Flashcards in Chapter 14: Climate Change Deck (41)
What is the Columbia Icefield?
The Columbia Icefield is a remnant of the massive ice sheet that once covered much of canada, sits upon some of the highest peaks of the canadian rockies
What is the athabasca glacier?
a valley glacier(one of 6) that flows like a huge river of ice from the columbia icefield
How has change in climate affected the athabasca glacier?
The glacier has lost one half of its volume, been retreating since 1844.
What did the Fourth Assesment Report of the Intergovernmental Panel say?
That climate is changing and we are the cause, and its impacts will only become more severe from here on.
The reflectivity of a surface
How much of the solar radiation towards earth is absorbed?
What are green house gases?
Atmospheric gases that absorb infrared radiation
What defines INFRARED radiation?
IF radiation has long wave lengths than visible light.
Give examples of green house gases
water vapour, Ozone(O3), Carbon dioxide(CO2), Nitrous Oxide(N2O), methane (CH4). Chloroflourocarbons(CFCs)
What is the greenhouse effect?
When GHGs absorb radiation, they re-emit infrared energy of slightly longer(lower energy) wavelengths. Some of this energy travels back down to the surface, warming the earths surface and troposphere
Global warming potential
Relative heat trapping ability in CO2 equivalents
Which is the GHG of primary concern?
CO2. Although it has the smallest global warming potential, it is far more abundant in the atmosphere than other GHGs.
how has the concentration of carbon dioxide in the atmosphere changed from the 1700s?
~280 ppm to 400 ppm
What is a SINK?
a reservoir that accept more of the material than they release
When was the main chapter of fossil fuel formation?
during the Carboniferous period 290-354 million years ago
Which greenhouse gas is most abundant and contribute most to the greenhouse effect?
give example of positive feedback cycle with respect to climate change
Earths climate gets hotter-->melting of glaciers lead to exposure of rock and soil--> rocks store more heat instead of being reflected back to space
give example of negative feedback cycle in terms of climate change
warming leads to evaporation->leads to water vapour-->causes increased cloudiness>> slows global warming
microscopic droplets that often add a cooling effect, can warm by absorbing solar energy
Radiative forcing: positive forcing ______ the surface, negative forcing ______ it.
think... good is bad and bad is good
periodic changes in earths rotation and orbit around the sun
when global surface temperatures drop and ice sheets move from the poles to the mid latitudes
how much radiation the sun emits
the ocean, as a sink, holds ___x more carbon than the atmosphere
t/f: carbon absorption by the ocean speeds global warming.
f... this slows global warming but does not prevent it. the absorption of co2 by ocean is problematic bc it xauses the acidification of ocean water, causing shells and skelotons to dissolve releasijg more co2 (positive feedback)
ocean water exchanges huge amounts of heat with the atmosphere, and ocean currents move energy from place to place
what are proxy indicators? examples?
indirecr evidence that serve as substitutes for direct measurements. ex glaciers hold clues to past climate
separation and differential concentration of isotopes of slightly different mass
evidence about our climate in the past