And now the Arctic's upper layers are getting less dense, for several reasons: melting Arctic glaciers, rising surface-water temperatures, increased precipitation and an absence of salt concentrations resulting from sea-ice formation.

ECONOMIST: The science

It has a freezing point well below 32 degrees Fahrenheit or zero Celsius and therefore is able to prevent the precipitation that falls into it from freezing on the plane's surface.

CNN: Airplane deicing: The how and why

An assessment of the impacts of climatic change in Latin America and the Caribbean supported by reliable data suggests that ??climate changes during the last century have included an increase in the surface medium temperature, particularly in medium and high latitudes, and changes in precipitation quantity and intensity in several countries of the Region (Southern Brazil, Paraguay, and Argentina).

UNESCO: Climatic Change