Lecture 9: Weather and Climate Flashcards
Weather
The state of the atmopshere at a specific time and place
-components: temp, Pressure, humidity, winds, clouds, visibility
Climate
- average of atmosphere over a long period
- calculated over 30 year period
Gases in Atomosphere
Nitrogen: added with decaying matter, removed with bacteria in soil
Oxygen: added with plants
CO2: added with burning fossil fuels, removed with plants
Water vapour: variable in conc.
Ozone: found in stratosphere, protects from UV
Methane: bacteria in second stomachs of cows, sheep etc., as well as mines, oil wells, gases pipelines, rice, landfills
Halocarbons: come from CFCs in the atmosphere
Atmosphere
gases
Hydrosphere
Large Water bodies
Lithosphere
Plate tectonics, orogeny (mountain formation)
Cryosphere
glaciers, ice sheets, snow cover
Biosphere
flora and fauna, and people
65 mya
- Earth was free of ice and warmer than today
- meteorite struck and rapidly cooled Earth by dust reflecting sun
Last Glacial Period
18000 years ago: all Canada iced (Yukon too dry for snow)
-Bering Land bridge was exposed with lower sea levels
Halocene Epoch
warming time 10000 years ago
-Medival warming period(900-1200AD) mild temps
The Little Ice Age: (1550-1700 AD) widespread cooling
SunSpots
cool region of high magnetism on the sun, surrounded by faculae
-sun spots have cycles every 11 years
Faculae
Bright areas on the sun that emit high amounts of energy
Maunder Minimum
period with no sunspots-> the Little Ice Age
Ice Cores
Width of Ice layer provides insight on temperature and snowfall that year
-up to 600 000 years
Dendrochronology
study of tree rings
- wide rings mean warmer/wetter years
- up to 1000 years
-Milankovitch Theory
3 phenomena of orbit that lead to climate change
-eccentricity, precession, obliquity
Eccentricity
Changes in orbit from circular to elliptical
- 100 000 years
- leads to ice ages
Precession
wobble in Earth’s axis
-23 000 years
Obliquity
- changes in the tilt of Earth’s axis
- 41 000 years
Stratospheric Ozone
- formed naturally in stratosphere
- blocks 7% of Sun’s energy in the form of UV
Photochemical Ozone
forms in troposphere with other gases
-bad for breathing in
Montreal Protocol
1987
-countries agree to lower the concentration of CFCs
Acid Precipitation
- acidified precipitation with pollutants (sulfur oxide, nitrogen oxide)
- slowstree growth, reduces fish population, erodes limestone
Canada-US Air Quality Agreement
1991
Same protocol across borders for acid precipitation
Positive Feedback
-event that encourgaes the amplification of a process
Climate Models
Estimating how much Earth will warm
- next 100 years, increase by 1.5 deg. C
- use series of mathematical equations
Kyoto Protocol
1997
Agreement to decrease greenhouse gases to 5% below 1990 levels by 2010
Impacts of Climate Change
-polar regions warm the most
-boreal forest shift north
-precipitation patterns change, affecting habitats
-increased intensity of tropical storms/hurricanes
ON HUMANS: food production, tourism, human health, malaria increase
ON BIODIVERSITY
-bleaching of coral
-loss of flora/fauna
-extinction of polar bears
