Nate Silver falls off

In 2012, Nate Silver faced a conservative and media-led backlash for bringing rigor to election forecasting. His newly launched journalism project is now facing a backlash for failing to live up to its promise.

I am probably the ideal audience for Nate Silver’s new journalism project FiveThirtyEight.com. I am someone who values data in a frequently-substance-free world of reporting. Although I am an unabashed Sam Wang PEC partisan, I certainly appreciated Silver mainstreaming election forecasting based on factors other than wishful thinking and journalism biases towards “the horse race” and “momentum”. When Silver was attacked by know-nothings in the media and the conservative blogosphere, I cheered him on, and savored his election day vindication, anti-climatic as it was.

Rather than topping my “must read” list, however, the new FiveThirtyEight is something I won’t be reading. Here’s why:

I became aware of Silver’s imminent launch by his public Twitter announcement of two hires to cover science for his new venture: Emily Oster, a University of Chicago economist famous for counter-intuitive revelations (sound familiar?); and Roger Pielke Jr.

Image courtesy of Flickr user “ferdicam”, used under Creative Commons.

Now, I am not going to get into Roger’s pathological attacks on climate scientists. I am not going to get into his sweaty delusions of persecution. I am not going to get into Roger’s complete misunderstanding of elementary aspects of climate science. I am going to focus on just two things: what Nate Silver is known for, and what Roger Pielke Jr. is known for.

Nate Silver’s reputation is based on being a stats wiz. This is what his blogging was devoted to, what his best-selling book is about, and the one thing he has that his competition/peers like Ezra Klein or Matt Yglesias don’t. And one of Nate Silver’s very first, very public hires (Roger Pielke Jr.) sucks at statistics. Not “published something in need of minor correction once or twice” sucks. “Doesn’t understand how a t-test works” sucks. “Doesn’t understand basic probability” sucks. Sucks out loud. Sucks on ice.

Roger’s very first article for Silver’s new site is, unsurprisingly, about Roger’s hobbyhorse. The claim that disaster losses are not increasing due to climate change.

Let’s be clear about some things. Climate change is real. Humans are not just “contributing” to it, we are responsible for essentially all of it over the past several decades. Our perturbation of the climate through our emissions of greenhouse gases is fundamentally changing the Earth system. The biosphere and human systems are going to have to adapt to a rate of change as of now unseen anywhere else in the paleoclimatic record. In the absence of emissions stabilization, a difficult but decidedly achievable outcome, the threat to the biosphere and society is daunting. The amount of climate change we’ve already experienced, while extremely serious, is tiny compared to the impacts we will see in world of unchecked fossil fuel exploitation. In addition to changes in the average or mean state of the system, we have already begun to see changes in some types of extreme weather events, and changes to the drivers of yet other extreme events.

Ostensibly, Roger Pielke Jr. accepts all of the above. He just doesn’t want you to focus on this big picture. Instead Pielke wants you to believe and to focus on the claim that we’ve seen no increase in “normalized” damages due to climate change. The fundamental conceit of this claim is that even though disaster losses are unquestionably on the rise, once you account for changes in the value of infrastructure being built in areas affected by disaster (due to population growth, inflation, etc.), there is no “statistically significant increase”.

This claim rests on our ability to account for factors which might spuriously inflate the damages caused by disasters, but also our complete failure to account for factors that have allowed us to avoid even greater losses.

The case of 2012’s Superstorm Sandy is illustrative. While Roger spent the first few days of the disaster trying to play down the magnitude of the mounting carnage, Sandy ultimately ranked among the most costly storms on record, even using normalized losses. Preliminary estimates range from $50-65 billion USD.

And yet it could have been so much worse.

Hurricane Sandy uncharacteristically failed to recurve out to sea, and barreled back towards the East Coast of the US. Due to the amazing advances we’ve seen in our ability to model the global weather system, we knew well in advance that this unexpected turn by Sandy was a real possibility.

This possibility was taken into consideration by those trying to game out the impact of Sandy’s landfall. The impact of rising sea levels on the frequency and severity of storm surge flooding was as well. Looking to a future of warming-boosted surges, researchers identified huge vulnerabilities in the New York transportation infrastructure to previously rare events. Such considerations ultimately led the MTA to shutdown the subway system in order to avoid the corrosive impact of salt water if the tunnels were flooded. This decision, informed by modeling and meteorological sophistication unimaginable in the early 1900s, saved the subway system and prevented New York City from being paralyzed for weeks and nearly doubling the economic damages.

Image via Twitter

Roger Pielke Jr.’s “normalized” disaster loss fixation takes none of this into account. Nor does it account for the benefits of building code improvements. Or other disaster prevention measures like dikes.

Paul Krugman is among a growing list of knowledgeable folks who were hopeful about Silver’s new enterprise but are less than impressed. Krugman writes:

… data are never a substitute for hard thinking. If you think the data are speaking for themselves, what you’re really doing is implicit theorizing, which is a really bad idea (because you can’t test your assumptions if you don’t even know what you’re assuming.)

I feel bad about picking on a young staffer [Note: not Pielke Jr.], but I think this piece on corporate cash hoards — which is the site’s inaugural economic analysis — is a good example. The post tells us that the much-cited $2 trillion corporate cash hoard has been revised down by half a trillion dollars…

… what does this downward revision tell us? We’re told that the “whole narrative” is gone; which narrative? Is the notion that profits are high, but investment remains low, no longer borne out by the data? (I’m pretty sure it’s still true.) What is the model that has been refuted?

“Neener neener, people have been citing a number that was wrong” is just not helpful. Tell me something meaningful! Tell me why the data matter!

Though Krugman is referring to a different 538 article, he could easily be making the same criticism of Pielke’s. Why do Pielke’s data matter? Are disaster losses not increasing? They are. Does “normalizing” the loss data tell the whole, unbiased, story? No, it doesn’t. Are extreme events, and drivers of yet more extreme events, changing in response to GHG emissions? They are.

If Nate Silver’s mission is to bring statistical cachet to good journalism, he’s off to a terrible start. One of his first big hires is terrible at statistics. If Silver wants to tell us something meaningful instead of peddling freakonomics-lite contrarianism, he’s similarly off to a poor start. Pielke’s personal hobbyhorse obscures far more than it enlightens. It offers a cocktail party morsel of contra-conventional wisdom instead of intellectual nourishment.

There are probably a lot of people who would like to see Silver fail. I’m not one of them. I just won’t be one of his readers, either, unless he makes some big changes to his current model.

What the government shutdown can tell us about the politics of climate legislation

This past Friday, the Diane Rehm show had a discussion about the recent shutdown of the Federal Government as Republicans tried to defund the Affordable Care Act.

There was a brief exchange that illustrates a dynamic I have been harping on for years, with respect to the idea of getting Republicans to vote for climate legislation. The panel is talking about the shutdown and the goal to defund the American Care Act, but the dynamic discussed would apply equally to voting for some sort of cap and trade, carbon tax, or fee and dividend program to cut domestic emissions.

Lori Montgomery:  We’ve reported, you know, endlessly, ad nauseam that Boehner himself, you know, told his rank and file not to try to fight Obamacare on the government funding bill. That was his preference. But you had this campaign led largely by outside groups, like the Jim DeMint-run Heritage Foundation and Sen. Ted Cruz and Sen. Mike Lee, who are Tea Party-backed guys. All summer, they were beating the drum against Obamacare. And they turned the heads of enough Republicans that Boehner could not proceed with a clean CR.

Ari Shapiro:  Lori… referenced outside groups which are a huge factor on this, which has gone under-remarked upon. Any Republican who acknowledges reality, that Obamacare is not going to be repealed, that at some point government funding is going to have to go into effect, that they probably will not get their fullest of demands. Any Republican who comes out and says that right now has a target painted on their back by some of these conservative groups that are very intent on funding primary challengers to force Republicans to adhere to this ideology that says we won’t budge.

[S]o many of these Republicans represent these blood-red districts where the demographic trends are going in the opposite direction from the rest of the country. The rest of the country is getting more diverse. It’s getting younger. These districts are getting more white. They’re getting older.

They represent districts where Romney beat Obama by a huge margin. And so the American people that they are representing do not necessarily look like the rest of the American people, and they have no incentive to negotiate with Democrats because that just means they’ll get primaried and kicked out in the next election.

Jeff Mason:  Well, and exactly. It also means that they won’t get punished for what some people think is really irresponsible behavior. It’s quite the contrary. What they’re seeing is that their political base is quite happy with the government shutdown and quite happy with the stand they’re taking on the Affordable Care Act.

Image courtesy of Flickr user “Fibonacci Blue”, used under Creative Commons

So we’re left with this. Even though there are Republicans who were amenable to funding the government rather than shutting it down as a last ditch attempt to sabotage health care legislation, they are constrained by outside interest groups who will primary them at the first sign of ‘appeasement’, and they’re also seated in districts with an increasingly fringe constituency, who are scared, angry and feel like they have lost control of the country.

The same seems to be true for the time being on climate legislation. Polling shows that while people don’t like what they imagine “ObamaCare” to be, they actually quite like the specific provisions of the actual Affordable Care Act. Similarly, polling shows that climate change isn’t perceived as a terribly immediate problem for the average voter, but specific actions relating to mitigating climate change are quite popular. But any Republican that shows a willingness to work on climate legislation is risking ideologically/industry-backed outside groups funding a primary challenge from their right, and their constituents are increasingly out of touch with the country on support for common sense actions on climate.

There are some people who would have you believe that this opposition to the Affordable Care Act, as well as climate legislation, is an organic, bottom up, ‘will of the people’ type thing. The irony of course is that the centerpiece of the Affordable Care Act was a conservative/Republican idea created as a market-based alternative to feared universal health care. Similarly, cap and trade was a conservative, market-based alternative to command and control options for pollution regulation, and until relatively recently, embrace of cap and trade (or a carbon tax) was a standard Republican position. The opposition to the Affordable Care Act and climate legislation does not stem from some organic, principled, groundswell of belief about what is best for the country, but rather is a form of tribal identity politics, which is fueled by special interests and think tank astroturfing and discourse policing.

Roger Pielke Jr.’s fevered delusions of persecution continue unabated

Image courtesy of Flickr user prd, used under Creative Commons

As longtime readers are quite aware, Roger Pielke Jr. sees vile McCarthyist attacks lurking around every corner. Some might find such incessant fears of persecution to be a worrying symptom of some underlying condition.

Most recently, Roger deduced that he was being given the boot from the editorial board of the journal GEC mid-term, as some kind of insidious payback for Roger failing to adhere to the All-Powerful Climate Orthodoxy.

In Roger’s world, apparently, the editorial boards of journals everywhere have nothing better to do than scan personal blogs day after day, searching for any hint of dissent from the party line, and retaliate with swift and merciless retribution.

The reality, as it always is, was not nearly so exciting. It seems that Roger dearest simply wasn’t living up to his end of the bargain:

In the original appointment letter we wrote that we expected Board Members to review up to five papers per year. We have invited you to review 18 papers in the six years, of which you agreed to review just six and submitted five reviews (on one occasion we uninvited you before submission of your review as the review process had been completed). Your last review was submitted in August 2010. Last year, in 2012, we invited you to review, and you declined to review, in January, May and August.

No doubt to Roger’s immense surprise (and his obvious disbelief), the editors make it clear that they weren’t even aware of Roger’s sniping at Brysse, et al. before Roger threw his tantrum. The decision had been made months before, and thus the timing was coincidental, they assure Roger:

The Editors reviewed the Board at our meeting in November 2012 and subsequently informed Elsevier of who to rotate off.

….

None of the Editors read your blog post of 15th February on Brysse paper till yesterday (20th February). We were not aware of it and no-one had commented on it or mentioned it to us.

The timing of you receiving a letter from Elsevier is a coincidence.

To a conspiracist, of course, there’s no such thing as coincidence.

Contrary to Roger’s dark insinuations of “special treatment”, he was simply one of several to not be carried on to a new term:

In addition to yourself, five other Board members have been not been reappointed for the new term and this has been conveyed to them in the past few days by Elsevier.

Nor was Roger sacked mid-term, contrary to his sputtering:

Your second three-year term on the Board was 2010-2012 and hence you are rotating off at the end of the term, not in the middle of the term.

To a martyr, of course, the world is always singling him out for special punishment.

“Erring on the side of least drama” appears to be an utterly foreign concept to dear Roger. 

Rapidly warming satellite data sends “skeptics” scurrying to models

Most people remotely familiar with climate “skeptics” know that if you can count on them for anything, it’s the following:

  1. “Skeptics” love satellite temperature data.
  2. “Skeptics” hate computer models. 

“Skeptics” claim to reject the surface instrumental temperature record because of alleged biases in the data, supposedly fraudulent “adjustments”, etc. These objections are not based in reality, as multiple analyses of the surface data have shown. In reality, “skeptics” reject the surface instrumental record for the same reason they reject so much of modern science: it doesn’t show what they want it to.

“Skeptics” claim that satellite temperature data, derived from microwave brightness soundings of the lower troposphere, are superior. The reality is that the satellite data cover a shorter record (and thus capture less of the warming), use a more recent baseline (and thus have cooler “anomalies” relative to the surface record), and are more sensitive to natural climatic variability like ENSO (and thus make the human signal harder to pick out visually). In other words, they like the satellite data because they show them more of what they want to see, and less of what they don’t. That one of the groups producing a satellite record is comprised of Roy Spencer and John Christy is icing on the cake.

And if there’s one thing “skeptics” disdain more than the surface instrumental record, it’s computer models. The ostensible justifications are legion, but the underlying cause is simple: they show things that “skeptics” don’t want to see.

So it was with great amusement that I took note of the “skeptic” reaction to the UAH satellite record’s rapid January warming, which reached temperatures exceeded only during the strong El Niño years of 1998 and 2010:

Rather than accept their beloved satellite data at face value, “skeptics” cast about for any alternative data set that didn’t show the inconvenient warming. Over at the wretched hive of scum and villainy known as WUWT, the innumerate and oft-beclowned Anthony Watts seized upon NCEP data showing much less January warming:

Of course NCEP isn’t actually an observational data set. It’s a reanalysis product created by those evil and untrustworthy models. You know, the ones “skeptics” demonize regularly in outlets like WUWT:

When the satellites don’t show what they want to see, “skeptics” waste no time in fleeing to the models they otherwise disdain.

Because climate “skeptics” are anything but skeptical.

And just for the record, the RSS satellite record showed a similarly large (+0.341°C) increase in January 2013.

Climate Change Communication – The Up Goer Five Edition

Image courtesy of Flickr user “njtrout_2000″, used under Creative Commons.

Reddit has a sub-reddit called Explain Like I’m Five, where people are attempt to explain often complex topics in simple, easy to understand language. The “like I’m five” part is often unsuccessful, but the idea is great.

Via Chris Rowan, people in the geosciences on Twitter have been talking about xkcd doing something similar, with the Up Goer Five. Basically, the challenge was to explain a spacecraft in relatively good detail in only the thousand most commonly used words in the English language.

This is a site that lets you try the concept out. Here is my first attempt at an explanation of the climate and energy challenge:

What is Going On?
Our home is changing because of some things we do, like burning stuff from the ground for power. One of the big changes is that we are warming up. What happens as we warm up is important! Some changes might be good: time for food growing may be longer. But lots of changes will be hard: where and how much or little rain we get, how hot and cold it gets, how much stuff is under water, how bad the air is to breathe, and a lot more things will all change. How we live, how we eat, and how we plan for things very much are tied to how things are around us. Big changes are hard to go through.

How Can We Know What Will Happen?
We can try to figure out what stuff might happen as we keep burning more and more stuff for power, and warm up. We can use computers to look forward. We can look at small changes from now and over the past couple hundred years, and think forward in time. We can even look way back into the very long ago past, at times when things warmed up or cooled down a lot, and learn from that!

Is It Too Late?
The important thing to know is this: what we do going forward matters very much to how things will change. Making very big changes to our home, or changing it less, is something we can decide. We need to think very carefully about how much we want to make our home change, and think about all of things that might happen as we change it. There is a lot we don’t know about what will change, and that makes it hard to plan for change. It may be safer to make little change, especially as we learn more about the bad stuff that happens with big changes.

What Can We Do?
There are a lot of new great things we can use for clean power that changes our home less. We can use the sun. We can use the wind. We can use water in many different ways. We can even use the same power the sun uses for its own power! All of these new ways of making clean power will keep our home more like it is now, and make it change a lot less than burning stuff for power. We can also use less stuff and power, and use the stuff and power we do use for doing more things. That will let us use less power to do the same stuff we do now.

How Do I Help?
What kind of home do you want? What kind of home do you want for your kids and their kids? Keep that in mind as you decide what to do. If you want to help, you can use less stuff and power, and tell people you want to use more of the things that use new clean power. You can also ask people who decide things to think about our home when they decide stuff, and to help us move to new ways of making clean power.

————————————————————–

This is an interesting exercise, and it might help if your intent is to de-technobabble a talk, or use wording that is friendly to translation software. As a communications tool, though, I don’t think it’s all that great. What makes ideas and concepts meme-like depends somewhat on simplicity, sure. But all of the other things that make ideas sticky are hamstrung by this. It’s really hard to use imagery, analogy, expectation-confounding, and all of the tools that make memorable ideas with such a limited vocabulary.

What do you think?

Same sh|t, different year

Image courtesy of Flickr user “epSos.de”, used under Creative Commons.

Hey, look!

It’s Daniel Sarewitz recycling a column from back in 2010 about how Republicans and science don’t mix and how it’s everyone’s fault but Republicans‘.

Sarewitz wrings his hands:

That President Barack Obama chose to mention “technology, discovery and innovation” in his passionate victory speech in November shows just how strongly science has come, over the past decade or so, to be a part of the identity of one political party, the Democrats, in the United States.

Huh?

President George W. Bush, according to his own scientific advisor, “included science and technology topics in his State of the Union speeches to an unprecedented extent.”

Does that mean during the Bush presidency “science was part of the identity of one political party” namely the Republicans? Would anyone make such an idiotic claim? Yet, this is the quality of “evidence” Sarewitz marshals for his “argument”.

Sarewitz seems to really love telling science what it “must” do, and it’s all rubbish. Science “must” bow down to religion for no particular reason other than Sarewitz’s own deficit of imagination. Science “must” cater to the hostile desires of Republicans for the tautological reason that Republicans are hostile to science.

As I have mentioned previously, I don’t think Democrats have some sort of special relationship with science. Far from it. I emphatically do not wish to see science as a whole become associated with any one political party, purely based on hostility from an opposition.

There are good arguments to make about how we can go about increasing Republican acceptance of science. But those arguments involve changing the way Republicans relate to science, rather than changing the institution of science itself. The only thing science “must” do is continue to get results. How people make use of the process is a vital but secondary concern.

Mainstream American Republican/conservative political ideology and self-identification has to a large extent become inextricably linked to the belief systems of unfettered industrial capitalism and to a somewhat lesser extent fundamentalist Christian religion. Both of these worldviews are hostile to scientifically-demonstrated phenomena because of the perception that said phenomena contradict their underpinnings. This is not a problem for science. It’s a problem for those ideologies, or at least the way their adherents approach science.

Berating science and scientists for problems that lie elsewhere is an easy, Slate-y piece of contrarianism and hippie-punching, but it will do nothing to fix the conflict.

How do the Sarewitz’s of the world imagine science can be even more accomodating to religion on the topic of evolution? How many other originally Republican/conservative solutions (pigovian taxation, cap and trade, etc.) to environmental problems need be proffered to Republicans?

As Alex Pareene put it, “Maybe scientists should just declare that climate change can be fixed by eliminating the estate tax, or bombing Iran. That should do it.”

At what point does the hippie-punching give way to addressing the roots of the problem where they actually lay?

Matt Ridley and the Wall Street Journal misrepresent paper cited in Ridley column

Equilibrium climate sensitivity (ECS) evaluated from paleoclimatic data (PALAEOSENS group, Rohling et al., 2012).

There’s more to say about the latest attempt to deny the mainstream estimate of equilibrium climate sensitivity (e.g. NRC, 1979; Annan and Hargreaves, 2006; Knutti and Hegerl, 2008; Rohling et al., 2012) by Matt Ridley (remember him?) at the Wall Street Journal later. But I just wanted to point out something rather troubling about one of Ridley’s and Nic Lewis’s (the source of Ridley’s claims) citations.

Ridley claimed:

Some of the best recent observationally based research also points to climate sensitivity being about 1.6°C for a doubling of CO2. An impressive study published this year by Magne Aldrin of the Norwegian Computing Center and colleagues gives a most-likely estimate of 1.6°C.

I recalled the Aldrin et al. paper from the last time it made the rounds in the “skeptic” blogosphere, when Chip Knappenberger cited it as finding a “low” climate sensitivity.

The funny thing about the Aldrin et al. paper is that it really doesn’t find a “low” ECS at all. Their main result is an ECS of 2.0°C, which is completely consistent with the IPCC AR4 range. Moreover, they caution that their main result is incomplete, because it explicitly does not account for the effect of clouds:

When cloud behavior is included as another term, the ECS increases significantly, from ~2.5°C to 3.3°C depending on the values used:

Surely this wasn’t the Aldrin et al. paper Riddley and Lewis were citing as finding an ECS of 1.6°C.

The 1.6°C value literally never appears in the text of the paper.

Of course, it was entirely possible that Aldrin had published another paper on ECS this year finding 1.6°C that I was simply unable to find. I reached out to Bishop Hill and Matt Ridley for some clarification:

  1. thingsbreak
    @aDissentient Which Aldrin 2012 paper was Lewis citing on your blog?
  2. thingsbreak
    @mattwridley Can you provide either the title or the DOI for the Aldrin paper you cited in your WSJ piece? Thanks!
  3. aDissentient
    @thingsbreak Environmetrics 2012; 23: 253–271 Panel A of Fig 6.
  4. thingsbreak
    @aDissentient The one that finds an ECS of 2.5-3.3K when it bothers to account for clouds (4.8)? LOL.
  5. mattwridley
    @thingsbreak wattsupwiththat.com/2012/12… Aldrin, M., et al., 2012. Bayesian estimation of climate sensitiv… Environmetrics, doi:10.1002/env.2140.
  6. thingsbreak
    @mattwridley Did you personally read the paper? Where does the 1.6 number come from? Did you read section 4.8?
  7. aDissentient
    @thingsbreak Most likely values still only 2 ish. If we are to include cloud lifetime effect shld we include other highly uncertain effects?
  8. thingsbreak
    @aDissentient If you’re making a comparison to IPCC values, should use most apples-to-apples comparison, which Aldrin et al. discuss in 4.8.
  9. thingsbreak
    @aDissentient Where does the 1.6 value come from anyway? Literally doesn’t exist in paper.
  10. aDissentient
    @thingsbreak He got it by measuring the graph (It’s actually slightly lower I believe).
  11. mattwridley
    @thingsbreak lewis calculated it from aldrin’s paper’s data/charts and aldrin agreed it is correct
  12. thingsbreak
    @mattwridley Aldrin agreed that apples to apples comparison with IPCC ECS estimates is 1.6K? Doubtful. Directly contradicts paper itself.

I posted the following to Nic Lewis at Bishop Hill’s blog:

I think that some readers, and probably the authors of a paper themselves, might find it at least slightly misleading for you to claim findings on their behalf that the paper itself does not actually state.

The main result from Aldrin et al., as reported by Aldrin et al., is an ECS of 2.0°C. The authors caution that this result probably isn’t an apples to apples comparison to other ECS estimates due to the unaccounted for cloud term, and find that the value increases to ~2.5-3.3°C with clouds.

Rather than report either of these values, you simply claim Aldrin et al. “an impressively thorough study, gives a most likely estimate for ECS of 1.6°C…”.

Ridley likewse claims, “An impressive study published this year by Magne Aldrin of the Norwegian Computing Center and colleagues gives a most-likely estimate of 1.6°C.”

It would be easy for me to lob accusations of bad faith, as we don’t know each other and this is just the internet. Instead, I would encourage you, if your goal is to reach as wide an audience as possible, and try to make an impact beyond the “skeptic” and conservative blogospheres, to be more upfront about the scientific literature about ECS.

Ignoring the two main findings of a paper for values that you’re either estimating from a curve or are creating yourself based on data not used by the paper will be seen by at least some people to be misleading. Claiming that ECS cannot be estimated by paleo data is absurd, especially when so many are aware of efforts like the PALAEOSENS project and various paleoclimatic intercomparison groups.

I won’t attempt to read minds or divine motivations. I will simply suggest that what you have been doing thus far will cause some people to dismiss what you’re trying to say due to perceived dishonesty.

I hope you take this criticism in the constructive context in which it is being offered. There will be plenty of time for name-calling and insults later.

References:

  • Aldrin, M., M. Holden, P. Guttorp, R. B. Skeie, G. Myhre, and T. K. Berntsen (2012), Bayesian estimation of climate sensitivity based on a simple climate model fitted to observations of hemispheric temperatures and global ocean heat content, Environmetrics, 23(3), 253–271, doi:10.1002/env.2140.
  • Annan, J. D., and J. C. Hargreaves (2006), Using multiple observationally-based constraints to estimate climate sensitivity, Geophys. Res. Lett., 33, 4 PP., doi:200610.1029/2005GL025259.
  • Knutti, R., and G. C. Hegerl (2008), The equilibrium sensitivity of the Earth’s temperature to radiation changes, Nature Geoscience, 1(11), 735–743, doi:10.1038/ngeo337.
  • National Research Council (1979),  Carbon Dioxide and Climate: A Scientific Assessment. Washington, DC: The National Academies Press.
  • Rohling, E.J., et al. (2012), Making sense of palaeoclimate sensitivity, Nature, 491(7426), 683–691, doi:10.1038/nature11574.