The drivers behind climate change denial look to be even more complex than we thought, with new research finding evidence of a "racial spillover" – in which racist attitudes have become linked with skepticism over climate change.

A new study examining attitudes to climate change during the Obama presidency found white Americans became significantly less concerned about climate change during the presidency, and that white racist attitudes could be helping to fuel climate denial.

"I'm not trying to make a claim in the study that race is the single most important or necessarily a massive component of all environmental attitudes" the researcher behind the study, political scientist Salil Benegal from DePauw University, told Sierra.

"But it's a significant thing that we should be looking out for."

To examine the extent that racist attitudes might be associated with views on climate change, Benegal examined trends in public opinion during the course of the Obama presidency.

Not only was Obama America's first black president, but over the course of his presidency he became a notable advocate of environmental causes, and Benegal wanted to examine the extent to which today's fractured climate debate on climate might have been influenced by his time in office.

"There has been increasing polarisation on this issue," Benegal told Think Progress, "and this is one thing my own research has been examining for a while - trying to figure out what are some of the root causes of this polarisation."

Benegal analysed nationally representative surveys conducted by Pew between 2006 and 2014 in which respondents were asked, among other questions, to rate the seriousness of climate change.

After controlling for the expected effects of factors such as political partisanship, ideology, and education, the data showed that – compared to the views of respondents who identified as black Americans – white Americans became 18 percent less likely to see climate change as a very serious problem over the course of Obama's presidency.

While the reasoning behind this racial divergence remains hypothetical, Benegal suggests it's possible that white voters with high levels of racial prejudice may have associated Obama with climate change and related policies.

To examine the possibility of this, Benegal looked at data collected by the American National Election Studies (ANES), which since the 1960s has asked voters questions measuring their levels of racial resentment toward African Americans, while more recently including questions about voters' views on climate change.

The ANES data showed that as racial resentment increases among white Republican voters, they are significantly more likely to disagree that climate change is occurring, or that it's due to human activity.

"I found that the racial resentment scale was incredibly significant in predicting whether or not people agreed with the scientific consensus," Benegal said.

In the researcher's view, these two factors are evidence of what Benegal calls a "racial spillover", where racial identity and concern over climate change have somehow become joined over the course of a two-term presidency.

"When certain voters associated Obama with an issue, they inherently saw Obama through this racial lens and immediately viewed almost anything he was associated with as some kind of racial issue," Benegal says.

While that argument remains hypothetical, it's not the first time researchers have observed these kinds of spillover effects in the political arena, with Benegal explaining in his paper it's been argued before in contexts like health care, immigration, and social welfare.

Given the huge challenges the world is facing right now with climate change, any insights that can help explain and deconstruct the political inertia we're up against from those in the denial camp are valuable to know.

"I think the important thing is to understand that racial attitudes and partisan identity are becoming more closely aligned and go hand-in-hand for an increasing number of issues," Benegal told Sierra.

"We're noticing the interactions between these factors more frequently."

The findings are reported in Environmental Politics.