Climate Change & Global Warming

Global sea ice thumbnail

NASA ice expert Claire Parkinson does the math on global sea ice and confirms that small gains around Antarctica do not cancel out large losses in the Arctic.

Saturday, August 1, 2009

  • The total amount of water on Earth isn’t increasing, but the volume of liquid that fills the ocean is growing as ice and snow on land melt. The water is also getting warmer, which makes it expand. 

  • Temperatures measured on land and at sea for more than a century show that Earth's globally averaged surface temperature is experiencing a long-term warming trend.

  • Human activities, mainly burning fossil fuels, are increasing the concentration of carbon dioxide in our atmosphere, amplifying the natural greenhouse effect.

  • Minimum sea ice extent observed by satellites each September has decreased by 13.7 percent per decade since the late 1970s. The seven lowest extents all occurred since 2007.