World Environment Day

SYDNEY, AUSTRALIA - JUNE 02: The Shell Oil refinery in Parramatta is seen June 2, 2007 in Sydney Australia. World Environment Day is marked on June 5 every year, and is the United Nations flagship environmental event, celebrated in more than 100 countries around the world. The event was first established in 1972 by the United Nations General Assembly, with the purpose being to concentrate global attention on the importance of the environment and to encourage political attention and action. According to the United Nations Environment Programme (UNEP), greenhouse gas emissions from human activities are causing the planet to increase in temperature. Carbon dioxide concentrations in the planetary atmosphere are higher now than at any time for the past 600,000 years, and the rate of increase is accelerating. (Photo by Ian Waldie/Getty Images)