For three decades, more than half of Americans have considered climate change a serious threat. Yet today, the U.S. still lags behind much of the rest of the developed world as understanding of global warming has become more widespread.

That's one finding of a new analysis of dozens of international climate polls since the 1980s by researchers at Cardiff University in Wales.

"Broadly speaking, people that are skeptical are in the minority across most of the world," said Stuart Capstick, a Cardiff scientist who studies public perceptions of global warming and was the lead author of the recent analysis.

Capstick and his colleagues found that during the 1980s and 1990s, there was increasing awareness and public concern about the issue around the globe. In many countries, skepticism about the scientific evidence of climate change took hold late in the following decade, and climate quickly became a partisan issue largely because of the global recession and concern that taking action would hurt economies.

But while most countries have since moved away from this partisan divide, the political split over climate change has only widened in the U.S., Capstick said. This reflects fossil fuel-funded denial campaigns and the widening ideological divide between conservative and progressives in the U.S. Australia and the U.K. have similar divides.

Capstick was careful to point out, however, that even with the partisan divide, the number of Americans who consider climate change a threat, "has for a very long time hovered between 50 and 70 percent."

"There is a tendency to focus on how many people don't accept climate change," but that's not the reality, Capstick said.

The study was published in the January/February issue of the peer-reviewed journal WIREs Climate Change. The authors examined climate beliefs as reflected in 39 peer-reviewed publications and 18 studies conducted by organizations such as Gallup and the Pew Research Center. They omitted polling data collected by news outlets, political organizations and environmental groups.

Among countries that are the biggest emitters of carbon dioxide, the U.S. falls roughly in the middle on beliefs about global warming. As of 2010, the last time a poll surveyed multiple countries' climate sentiment at the same time, 53 percent of Americans considered global warming a serious threat. That was well below Japan's 75 percent, Canada's 71 percent and Germany's 59 percent. However, it was higher than in Russia at 41 percent, India at 30 percent and China, the world's largest emitter, at 21 percent. Capstick said more recent data is needed to determine whether those values are still the same.

Developing countries, including those in Sub-Saharan Africa and Asia, have historically had some of the slimmest understandings of climate change, mainly because people hadn't heard of the concept or learned about it, Capstick said. That is quickly changing, he said. These nations are some of the most vulnerable to climate impacts such as rising seas, drought and flooding, and they don't have the political polarization and fossil fuel influence that the U.S., Australia, Canada and the U.K. have.