BERLIN (Reuters) - Europeans view the militant group Islamic State as the biggest threat facing their countries, ahead of climate change, economic instability and refugees, a survey by the Pew Research Center showed on Monday.

Respondents in nine of 10 European countries surveyed said they saw IS, also known by the acronyms ISIS and ISIL, as the greatest danger, with 93 percent of Spaniards and 91 percent of French describing the group as a "major threat".

Most of the surveys were conducted in April, a month after militants loyal to IS killed 32 people at the Brussels airport and metro. The Pew report was published a day after a gunman who had pledged allegiance to IS killed 49 people at a nightclub in Orlando, the deadliest mass shooting in U.S. history.

Greece, struggling to return to growth after nearly seven years of recession, was the only country where respondents did not list IS as the top threat. Instead, 95 percent of Greeks said that global economic instability posed the greatest risk to their country.

Strong majorities in all 10 countries listed global climate change as a major threat, but the Pew survey showed stark divisions within Europe over refugees.

In Poland, 73 percent of respondents listed the arrival of large numbers of refugees from war-torn countries like Syria and Iraq as a major threat, the same percentage that listed Islamic State as a top danger.

By comparison, only 31 percent of Germans and 24 percent of Swedes said they viewed refugees as a major threat, despite the fact that these two countries have accepted among the most refugees per capita in all of Europe.

On average, roughly a third of respondents across all 10 countries described tensions with Russia as well as China's emergence as a world power as major threats.

Poland was again an outlier, with 71 percent of respondents there listing Russia as a significant danger, more than double the percentages in Italy, France, Germany and Britain.

(Reporting by Noah Barkin; Editing by Mark Heinrich)