enviro unit 9

how scientists learn about past

how scientists learn about past

tiny air bubbles trapped in ice cores that show high CO2 levels in troposphere

• troposphere composition, temperature trends, greenhouse gas concentrations, solar/snowfall/forest fire activity

relationship between CO2 and temperature

high CO2 = high temperature

stratospheric ozone

• good ozone

• blocks and filters harmful UV radiation

• forms through breakdown of O2 by UV rays. some of the free oxygen rebinds w/ oxygen gas, forming ozone.

• UV rays break down the ozone - process repeats

tropospheric ozone

• bad ozone from smog

• harmful to organisms

3 types of UV rays

• UV-A: low energy UV radiation

• UV-B: shorter, higher energy wavelengths

• UV-C: shortest, highest energy wavelengths

chlorofluorocarbons (CFCs)

group of chemicals responsible for ozone depletion in the stratosphere

• were used for cooling appliances but banned because one atom of the chlorine can destroy 100,000 ozone molecules.

Montreal Protocol

commitment by 24 nations to reduce CFC production by 50% by the year 2000

Copenhagen Amendment

signed by 180 countries, stopping CFC production

what is ozone measured in

Dobson units

ozone thinning

caused by CFCs and other ozone depleting chemicals (ODCs)

increased UV radiation reaching Earth’s surface is harmful to…

• human health

• crop productions

• forests

• animals

• plankton

• materials

• It does NOT lead to global warming!!

squamous cell cancer

top layer of skin; spreads fast (metastasize)

basal cell cancer

develops slowly; rarely metastasizes; curable if caught early and treated

melanoma

most deadly of the skin cancers; fast growing; metastasizes quickly

global change

includes climate change and global warming; it is a change in the chemical, biological, and physical properties of the planet

the rate of change for many global change issues and the causes can be traced back to…

human activities

global climate change

changes in the average weather in an area over years/decades

greenhouse effect

absorption of infrared radiation by atmospheric gases and reradiation of the energy back toward the Earth

runaway greenhouse effect

w/ addition of greenhouse gases, the normal process is exacerbated

greenhouse gases (least to most concern)

• water vapor H2O

• carbon dioxide CO2

• methane CH4

• nitrous oxide N2O

• CFCs

greenhouse warming potential (GWP)

estimate of how much a molecule of any compound can contribute to global warming over a 100-yr period relative to 1 molecule of CO2

natural sources of greenhouse gases

• volcanic eruptions

• decomposition and digestion

• denitrification

• evaporation and evapotranspiration

anthropogenic sources of greenhouse gases

• burning fossil fuels

• agricultural practices

• deforestation

• landfill use

• industrial production of new chemicals

Evidence that Earth is warming

• 20th century was hottest century in 1000 years

• Since 1900, average temperature has been higher

• Arctic temperature higher over the past 50 years

• Glaciers melting/shrinking rapidly

• Floating sea ice melting/shrinking rapidly

three countries with highest greenhouse gas emissions

US, China, India

global climate change leads to…

• melting polar ice caps

• rising sea levels

• glaciers are melting and not re-freezing

• exposed soil absorbs more heat, decreasing albedo

• more freshwater, altering circulation

• Europe colder temperatures

• melting of permafrost

climate change effect on coastal cities

more vulnerable to flooding, saltwater intrusion, erosion

how do melting ice caps affect polar bears

they can’t hunt efficiently because they have to swim so far, rather than jumping from ice to ice

Greenland

• world’s largest island

• 80% covered by glaciers

• holds 10% of the world’s freshwater

• glacial melting and movement accelerating

CO2 and ocean water

it is very soluble (mixes really well)

warmer oceans…

• increased acidity of surface waters by 30%

• threatens corals/snails/phytoplankton/organisms with shells

equation for ocean acidification

CO2 + H2O —> carbonic acid (H2CO3)

as CO2 concentrations increase in the atmosphere, the ocean acts as a ____________ for absorbed CO2

sink (reservoir)

when CO2 entered the ocean, it is converted into ________ when combined with water, lowering the pH of the water and causing _____________________

carbonic acid

ocean acidification

importance of phytoplankton

they produce oxygen for the ocean and humans, and are the base of the food chain

decrease in pH causes the calcium carbonate to dissolve, so species will not be able to grow large or will die, as in the case with _______________

coral bleaching

Kyoto Protocol

1997 agreement that set a goal for global emissions of greenhouse gases from all industrialized countries to be reduced by 5.2% below their 1990 levels by 2012

carbon sequestration

capturing carbon before it goes to the atmosphere and storing it

Paris Climate Agreement

2015; established as a pledge to keep global warming less than 2°C above pre-industrial levels

climate change is difficult because..

• global

• long-lasting

• political

• benefits not spread evenly

• controversial solutions

• humans are not “hard-wired” to respond

carbon footprint

carbon generated directly or indirectly by a person/group. diet, non-food purchases, every little choice adds up

what do invasive species tend to be

r-selected and generalists

African Honeybees

intentionally introduced to California to generate more honey and help pollinate. They ended up killing native California honeybees

Kudzu vines

brought intentionally to reduce erosion, but have overrun other plants

Silver carp

Brought to the US as a food source from Asia; escaped into the Great Lakes/river systems, spreading to the Mississippi River

best method to control invasives?

prevention

6th mass extinction

driven by human activities

endangered species

likely to go extinct in the near future

other species categories

threatened, near-threatened, and least-concern

which species face most threat of any other types of animals

amphibians

factors that determine whether a species may become endangered

• reproductive rate

• habitat preference

• relationship to humans (food, etc)

• success in competition

HIPPCO

main causes of declining biodiversity

• Habitat destruction

• Invasive species

• Population growth (human)

• Pollution

• Climate change

• Overexploitation/Overharvesting

which letter in HIPPCO is the most impactful

H - habitat destruction

HIPPCO is the main cause for…

premature extinction

Purple Loosestrife

introduced to control erosion

Burmese pythons

accidentally introduced to Florida; eating animals

Passenger pigeon

at one point the most numerous bird on earth; it is now extinct

poaching

capturing/killing plants and animals illegally

ex: rhinoceros, elephants

single-species approach

focusing on one species, putting money into breeding programs and saving habitats where that species resides

ecosystem approach

protects the entire habitat of that species. more liked by scientists because it benefits all species that live within that protected habitat

Corridors (passageways)

allow a safe passage for animals from one protected habitat to another

Lacey Act

prohibits interstate shipping of all illegally harvested plants/animals

Marine Mammal Protection Act

prohibits the killing of all marine mammals in the US and the import/export of any marine mammal body part

Endangered Species Act

designed to protect species from extinction

CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora)

controls the international trade of threatened plants/animals

Pelican Island, Florida

first wildlife refuge in the US

no-regrets strategy

any actions against climate disruption will lead to important benefits; only issue will be if we don’t do anything now