Is There Consensus?

Part 2 of a series of 5 for NextGen Journal

We hear the phrase “climate change consensus” tossed around all the time. But what does that even mean? And does it actually exist?

In Part 1 we discussed the concept of a scientific consensus: overwhelming agreement (but rarely unanimity) among experts. Of course, such a consensus could be wrong, but it wouldn’t be very sensible for the public to ignore it or bet against it. If 19 out of 20 doctors said you needed surgery to save your life, would you sit in the hospital bed and argue about their motives?

When it comes to climate change, the consensus view can be summarized as follows:

  1. Human emissions of greenhouse gases, mainly from the burning of fossil fuels, are a significant force on the global climate.
  2. The expected warming from this force is beginning to show up.

Often, people will write these two points in opposite order: the Earth is warming, and it’s due to our actions. However, that’s not the order that scientists discovered them. The academic community realized the Earth was going to warm decades before that warming became clear. Flipping around these observations might imply “that the entirety of climate science is based upon a single correlation study”.

So, what do the scientists say? In fact, publishing climatologists – the most specialized and knowledgeable people there with regards to climate change – are almost unanimous in their position. 96.2% say the Earth is warming, and 97.4% say humans are causing climate change. It’s hard to know why the second figure is higher than the first – perhaps one scientist in the study thought the effects of our actions hadn’t shown up yet (i.e., point 1 but not point 2).

A year later, others built on this study. They had a larger sample of climate scientists, 97-98% of whom agreed with the consensus position. Additionally, those who agreed had higher academic credibility than those who disagreed: they had published more papers (“expertise”) and been cited more times (“prominence”).

However, it doesn’t really matter what a scientist says, as much as how they back it up. Having a Ph.D. doesn’t mean you get to stop supporting your claims. In the academic community, this is done in the peer reviewed literature.

In 2004, a random sample of almost 1000 scientific studies on climate change were examined. 75% of the studies explicitly supported the consensus position, while the remaining 25% didn’t mention it – for example, some papers wrote about climate change millions of years ago, so today’s climate wasn’t relevant. Incredibly, not a single one disagreed with the consensus.

This still doesn’t imply unanimity – remember, it was a random sample, not the entire literature. A very few dissenting studies do get published each year, but they are such a tiny fraction of the total papers that it’s not surprising that none showed up in a sample of one thousand. Additionally, these papers generally fail to stand up to further scrutiny – their methods are often heavily critiqued by the academic community. See, for example, Lindzen and Choi, 2009 and its response.

It’s clear that individual polls have limitations. They are restricted to a sample of scientists or papers, rather than the entire community. They don’t take into account which claims stood the test of time, and which were refuted. Luckily, the climate science community has another way to summarize the balance of evidence on global warming: the Intergovernmental Panel on Climate Change (IPCC). Since 1988, four assessment reports have been written by thousands of volunteer scientists worldwide. They examine the entire body of academic literature on climate change and create a summary, which is then painstakingly reviewed and scrutinized by others.

The latest report, published in 2007, is already quite out of date – due to the long review process, most of the data is from 2002 and earlier. However, it is still used by governments worldwide, so let’s look at some of its key findings:

  • “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level.”
  • “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.”
  • “Anthropogenic warming over the last three decades has likely had a discernible influence at the global scale on observed changes in many physical and biological systems.”
  • “Altered frequencies and intensities of extreme weather, together with sea level rise, are expected to have mostly adverse effects on natural and human systems.”
  • “Anthropogenic warming could lead to some impacts that are abrupt or irreversible, depending upon the rate and magnitude of the climate change.”

The final place to look for scientific consensus is statements from scientific organizations, such as the National Academy of Sciences. Not a single scientific organization worldwide disputes the consensus view, and many have published statements explicitly supporting it. A full list is available here, but here are some samples:

Climate change and sustainable energy supply are crucial challenges for the future of humanity. It is essential that world leaders agree on the emission reductions needed to combat negative consequences of anthropogenic climate change[.]
Thirteen national academies of science

It is certain that increased greenhouse gas emissions from the burning of fossil fuels and from land use change lead to a warming of climate, and it is very likely that these green house gases are the dominant cause of the global warming that has been taking place over the last 50 years.
Royal Society (UK)

The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society.
American Association for the Advancement of Science

[C]omprehensive scientific assessments of our current and potential future climates clearly indicate that climate change is real, largely attributable to emissions from human activities, and potentially a very serious problem.
American Chemical Society

Emissions of greenhouse gases from human activities are changing the atmosphere in ways that affect the Earth’s climate…The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth’s physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now.
American Physical Society

The Earth’s climate is now clearly out of balance and is warming. Many components of the climate system…are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century.
American Geophysical Union

It’s clear that a scientific consensus on climate change does exist. Since unanimity is virtually impossible in science, agreement over climate change can’t get much stronger than it is already.

Could all of these scientists, papers, reports, and organizations be wrong? Of course – nobody is infallible. Could that 3% of dissenting scientists triumph like Galileo? It’s possible.

But how much are you willing to risk on that chance?

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Be Critical of Critics

Cross-posted from NextGen Journal

Of all the inane arguments made against the phenomenon of anthropogenic global climate change, the strangest – in my opinion – are the conspiracy theories.

Yes, scientific fraud does happen, but on the scale of one author, not an entire multi-disciplinary field stretching back for over a century. Imagine the scale of fabrication that would be necessary for this to be true, and the amount of journal editors, expert reviewers, and students who would have to be in on the conspiracy. Scientists are just not that organized.

And for what reason would they do this? Yes, there’s the old Communist-overthrow-of-the-world argument that Fox News pundits argue would somehow result from using capitalist market strategies to put a price on carbon…but many scientists who fully accept the reality of climate change are self-proclaimed Independents and Republicans.

Even if they don’t claim out-and-out fraud, many politicians, journalists, and citizens believe that scientists’ conclusions on climate change are influenced by the lure of grant money. This position shows a fundamental misunderstanding of the way scientific grants work. As Dr. Andrew Weaver, top Canadian climatologist, argued in his fantastic book Keeping Our Cool: Canada in a Warming World, if scientists were purely interested in grant money, it would be more beneficial for them to claim uncertainty in their work. Research dollars give preference to areas of science that remain fundamentally mysterious, not those that are just ironing out the details of well-understood basic processes. Additionally, as meteorology professor Scott Mandia recently showed, the grants that scientists receive for their research don’t actually influence their salaries.

Incredibly, even the Intergovernmental Panel on Climate Change (IPCC) – a highly credible organization that painstakingly summarizes the scientific literature on climate change – is comprised of volunteer scientists. Even the chair, Rajendra Pachauri, doesn’t receive a cent for his work with the IPCC.

Of course, the prospect of a global warming fraud isn’t impossible. Nothing is. But remember, fraud is a criminal charge, and should not be thrown around lightly. Climate scientists, just like anyone else, have the right to be presumed innocent until proven guilty. They shouldn’t have to endure this endless harassment of being publicly labelled as frauds without evidence.

Here’s an example, from a retired American physics prof named Harold Lewis. He recently resigned from the American Physical Society because he didn’t think his views on climate change were being taken into account in the society’s statement. His resignation letter reads almost like satire:

It is of course, the global warming scam, with the (literally) trillions of dollars driving it, that has corrupted so many scientists, and has carried APS before it like a rogue wave. It is the greatest and most successful pseudoscientific fraud I have seen in my long life as a physicist. Anyone who has the faintest doubt that this is so should force himself to read the ClimateGate documents, which lay it bare…I don’t believe that any real physicist, nay scientist, can read that stuff without revulsion. I would almost make that revulsion a definition of the word scientist.

The scientists involved in ClimateGate, the scandal that wasn’t, have been cleared by five independent investigations to date. While some reasonable issues about data archival and sharing have been raised, absolutely no science was compromised by the contents of the stolen private correspondence. For Lewis to say otherwise and fail to provide evidence for this potentially libelous accusation is unduly irresponsible.

I disagree that the definition of scientist is “someone who feels revulsion and jumps to the conclusion of fraud from emails that show, at most, that climate scientists are not always very nice”. On the contrary, I would expect that a scientist would assess media coverage of these emails with a critical eye, examine the context in which they were written, and read the published work of the scientists in question – many of the so-called damning phrases (“hide the decline”, “lack of warming at the moment”) had already been discussed at length in the literature (Briffa et al 1997 and Trenberth et al 2009 respectively).

On a side note, where did he get “literally trillions of dollars” from? The world GDP, according to the World Bank, is approximately $61 trillion. It seems staggering to imagine that a minimum of 3% of the world economy is devoted to climate change research alone.

Let’s see what else Harry Lewis has to say:

In the interim the ClimateGate scandal broke into the news, and the machinations of the principal alarmists were revealed to the world. It was a fraud on a scale I have never seen, and I lack the words to describe its enormity. Effect on the APS position: none. None at all.

And rightly so. Even if, for the sake of argument, the CRU emails had discredited all of the research group’s data and publications, their conclusions about the current planetary warming have been independently replicated by multiple land- and satellite- based databases. In the United States alone, there is NASA GISS, NOAA NCDC, RSS, and UAH. All show the same global warming that CRU detected. Some, due to complexities in the measurement of Arctic temperatures, show even more.

The scientific literature fully supports the general premise of the APS statement on climate change: the world is warming, humans are causing it, and unless we reduce carbon emissions quickly and dramatically, it’s going to be bad. No alternative explanation for the situation has been able to withstand the scrutiny of peer-review.

Science is about looking at all sides of an issue, but it’s not a free-for-all. If someone can’t back up a claim, they don’t have an inherent right to get it published regardless. Unfortunately, in the Internet age, that doesn’t matter – if what they’re looking for is media attention, not scientific accountability.

There’s a difference between “lacking the words to describe the enormity” of a so-called fraud, and lacking the evidence to support such an accusation. As scientists (and prospective scientists, such as myself!), we need to be critical in our assessment of all claims – including the claims of critics and contrarians. Being objective isn’t always the same as being neutral.

Party Line

Brad Johnson from The Wonk Room recently released a comprehensive list of what Republican contenders for the U.S. Senate understand about climate change, inferred from their public statements. The result? 47 of the 48 deny the existence of anthropogenic climate change and/or oppose mitigating action to curb greenhouse gas emissions.

Take a look – many of the statements are what you would expect from trolling YouTube commenters, not politicians aspiring to run the most powerful country in the world. Through a combination of framing science as personal opinion, promoting artificial balance, and re-iterating the same misconceptions that people like you and I have been fighting to correct for years now, the Republican party has adopted a position that, frankly, terrifies me.

“There are dramatic environmental changes happening the Arctic region – whether one believes they are man-made or natural.” – John McCain, Arizona

“While I think the earth is warming, I don’t think that man-made causes are the primary factor.” – Ken Buck, Colorado

“The climate is always changing. The climate is never static. The question is whether it’s caused by man-made activity and whether it justifies economically destructive government regulation.” -Marco Rubio, Florida

“[Scientists] are making up their facts to fit their conclusions. They’ve already caught them doing this.” – Rand Paul, Kentucky

“There isn’t any real science to say we are altering the climate path of the Earth.” -Roy Blunt, Missouri

“I don’t buy into the whole man-caused global warming, man-caused climate change mantra of the left. I believe that there’s not sound science to back that up.” -Sharron Angle, Nevada

“There is much debate in the scientific community as to the precise sources of global warming.” -Pat Toomey, Pennsylvania

“It’s going to keep snowing in DC until Al Gore cries ‘uncle’.” -Jim DeMint, South Carolina

“If you have one volcano in the world, that one volcano puts out more carbon dioxide than everything man puts out.” -John Raese, West Virginia

“I absolutely do not believe that the science of man-caused climate change is proven. Not by any stretch of the imagination. I think it’s far more likely that it’s just sunspot activity, or something just in the geologic eons of time where we have changes in the climate.” -Ron Johnson, Wisconsin

Who are these people to make statements about what the scientific community knows and does not know about climate change, when organizations like the NAS are quite capable of doing that themselves, and tell a very different story to these prospective Senators when they do?

Who are they to make informal analyses on the attribution of recent temperature change – assessing the likelihood of different causes via gut instinct, rather than looking at fingerprints like stratospheric temperature and tropopause height?

Who are they to spread around blatant mistruths like “a single volcano puts out more CO2 than people do”? Who are they to make damaging accusations about scientific fraud and false data, especially when these accusations have already been investigated multiple times, coming up completely clear?

I had hoped that politicians would be slightly more informed than the general public on scientific matters that have implications for policy. However, I must now change my mind, and hope instead that the American public realizes how off the mark this position is. If they don’t, there could be consequences up to millenia from now.

Open Letter from U.S. Scientists on the IPCC

Joining the push for better climate science communication are over 300 US scientists. On March 13, they sent an open letter to US federal agencies about why a few errors in the IPCC AR4 do not impact our understanding of the climate system and the changes occurring, and should not impact our efforts to mitigate and adapt to such changes.

The introduction to the letter reads:

Many in the popular press and other media, as well as some in the halls of Congress, are seizing on a few errors that have been found in the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) in an attempt to discredit the entire report.  None of the handful of mis-statements (out of hundreds and hundreds of unchallenged statements) remotely undermines the conclusion that “warming of the climate system is unequivocal” and that most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to observed increase in anthropogenic greenhouse gas concentrations. Despite its excellent performance for accurately reporting the state-of-the-science, we certainly acknowledge that the IPCC should become more forthcoming in openly acknowledging errors in a timely fashion, and continuing to improve its assessment procedures to further lower the already very low rate of error.

Read the full text here.

Over 300 US scientists have signed the letter, and signatures are still being collected. You can view the list of signatures here. I see a few familiar names already (eg Scott Mandia)!

However, I must say that I am profoundly disappointed that the letter can only be signed by American scientists. Although it is intended for American federal agencies, what the US does about climate change will impact the whole world. Firstly, many countries (*cough*cough* Canada) plan to delay action on climate change until the US has a clear plan, so they can follow suit. And, perhaps most importantly, having the largest per-capita emissions and cumulative emissions, as well as the second-largest annual emissions, the US is driving the changes in the climate system with disproportionate responsibility. As its actions will have international repercussions, both politically and environmentally, I believe that the list of signatures should be open to scientists worldwide.

What The Press Should Cover, and Won’t

The first of three investigations into the CRU emails has been released. You can read the British House of Commons’ entire report here, but I found the summary on page 7 to be just as useful. In part, it reads:

We believe that the focus on CRU and Professor Phil Jones, Director of CRU, in particular, has largely been misplaced. Whilst we are concerned that the disclosed emails suggest a blunt refusal to share scientific data and methodologies with others, we can sympathise with Professor Jones, who must have found it frustrating to handle requests for data that he knew – or perceived – were motivated by a desire simply to undermine his work.

In the context of  the sharing of data and methodologies, we consider that Professor Jones’s actions were in line with common practice in the climate science community. It is not standard practice in climate science to publish the raw data and the computer code in academic papers. However, climate science is a matter of great importance and the quality of the science should be irreproachable. We therefore consider that climate scientists should take steps to make available all the data that support their work (including raw data) and full methodological workings (including the computer codes). Had both been available, many of the problems at UEA could have been avoided.

We are content that the phrases such as “trick” or “hiding the decline” were colloquial terms used in private e-mails and the balance of evidence is that they were not part of a systematic attempt to mislead. Likewise the evidence that we have seen does not suggest that Professor Jones was trying to subvert the peer review process. Academics should not be criticised for making informal comments on academic papers.

In the context of Freedom of Information (FOIA), much of the responsibility should lie with UEA. The disclosed e-mails appear to show a culture of non-disclosure at CRU and instances where information may have been deleted, to avoid disclosure. We found prima facie evidence to suggest that the UEA found ways to support the culture at CRU of resisting disclosure of information to climate change sceptics. The failure of UEA to grasp fully the potential damage to CRU and UEA by the non-disclosure of FOIA requests was regrettable. UEA needs to review its policy towards FOIA and re-assess how it can support academics whose expertise in this area is limited.

DeSmogBlog also has a great summary which you can read here.

We know that the system of climate science is not perfect, and that the folks at CRU did not handle things in the best of ways all the time, but who ever does, especially when you are the target of organized campaigns to discredit your field? The real problem, though, is that everyone who keeps up with North American or British news heard that climate scientists were accused of fudging and manipulating data. There is no evidence to support these allegations, and the House of Commons’ report confirms this. However, I’m not naive enough to believe that the media will cover the result of this “scandal” as intensely as they covered the allegations themselves.

Imagine that you read in the newspaper that a man has been charged with murder. It will be months before you find out the verdict of his trial, and unless it’s OJ Simpson, you probably won’t hear the verdict at all. Many, perhaps most, people would assume that the man is guilty.

We assume that allegations have merit, when – at least when it comes to climate science – they just as often do not.

Where to Go for Answers

To all of our new readers, thanks to CBC and StumbleUpon, this is for you!

Most of us don’t read scientific journals. We read the newspaper instead. We read our news feeds. We watch CNN.

These sources, as we know, are fairly low on the credibility spectrum. But how are people like you and I supposed to understand the more credible sources? Scientists don’t seem to speak plain English. And you can’t even read most of their studies without a subscription.

Usually this isn’t much of a problem, because the popular press and the scientific journals say basically the same things – that there’s going to be a lunar eclipse on a certain date, that red meat increases your risk of a heart attack, that a new kind of dinosaur was just discovered.

However, when you start reading about climate change, the newspapers start going crazy.

The world is warming. The warming is caused from the world coming out of an ice age. The warming stopped in 1998. Glaciers are melting. The warming is caused by human activity. The warming is caused by sunspots. The warming is inconsequential. The warming is catastrophic and is going to kill us all. New York is going to be underwater. Scientists faked the whole thing.

As someone who keeps up-to-date with the scientific literature – that is, sources from the top few tiers of the credibility spectrum – I can tell you that it is not under the same confusion as the mass media. There are a lot of myths about climate change that go around the newspapers and the Internet, but were never in any sort of legitimate scientific study. I cannot stress this point enough.

For example, have you heard the one about NASA getting the Y2K bug, and later discovering that the warmest year on record wasn’t 1998, but in fact – whoops – 1934? Global warming must be fake!

Actually, that’s not correct at all. NASA discovered that 1934 was the warmest year on record in the United States. And that “United States” part got dropped in translation somewhere in the blogosphere. Contrary to what American media would have you believe, the United States is not the whole world. It makes up less than 2% of the Earth’s surface. And the warmest year on record globally is either 1998 or 2005, depending on how you measure the Arctic temperatures.

There are dozens of stories like that. So many of the explanations you hear for global warming being natural/nonexistent/a global conspiracy are based on misconceptions, miscommunications, discredited data, or flat-out lies. They were never in the scientific literature. They are not endorsed by the sources at the top of our credibility spectrum. They are, shall we say, urban myths.

But how are we, humble non-scientists, scanning through the newspaper on the way to work each morning, supposed to know that? We need some kind of a link between the scientists and the public. Some journalist who actually knows what they’re talking about, and cites all of their claims with credible sources. Some sort of encyclopedia that will dispel all the myths about climate change.

Luckily, there are many of these encyclopedias. There are a lot of people out there trying to fulfill this very purpose.

One of my favourites is Peter Sinclair’s Climate Denial Crock of the Week video series on YouTube. He debunks common claims like “global warming stopped in 1998”, “global warming is caused by the sun”, and “temperature leads CO2 in the ice cores”. Sinclair is a professional journalist, so all of the videos are well explained, easy to understand, and fun to watch.

Another great source is Coby Beck’s How to Talk to a Climate Skeptic series. These articles cover just about every objection out there. Equally comprehensive is Skeptical Science. They’ve even compressed their explanations into “sound bites”, so you can answer your uncle’s objections in just a few sentences over Thanksgiving dinner.

Some of the sources from the top of our credibility spectrum have also chimed in. Environment Canada has created a fantastic FAQ document about climate change. It covers everything you need to know to wade through YouTube comments or online debates, along with citations you can actually trust.

Finally, Scott Mandia, a regular reader here at ClimateSight and a meteorology professor in New York, has just posted a copy of his presentation to the public about climate change. What I like about this document is that it’s very up-to-date. All of the graphs are the most recent of their kind. It also provides some philosophical perspectives to really sink your teeth into, like an analogy about medical advice, and some memorable quotes at the end.

We shouldn’t have to double-check everything the newspaper says about climate change. But the objections to anthropogenic global warming have such an awful track record that we really should, at least before we go and spread them around. These sources will cover just about everything you need to know.