Our changing climate

Increasing awareness- Paris Climate Conference (COP21)- possibly one of the most important conferences of all time. Need to keep temperature below 2 degress celsius. 2020 implementation.

Current CO2 concentration- 400ppm (2015). Pre-industrial= 280ppm

Climate= presistent weather patterns and long-term regional trends (30 years). e.g. maima, minima & average temperatures, pressures, precipitation etc. 

Climate controls:

• Latitude- determines insolation
• Altitude- elevation is linked to temperature- due to atmospheric pressures etc
• Maritime climatic factor- oceans/ water bodies regulate temperatures- fewer extremes
• Ocean current proximity- e.g. Gulf stream warms Europe- temperatures are affected
• Mountain range proximity- can funel air flow/block winds; also orographic lifting of air masses=rainfall. Leeward side= rain shadow=dry climate.
• Proximity to high and low pressure cells- dependent upon latitude e.g. Azores high- determines humidity and prevailing winds

Climate belts- are classified on the basis of temperature, precipitation and vegetation characteristics

Variability

Cyclical patetrns-

• El Nino- 2015/16= El Nino year= reversal of usual trade winds because pressure systems over S. Pacific switch. Usually- high in S. America and low over Australia. Winds travel west. El Nino- low presure over coast of Peru + trade winds travel east. Rainfall and upwelling zones are altered.  Influences global climate worldwide- despite being in S. hemisphere.

• North Atlantic Oscillation: Pressure gradient between Azores high and Icelandic low. When bigger pressure difference- more storms- sucked in by deep low pressure over Iceland- Northly route. When pressure difference is less- storms travel further South- into Mediterranean- drier winter in UK.

• Hydrological cycle- water moves between biological and physical reservoirs.

• Carbon cyce- biogeochemical cycle regulates climate. Crabon can stored out of the cycle: limestones, fossil fuels, organic shales, methane hydrates on the ocean floor. Returned to atmosphere during biotic respiration, rapid oxidation (burning), metamorphism of carbonate rocks. 

Climate over time: 

We can…