Urbanization and the Environment

Global Change II

Dr. Vincent J. Abreu

"Urban Heat Islands."

What causes this to happen?

• There are fewer trees, shrubs, and other plants to shade buildings, intercept solar radiation, and cool the air by "evapotranspiration."

• Buildings and pavement made of dark materials absorb the sun's rays instead of reflecting them away, causing the temperature of the surfaces and the air around them to rise.

• Surface roughness serves to reduce the wind speed and reduce ventilation.

Evapotranspiration

• Evapotranspiration occurs when plants secrete or "transpire" water through pores in their leaves. 

• The water absorbs energy as it evaporates, cooling the air in the process.  

• A single mature, properly watered tree with a crown of 30 feet can "evapotranspire" up to 40 gallons of water in a day, which is like removing all the heat produced in four hours by a small electric space heater.

Heat Islands and Energy Use

Higher temperatures in urban heat islands greater demand for air conditioning increased energy use power plants burn more fossil fuels

Increase both the pollution level and energy costs.

Photochemical Smog

• Photochemical smog forms when oxides of nitrogen in motor vehicle exhaust and hydrocarbons (from various anthropogenic and biogenic sources) react in the presence of sunlight to produce a mixture of aerosols and gases (ozone (O3), formaldehyde (CH2O), ketones, and PAN (peroxyacetyl nitrates).

• Average ozone level at the earth’s surface: 0.02 ppm• Ozone concentration may exceed 0.5 ppm in thick

photochemical smog.

Urban heat islands and smog

• Urban heat islands are smoggier. • Smog is created by photochemical reactions of

pollutants in the air. These reactions are more likely to occur and intensify at higher temperatures.

• In Los Angeles, for example, for every degree Fahrenheit the temperature rises above 70°F, the incidence of smog increases by 3%.

Worldwide net renewable water distribution by region and per capita.

Data as of early 1990s. source: www.worldbank.org/html/extdr/offrep/mena/Focus/BOOKLET.ARA.html]

Region Net Annual Renewable Water Resources

(Billions cubic meters)

Population

(millions)

Per capita Water Availability

(cubic meters) Oceania 769 21 36,619 Latin America 10,766 466 23,103 North America 5,379 287 18,742 Easter Europe1 7,256 495 14,659 Africa 4,184 559 7,485 Western Europe 1,985 383 5,183 Asia 9,985 3,041 3,283 MENA2 355 284 1,250 1includes Central Asia 2Middle East/North Africa

In 2002, the United Nations Committee on Economic, Social and Cultural Rights, the Covenant’s supervisory body, adopted a General Comment stating “the right to water clearly falls within the category of guarantees essential for securing an adequate standard of living, particularly since it is one of the most fundamental conditions for survival.”

Why does defining water as a human right make a difference?

Ensuring that access to sufficient safe water is a human right constitutes an important step towards making it a reality for everyone. It means that:

● fresh water is a legal entitlement, rather than a commodity or service provided on a charitable basis;

● achieving basic and improved levels of access should be accelerated;

● the “least served” are better targeted and therefore inequalities decreased;

● communities and vulnerable groups will be empowered to take part in decision-making processes;

● the means and mechanisms available in the United Nations human rights system will be used to monitor the progress of States Parties in realizing the right to water and to hold governments accountable.

Urbanization and Water• Water is a key issue in urban areas. • The intensity of demand in cities can quickly

exceed local supply. • The price of water is typically lower than the

actual cost of obtaining, treating and distributing it, partly because of government subsidies.   

• Pollution from urban run-off, sewage and untreated discharges of industries has adversely affected many water bodies, leaving many cities with unsafe water supply.

Urbanization and Water

• Urbanization has had significant impacts on the hydrology of the environment by controlling:

• Nature of runoff (water from precipitation or irrigation that does not evaporate or seep into the soil but flows into rivers, streams, or lakes, and may carry sediment);

• Rates of soil erosion; and • Delivery of pollutants to rivers, streams,

lakes and ocean.

Sewers and Drains• Sewers and drains carry domestic and industrial wastes

that might have been widely deposited on the soil, but have been channeled into rivers and other bodies of water.

• The storm sewer system is designed to carry the excess water that flows over land during and after a rainfall directly into a river, stream or lake.

• The sanitary sewer system carries sewage from residential, commercial, and industrial sources to the waste water treatment plant.

• At a waste water treatment plant most harmful substances are removed from sewage before it is piped to a nearby body of water.

Impervious surfaces and sewers cause runoff after a rainstorm to occur more rapidly and with a greater peak flow that under non-urban conditions.

Effect of urbanization on floods

• Urbanization increases the intensity and decreases the lag time of floods.

• Urbanization increases the frequency of small floods.

• The size of small floods is increased by urbanization, while during large, infrequent floods there are no significant differences between the way rural and urban areas behave.

EROSION

• Runoff on bare land leads to erosion.• Grass, trees and other plants hold the soil in

place and avoid erosion.• The highest rates of erosion are produced in

urban areas during construction.• Erosion is the source of sediment that fills

streams, pollutes water, kills aquatic life, and shortens the useful life of dams and reservoirs.

Examples of Rates of Erosion associated with construction and

urbanization

Location Land Use Source Rate (t km-2yr-1

Maryland Forest Agriculture Construction Urban

Wolman (1967) 39 116-309 38,610 19-39

Detroit General non-urban Construction Urban

Thompson (1970) 642 17,000 741

Water Pollution

• Point source pollution– Industrial plant effluent pipe

• Non-Point source pollution– Surface runoff from precipitation; responsible

for most pollution.

Pollution includes:

Chemicals, sediments, heat, disease causing organisms

Water Pollutants

• Suspended solids decrease in photosynthesis decrease in oxygen

• Coliform Bacteria – if present in amounts greater than 200 colonies/ml of water, it is likely that other pathogens are present.

• Chlorides – salt for de-icing

• Phosphorus and nitrogen – plant nutrients

O2

Dissolved in Water

Biochemical Oxygen Demand

Oxygen enters water by:

•Ocean Spray•Waves•Photosynthesis of algae and large aquaticplants

Oxygen depletion by:

Decomposition of organic material by bacteria

Respiration of organisms

Enhancement in Dissolved Nutrients (phosphorus and nitrogen)

Depletion of O2

Algae growthDecompositionby bacteria

CulturalEutrophication

Health Effects of Pollutants

The relationship between water resources and health has occupied a position of special significance throughout human history.

Sewage Industrial Pollutants

Infectious Non-infectiousDiseases Diseases- cancers, infertility

thyroid dysfunction, birth defects,behavior problems, immune systemsuppression, deformities, etc.

Common diseases transmitted to humans through contaminated drinking water. From Miller (1995).

Type of Organism Disease Effects Bacteria Typhoid fever Diarrhea, severe vomiting, enlarged spleen,

inflamed intestine; often fatal if untreated Cholera Diarrhea, severe vomiting, dehydration, often

fatal if untreated Bacterial

dysentery Diarrhea, rarely fatal except in infants without proper treatment

Enteritis Severe stomach pain, nausea, vomiting, rarely fatal

Viruses Infectious hepatitus

Fever, severe headache, rarely fatal but may cause permanent liver damage

Parasitic Protozoa Amoebic dysentery

Severe diarrhea, headache, fever, if not treated can cause liver damage and death

Giardia Diarrhea, cramps, flatulence, fatigue Parasitic worms Schistosomiasis Abdominal pain, rash, anemia, chronic fatigue

Health Effects of Pollutants

Synthetic chemicals in pesticides and industrial products have been identified as hormone disruptors

Like hormones, these chemicals affectthe endocrine systems of animals andhumans in minute amounts – partsper trillion.

Hormone Disruptors

•Mimic naturally produced hormones such as estrogen and testosterone.

•Hormone blockers “lock up” a cell receptor”preventing naturally produced hormones from entering and performing their function.

•Trigger set off reactions in the cell that would not normally be produced by a hormone. Dioxin acts this way.

Where do we find them?

• Endocrine-Disrupting Chemicals such as nonylphenol, alkylphenol ethoxylates (APEs) and phthalates are often found in common household items, such as detergents, cosmetics, household cleaners as well as even plastic food containers.

• Several pesticides contain known or suspected endocrine disrupters that enter our bodies through residues on food. Heavy metals like lead, mercury and cadmium may be tracked in from outdoors.

Hormone Disruptors

• Mostly affects the offsprings of exposed organisms.

• Health effects on humans include lower sperm counts, undescended testicles, early puberty, and thyroid dysfunction.

• In wildlife, the health impacts include smaller penises, and/or testicle size, undescended testicles, lower sperm count, reproductive abnormalities, thyroid dysfunction, feminization of males or masculinization of females.

Environmental Economics views the economy in which we live

and work as an “open system”.

Extract resources from the environment - renewable and exhaustible resources

Dispose of large amountsof dissipated and/or chemically transformed resources back into theenvironment.Process

Resources

ResourceDepletion

Pollution

Why do we pollute?

Pollution –waste that has been disposed off in the air, in water, or on land, and that reduces the value of those resources for alternative uses.

In the case of air and water pollution, the damage is done because they are open access resources, i.e. no one owns them, and there is no individual incentive to restrict pollution.

Pollution reduction is an economic problem: How much money are we willing to spend to reduce pollution?

• Ideal world – no pollution –costs would be very high

• The other extreme is to live in a world with no pollution control

• The real world is somewhere in between these two extremes, i.e., it is necessary to achieve a balance between the costs and social benefits of reducing pollution.

NO POLLUTION CONTROL

Production of

Goods

EnvironmentalPollution

Consumer

Taxpayer

Costs:Cleaning environmentHealth problems

Cost ofProduction

Negative Externality

Mechanisms to achieve pollution reduction

Society decides on an acceptable level of environmental quality

Free market transactions are usually unregulated:there is no mechanism for charging polluters a feeto correct for the damage done by their emissions.

Government Intervention

Government Intervention:Subsidies based on Cost-Benefit Analysis

IndustrialProduction

ReducedEnvironmental

Emissions

Consumer

Government InterventionSubsidies:

•Tax Incentives•Credits

Regulations

Cost ofProduction

What is the Clean Air Act? 

The Clean Air Act is the federal law designed to make sure that all Americans have air that is safe to breathe.

Main Goals:• Public health protection is the primary goal.• The law also seeks to protect our environment from damage caused by air pollution.

Congress passed the core provisions of the Clean Air Act in 1970. The law was amended in 1977 and again in 1990 to extend deadlines but also to specify new strategies for cleaning up the air.

The basic framework of the law and its public health objective have remained intact.

When was the Clean Air Act passed?

How does the Clean Air Act work?

 The Clean Air Act requires that:

• The U.S. Environmental Protection Agency sets national health-based air quality standards to protect against common pollutants including ozone (smog), carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and particulate soot. EPA is directed to review these standards every five years. 

• State governments must devise cleanup plans to meet the health standards by a specific date. Areas with the worst smog have a longer time to meet the standards.

• In addition, the EPA sets national standards for major new sources of pollution including automobiles, trucks and electric power plants.

• The agency also is charged with developing controls for major sources of toxic pollutants, such as benzene.

How does the Clean Air Act work?

By any objective measurement, the act has been a tremendous success:• The air is cleaner and public health has improved.• Emissions of toxic lead have dropped 98 percent.• Emissions of sulfur dioxide have dropped by 35 percent even though the gross domestic product has more than doubled. • Emissions of carbon monoxide have dropped by 32 percent even though driving has increased 127 percent. • Even so, many areas of the country still violate the basic health standards, and the health of tens of millions of Americans remains at risk.

How well has the Clean Air Act worked?

The Clean Water Act

The Clean Water Act (CWA), intended to ". . .restore and maintain the chemical, physical, and biological integrity of the Nation's waters". To accomplish that objective, the act aimed to attain a level of water quality that "provides for the protection and propagation of fish, shellfish, and wildlife, and provides for recreation in and on the water" by 1983 and to eliminate the discharge of pollutants into navigable waters by 1985. 

The CWA has five main elements: 

(1) A system of minimum national effluent standards for each industry. The CWA requires the EPA to establish effluent limitations for the amounts of specific pollutants that may be discharged by municipal sewage plants and industrial facilities.(2) Water quality standards. The two-step approach to setting the standards includes: (a) establishing a nationwide, base-level treatment through an assessment of what is technologically and economically achievable for a particular industry and (b) requiring more stringent levels of treatment for specific plants if necessary to achieve water quality objectives for the particular body of water into which that plant discharges.

(3) A discharge permit program that translates these standards into enforceable limits. Under the National Pollutant Discharge Elimination System program any person responsible for the discharge of a pollutant or pollutants into any waters of the United States from any point source must apply for and obtain a permit.(4) Provisions for special problems such as toxic chemicals and oil spills, and (5) A revolving construction loan program for publicly-owned treatment works.

Emission Control Policies

Emission charges are prices established for the right to emit a unit of a pollutant.

Emission standards are limits established by government on the annual amounts and kinds of pollutants that can be emitted into the air or water by producers or users of certain products.

Command and control regulation: a system or rule that requires the use of specific pollution control devices on certain sources of pollution or applies strict emission standards to specific emitters.

• Emission offsets allows a new firm to be established in an area where additional polluting emissions resulting from the firms operations normally would prevent the firm from being approved by EPA. Under this policy the new firm, before it is approved, most induce other firms in the area to reduce emissions usually through a cash payment.

• The Bubble allows a firm to exceed the amount of emission of a pollutant if it reduces another pollutant by more than the current standard.

• Banking of emissions: a firm that emits less than the specified level of a pollutant is given a credit that allows them to emit more than the standard at some time in the future. The firm is also allowed to sell these credits for cash to other firms who want to exceed the standards.

Pollution rights: a government-issued permit allowing a firm to emit a specified quantity of polluting waste.Ex. Michigan’sAir Emissions Trading Program.Advantages:•Pollution permits are tradable at free market prices.•Regulatory authorities can control the amount of pollution by limiting the number of certificates.•Provides a choice: purchase permits and pollute or reduce pollution and save the cost of permits.•Provides an incentive to reduce emissions in order to sell previously purchased pollution rights.Disadvantages:•A firm in a very polluted region is allowed to buy emission permits from a firm in a region where there is no pollution.

Failure of Government Intervention

• They may favor the interests of some part of the community rather than the community as a whole.

• Governments are not very good at obtaining the right information about the full consequences of a particular action.

• They may have problems translating good intentions into practice because of lack of competence among the government bureaucracy.

Reducing pollution at the global level

In some instances pollution is the result of activities at the global level and nations may be required to implement international agreements that address current pollution practices:

• The Montreal Protocol

• The Kyoto Protocol

Definitions:

• Protocol – A preliminary memorandum often formulated and signed by diplomatic negotiators as a basis for a final convention or treaty; examples: Montreal Protocol, the Kyoto Protocol on Climate Change.

• Convention – An agreement between states for regulation of matters affecting all of them (Merriam Webster’s Collegiate Dictionary, Tenth Edition); example: The United Nations Framework Convention on Climate Change.

Party – a state which has consented to be bound by a treaty and for which the treaty is in force. Date of adoption – when states participating in the negotiation of a treaty agree on its final form and content. Date of signature – when a state expresses its consent to be bound by a treaty. Date of ratification – when a state makes a final formal expression of its consent to be bound by a treaty. Date of entry into force – when a treaty becomes binding upon the states which have expressed their willingness to be bound by it. This is usually triggered by a clause in the text of the treaty saying something like “ this treaty shall enter into force when n states have signed it …”.

There is broad consensus in the scientific community that climate change is happening faster and to a greater extent than previously expected, confirmed by the Third Assessment Report from the Intergovernmental Panel on Climate Change (IPCC), which was the outcome of a process involving 2000 international scientific experts.

Due to the projected growth of emissions of greenhouse gases, the world's climate could warm up by up to 5.8°C by the end of this century.

History of the Kyoto Protocol

The agreed to plan in Kyoto makes use of global free market forces to protect the environment.

The Kyoto Protocol was opened for signature in March 1998. To enter into force, it must be ratified by at least 55 countries, accounting for at least 55% of the total 1990 carbon dioxide emissions of developed countries. The United States produces 33% of the emissions and the EU produces 24.3%.

History of the Kyoto Protocol

The 20th United Nations Conference on the Environment and Development convened in Rio de Janeiro on June, 1992. Outputs:

• Agenda 21, a plan of action to confront and overcome the economic and ecological problems of the late 20th century, and to guide the development of the Earth in a sustainable manner.

• A convention on biodiversity and a convention on climate change. These were signed by 154 countries.

History of the Kyoto Protocol

• The United Nations Framework Convention on Climate Change entered into force on 21st March 1994, after ratified by 50 states.

• The Convention’s general objective is the “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.

• To achieve this the Convention elaborates legally binding commitments some of which apply to all Parties, while other apply to specific countries.

History of the Kyoto Protocol

• Institutions created under the Convention are the Conference of the Parties (COP) and two subsidiary bodies.

• One of the primary functions of the COP is periodic examination of the obligations of the Parties and the institutional arrangements under the Convention.

• If the commitments established during the Convention are found to be inadequate, the COP could adopt amendments or one or more protocols to the Convention that would dictate additional commitments.

• The COP met in Kyoto in December 1997 with this goal. The Kyoto Protocol on Climate Change is the product of this conference.

The Kyoto Protocol was ratified by the European Union and its Member States on 31 May 2002. The Kyoto Protocol commits the EU to reducing its greenhouse gas emissions by 8% below 1990 levels during the first "commitment period" 2008 to 2012.

The Kyoto Protocol entered into force on February 16, 2005 after being ratified by 55 countries accounting for 55% of the total carbon dioxide emissions in 1990.

The only countries that not ratified the treaty were:Zambia, Croatia, Kazakhstan and the United States.

The developed countries commit themselves to reducing their collective emissions of six key greenhouse gases by at least 5%.

This group target will be achieved through cuts of 8% by Switzerland, most Central and East European states, and the European Union (the EU will meet its target by distributing different rates among its member states); 7% by the US; and 6% by Canada, Hungary, Japan, and Poland. Russia, New Zealand, and Ukraine are to stabilize their emissions, while Norway may increase emissions by up to 1%, Australia by up to 8%, and Iceland 10%.

The six gases are to be combined in a "basket", with reductions in individual gases translated into "CO2 equivalents" that are then

added up to produce a single figure.

Each country’s emissions target must be achieved by the period 2008-2012. It will be calculated as an average over the five years.

Cuts in the three most important gases – carbon dioxide (CO2), methane (CH4), and nitrous oxide (N20) - will be measured against a base year of 1990 (with exceptions for some countries with economies in transition).

Countries will have a certain degree of flexibility in how they make and measure their emissions reductions.

In particular, an international "emissions trading" regime will be established allowing industrialized countries to buy and sell emissions credits amongst themselves.

They will also be able to acquire "emission reduction units" by financing certain kinds of projects in other developed countries through a mechanism known as Joint Implementation.

In addition, a "Clean Development Mechanism" for promoting sustainable development will enable industrialized countries to finance emissions-reduction projects in developing countries and receive credit for doing so.

The Protocol will advance the implementation of existing commitments by all countries.

Under the Convention, both developed and developing countries agree to:

• Take measures to limit emissions and promote adaptation to future climate change impacts; • Submit information on their national climate change programs and inventories; • Promote technology transfer; • Cooperate on scientific and technical research; and promote public awareness, education, and training.

The Protocol also reiterates the need to provide "new and additional" financial resources to meet the "agreed full costs" incurred by developing countries in carrying out these commitments.