Evidence for Climate Change (OCR GCSE Geography B)

Past Patterns of Climate Change

Changes in the global climate

• Climate change is large-scale, long-term changes in the average temperatures and weather patterns

• The global climate conditions of the Earth change over time leading to colder and warmer periods

• The last 2.6 million years are the Quaternary period when there have been 60 cold periods and warmer interglacial periods

• The last ice age ended approximately 25,000 years ago

Ice core data: changes in temperature over the last 11,000 years

Evidence for Climate Change

• The evidence for the climate change comes from a range of sources

Ice cores 

• These trap ash, air bubbles and microbes.

  • The air bubbles contain CO₂ providing information about past temperatures

  • Ice cores give information regarding the climate for the last 2.6 million years

Preserved pollen

• Allows scientists to know which plants were located where 

  • The climate requirements of those plants can then be used to know what the climate conditions were 

Historical sources

• Diaries and art: such as paintings of the Thames River frost fairs

  • These are subjective and so may be inaccurate

Tree rings

• Each ring of the tree shows a year's growth

  • During warmer and wetter years trees grow more and so the rings are larger

  • Fossilised tree remains enable scientists to examine the climate over thousands of years

Art and diaries

• Paintings and diaries provide evidence seen by people during past colder and warmer periods

  • Paintings of the frost fairs on the river Thames in London in the 19th Century

  • Diaries kept by people such as a gentleman farmer from North-West England dating back to 1815