lecture 6: human environment relations

Question 1

Climate is a function of the interaction of many spheres:

Answer 1

atmosphere: gases
* hydrosphere: oceans, large bodies of water
* lithosphere: plate tectonics
* cryosphere: glaciers, ice sheets, snow cover
* biosphere: vegetation, animals, humans

Question 2

the last glacial period:

Answer 2

all of Canada covered in ice expect for northern yukon

lower sea levels at that time exposed the bering land bridge

Question 3

causes of climate change:

Answer 3

1. variations in solar radiation
2. changes in composition of the atmosphere
3. changes in earths surface
4. variations in earths orbit

Question 4

variations in solar radiation

Answer 4

the sun tends to emit more energy during periods of high sunspot activity

Question 5

sunspot:

Answer 5

a cool ration of high magnitude on the sun (dark and black)
* Sunspots occur in cycles and reach a maximum every 11 years
* sunspots are cool areas on the sun that are surrounded by faculae
* solar output changes on the order of 0.1 - 0.2% in relation to sunspot cycles
* more sunspots = increased solar output

Question 6

faculae:

Answer 6

bright areas with high amounts of energy

Question 7

Maunder Minimum:

Answer 7

a period with no sunspots; this corresponds to a time known as the little ice age
changes in composition

Question 8

greenhouse gases

Answer 8

addition of greenhouse gases (CO2, water vapour, methane) increases global temperature
* CO2 has long residence time in the atmosphere – even though we are reducing CO2 effects will not be felt for decades
* A warming climate appears to be inevitable during our lifetimes

Question 9

Ice cores

Answer 9

• width of an layer provides insight on the temp and snowfall of that year
• Each year a new layer of ice forms
• bubbles of air trapped in the ice
• Ice cores can provide data for up to 600,000 years in the past

Question 10

denderochronology

Answer 10

• the study of tree rings
• wider rings = warmer or wetter years
• tree rings provide data up to 1000 years in the past

Question 11

theory of plate tectonics

Answer 11

• the continents have moved over time
  the collision of converging plates = an uplift and the creation of mountains
• implications: affects wind, temp and precipitation patterns on surrounding landscapes
  variations in earths orbit

Question 12

The greenhouse effect: why does it exist?

Answer 12

greenhouse gasses allow solar radiation to pass through, but they also absorb infrared radiation from earth
* Main greenhouse gases: carbon dioxide, water vapour, methane

Question 13

Milankovitch theory:

Answer 13

three seperate phenomena relating to earths orbit contirbute to climate change (3 cycles)
1. eccentricity: changes in the shape of the earths orbit from circular to elliptical, 100,000 year cycle (accounts for ice ages)
2. precession: wobble of earths axis, 23,000 year cycle
3. obliquity: changes in the tilt of earths axis, 41,000 year cycle

Question 14

enhancement of the greenhouse effect:

Answer 14

the greenhouse effect itself is not a concern however the enhancement effect by humans is a concern.. why? - adding greenhouse gas = climate change
* increasing the amount of CO2 enhance the greenhouse effect.. why? Because more infrared radiation from the earth is absorbed in the atmosphere
* CO2 emissions are increasing in China and India as the economies in these countries continue to industrialize

Question 15

ozone

Answer 15

• gas composed of oxygen with a pungent smell
• forms naturally in the stratoshpere
• forms in the troposphere by chemical reactions with other gases

Question 16

Ozone in the stratosphere

Answer 16

important because 7% of suns radiation is ultraviolet
* layers protect us from UV rays
* UV rays can cause great damage to unprotected skin

Question 17

destruction of the ozone layer

Answer 17

chlorofluorocarbons (CFCs) are the major reason for the depleting of the ozone during 1900s
* CFCs were found in inefficient appliances, spray cans, and industrial processes
* Non essential uses of CFCs were banned in north america
* ultraviolet radiation breaks up CFC molecules causing the release of chlorine
* chlorine destroy ozone
* A CFC molecule can remain in the atmosphere for many decades
* through CFCs have declined since 1970, there is little decline recognized in the atmosphere… why? Because of high residence time of CFCs
* decreased amounts of stratospheric ozone have resulted in increased cause of skin cancer (skin cancer rates have doubled since 1950)

Question 18

montreal protocol (1987)

Answer 18

a highly successful worldwide agreement among countries to reduce CFC concentrations

Question 19

Acid precipitation

Answer 19

precipitation that combines with pollutants that turn the precipitation acidic
* Main sources: sulfar oxides, nitrogen oxides
* effects of acid precipitation: slow tree growth, reduces fish population in lakes and erodes materials
* 14, 000 lakes in Canada are acidified
* PH scale is a measure of acidity —> 0-14, 7 is neutral and below 7 is acidic
* precipitation is naturally acidic (5.5)
* Most common in eastern north america
* canada - us air quality agreement
* nitrogen and sulfar oxides react with water molecules to form nitric and sulfuric acid
* Aquatic life cannot survive when PH < 4.8

Question 20

positive feedback

Answer 20

process that encourages the continuation of the original process

Question 21

Example specific to climate change:

Answer 21

less snow/ice decreases the reflectivity of solar radiation (cause snow is highly reflective)
* after snow/ice melts, more solar radiation is absorbed rather than reflected
* This process leads to warmer conditions
* the reason why polar regions are warming the fastest

Question 22

loss of sea ice

Answer 22

• by 2050, remaining Arctic sea ice in summer is expected to be around ellesmere island and northern Greenland
• Since 1980, has declined by 30%

Question 23

How do the climate models work?

Answer 23

• by solving a series of mathematical equations

Question 24

What do the variables in the equations represent?

Answer 24

greenhouse gases, solar radiation, other climatological components

Question 25

Kyoto protocol (1997)

Answer 25

a global agreement aiming to slow climate change * objective: to reduce greenhouse has emissions to 5% below 1990 levels by 2010

Question 26

Impacts of climate change

Answer 26

polar areas will warm the most * boreal forests will expand northward, agriculture will shift northward * precipitation patterns will change affect in habitats * increased intensity of tropical storms and hurricanes

Question 27

sea level rise

Answer 27

as sea levels rises, erosion affecting areas inland; some eroding 10m * Sea level is projected to rise as global climate changes and ice sheets continue to melt * Vancouver, miami, new york * 80% of then country is less then 1m above sea level * Seawalls have built around the islands

Question 28

impacts on humans

Answer 28

climate change affects food production, tourism and human health * Most common impact is the speed of malaria

Question 29

Impacts on biodiversity (warming temps will)

Answer 29

* bleaching corals * Loss of flora and fauna * extinction risk for polar bears

Question 30

what is the relationship between humans and nature?

Answer 30

1. humans are simply one component of the natural world 2. Humans are separate from nature

Question 31

our relationship with nature dictates our actions

Answer 31

1. living in harmony with nature (sustainable development) 2. Exploiting nature for economic growth (ignore the true costs of resource extraction)

Question 32

The realities of natural resources

Answer 32

1. many natural resources are finite 2. using resources creates waste products problem: developed countries have created societies and economies which these realities are neglected * there is resistance to changing the way resources are extracte

Question 33

The precautionary principle: examples of its use

Answer 33

1. insurance policies 2. preventative maintenance (if there is risk we should still act even if their is uncertainty) there is a social responsibility to protect the people and the environment from harm Applied to environmental change: decide between harm and cost of inaction compared to wasted costs of acting unnecessarily * the depletion of the ozone layer showed that surprise problems can develop rapidly and unexpectedly

Question 34

Photovoltaics

Answer 34

convert light directly into electricity

Question 35

wind energy:

Answer 35

- creates 6MW of power (1000 small buildings) * renewable and pollution free source of energy * Viable in areas with constant moderate winds

Question 36

Issue preventing the growth of wind farms:

Answer 36

* habitat distruption * appearance * Noise

Question 37

hydroelectric energy: implications of large projects

Answer 37

1. loss of land due to flooding 2. displaced population 3. leaching 4. destruction of habitats * smaller generators on smaller rivers are more desirable but can be very costly