Posts Tagged ‘false balance’

Survey confirms scientific consensus on human-caused global warming

August 11, 2014
  • A survey among more than 1800 climate scientists confirms that there is widespread agreement that global warming is predominantly caused by human greenhouse gases.
  • This consensus strengthens with increased expertise, as defined by the number of self-reported articles in the peer-reviewed literature.
  • The main attribution statement in IPCC AR4 may lead to an underestimate of the greenhouse gas contribution to warming, because it implicitly includes the lesser known masking effect of cooling aerosols.
  • Self-reported media exposure is higher for those who are skeptical of a significant human influence on climate.

In 2012, while temporarily based at the Netherlands Environmental Assessment Agency (PBL), my colleagues and I conducted a detailed survey about climate science. More than 1800 international scientists studying various aspects of climate change, including e.g. climate physics, climate impacts and mitigation, responded to the questionnaire. The main results of the survey have now been published in Environmental Science and Technology (doi: 10.1021/es501998e).

Level of consensus regarding attribution

The answers to the survey showed a wide variety of opinions, but it was clear that a large majority of climate scientists agree that anthropogenic greenhouse gases are the dominant cause of global warming. Consistent with other research, we found that the consensus is strongest for scientists with more relevant expertise and for scientists with more peer-reviewed publications. 90% of respondents with more than 10 climate-related peer-reviewed publications (about half of all respondents), agreed that anthropogenic greenhouse gases (GHG) are the dominant driver of recent global warming. This is based on two different questions, of which one was phrased in similar terms as the quintessential attribution statement in IPCC AR4 (stating that more than half of the observed warming since the 1950s is very likely caused by GHG).

Verheggen et al - Figure 1 - GHG contribution to global warming

Figure 1. The more publications the respondents report to have written, the more important they consider the contribution of greenhouse gases to global warming. Responses are shown as a percentage of the number of respondents (N) in each subgroup, segregated according to self-reported number of peer-reviewed publications.

Literature analyses (e.g. Cook et al., 2013; Oreskes et al., 2004) generally find a stronger consensus than opinion surveys such as ours. This is related to the stronger consensus among highly published – and arguably the most expert – climate scientists. The strength of literature surveys lies in the fact that they sample the prime locus of scientific evidence and thus they provide the most direct measure of the consilience of evidence. On the other hand, opinion surveys such as ours can achieve much more specificity about what exactly is agreed upon and where the disagreement lies. As such, these two methods for quantifying scientific consensus are complementary. Our questions possibly set a higher bar for what’s considered the consensus position than some other studies. Furthermore, contrarian viewpoints were likely overrepresented in our study compared with others.

No matter how you slice it, scientists overwhelmingly agree that recent global warming is to a great extent human caused.


The fallacy of the middle ground

August 5, 2013

There’s been quite some climate discussion in the Political Science section of the Guardian lately. Warren Pearce had an invited post in which he asked the rhetorical question “Are climate sceptics the real champions of the scientific method?

He makes some good observations about the dynamics of the public debate and the nature of skepticism (e.g. most contrarians don’t deny the basic physics underlying the greenhouse effect, but rather dispute the magnitude of warming that would result from an increased greenhouse effect). On the other hand, he misses the mark in other areas (e.g. he correctly describes how contrarians see themselves but doesn’t investigate how their argumentation really stacks up; often they are guilty of what they accuse mainstream science of).

My main beef with his piece though is his flawed argument of why a well-known contrarian blogger like Anthony Watts, according to Pearce, should be seen as someone who “seeks to uphold standards, through transparent and auditable scientific practice” and “a ‘mainstream’ sceptic who can challenge key areas of climate science without entering into pseudoscience”. Why this praise? Because Watts publicly disagreed with the fringe group Principia Scientific who deny the basic physics underlying the greenhouse effect (which was first established in the 19th century).

That is not a logical argument to make though: Regardless of what one may think of Watts, contrasting an extremist with someone who is even more extreme doesn’t make him mainstream. Regardless of what one thinks of Watts, contrasting someone who frequently flirts with pseudoscience with an all-out pseudo-science lover doesn’t free the former from any link with pseudo-science.

That is what I would call the fallacy of the middle ground.


Science communication: Who is responsible (for its failing)?

March 9, 2011

There’s a semi-continuous argument going on about who’s to blame for the lack of public understanding about climate change. I’ve discussed the communication conundrum a few times as well, and assigned blame to various quarters, e.g

The media:

The popular media often paint a false picture of the scientific debate by giving the tiny minority viewpoints equal footing as the consensus viewpoints.


Most scientists are very bad at talking about their scientific field in plain, understandable language.

Though of course both statements in isolation miss the broader point, which is that

there are weaknesses in all parts of the chain that hamper the communication and use of climate science: A lack of good communication by scientists, a lack of scientific literacy amongst the public, the education system, the political system, a lack of fact-checking by the media, disinformation by vested interests, etc.

Enough self-quotation. Discussions are raging at Keith’s, Eli’s (check out John Fleck’s comments), mt’s, Stoat, with very interesting discussions in the comments sections.


John, tell your friends to get off the all scientists are lousy communicators and it’s their fault that the science is not being communicated kick and maybe we can talk.

To which many journalists would understandably reply: Exchange “scientists” by “journalists” as well while you’re at it. And both would be right.

John Fleck points out that, apart from egregious examples that exist e.g. in the opinionsphere journalism,

the data would suggest that journalists across the major press publications in the area I deal with most closely – climate change – are doing a creditable job.

Max Boykoff, now at the University of Colorado, has done the most work on this. His most recent analysis of newspaper coverage of climate change found that the British tabloid press “significantly diverged from the scientific consensus that humans contribute to climate change,” but that what Boykoff calls the “prestige press” (NY Times, Guardian, LA Times, Washington Post, etc.) pretty much gets the story right. Despite the widespread belief in a “false balance” problem, Boykoff’s most recent data showed a steady decline in the problem, such that in 2006 (the most recent year for which he’s got data, sadly), just 3 percent of the US and UK stories he surveyed did the “false balance” thing.

William puts the lion’s share of responsibility with the public:

But if the public wanted intelligently written journalism that actually explored issues carefully, they would get it. Alas (as far as I can tell), most of them want entertainment, but they want to feel good about watching it, so they want to pretend they are watching news, so effectively they are asking to be lied to. And that is what they get.

There’s something to that. Over the years, even the evening news and the weather forecast have changed in its narrative and appearance so as to be more about entertainment than about information. Election debates. Blogs. People want entertainment and they want it now. Gimme a quick fix, quick. Next, what’s next? There’s no time for learning or reflection.

Jonathan Gilligan has a similar line of thought as William, putting the responsibility on the public to consume the information they chose to:

There are lots of great books by scientists and journalists, so why do we assume that deadline journalism is so much more important than books for getting accurate and clear information to the public?

Yes, there’s bad journalism and there are bad books, but there are also excellent examples of both and if we can’t trust the general public to figure out what’s trustworthy, then it’s game over for democracy regardless what we do for the environment.

While rather gloomy in its ending, I think Gilligan is right that news journalism (interesting discussion on that thread, esp. the back and forth between Gilligan, Kloor and Tobis) isn’t the type of medium that we can expect to cover slowly unraveling stories in any depth. But even deadline news journalism is usually put in a certain context, where such issues can be touched upon. And there’s also background journalism, science journalism, and other kinds of communication (by scientists, journalists or whomever) that could rise to the occasion.

Which gets us to the point that it’s really about. Quoting mt:

the real question isn’t “whose fault?” It’s “what now?”


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