Stanford professor Jon Krosnick (a good friend of mine) has published an op-ed in The New York Times dealing with polling and global warming. In part he's reporting on the results of a new study his Political Psychology Research Group conducted on the environment and energy.
Of interest to me is Jon's discussion of recent polls -- including those by Gallup -- that show a declining concern about global warming on the part of the American public.
The way the piece ended being published in the New York Times did not make it crystal clear just what Jon was attempting to say about the trend polls. I think it may have been the observation that -- despite the polls that show a declining conviction and concern about global warming -- a majority of Americans still are convinced and concerned about global warming.
But at several points Jon appears to criticize conclusions based on the trend questions showing the decline. He also criticizes a couple of the questions themselves. The naive reader might be excused for coming away from the piece thinking that it would be wrong to interpret these polls as showing that "fewer and fewer Americans believe that climate change is real, human caused, and threatening to people."
Technically speaking here, Jon may be saying that a decline in public concern about global warming does not necessarily conflict with the finding that a majority of Americans on some questions still believe that global warming is occurring and is serious. Which is, of course, true. But that doesn't negate the fact that such a decline has occurred and has been replicated across a number of survey questions.
Jon starts his discussion of trend questions on global warming thusly:
"Consider, for example, the most publicized question from a 2009 Pew Research Center poll: 'From what you've read and heard, is there solid evidence that the average temperature on earth has been getting warmer over the past few decades, or not?' This question measured perceptions of scientific evidence that the respondent has read or heard about, not the respondents' personal opinions about whether the earth has been warming. Someone who has had no exposure to scientific evidence or who perceives the evidence to be equivocal may nonetheless be convinced that the earth has been heating up by, say, the early blossoming of plants in his garden."
Just by way of background, here are full results of the Pew question:
June 2006 ---70%
July 2006 -- 79%
August 2006 -- 77%
January 2007 -- 77%
April 2008 -- 71%
Sept-Oct 2009 -- 57%
These data show a demonstrable drop from the 79% and 77% who agreed with the statement in 2006-2007 down to 57% this past fall.
The more I look at it, the more I'm not sure how to interpret Jon's statement "This question measured perceptions of scientific evidence that the respondent has read or heard about, not the respondents' personal opinions about whether the earth has been warming".
Would it be possible for a person to say there is solid evidence that the earth has been getting warmer, but not hold this as a personal opinion? Possibly. But this question stands on its own regardless. The question responses show a measurable drop in the percent of Americans who say there is solid evidence for global warming. Which is an important finding in and of itself.
Jon doesn't cite the results of a second Pew question:
In your view, is global warming a very serious problem, somewhat serious, not too serious, or not a problem?From what you've read and heard, is there solid evidence that the average temperature on earth has been getting warmer over the past few decades, or not?
Of interest to me is Jon's discussion of recent polls -- including those by Gallup -- that show a declining concern about global warming on the part of the American public.
The way the piece ended being published in the New York Times did not make it crystal clear just what Jon was attempting to say about the trend polls. I think it may have been the observation that -- despite the polls that show a declining conviction and concern about global warming -- a majority of Americans still are convinced and concerned about global warming.
But at several points Jon appears to criticize conclusions based on the trend questions showing the decline. He also criticizes a couple of the questions themselves. The naive reader might be excused for coming away from the piece thinking that it would be wrong to interpret these polls as showing that "fewer and fewer Americans believe that climate change is real, human caused, and threatening to people."
This would be a mistake. After reading through the op-ed piece, I end up with no change in my conclusion that there is strong empirical evidence showing that fewer and fewer Americans believe that climate change is real, human caused, and threatening to people.
I think this demonstrable and replicated decline in the public's concern and convictions about global warming is one of the most important findings relating to public opinion and global warming in the last couple of years. Thus, the key scientific issue at the moment -- to me -- is why this decline occurred, not attempts to marginize it.
In the piece, Jon outlines a number of findings from his recent poll, and then writes: "Our findings might seem implausible in light of recent polls that purport to show that Americans are increasingly skeptical about the very existence of climate change. But in fact, those polls did not produce conflicting evidence at all."I think this demonstrable and replicated decline in the public's concern and convictions about global warming is one of the most important findings relating to public opinion and global warming in the last couple of years. Thus, the key scientific issue at the moment -- to me -- is why this decline occurred, not attempts to marginize it.
Technically speaking here, Jon may be saying that a decline in public concern about global warming does not necessarily conflict with the finding that a majority of Americans on some questions still believe that global warming is occurring and is serious. Which is, of course, true. But that doesn't negate the fact that such a decline has occurred and has been replicated across a number of survey questions.
Jon starts his discussion of trend questions on global warming thusly:
"Consider, for example, the most publicized question from a 2009 Pew Research Center poll: 'From what you've read and heard, is there solid evidence that the average temperature on earth has been getting warmer over the past few decades, or not?' This question measured perceptions of scientific evidence that the respondent has read or heard about, not the respondents' personal opinions about whether the earth has been warming. Someone who has had no exposure to scientific evidence or who perceives the evidence to be equivocal may nonetheless be convinced that the earth has been heating up by, say, the early blossoming of plants in his garden."
Just by way of background, here are full results of the Pew question:
June 2006 ---70%
July 2006 -- 79%
August 2006 -- 77%
January 2007 -- 77%
April 2008 -- 71%
Sept-Oct 2009 -- 57%
These data show a demonstrable drop from the 79% and 77% who agreed with the statement in 2006-2007 down to 57% this past fall.
The more I look at it, the more I'm not sure how to interpret Jon's statement "This question measured perceptions of scientific evidence that the respondent has read or heard about, not the respondents' personal opinions about whether the earth has been warming".
Would it be possible for a person to say there is solid evidence that the earth has been getting warmer, but not hold this as a personal opinion? Possibly. But this question stands on its own regardless. The question responses show a measurable drop in the percent of Americans who say there is solid evidence for global warming. Which is an important finding in and of itself.
Jon doesn't cite the results of a second Pew question:
In your view, is global warming a very serious problem, somewhat serious, not too serious, or not a problem?From what you've read and heard, is there solid evidence that the average temperature on earth has been getting warmer over the past few decades, or not?
% very serious
June 2006 ---41%
July 2006 -- 43%
Jan 2007 - -- 45
April 2008 -- 44%
April-May 2009 -- 47%
Sept-Oct 2009 -- 35%
This seems about as straightforward a measure of personal opinion as there is. A drop of 12 points in the percent of Americans who believe that global warming is a very serious problem.
Jon moves on to the Gallup poll:
Jon moves on to the Gallup poll:
"Or consider a widely publicized Gallup question: "Thinking about what is said in the news, in your view, is the seriousness of global warming generally exaggerated, generally correct, or is it generally underestimated?"
Here is a graphic representation of those data:
Here's what Jon says about this: "This question asked about respondents' perceptions of the news, not the respondents' perception of warming. A person who believes climate change has been happening might also feel that news media coverage of it has been exaggerated. "
Well yes, that's true. The question does ask about news reports, and it is true that a person could believe that climate change is happening and still believe news media coverage has been exaggerated.
But this question doesn't attempt to ascertain whether or not people believe in climate change per se (more on questions that do below). The question measures whether Americans believe that news reports about the seriousness of global warming are exaggerated. And the data show a significant uptick in the percent saying yes -- 48% today, compared to 30% as recently as 2006. This is a significant increase and certainly suggests more skepticism on the part of the average American when they hear, read or see news accounts about global warming.
Gallup's report of the above question was accompanied by four other questions which Jon's op-ed piece does not cite. The graphs for each are below.
Well yes, that's true. The question does ask about news reports, and it is true that a person could believe that climate change is happening and still believe news media coverage has been exaggerated.
But this question doesn't attempt to ascertain whether or not people believe in climate change per se (more on questions that do below). The question measures whether Americans believe that news reports about the seriousness of global warming are exaggerated. And the data show a significant uptick in the percent saying yes -- 48% today, compared to 30% as recently as 2006. This is a significant increase and certainly suggests more skepticism on the part of the average American when they hear, read or see news accounts about global warming.
Gallup's report of the above question was accompanied by four other questions which Jon's op-ed piece does not cite. The graphs for each are below.
And, Jon mentions a trend uncovered in his own research:
"Our surveys did reveal a small recent decline in the proportion of people who believe global warming has been happening, from 84 percent in 2007 to 80 percent in 2008 to 74 percent today."
So, all in all, we have at least eight different questions across three different polls pointing to changes in the percent of Americans who believe in various dimensions relating to global warming.
1. An decrease in the percent of Americans who say there is solid evidence that the average temperature on the Earth has been getting warmer.
"Our surveys did reveal a small recent decline in the proportion of people who believe global warming has been happening, from 84 percent in 2007 to 80 percent in 2008 to 74 percent today."
So, all in all, we have at least eight different questions across three different polls pointing to changes in the percent of Americans who believe in various dimensions relating to global warming.
2. An decrease in the percent of Americans who perceive that global warming is a very serious problem.
3. An increase in the percent of Americans who say that the news media have exaggerated the seriousness of global warming.
5. An increase in the percent of Americans who believe that changes in the Earth's temperature are due to natural causes and not human activity.
6. A decrease in the percent of Americans who believe the effects of global warming have already begun or will begin in a few years.
7. A decrease in the percent of Americans who believe that most scientists believe that global warming is occurring.
8. A decrease in the percent of Americans who say global warming "has been happening."
These are important and key findings.
Jon addresses these trends in two ways -- at least partially -- in his piece.
He attempts to explain away one Pew and one Gallup finding (as noted above) -- although he does not mention five other Pew and Gallup findings.
He explains the 10-point drop in his own poll as a result of reaction to the colder temperatures in the last year or two. "Statistical analysis of our data revealed that this decline is attributable to perceptions of recent weather changes by the minority of Americans who have been skeptical about climate scientists."
This last approach is relevant and appropriate. Looking for the explanations and causes for the decline in the public's belief that global warming is occuring is an important scientific objective. Certainly there are a number of possible explanations in addition to shifts in the short-term world temperature, including the controversy over some scientists who deal with global warming data, the concerted effort to criticize global warming among some conservatives, and the bad economy.
Overall, existing data document a decline in belief in and concern about global warming among the American population, one that has been found across polls and across different question wordings. It is not totally clear what has caused this, or how temporary or permanent it may be. It is also true that these trends are not so huge that they have flipped American public opinion on its head in a matter of a few years. But after a number of years in which those concerned about climate change have mounted substantial efforts to raise the consciousness of the American public about the issue, the finding that public opinion trends have moved in exactly the oppose direction is certainly significant -- and deserving of full scientific focus.
Jon addresses these trends in two ways -- at least partially -- in his piece.
He attempts to explain away one Pew and one Gallup finding (as noted above) -- although he does not mention five other Pew and Gallup findings.
He explains the 10-point drop in his own poll as a result of reaction to the colder temperatures in the last year or two. "Statistical analysis of our data revealed that this decline is attributable to perceptions of recent weather changes by the minority of Americans who have been skeptical about climate scientists."
This last approach is relevant and appropriate. Looking for the explanations and causes for the decline in the public's belief that global warming is occuring is an important scientific objective. Certainly there are a number of possible explanations in addition to shifts in the short-term world temperature, including the controversy over some scientists who deal with global warming data, the concerted effort to criticize global warming among some conservatives, and the bad economy.
Overall, existing data document a decline in belief in and concern about global warming among the American population, one that has been found across polls and across different question wordings. It is not totally clear what has caused this, or how temporary or permanent it may be. It is also true that these trends are not so huge that they have flipped American public opinion on its head in a matter of a few years. But after a number of years in which those concerned about climate change have mounted substantial efforts to raise the consciousness of the American public about the issue, the finding that public opinion trends have moved in exactly the oppose direction is certainly significant -- and deserving of full scientific focus.