Climate change is the most widespread concern of the more than 45,000 people surveyed in a 40-nation Pew Research Center poll Enlarge Climate change is the most widespread global concern. measuring perceptions of international challenges. The survey found that a majority of people in Latin America and Africa are very concerned about climate change. In Peru and Brazil, where years of declining deforestation rates have slowly started to climb, three-quarters of people surveyed expressed anxiety about climate change. Sub-Saharan Africans also voiced substantial concerns about climate change, with a median of 59 percent saying they are very concerned. Indians (73 percent) and Filipinos (72 percent) are also particularly worried, the poll found. European nations and the U.S. are significantly less worried — only 42 percent of people in these areas say they are very concerned about the climate. In a list of potential global threats, climate change ranked sixth of seven for people surveyed in the U.S., the Pew Research Center found.