Environmental Science

atmosphere

thin layer of gases that envelops the planet

Troposphere = bottommost layer (11 km [7 miles])

air for breathing

air movement drives planets weather

colder altitude

Stratosphere = 11–50 km (7–31 mi) above sea level

radiation blocking ozone in ozone layer

how air density changes/ pollution

gravity pulls on a molecule.

The closer you are to sea level, the more air molecules are tightly packed together.

Normal air quality

warm air @ surface colder higher up. Warm air rises and it takes pollution with it.

Temp inversion

cool air @ surface trapped under warmer air trap and build up pollutants in air

cities with inversions: Mexico city, LA, Sao Paulo., Denver

Weather

atmospheric conditions over short time periods (hours/days) w/in relatively small geographic area

Climate

patterns of atmospheric conditions across large areas over long time periods

outdoor air pollution

wild fires, volcanoes

Primary pollutants

hazardous substances emitted in a form that is directly harmful

Secondary pollutants

hazardous substances produced through reactions of substances

The EPA sets nationwide standards for:

1. Emissions of several key pollutants (Examples = lead, carbon monoxide, tropospheric ozone)

2) Concentrations of key pollutants in air

In us, air pollution has been reduced

pollution in developing countries is high

asian brown cloud- 2 mile thick layer of pollution that hangs over S. Asia

Smog

an unhealthy mixture of air pollutants over urban areas resulting from burning of fossil fuels.

Industrial (gray air) smog =

from industries burning coal or oil

Photochemical (brown air) smog

• Light-driven reactions of pollutants and atmospheric compounds

Ozone layer = ozone in the lower stratosphere (is good!)

Ozone is highly reactive & damages tissue when breathed in.

blocks incoming UV radiation

Chlorofluorocarbons (CFCs) = a halocarbon used as refrigerants, in fire extinguishers, in aerosol cans, etc.

destroys ozone

Indoor air pollution in the developing world

Burning wood, charcoal, dung, crop wastes with little to no ventilation

7% of all deaths worldwide each year. That’s terrible!

Indoor air pollution in the developed world

Secondhand smoke from cigarettes is very dangerous, as are e-cigarettes • Radon causes 21,000 deaths a year in the U.S.

Global climate change =

changes in Earth's climate, including temperature, precipitation, and storm intensity

Global warming =

an increase in Earth's average temperature (one aspect of climate change)

Milankovitch cycles

periodic changes in Earth’s rotation and orbit around the sun.

Milankovitch cycles

alter the way solar radiation is distributed over Earth, triggering climate variation

The last several thousand years have been very conducive to human success

Greenhouse Gases

Absorb infrared radiation emitted from earth’s surface, warming the atmosphere and surface.

• Carbon dioxide =

major factor in climate change- very abundant. From burning fossil fuels.

• Methane =

levels have doubled since 1750. From burning fossil fuels, livestock, and landfills

• Nitrous oxide =

emission, feedlots, and synthetic fertilizers

greenhouse gases concentrations are rising fast

Atmospheric levels of CO2 are rising steeply

What is happening today?

• Average surface temperatures increased 1.1ºC (1.6ºF).

since 200, we have experienced 17 of the 18 warmest years in the last 140 years

temps are also rising in the USA

Precipitation is changing, too

Some regions are receiving more precip than usual, others receiving less • Droughts have become more frequent and severe • Heavy rains contribute to flooding

Changes in the jet stream

Can cause extreme weather events

Melting snow and ice

Mountaintop glaciers are disappearing

Climate change affects our… • Health • Wealth • National Security

heat/cold exposure, insurance premium up, refugees crisis, war, military bases next to coast

Mitigation

actions that reduce greenhouse gas emissions to lessen the severity of climate change

Adaptation

pursue strategies to cushion ourselves from the impacts of climate change.

Paris Agreement on Climate Change (2015)

Goal: keep the global temperatures from rising above 2°C this century. • 194 countries have signed the treaty. In 2017 Trump Administration sent notice to the UN that US is withdrawing, but we’re back in it now!

ICPP 2018 Report

• Scientists examined 6000 studies • World has 12 years for global warming to be kept within a reasonable level • Urgent and unprecedented changes are needed to reach the target • Carbon pollution must be cut 45% by 2030 • The world is on course for disastrous warming

Fossil Fuels

Highly combustible substances formed from the remains of organisms from past geologic ages.

• Energy returned on investment (EROI) =

Ratio determined by dividing the quantity of E returned from a process by the quantity of E invested in the process

Higher values mean more E is produced from each unit of E invested.

Tar sand EROI

EROI: Tar sands 3:1 or 5:1

Coal

world’s most abundant fossil fuel

Mercury generated from coal smoke

Coal extraction brings environmental impacts

Strip mining – destroys large areas of habitat and causes extensive soil erosion • Creates chemical runoff into waterways • Mountaintop removal is devastating

Natural Gas

burns more cleanly than coa

Natural Gas extraction brings environmental impacts

Hydraulic Fracturing ‘fracking’ – chemicals are mixed with pressurized water and sand and injected deep underground.

may pollute water for drinking, create unhealthy air, use large amounts of water, cause earthquakes

Crude oil =

a mixture of hundreds of different types of hydrocarbon molecules

Oil extraction brings environmental impacts

Lots of infrastructure needed (roads, housing, pipelines, ponds to collect sludge, etc.) that damages the environment. • Oil can be extracted by fracking like gas. • Tar sands are devastating to the environment.

Peak oil will pose challenges

The point at which production of oil comes to a peak, and then starts to decline. Supply will fall behind while demand increases.

cost of fossil fuel use

costs for environmental cleanups

burning fossil fuels= release carcinogens & other irritants (mercury from coal)

medical expenses

Energy efficiency =

obtaining the same output with less E input

results from technological improvements

Nuclear power

nuclear fission releases energy

Nuclear fission

Splitting apart of atomic nuclei

chain reaction

constant energy output

uranium ore

a nonrenewable energy source

Advantage of nuclear over fossil fuels

nuclear is cleaner that fossil fuels

nuclear risks

very small risks, but can result in large catastrophes

Problems with nuclear waste

waste is held in temporary storage and runs out of room

waste emits radiation for millions of years

Yucca mountain

Store all waste in one place that can be heavily guarded

nuclear power pros

less uranium needed as the power source vs coal , no greenhouse gas emissions, fewer health risks

nuclear power Cons

eye sore, uranium, nonrenewable resource, nuclear waste, small risk of meltdown or disaster or sabotage, expensive, run and maintain

Bio energy (biomass energy)

The energy obtained from organic material makes up organisms

ethanol

biofuel made by fermenting carbohydrate-rich crops

Why is Ethanol not a sustainable choice?

ethanol competes with food and raises prices,

Growing corn takes up millions of acres of land and intensifies pesticide, fertilizer, and water use.

EROI: 1.3:1

Two novel biofuels

algae and switchgrass

Hydropower

uses the energy of moving water to turn turbines or generate electricity

Pro/ con hydropower

Renewable: no emissions, EROI:10:1

con: very limited places to put in hydrodams. Also very destructive downstream if collapses.

cost for renewable are going down

wind is cheap as natural gas, cheaper than coal or nuclear power

conventional E and subsidies

Environmental energy has received way less government subsidies.

solar energy

energy that comes from the sun

passive solar

building are designed to maximize absorption of sunlight in winter and minimize in summer

active solar

devices focus more or store E

concentrated solar power

focuses sunlight from a large area onto a small area

photovoltaic (PV) cells

convert sunlight directly into electrical energy

Benefits of solar energy

Cost is coming down/much cheaper than before, quiet, safe, little maintenance, lasts 20-30 years, no fuel.

Wind power

using wind energy to spin turbines that generate electrical energy

Pros of wind

cost comparable to fossil fuels (or less).

EROI: 23:1

farmers and ranchers can generate extra income

generated lots of green collar jobs

Cons of Wind

not all locations are suitable, NIMBY, kills birds and bats, disrupts farm ground during installation.

How much has wind power grown

Wind power has doubled every three years in recent years

Offshore WInd

wind speeds are 20 % faster over water than land

also less air turbulence over water

Geothermal energy

Thermal E that rises from beneath earths surface

Geo thermal Pros

no emissions, green collar jobs

Geothermal Cons

Limited areas where E can be tapped, expensive

Environmental justice

A social movement that occurs when poor or marginalized communities are harmed by hazardous waste, etc.

MLK and Environmental Justice

1968 Memphis TN

MLK joined African American sanitation workers striking for better wages & work conditions.

One of the earliest links between civil rights and environmental health concerns.

History of Warren County

NC state government decided to bury PCB laced soil in a landfill in the predominately African American and poor Warren County.

Residents/supporters from civil rights groups filed two lawsuits, which failed. • In 1982, people laid down in the roads to stop the trucks.

500 arrested for civil disobedience.

Environmental Racism

Disproportionate burden placed on communities of color + marginalization of their voices.

Economic blackmail:

false choice presented between financial worth and environmental protection that deflects away from the fact that jobs can be provided while meeting basic health and environmental standards

Sacrifice Zones

Exist outside of dominant population areas, making their it easier for those who don’t live in those communities to ignore.

cruel irony

those who have contributed to and benefitted least from the energy policies that cause climate change have been and will continue to be impacted the most by climate change.

Civil disobedience

A peaceful form of protest that violates laws (through trespassing, road blockage) while accepting the legal consequences.