Chapter 7- Climate Change Flashcards
weather
atmospheric condition at any time or place
- temperature
- precipitation and humidity
- wind
- air pressure
Climate
- over long term
- summary of variation in day to day weather for a given period
- mean (average) plus extremes (variation)
Climate Change
long-term shift or alteration in the climate of a specific location, region or the entire planet
-looking at long term & on specific scales
Category 4 & 5 hurricanes have
doubled in the last 30 years
malaria has…
spread to higher altitudes in places that are 7000ft above sea level (Colombian Andes)
-temps is limiting factor of mosquitoes
flow of ice from glaceirs in Greenland has…
doubled over the past decade
Causes of climate (long term change)
- differential short-wave radiation from the sun (radiant energy)
- global circulation system (wind currents, ocean currents)
- return of solar radiation back to space
Short Tem Changes in Climate
- large volcanic eruptions
- changes in ocean currents (El NIno, La Nina) (trade winds stop blowing=warming of waters)
Long Term Changes in Climate
shape of Earth’s orbit around the sun- wobble of Earth’s axis, allows sun to hit at a certain angle
-changes intensity of solar radiation coming in
Greenhouse effect
intensify concentration of gas in atmisphere so molecules hold onto heat in the atmosphere
-now on a global level
Climate change evidence
Globally change in temperature of 0.6C +/- 0.2C. North hemisphere increased 3 to 6C
- greenhouse gas concentrations rising (increase in CO2 emissions and methane) from ice core analysis
- glaciers receeding in most areas
- reduced snow and ice cover
- arctic sea ice coverage (declining at a rate of 13% per decade, 40% thickness (happening rapidly due to +ve feedback loop and albedo effect)
- melting permafrost
- rising sea levels past 0.1to 0.2mm/yr to 1-2mm/yr
Explanations
- Significant increase in greenhouse gases in atmosphere since the industrial revolution
- fall in atmospheric O2 at the same rate as fossil fuel emissions (CO2) increasing
- Change in proportion of carbon isotopes in atmosphere- atmosphere being enriched with carbon from fossil fuel sources (70-90% increase) *direct link to humans
Carbon
sources- fossil fuel combustion
-deforestation (takes away ability to take CO2 from atmosphere and stored as biomass)
Methane
-smaller quantities but traps 25 to 30x the heat
Sources: organic decay, natural gas production, burning vegetation (+deforestation), wetlands drying, manure, ^forest fires
-DANGEROUS
Nitrous Oxide
sources- nitrogen fertilizers, burning of fossil fuels and biomass, nylon production, manure production, types of crops, leaching, spraying fertilizers, tailpipe emissions
Ozone
reduces warming in stratosphere (why we don’t want holes in ozone)
- greenhouse gas in troposphere
- sources- photochemical reaction with combustion gases to form smog
- ground level smog= tailpipe emissions high density traffic flow
4 components of the atmosphere
troposphere- weather 99% water vapour, region where gases mix
Stratosphere- blocks UV, ozone layer
Mesosphere- coldest part of atmosphere
Thermosphere- outer space, satellites, aurora borealis
Climate Change Model Consider 5 components
- Net Radiation
- Energy Dynamics
- Surface processes
- Chemistry of atmosphere
- Scales of time and place
General Circulation Model (GCMs)
Strengths- very complex, 3D dimensions, good at temperature prediction,
Limitations- very complex, highly variable, scarcity of data, poor predictor of precipitation and oceans, can be wrong, don’t have all the data we need and can’t get all of it, data you put in MUST be very very good
Which 3 main greenhouse gases produced by human activity were identified in the Kyoto Protocol?
- CO2
- Nitrous oxide
- Methane
What are 3 oher GHGs released in small quantities but are also long lasting and significant?
- hydrofluourocarbons (HFCs)- refridgerant
- perfluorocarbons (PFCs)- medical applications
- Sulphur hexaflouride- SF6- used in electrical industry and filling space in windows
In December 2002 Canada signed on to the Kyoto Protocol and vowed that by 2012 it would reduce emissions from the 1990 level by 6%. What are the current emisisons in Canada relative to 1990?
+27% and growing!
What is a main repository for carbon?
Forests- deforestation is a main cause in increasing CO2. Much of carbon returned to atmosphere when trees are cut down
planting trees=big carbon absorption
Which greenhouse gas traps 25 to 30 times more heat per molecule than CO2?
Methane (organic decay in wetlands, manure, waste products of ruminants (sheep and cattle), land-use change (waste disposal sites increase 0.75 to 1% every year)
