Introduction to Environmental Science (continued)

Ozone and theSolar Spectrum

UV-A = 315-400 nm

UV-B = 280-315 nm

UV-C = 100-280 nm(ref: ASTM)

Biological Sensitivity to UV

Chapman Cycle (natural)

O2 + O O3

O + O3 2 O2

O2 2 O< 240 nm

O3 O2 + O< 320 nm

(1)

(2)

(3)

(4)

OZONE FORMATION

OZONE DECOMPOSITION

A balanced system!A balanced system!

Ozone Loss through Catalysis (such as with CFCs)

.X + O3 XO. + O2

XO. + O .X + O2

Catalysts are not destroyed andmake the net reaction occur faster!

Net reaction: O3 + O 2 O2

So Ozone is destroyed faster than it is produced!So Ozone is destroyed faster than it is produced!

Current StatusSource: NASA TOMS data, http://jwocky.gsfc.nasa.gov/multi/oz_hole_area.jpg

• Montreal Protocol signed in 1987

• Production of CFCs halted in US in 1996

So the averagetemperature on Earth is+15oC rather than–18oC!

Greenhouse Effect

Greenhouse effect

Our atmospheric gases trap and return a major portion of the heat radiating

from the Earth.

It is a natural, necessary process.

The Earth’s Energy Balance

Trends in Global Temperature

ISAT 112

Temperature Trends

More Temperature Trends…

Weihenstephen Brewery in Freising starts, 1040!

These gases have differential ability to capture outgoing IR radiation from the earth, absorb that radiation, and re-radiate it back to Earth.

Comparison of Greenhouse Gases

Gas Factor Abundance% Impact

• CO2 1 3.7*10-2 1

• CH4 30 1.8*10-4 0.145

• N2O 160 3.1*10-5 0.132

• O3 2000 4.0*10-6 0.22

• CCl2F2 25,000 5.2*10-8 0.035

Produced by rapeseed???

CO2 and Temperature over millenia

CO2 Measurements - Hawaii2005: 379.5 ppm

2010: 392.9 ppm

http://www.esrl.noaa.gov/gmd/ccgg/trends/

Collecting glacial ice cores

The concentration of carbon dioxide (blue) and the global temperature (red) are well correlated over the past 400,000 years as derived from ice core data.

The Vostok ice core goes back 400,000 years. The current concentration of atmospheric carbon dioxide is 100 ppm higher than any time in the last million years.

The carbon cycle

Causes of GG increase

• Increased combustion– Industrial revolution– Fossil fuels

• Deforestation– Amazon rainforest = 4,224,905 football fields/yr

8 football fields/minute• Agriculture

• Melting of permafrost

CO2 Emissions by Country:Total emissions since 1950 (b tons)

Graphic from: Michael Glantz, “What Makes Good Climates Go Bad? … and … “Why Care?” USAEE/IAEE Meeting, 9-19-05.

Projected future regional patterns of warming based on three emissions scenarios (low, medium, and high growth). Source: NASA Earth Observatory, based on IPCC Fourth Assessment Report (2007)

Temperature projections to the year 2100, based on a range of emission scenarios and global climate models.

Fig. 3.17 US Sources of Fossil CO2

Global Climate Change bottom line• There is ample evidence that

– the Earth experiences (and we rely on) the “greenhouse effect”

– carbon dioxide is a “greenhouse gas”– the temperature of the atmosphere has been rising over

the past century– the concentration of carbon dioxide is also rising, and

correlates both to this increase in temperature and the use of fossil fuels

• What is debated is whether humans are causing these changes

• The Intercontinental Panel on Climate Change (IPCC) has said yes for years, and the Kyoto Protocol was intended to address this

What might be true:

• CO2 and other gases generated by human activity contribute to the temperature increase.

In a recent poll, 97% of climate scientists believe that this is true.

(http://www.sciencedaily.com/releases/2009/01/090119210532.htm)

• The average global temperature will continue to rise as emissions of anthropogenic greenhouse gases increase.

Energy Consumption

0 2000 4000 6000 8000 10000

Kenya

India

China

Iran

South Africa

Denmark

United Kingdom

Japan

Germany

France

Sweden

United States

Canada

kg oil equivalent per capita

1990 2000 2003

World Resources Institute

Consumption in the United States

Today

Energy Over Time

Worldwide commercial energy production

Coal Reserves

Fig. 12.8Oil Reserves

Alternative Energy Options

Alternative Energy Options

Alternative Energy Options

Geothermal Energy

Hydropower

Alternative Energy Options

Tidal Energy

Alternative Energy Options

Nuclear Power?

Other Environmental Issues

Loss of Habitat/Biodiversity

• Extinction of species of flora and fauna is occurring at a very rapid rate

• Many believe that reductions in biodiversity threaten the ability of ecosystems to tolerate stresses and changes

• Biodiversity is also considered a potential resource for medicines, &c

• The Rio conference in part addressed this

Biodiversity Hotspots

http://www.conservation.org/xp/CIWEB/strategies/hotspots/hotspots.xml

The 25 biodiversity hotspots contain 44 percent of all plant species and 35 percent of all terrestrial vertebrate species in only 1.4 percent of the planet's land area.

The importance of climatic variables

• Temperature• Rainfall• Seasonality• Potential Evapotranspiration

– function of daily rainfall average, heat, wind– high heat, low rainfall = desert– low heat, low rainfall = tundra– seasonal shifting for all other biomes

Fig. 5.2Biomes

General distribution of biomes

Acid Deposition

• Rainwater is naturally acidic– H2O + CO2 carbonic acid

• But pollutants increase acidity:– H2SO4

– HNO3

– HCl

• Can be wet or dry deposition

Sources of SOx and NOx

C135H96O9NS

coal

Overview: Acid Precipitation

Soil Degradation

• Loss of topsoil– Loss of nutrients

• Contamination of topsoil– Heavy metals– Chlorinated compounds

Visibility

• ≡ “the greatest distance over which one can see and identify familiar objects with the unaided eye.”

• Visibility is reduced by scattering of light by particles, water droplets, and gas molecules

• In the US, human pollution accounts for 1/3 of visibility limitation in the rural west, and over 80% in the rural east

Herbicides and Pesticides

• Herbicides and pesticides are meant to be biologically damaging

• Dangers with use are offset by need to producing larger and larger crops for growing population

• Alternative methods offer some hope

Radionuclides

• Radionuclides are sources of ionizing radiation

• Most exposure is background radiation (both cosmic and earth) as well as intentional sources (such as medical X-rays or frequent air travel)

• Industrial sources of radionuclides can be a problem, especially regarding waste disposal or seepage into groundwater

Toxics in Sludge

• Sludge is the semi-solid that results from treatment of sanitary or industrial wastewater

• Sludge often contains nutrients that are beneficial to crops when applied to fields

• But it can also contain heavy metals and other anthropogenic toxins, such as medicines– Medicines are already having a significant impact on fish

populations

• Generation of biogas from sludge is an active area of research at IZES.

Oil Spills

• Spills of petroleum are routine events, both on land and at sea

• While such spills often attract a great deal of attention, the biodegradability of petroleum helps the affected ecosystem to recover relatively rapidly

Toxics in Sediments

• Chemical spills on land and in the water often result in the accumulation of toxic materials in sediments– z. B. Dupont and Mercury in the Shenandoah River

• Pesticides, herbicides, and heavy metals are particularly hazardous and persistent

• It is not always clear whether remediation by dredging does more good than harm

Hazardous Waste Sites

• Hazardous waste is generated by an extraordinary variety of industries

• Safe disposal of these wastes is an issue brought into the news by such disasters as the Love Canal (USA)

• In the US, CERCLA (Superfund) and RCRA laws resulted from the attention brought by these disasters