Seasonal temperature variations and long-term climate change cause melting of the polar ice caps. As of 2014, temperatures in the Arctic are increasing at double the rate of elsewhere in the world. As a result, ice in the Arctic is thinning and melting. Arctic ice is decreasing by 9 percent each decade, according to data derived from NASA satellite images.
Scientists say that the melting trend is part of overall global warming that is caused by burning coal, gas and oil. The burning of fossil fuels traps gases that cause the Earth's temperature to increase.
Between 1906 and 2005, the average temperature at the Earth's surface increased by about three-fourths of a degree Celsius. For the last half of the period, warming occurred at nearly twice the rate of the first half of the period. NASA estimates that the years between 2005 and 2010 were the warmest since temperatures have been reliably measured in the late 1800s.
Temperatures appear to have been mostly stable for up to 2,000 years prior to 1850 despite some regional variations. The increase in sea levels is consistent with data showing rising temperatures at the surface of the Earth. The Earth's oceans also show an increased temperature due to the overall warming.