CLIMATE CHANGE Lessons from Antarctica

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CLIMATE CHANGELessons from Antarctica

• Dr John Shears
• Environmental Officer
• British Antarctic Survey
• Cambridge

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Aims of the talk

• The Antarctic climate
• Current climate change in Antarctica
• Ice cores a unique record of past climate
• The impact of climate change in the UK
• Conclusions

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The Antarctic climate

• Antarctica is the coldest continent.
• Significant variations in climate between various
  locations.
• Climate influenced by latitude, altitude, the ice
  sheet, the Southern Ocean, and seasonal changes
  in sea ice cover.
• Todays temperatures
• 0.4o C Rothera
• - 32.9o C South Pole

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Current climate change in Antarctica

• The Antarctic Peninsula has warmed by 3oC over
  the last 50 years.
• This has caused the collapse of several ice
  shelves. Larsen B disintegrated in March 2002
  releasing over 500 billion tonnes of ice.

Top. NASA Terra satellite image showing the
collapse of Larsen B ice shelf. Image is 300 x
300 km. Left. Aerial photograph of Larsen B.
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Ice cores a unique climate record

• Ice cores contain a unique record of past climate
  over thousands of years.
• Scientists analyse pockets of air trapped in the
  layers of ice.
• BAS plays a leading international role in this
  vital research.

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CO2 levels over the last 400,000 years
Source Dr Anna Jones (2003), British Antarctic
Survey.
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Present day CO2 levels
CO2 levels at South Pole are over 370 ppm.

• Over the past 100 years there has been a massive
  and rapid rise in global carbon dioxide levels.
• This is due to the increased burning of forests
  and fossil fuels.
• At about 372 ppm, todays carbon dioxide level is
  higher than at any time in at least the past
  400,000 years.

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UK climate change Thames barrier
Number of closures per year of the Thames
barrier. Source DEFRA, 2003.

• The Thames Barrier protects London from flooding.
• It was used once a year in the 1980s. Now it is
  raised more than six times a year.
• A clear measure of increasing flood levels in the
  River Thames and storm surges in the North Sea.

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Conclusions

• Global climate is almost certainly changing due
  to increased greenhouse gas emissions.
• Analysis of Antarctic ice cores shows CO2 levels
  are higher than at any time over the last 400,000
  years.
• Climate change is unquestionably the most urgent
  environmental challenge (Prime Minister Tony
  Blair, 23/02/03).
• A concerted international effort is needed to
  reduce emissions.

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Further information

• Antarctic Schools Pack (1999)
• British Antarctic Survey
• www.antarctica.ac.uk
• The Met. Office
• www.met-office.gov.uk
• Intergovernmental Panel on Climate Change
• www.ipcc.ch