The most comprehensive evaluation of temperature change on Earth's continents over the past 1,000 to 2,000 years indicates that a long-term cooling trend -- caused by factors including fluctuations in the amount and distribution of heat from the sun, and increases in volcanic activity -- ended late in the 19th century.
Fuente : http://www.eurekalert.org/pub_releases/2013-04/nsf...
Fuente : http://www.eurekalert.org/pub_releases/2013-04/nsf...