chapter 19

Question 1

factors in climate shifts

Answer 1

• volcanic emissions
• changes in solar input
• continents moving on shifting plates
• meteor strikes

Question 2

glacial/interglacial periods

Answer 2

alternating cycles of freezing & thawing

Question 3

factors that provide information about past atmospheric conditions

Answer 3

• antarctic ice cores
• sediment cores, analysed for pollen & fossil
• direct temperature records going back to 1861
• air samples from different locations, analysed for chemical composition & changes

Question 4

greenhouse effect

Answer 4

certain gases in the atmosphere absorb heat; warms the lower troposphere and surface
- earth’s temperature will rise at least 2deg C by 2050

Question 5

major ghgs in the lower atmosphere

Answer 5

• water vapour
• carbon dioxide (co2)
• methane (ch4)
• nitrous oxide (n2o)
• chlorofluorocarbons (cfcs)

Question 6

this country releases more ghgs/person than any other country

Answer 6

usa rahhhhh!H!H!!

Question 7

sources of major air pollutants & ghgs

Answer 7

• burning of fossil fuels
• deforestation, slash & burn

Question 8

intergovernmental panel on climate change

Answer 8

ipcc
- formed in 1988
- evaluates possible future climate changes
- findings include: 20th century was the hottest century in the past 1000yrs, 10 warmest years since 1861 occurred since 1990, arctic temperatures have risen 2x as fast as those in the rest of the world, melting permafrost in alaska & russia releases more ghgs into the troposphere, world’s sea level rise by 10-20cm

Question 9

global warming

Answer 9

refers to temperature increases in the troposphere, causing climate change

Question 10

global climate change

Answer 10

broader term refers to changes in any aspect of earth’s climate

Question 11

water vapour

Answer 11

• water vapour comes from evaporation, not directly from human activity
• the amount of water vapour the atmosphere can hold is entirely a function of temperature; as temperature rises, more evaporation occurs, more water vapour is in the atmosphere
• emission of ghgs -> warmer temperatures -> more water vapour -> warmer temperatures; positive feedback loop

Question 12

role of distribution of clouds in global warming

Answer 12

clouds may (1) increase warming by absorbing & releasing more heat into the troposphere or (2) have a cooling effect by reflecting more sunlight back into space

Question 13

pollution (particles & aerosol) dimming sunlight

Answer 13

• soot particles in the atmosphere reflect some sunlight back into space
• airborne particles result in more water vapour, leading to ticker, darker clouds

Question 14

two major sources of methane gas (being released)

Answer 14

• bogs/wetlands
• methane hydrates trapped under arctic permafrost

Question 15

arctic ice

Answer 15

• higher temperatures -> less ice -> less sunlight being reflected back into space -> higher temperatures; positive feedback loop

Question 16

benefits of reducing ghgs

Answer 16

• reduce air pollution; reduce negative health effects (asthma, lung cancer, bronchitis, emphysema)
• reduce dependence on foreign energy sources
• reduce environmental effects (habitat destruction, acid rain)
• save money in the long term through renewable energy
• bad news: will cost money in the short term

Question 17

effects of global warming on oceans

Answer 17

• alter ocean currents & cause excessive warming/cooling in some parts of the world
  
  • oceans moderate earth’s average surface temperature by absorbing co2 and heat from atmosphere
• desalinisation of oceans; acceleration of the global water cycle, affecting precipitation patterns
• increased acidity -> decreased ability to remove & store co2
• decreased nutrient supply & phytoplankton

Question 18

effects of global warming to land ecosystems

Answer 18

• change distribution & population sizes of species
• shift locations of ecosystems
• threaten reserves, wetlands, & coral reefs
• endanger species that cannot adapt to rapid warming
• increased wildfires, destroying wildlife habitats & releasing high amounts of co2
  
  • increased co2 levels have been changing the composition of species found in various areas

Question 19

why is climate change difficult to deal with?

Answer 19

• the issue is global
• effects will last a long time
• long-term political issue
• harms & benefits of climate change are not distributed evenly
• disruption of economies & lifestyles (i.e. phasing out fossil fuels)
• economic, political, ethical, scientific questions

Question 20

three major strategies in slowing global warming

Answer 20

• improve energy efficiency to reduce fossil fuel use
• shift from carbon-based fossil fuels to a mix of carbon-free renewables
• store as much co2 as possible in soil, vegetation, underground, and in the ocean

Question 21

strategies for removing & storing co2

Answer 21

• planting trees to store co2 in biomass
• soil sequestration (storage); although, warmer temperatures can increase soil decomposition
• no-till cultivation, letting fields lie fallow; will reduce release of co2 and n2o
• smokestacks; pump co2 deep underground or inject it into the ocean
• adding iron to oceans to increase algae; will temporarily remove co2 through photosynthesis

Question 22

what can the govt do to reduce ghg emissions?

Answer 22

• implement carbon taxes
• increase subsidies/tax breaks for saving energy and using renewable energy
• decrease subsidies/tax breaks for fossil fuels
• transfer knowledge & tech from developed to developing countries to promote renewable energy

Question 23

kyoto protocol

Answer 23

• 1997
• requires 38 developed countries to cut emissions of some ghgs by 5.2% by 2012
• ratified by over 120 countries by 2004
• 2001: usa withdraws from kyoto

Question 24

world’s largest ghg emitters

Answer 24

• usa
• india
• china
• russia

Question 25

copenhagen

Answer 25

- cop15, 2009 - 194 countries signed on - goal was to keep temperatures from rising more than 2deg C - to phase out ozone-depleting chemicals

Question 26

paris

Answer 26

- cop21, 2015 - significant contributions & pledges by china & usa--the 2 largest carbon emitters - 174 countries signed on - goal was to limit global warming to 1.5deg C - this requires a target of zero emissions sometimes between 2030 and 2050

Question 27

chloroflurocarbons

Answer 27

- cfcs; freons are the most widely sued - lower the average concentration of ozone in the stratosphere - insoluble in water, chemically unreactive -> remain in atmsophere for long periods of time (65-385 years) - break down under uv radiation; chlorine, very reactive, is released; fluorine & bromine are also released -> ozone is broken down faster than it is formed

Question 28

ozone in the troposphere vs stratosphere

Answer 28

- ozone in the troposphere acts as a ghg; increases temperatures on earth 👎; burning of fossil fuels increases ozone in the troposphere - ozone in the stratosphere absorbs uv radiation before it can hit the earth 👍

Question 29

ozone thinning is seasonal

Answer 29

- severe in antarctica - during the winter, ice crystals in the air collect cfcs; no sunlight to catalyse ozone destruction -> ClO combine to form Cl2O2; accumulates in the atmosphere - during the summer, the sun comes back & breaks up the stored molecules -> releases large numbers of chlorine atoms -> loss of ozone

Question 30

harmful effects of ozone depletion

Answer 30

- all effects stem from increased uv radiation - harmful to human health (skin cancer, melanoma) & animal health - crop depletion - degredation of paints & plastics

Question 31

uv radiation causes cancer

Answer 31

- primary cause of squamous cell & basal cells skin cancers is years of exposure to uv-b radiation - melanoma may occur anywhere on the body; kills a fourth of its victims within 5 years

Question 32

montreal

Answer 32

- 1987 - goal was to cut emissions of cfcs by 35% between 1989 and 2000 - actions taken in compliance with montreal & copenhagen have been proven to work; repairing ozone layer, cooling the troposphere