Climate Change - Causes and impacts
Climate and weather
Weather-the daily changes in pressure, temp and precipitation at a local level
Climate-‘average’ weather over the long term (e.g. years) often at a regional level
Both are affected by - Ocean and atmospheric circulation systems,GHGs,Volcanic activity,Feedback cycles
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Climate change
LONG TERM CHANGE IN THE CLIMATE
Fluctuations in solar insolation( amount of solar radiation reaching) Affecting temperature
Changing proportions of gases in the atmosphere
Ocean and atmospheric circulatory systems-Energy from the equator is transferred toward the poles through atmospheric and ocean circulation systems.
Ocean circulation systems are caused by winds and difference in water temperature and salinity.
Wind occurs as a result of differences in air pressure.movement of air from high to low pressure (replacing rising air) creates wind.
MENTION EL NINO effects.
GHGs trap heat and increase the temperature. Anthropogenic activity increases GHGs in the atmosphere. Global Warming Potential(GWP) - It is a relative measure of how much heat a known mass of GHG traps over a number of years compared to same mass of carbon dioxide.GWP of CO2 is 1 and methane 21.READ abut methane in Oxford-page 326
Volcanic activity- short term effect ,Emissions from volcanic activity include ash and gases such as sulphur dioxide. The latter reacts in the atmosphere forming a sulphate aerosol that reflects solar radiation back into space and causes global cooling.Evidence- Ash from Mt. Pinatubo, in the Philippines on 15 June 1991 led to a cooling of the earth for about three years.
FEEDBACKS
Positive - WATER VAPOUR .MORE TEMP,MORE WATER VAPOUR ,MORE TEMP..CYCLE CONTINUES. ALSO ICE ALBEDO(REFLECTION by ICE),PERMAFROST MELTING produces methane.IT is a GHG
NEGATIVE-Plant photosynthesis
If temperatures increase, levels of plant photosynthesis can rise and more carbon dioxide is absorbed. This reduction in overall atmospheric levels of carbon dioxide results in a reduction in global temperature
IMPACTS OF CLIMATE CHANGE
ENVIRONMENTAL
ON SOCIETY
ON BIOSPHERE and ECOSYSTEMS
ON LAND
ON SEA LEVEL
HEALTH
ECONOMY
Impact on Agriculture and fisheries
ON GLOBAL TEMPERATURE
Water resources
ENVIRONMENTAL REFUGEES
COASTAL CITIES