Changing climate

We know climate has changed by: 

Volcanic eruptions

• Large eruptions produce dust and gas like sulpher dioxide
• Blocks or absorbs solar radiation so earth cools
• Large asteroid collisions have similar effects
  • Mt Pinataubo in 1991
  • Laki eruption in 1783

Sunspot Activity

• Darker areas on the suns surface- greater solar activity
• coincide with the little ice age- very few were seen

Changes in Earth's orbit

• Precession- earth wobbles on axis over a period of 26,000 years
• Changes solar energy recieved
• Tilt varies between 21 and 24 degrees

The Little Ice Age lasted from 1300-1870

The average temperatures were 1 degree lower than today

Impacts include:

• Baltic sea and the Thames froze over
• Sea ice reached Iceland
• Winters were colder and longer- reduced growing season
• widespread crop failure and famine
• Greenland was abandonned 
• Price of grain increased 
• Glaciers moved, overrunning towns and farms

Megafuana are large animals such as;

This is an example of a mass extinction event.

Related events have happened in the past possibly due to;

• Not being able to cope with the climate change- preferred food dies out so they perish also
• Human beings hunted them

At the moment species are dying out at 1000 times the 'normal' rate.

The UK has a temperate maritime climate. This means it is mild and wet.

• Prevailing south-westerly winds bringing moist air from the atlantic
  • this produces precipitation
• Seas surrounding the UK reducing summer temperatures
  • makes winters mild
• The Gulf Stream ocean current brings warm water across the Atlantic
  • this warms the air

Recent changes in CO2 are as a result of burning fossil fuels. CO2 is also created when making cement and steel. Japan, China, USA, Russia and India are the main contributors of CO2.

Since the Industrial revolution levels of greenhouse gases have risen. This contributes to an enhanced greenhouse effect.

The poorest 25% of the population contribute less then 2%of the global total of CO2

Rapid industrialisation in India and China is pushing this number up

Nitrous oxide is produced by jet engines, fertilisers and sewage farms

Methane is produced by cows- 200 litres a day. Cow numbers have doubled in the past 50 years.

Deforestation has two effects;