Climate change Flashcards
Diff in radiation absorbed by earths surface and emitted by surface
most of visible light is absorbed, not reflected like infrared, where most is reflected
this means most radiation stays-meaning more heat if trapped
what is a greenhouse gas
Any gas that is better at absorbing infa-red than average for the atmosphere
Changes in cryosphere
cryosphere has been affected by rising temps
Snow in the middle of Antarctica is pushed out to the ocean due to a build up of snow in the middle-making the glacier (built on land) an ice shelf (built on water)
The East side is high above sea level, the West side is below the sea level so the west melts faster
Less ice=flow of ice=faster=more melting
Ice shelfs do not affect sea levels as the volume is (mostly) already in the ocean
Rising sea levels are caused when ice breaks from an ice shelf
Sea ice
does not directly affect sea levels-it has a high albedo and reflects sunlight-less ice=less sunlight-more sunlight is absorbed=higher temp - This then becomes positive feedback mechanism
Rising sea levels
Melting land ice-Ice falls into oceans-increasing volume
Thermal expansion of water-Warm atmosphere heats seawater which expands-yet it would take a really long time
changes in climate processes
Wind-causes SW to move
Evaporation-W that has evaporated causes the flow water to replace it
Heat/cooling-changes water density which affects sinking rate
Salinity-affected by evaporation/introduction of freshwater from land ice.-can affect the rate of water sinking
examples of changes in CP
Gulf stream-North Atlantic conveyer involves movement of layers of surface and deep waters in the North Atlantic ocean. It distributes heat energy and controls the climate.
Brings tropical water to the UK and prevents the UK from being as cold as other regions on the same latitude
Warm water from the SW is blown across the Atlantic by strong winds. As this hot surface water gets colder it becomes less dense and sinks drawing water in to replace it.
A global increase in temp of atmosphere can affect the conveyer belt. As ice continues to melt in Greenland, The freshwater ice goes in the ocean making the water less saline
El Nino
Warming of sea surface temp that occurs every few years, typically concentrated in Pacific-around equator-can affect weather around the world-changing floods/heat
Wind usually goes from east to west, and pushes air and so warm water to the west, with cold water being in the east. When el nino happens, this is weakened and less warm water is on the west-warm water spreads around and then the weather patterns change which has a knock-on affect for other factors
Why is it difficult to draw conclusions from el Niño events
There are too many infrequencies
why are there annual CO2 fluctuations
Sunlight times change, so rate of photosynthesis goes down
IPCC 3 conclusions
globally, the troposphere, upper ocean has warmed and there will be more frequent hot temperatures
Ice Core uses
The ice layers hold particles/imprints and so hold physical evidence of last thousands of years. Temp imprints and air pockets also hold samples of gases and so the atmosphere
how is the validity of a computer model tested
if they can predict the past, they can predict the future
what’s the biggest uncertainty in climate change modelling
how clouds will respond to climate change
which feedback mechanism is hard for computers to be accurate
albedo affect as positive
