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CLIMATE CHANGE Lessons from Antarctica. Dr John Shears Environmental Officer British Antarctic Survey Cambridge. 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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CLIMATE CHANGELessons from Antarctica Dr John Shears Environmental Officer British Antarctic Survey Cambridge
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
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. • Today’s temperatures: + 0.4o C Rothera - 32.9o C South Pole
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’.
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.
CO2 levels over the last 400,000 years Source: Dr Anna Jones (2003), British Antarctic Survey.
Present day CO2 levels • 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, today’s carbon dioxide level is higher than at any time in at least the past 400,000 years. CO2 levels at South Pole are over 370 ppm.
UK climate change – Thames barrier • 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. Number of closures per year of the Thames barrier. Source: DEFRA, 2003.
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.
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