of ozone within

the stratosphere• Copenhagen Protocol of 1992

– Phasing out of Ozone Depleting Compounds (ODC).– End all use of

• CFC by 1995• Halons by 1993• C-tetra- Cl by 1995• HCFC by 2020

Copenhagen Protocol of 1992

• Amendment of Montreal to include…• Phasing out of Ozone Depleting Compounds

(ODC).• End all use of – CFC by 1995– Halons by 1993– C-tetra- Cl by 1995– HCFC by 2020