Unit 3 Flashcards
What is the cryosphere
areas where permanent snow and ice are possible, vast majority at the north and south poles
what are ice sheets vs ice shelves
ice sheets are on land and ice shelves are over the sea but fixed to land
what is the grounding line
the boundary where ice sheets become ice shelves
what is it called when ice shelves break off into the sea
calving
what is important about east antarctica
it is the only major land area without clear evidence of warming
why is east Antarctica not warming
can be attributed to intensifying wind, more storms, and more snow
what are some key west antarctic ice shelves
Wilkins, larsen C
what effects do melting ice sheets have
as ice sheets melt the water flows into the oceans increasing sea levels
how much ice is melting into the oceans currently
50b tonnes of ice per year
how much of the worlds ice is in antarctica
90%
why is sea ice compared to an accordion
it expands and contracts with the seasons
what is the decline in sea ice area and thickness since 1980
sea ice area today is half what it was in 1980, thickness is half what it was aswell
what is the change in arctic ice pack
ice pack is only a quarter what it was a few decades ago
how does sea ice affect albedo
sea ice is one of the main contributors to earth albedo so less ice means more heat absorbed by earth
how does thawing permafrost increase climate change
releases CO2 and MH4 which are both greenhouse gasses
what is permafrost made up of
mainly soil, gravel, and sand, bound by ice
how does the thawing of permafrost release GHG
as it thaws microbes emerge to decompose ancient biomass releasing the GHG
how much carbon is in permafrost
1500B tonnes which is 2x that of the atmosphere
how much has the permafrost line in Canada retreated
130km in the past 50 years
Where are the greatest GHG stores in permafrost
Siberia
What are thermohalive forces
the annual pulse cause by changes in temp and salinity in arctic waters that drive deep ocean currents
What is the double whammy of deforestation
pulse in CO2 emissions from deforestation and decrease in ability to sequester CO2
when is the point of no return in terms of deforestation
1-2 decades on current trajectory
what is the positive feedback from forest fires
increased warming leads to more fires which releases CO2 into the atmosphere furthering heating
Which is warming faster oceans or land
Land
How is ocean warming affecting reefs
as oceans warm the reefs expel algae effectively starving the ecosystem of the reef
what is ocean acidification
the process of the oceans pH changing due to increased absorption of CO2
Why will warming increase even if emissions are decreased
momentum from positive feedbacks, CO2 has a hundred year residence time in atmosphere, oceans lag behind surface in warming,
what are the common warming targets
2 degrees then 1.5 degrees after 2015
what CO2 concentration is needed for chance at safe warmingf
350ppm
what is the current atmospheric CO2
420
