Global Warming Skepticism

Many people question why there seems to be so many people who are skeptical of man-made (anthropogenic) global warming (AGW) when the scientific evidence supporting it seems so strong.  In addition to the scientific evidence, there is also a scientific consensus supporting AGW.  Global warming and climate change are complex subjects which require a substantial amount of research to understand, and generally with regards to complex subjects, rather than do the research many people choose to trust the experts.  So it's a logical question to ask why so many people remain skeptical about AGW.

 Public Opinion

It's first important to realize that while these skeptics make a lot of noise and sometimes appear to make up a large percentage of the population, in reality that's not the case.  In fact, in the USA roughly 70% of the populace views human activity as a significant cause of climate change.  Worldwide, that figure is roughly 80%.

These skeptics tend to feel very strongly about the subject, because they're in the minority.  The majority of people believe humans are causing global warming, but they don't make a lot of noise about it.  They don't need to, because they're already in the majority.  It's the consensus view.

Consensus

Some people are skeptical of AGW because they don't believe there's a consensus on the subject.  One reason for this is that media outlets - particularly in the USA - have a tendency to try and be "unbiased".  In order to accomplish this, journalists often feel the need to present "both sides" of a story.  In the case of global warming, this often means interviewing one 'expert' who believes humans are causing global warming and a second 'expert' who doesn't.  However, when the vast majority of scientists are in agreement, but both sides are presented equally in the media, this creates a false perception among the viewing public that there is widespread dissent.  In fact, by attempting to be "unbiased" or "fair and balanced", the media is creating a false bias.

However, the scientific consensus on AGW has been well-documented by several studies.  The first such study was done by Naomi Oreskes in which she analyzed 928 abstracts, published in refereed scientific journals between 1993 and 2003, and listed in the ISI database with the keywords "climate change".  Dr. Oreskes found that 75% of these papers either explicitly or implicitly accepted the consensus view; 25% dealt with methods or paleoclimate, taking no position on current anthropogenic climate change; and none of the papers disagreed with the consensus position.

Benny Peiser soon repeated this study by reviewing 1,247 peer-reviewed journals and abstracts using the same search criteria, and claimed to find 34 that refuted the consensus (2.8%).  However, subsequent review of these 34 papers revealed that Peiser's method was flawed, and in reality just 1 of those papers rejected the consensus, and it was an opinion article, not a peer-reviewed scientific study.  Peiser eventually admitted that his conclusions were wrong, stating:

"Only [a] few abstracts explicitly reject or doubt the AGW (anthropogenic global warming) consensus which is why I have publicly withdrawn this point of my critique."

"And when we pressed him to provide the names of the articles, he eventually conceded - there was only one."

In fact, anybody can repeat this study to see the results for themselves.  Peter Norvig (Engineer Director at Google) did just that and came up with these results:

Additionally, every scientific organization which has published a statement with regards to AGW has supported it.  A nice list can be seen here.

Further, a 2009 study performed by scientists at the University of Illinois at Chicago polled thousands of Earth scientists and found that 97% of climate scientists and 82% of Earth scientists agree that humans are significantly contributing to global warming.

As for what the consensus is exactly, the climate scientists at RealClimate sum it up nicely:

1. The earth is getting warmer (0.6 +/- 0.2°C in the past century; 0.17°C/decade over the last 30 years)
2. People are causing this
3. If GHG emissions continue, the warming will continue and indeed accelerate
4. (This will be a problem and we ought to do something about it)

The perception that there is no scientific consensus on global warming is simply one of many myths about the subject.

Myths

Because we are so completely reliant on fossil fuels - the main cause of the current global warming - many people are very resistant to accepting the scientific reality of the situation.  Additionally, because many influential groups have a vested interest in maintaining the status quo with regards to fossil fuels, there are many myths regarding global warming floating around.

Sometimes it's difficult to determine whether or not information is true.  Particularly when the information is coming from the media, which is often a source that we rely on to inform us.  The many myths floating around regarding global warming conflict with the correct information, and this conflict also fuels the misperception that there is a large degree of disagreement on the subject among scientists.

Lists of skeptical scientists

There have frequently been lists of scientists published who are skeptical of AGW.  For example, Senator Inhofe once publised a list of 400 "prominent scientists disputing man-made global warming claims".   Among these 400 "prominent scientists":

• 84 have either taken money from, or are connected to, fossil fuel industries, or think tanks started by those industries.

• 49 are retired

• 44 are television weathermen

• 20 are economists

• 70 have no apparent expertise in climate science

• Several supposed skeptics have publicly stated that they are very concerned about global warming, and support efforts to address it. One claims he was duped into signing the list and regrets it.

Even if every name on the list were a climate scientist, there are approximately 20,000 climate scientists in the American Geophysical Union, so 400 would be rougly 2% of the climate scientist population.  And this disregards the fact that most of the names on Inhofe's list are not climate scientists.  In short, Inhofe's list essentially shows that less than 1% of climate scientists are skeptical of AGW.

Another frequently cited list is the Oregon Petition, which recently published a second version of their list.  The fact that they created an entirely new version rather than continuing to add to their original list raises some questions.  The reason for the abandonment of the original list was that many signatures were found to be fraudulent.

"Several environmental groups questioned dozens of the names: "Perry S. Mason" (the fictitious lawyer?), "Michael J. Fox" (the actor?), "Robert C. Byrd" (the senator?), "John C. Grisham" (the lawyer-author?). And then there's the Spice Girl, a k a. Geraldine Halliwell: The petition listed "Dr. Geri Halliwell" and "Dr. Halliwell."

The original version contained approximately 17,000 signatures and the newly released version contains 31,000 signatures.  However, it's important to note that in addition to the apparent ease of adding false signatures to this list, the only requirement of signatories is to have any kind of college science degree.  In other words, a guy who got a bachelor's degree in biology 40 years ago and knows absolutely nothing about global warming can sign the Oregon Petition.

Even disregarding the obviously weak signature criteria, consider the fact that in the USA there are tens of millions of people with bachelor's (or better) degrees in science.  If just 10% of the US population has such a degree (according to the US census, 25% of Americans have a bachelor's degree or better), then the 31,000 names on the Oregon Petition make up ~0.1% of the pool of possible signatories.  So what exactly is one-tenth of one percent supposed to prove?

Essentially the only purpose of these lists is to confuse people into thinking there is no consensus on the subject, because 400 and 31,000 sound like large numbers.  In reality, even disregarding the many flaws with these lists, these are fractions of a percent of their respective populations.

Selfishness, Fear, and Paranoia

Many people simply need AGW to be wrong for political reasons.  They're afraid that global warming will lead to a carbon tax, and for many people (particularly the politically conservative), "tax" is a four-letter word.  Some people have gone as far as to claim that global warming is just a UN or communist plot to create some sort of one world order.  Rather than attempt to make scientific arguments, these people generally make political arguments to justify why they believe humans are not causing global warming.  Or at best they'll repeat the same old global warming myths.

However, global warming is a scientific issue.  What we choose to do about global warming is a political issue (except on an individual level), and it is this which can be debated.  At this point, with the overwhelming amount of scientific evidence showing that humans are causing global warming, it's fair to say that the cause of global warming is no longer debatable.  That's not to say that people are unwilling to explain the scientific evidence or why the myths are wrong, but the causes are abundantly clear.  Even the IPCC has decided to shift its focus to practicality and precision - providing more information about the actual impacts of global warming and what can be done to reduce GHG emissions growth, rather than what's causing it.

In short, there is no basis to the claim that there's no scientific consensus on AGW.  Putting your faith into these lists trying to prove otherwise is often like asking a chemist to perform open-heart surgery.  Unfortunately we're so heavily reliant (it's fair to say addicted) to fossil fuels that some people simply can't deal with the fact that our oil consumption is having a hugely adverse environmental impact.  They would prefer to cling to any piece of information claiming otherwise to maintain denial on the subject.  Fortunately a large enough majority of the population has accepted the scientific reality of the situation for us to make progress in finding solutions.