Spanish weather authorities say 32 million people in the southern European country, or around two-thirds of Spain's population, are having to deal with higher temperatures, longer summers and more frequent tropical nights as a result of climate change.

The national weather agency, AEMET, said Tuesday that four decades of data show how a semi-arid climate, which was prevalent only in southern Spain and some river basins, has taken root over 30,000 square kilometers (12,355 square miles), equivalent to 6 percent of the country's land mass.

AEMET spokesman, Ruben del Campo, also says summers have extended by an average of nine days per decade and are now five weeks longer than in the early 1980s.

AEMET is making its climate change data, fed by 58 observatories, publicly available from April.