Long-Term Climate Change

- Changes in the Earth orbit every 100,000 to 400,000 years

- Changes in the tilts of the Earth's axis - every 41,000 years 

- Changes in the orientation of the Earth's axis - every 21,000 years 

- Continental drift - reducing the effect of the North Atlantic drift

- Volcanic emissions- volcanic dust and sulphur oxide block out insolation and increase the Earth's albedo

- Sunspot actvitiy - every 11 years 

- Human activity- deforestatio, burning fossisl fuels, consuming agriculture, changing atmospheric composition 

- Changes in jet stream activity and Rossby Waves causing blocing anti-cyclones 

- Earth warmed during the day by short-wave radiation from the sun and cooled at night by outgoing longer-wave infared radiation 

- Sometimes some of the outgoing radiation is trapped by a blanket of trace gases 

- Without these natural greenhouse gases the Earth would be 33° colder than it is today 

- In the most recent 150 years there has been an increase in the radiation getting caught in the blanket of trace gases because it has got thicker 

- This is because of the growing population and the corresponding growth in human activity 

- The Greenhouse Effect is a main contributor to Global Warming 

Water vapour - sourced from evaporation of the ocean and evaportranspiration from the ocean 

Carbon dioxide - sourced from the burning of fossil fuels, buring rainforests and respiration 

Methane - sourced from decaying vegetation, farming, sewage disposal and landfill sites 

Nitrous oxide - sourced from vehicle exhausts, fertiliser, nylon manufacture and power stations 

CFCs - sourced from refrigerators, aerosol sprays, solvents and foams 

- As the atmosphere gets warmer so do the oceans 

- As the sea warms, it expands causing the sea levels to rise by 0.25 - 1 metre by 2100

- Partly submerging low lying land such as the Maldives 

- Also increase flooding in places with larger deltas 

- Melt glaciers and edges of ice sheets, the increased snowfall expected in wetter climates 

- Distibution of precipitation across the world altered