Climate Change

Climate Change

1. Atmosphere

   • Primary composition: solar winds
   • Secondary composition: volcanic and gases in general (aerosols, water vapor)
   • 3 main gases: N2, O2, Ar
     • Greenhouse gases: Interact with visible and infrared light (they absorb energy to radiate it back to earth)
   • gaseous envelope that surrounds a celestial body
   • 4 main layers
     • Troposphere: weather occurs here
     • Stratosphere: O3
     • Mesosphere: coldest layer
     • Thermosphere: reach the highest temperatures
   • Atmospheric pressure: Force exerted by weight of air against a specific point placed at the earth's surface

2. System

   • isolated: nothing coexisting
   • closed: heat exchange
   • open: everything interacting
   • Subsystems
     • geosphere: non living things
     • hydrosphere: water
       • cryosphere: ice
         • Ablation: loss of ice and snow because of melting
         • Information from 400,000 years up to 10,000 of information regarding the climate can be found in the ice-cores layers.
     • atmosphere: air
     • biosphere: life
     • antrosphere: depends on demand

3. The sun = Motor of the climate system

   • Latent heat: Heat that causes a change of state with no change in temp
   • Sensible Heat: Heat that causes a change in temp
   • Albedo: amount of energy reflected (depends on the type of surface)
   • Radiative Forcing- is the capacity of a gas/ agent to affect the energy balance
   • energy moves from high to low.
   • Pressure gradient:Rate at which pressure changes at different locations
   • Wind: Air in motion that travels from a high to lower pressure zone.
   • Adibatic process: air temperature, changed by pression
     • warm air: humidity

4. Global climate

5. To change radiation balance

   • altering long wave radiation
   • changing physical (latent and sensible heat) or chemical (atmosphere's composition)

6. Coriolis effect: deflection of fluxes to the right in the N hemisphere and no the left on S

   • Afect ocean currents and winds
     • Ekman transport

7. Climate Change through history:

   • 600 to 300 million years-Presence of high CO2 concentration.
   • 120 to 100 million years ago, there was intense tectonic activity.
   • 90 to 5 million years ago, the tectonic activity ceased and the CO2 levels decreased.
   • 2 million years ago-Glacial and interglacial cycles-Milkovich cycle.
   • 15,000 years-Younger Dryas-Cold Period.
     • Event caused by the reduced salinity of the ocean currents.
   • 5,000 to 1,500 years to the present-Medieval warm epoch-Little ice age.
     • Medieval warm epoch: “Time of warm climate in the North Atlantic region that may also have been related to other climate events”. Little ice age: “Period of cooling that occurred after the Medieval Warm Period”