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Learning objectives. <ul><li>How do people use polar environments? </li></ul><ul><li>What challenges do polar environments pose? </li></ul>
Global warming. <ul><li>Everyone has heard of global warming but in Britain we don’t see much evidence of it. The impact in polar regions has been more dramatic. Scientists in Antarctica have been able to study global warming in action. </li></ul>
Larsen B ice shelf In 2002, the Larsen B ice shelf –a 200-meter- thick slab of ice the size of Cornwall floating on the sea – broke off from the Antarctic peninsula. The event was seen from space 17 th Feb 2002 5 th march 2002 (16days later)
<ul><li>The Antarctic peninsula has warmed by 2.5°C over the past 50years – four times faster than the rest of the world. This makes it an excellent place to study the impact of global warming. </li></ul>
Antarctic peninsula; Temperatures have risen 2.5°C in 50years. In the 20 th century 20,000 Square kilometres of ice shelf Was lost. West Antarctic ice sheet; There are signs that this ice sheet Is thinning and melting At the edge. As ice at the coast melts The ice sheet could start To move quicker. East Antarctic ice sheet; The Antarctic peninsula is only 4% of the continents Land area. There is no evidence of temperatures raising in the other 96%. The large east Antarctic ice sheet Is not melting.
Global warming affects the ocean as well as the land. Sea ice melts earlier in antarctic when spring comes and more of the southern ocean is now ice – free in the summer. (the arctic ocean around the north pole is expected to be completely ice-free in summer by 2080.)
the antarctic marine ecosystem; Melting ice means warmer water. This has a big impact on the antarctic marine ecosystem. Krill – a small shrimp – like creature – is the main food in the ecosystem. It, in turn, feeds on phytoplankton – an algae – which thrives in the cold, antarctic water.
<ul><li>As the water warms up there is less krill. Krill numbers have dropped by 80% since the 1970’s, leading to a decline in the population of other species. </li></ul>