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This blog is expressly directed to readers who do not have strong training or backgrounds in science, with the intent of helping them grasp the underpinnings of this important issue. I'm going to present an ongoing series of posts that will develop various aspects of the science of global warming, its causes and possible methods for minimizing its advance and overcoming at least partially its detrimental effects.

Each post will begin with a capsule summary. It will then proceed with captioned sections to amplify and justify the statements and conclusions of the summary. I'll present images and tables where helpful to develop a point, since "a picture is worth a thousand words".

Friday, March 11, 2011

Public Attitudes on Global Warming and Effects on Politics

Summary.  A survey of Americans in 2010 shows a majority believe in global warming, many of whom understand that greenhouse gases are responsible for global warming.  Half of respondents believe that human activity is responsible for global warming, and two-thirds understand that carbon dioxide, a significant greenhouse gas, arises from burning fossil fuels.  Those surveyed understand that many remedial actions can be taken to reduce greenhouse gas emissions.  The individual attitudes reflected in the survey results are mirrored in the way people identify with the political parties active in the U. S.

Introduction.  In the United States, political action to establish a framework addressing global warming under law has so far not been possible.  In spite of persistent efforts by environmental groups helping to draft an environmental policy act, other interests from the energy industry and related sectors of the economy have mounted effective campaigns opposing environmental advocates, seeking to weaken or defeat proposed legislation. 

In such a polarized political environment, it is important to understand the opinions of the public on this issue.  This post presents the results of a survey of Americans on the topic of global warming.

A Survey of Public Opinion on Climate Change.  A. Leiserowitz and coworkers (see Note below) conducted a detailed survey of 2030 American adults in the summer of 2010. 

The survey asked over 50 questions, some of which included more than one part.  Some questions were directed toward beliefs or opinions. Other questions sought to establish the level of objective knowledge about global warming that the respondents have; these questions had factually correct and incorrect answer choices.

Global warming.  63% of respondents think global warming is happening, and 19% didn’t know.  Of those who did think global warming is happening, 95% were at least somewhat sure.  Of those who did not think global warming is happening, 94% were at least somewhat sure.

Scientific basis for global warming.  If it is assumed that global warming is occurring, 50% of those surveyed correctly believe that it is due mostly to human activities, and 35% think incorrectly that it is due mostly to natural changes in the environment.  39% correctly think that most scientists believe global warming is happening.  38% think there is disagreement among scientists on whether global warming is or is not happening.  66% correctly understand that greenhouse gases in the atmosphere trap heat.  However, 21% think incorrectly that greenhouse gases refer to gases that deplete the UV-protective ozone layer in the atmosphere.  This likely is a holdover from the 1990’s alarm over, and subsequent international agreement to limit, the fluorocarbon gases that were used in refrigerators and in other applications.  67% of respondents correctly understand that carbon dioxide, an important greenhouse gas, is produced by burning fossil fuels.  Even so, more than 75% of respondents did not know the amounts of carbon dioxide in the atmosphere now, or in 1850 before the industrial revolution began.  40% correctly understand that carbon dioxide in the atmosphere is growing exponentially (compounding year-by-year), while a similar 41% of respondents incorrectly believe that this growth follows a straight line.

Sources of greenhouse gases.  More than half of respondents correctly identify cars and trucks, and use of fossil fuels for generating electricity and for heating, deforestation and raising of cows and cattle as being origins of greenhouse gas emissions.  On the other hand, they incorrectly identify such sources as aerosol cans and nuclear power generation as giving rise to greenhouse gases.  Again, the misidentification of aerosol cans probably comes from the earlier scare concerning destruction of the ozone layer.

Past and present patterns of climate.  Only 41% of respondents understand correctly that the earth has been warmer in the past 10,000 years compared to the past million years.  The survey provided the information that the current global average temperature is about 58ºF.  Many respondents think incorrectly that the average temperature during the last ice age was 32ºF; the actual estimate is 46-51ºF.  Respondents tended to guess that average temperatures would be slightly higher in 2020 and 2050 than the climate scientific models, 58.4ºF and 60-61ºF, respectively.

If burning of fossil fuels and the production of carbon dioxide were to stop now, 62% of respondents correctly understand that global warming would continue.  Even so, 57% of respondents incorrectly believe that the carbon dioxide concentration in the atmosphere would immediately fall.  Furthermore, only 19% of respondents correctly understand that carbon dioxide endures in the atmosphere for hundreds of years or more.

Personal concern about global warming.  55% of those surveyed were at least somewhat worried about global warming, while 45% were not very worried or not at all worried.

In a series of related questions, respondents felt that they were at least fairly well informed, or very well informed, in a range of 62-66%, about the causes of, the consequences of, and things that could be done about, global warming.

Beliefs related to arguments expressed by global warming skeptics or deniers.  42% of respondents confuse weather prediction with climate prediction, for they believe incorrectly that since weather cannot be forecast for longer than a few days ahead, the same is true of global or regional climate predictions.  One third of respondents incorrectly feel that humans should not be held responsible for global warming today because the earth’s climate has undergone natural variations in the past.

Understanding the consequences of global warming.  68% of those surveyed correctly understand that warming will not be uniform across the globe, causing some places to become wetter and others to become more arid.  They understand that such effects will also impact crop yields, raising them in some places and decreasing them in others.

Only 21% of those surveyed correctly understand that most of the glaciers are melting across the planet, whereas 48% say that only some glaciers are melting.  Of these, 84% correctly understand that the rate of melting of glaciers is increasing over the past 100 years.  Large majorities, in the range of 60-73%, correctly understand that melting of glaciers over land in Antarctica, mountain glaciers, and warmer temperatures in the oceans, will contribute to a rise in sea levels.

Remedial actions to reduce global warming.  Americans surveyed correctly identified several measures that can be taken to reduce greenhouse gas emission, in the range of 65-75% for reducing use of fossil fuels by changing to renewable sources, planting new trees, reducing deforestation in tropical forests, changing from gasoline-fueled cars to electric cars, driving less, increase the use of public transit, and insulating buildings.

Many respondents, however, had misconceptions when asked about other measures that might reduce greenhouse gases, incorrectly believing that toxic waste contributed to global warming, and that banning aerosol spray cans would contribute as well.

53% of respondents either didn’t know or did not think that imposing a large tax on all fossil fuels would reduce global warming, or limiting families to 2 children (zero population growth, 60%), or stopping the consumption of beef (69%).  But about one-third of respondents picked switching from fossil fuels to renewable energy sources to be the one step that would do the most to lower greenhouse gas emissions.

Political affiliation and global warming.  In a related survey of American voters , belief in global warming was distinguished by political party or affiliation of the respondents.  The Democratic party is the more liberal or progressive party, and the Republican party is the more conservative party, frequently supporting positions that are favorable to businesses and corporations.  The tables below give respondents’ answers to the questions heading the tables (columns may not add to 100% due to rounding errors).

Do you think that global warming is happening? (%)
Don’t Know

This result indicates that Democrats are very likely to believe in global warming and extremely unlikely not to believe.  Only half of Republicans, on the other hand, believe in global warming and almost 2/5 of them do not believe.  A majority of Independents or Others believe in global warming; this group has a larger percent that doesn’t know than either Democrats or Republicans.

How worried are you about global warming? (%)

Very worried
Somewhat worried
Not very worried
Not at all worried

The results in this table show that almost 80% of Democrats are somewhat or very worried about global warming, but that only 32% of Republicans have this concern.  This is consistent with the results in the first table, showing that Republicans believe in global warming to a far less extent than do Democrats.  Among Independents and Others, almost 70% of respondents were only somewhat worried or not very worried, i.e., chose answers in the middle range of the choices offered.

Assuming global warming is happening, what do you think is mostly the cause? (%)
Human activities
Natural changes
Both human and natural
None, because global warming isn’t happening

If it is given that global warming is occurring, almost 70% of Democrats believe that human activities are responsible, and only 2% dismiss the premise by saying that global warming is not happening.  Among Republican respondents, on the other hand, only one-third believe that human activities are mostly responsible.  Instead, exactly half of Republicans believe that global warming arises from natural changes.  This could help explain why Republicans are not very worried or not at all worried about global warming (2nd  Table).

Democratic respondents were quite consistent, since 3% of Democrats do not believe global warming is happening (in the 1st Table) and 2% say global warming is not happening (in the 3rd Table), and 7% of Democrats are not at all worried about global warming (2nd Table).  Among Republicans, the answers to these questions are more scattered.  While 38% say global warming is not happening (1st Table), only 11% say it is not happening (3rd Table), and 34% are not at all worried about global warming (2nd Table).   Further, among Republicans, the fact that 50% believe that the occurrence of global warming is due to natural changes is consistent with the fact that almost 70% of Republicans are not very worried or not at all worried about global warming.

The behavior of American politicians concerning global warming.  Our legislators are elected by voters who reflect the attitudes, according to party, that are discussed in the preceding section.  The legislators, in turn, are likely to make voting decisions based on their constituents’ feelings as well as on other considerations such as the urgings of interested persons and corporations, and perhaps financial contributions to their election campaigns as well.

In the United States, in the 111th Congress, elected in November 2008, the House of Representatives (the lower chamber) had a Democratic majority.  It passed an energy bill (the Waxman-Markey bill) incorporating a cap-and-trade mechanism for reducing greenhouse gas emissions, in 2009 by a vote of 219-212 with 3 not voting.  Of 254 Democrats voting, 210 voted in favor.  169 of the 179 Republicans voting opposed the bill. This bill was not taken up for consideration in the Senate (the upper chamber), where as few as 40 votes of the total of 100 can prevent passage.  The Senate of the 111th Congress had 41 Republicans.   

In the 112th Congress, elected in November 2010, the House of Representatives now has a Republican majority, 242 of a total of 435 members.  The House is considering a bill to strip an executive agency, the Environmental Protection Agency, of its power, granted by statute and reinforced by a decision of the Supreme Court, to regulate the emission of greenhouse gases. (If passed this bill will likely not become law because the Senate is not expected to pass it, and in all likelihood the President would not grant his approval even if passed by the Senate.)

These efforts in the U. S. Congress show that, although the legislators should reflect the opinions and interests of the voters that elected them, their voting decisions can be affected by other factors as well.  When all is said and done, it is the voters who must decide whether their elected representatives reflect and support their own attitudes.

Conclusion.  In a survey of about 2000 Americans taken in the summer of 2010, 63% believe global warming is happening, but may not fully understand how this comes about.  Lack of knowledge, or misconceptions about the scientific basis of global warming is reflected in smaller percentages of people who understand that greenhouse gases trap heat in the atmosphere, that carbon dioxide is a greenhouse gas, or who realize that human activities lead to global warming.  Significantly, a majority also mistakenly believes that the ozone hole in the atmosphere, and use of aerosol spray cans, are related to global warming.  On the other hand, many Americans do realize that emissions from burning fossil fuels, including the fuels for cars and trucks, are a source of global warming, and that a transition from use of fossil fuels to renewable energy sources would be an important way to help change the trend of increasing warming of the globe by greenhouse gases.

When political beliefs of respondents are taken into account, Democrats (more liberal) believe that global warming is occurring, are worried about global warming, and believe that human activity contributes to global warming.  Republicans (more conservative), on the other hand, are likely not to believe that global warming is occurring, that, if it is occurring it is due to natural changes, and are not worried about it.  These attitudes are reflected among the Democratic and Republican lawmakers elected to Congress in their votes on energy policy and regulation of greenhouse gas emissions.

If public opinion could more vigorously support the objectives of limiting global warming and measures needed to achieve this goal, perhaps lawmakers would be more disposed to enacting laws that promote remedial measures to combat this phenomenon.

Leiserowitz, A., Smith, N. & Marlon, J.R. (2010) Americans’ Knowledge of Climate Change. Yale University. New Haven, CT: Yale Project on Climate Change Communication.

© 2011 Henry Auer

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