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Yes, the climate has always changed. This shows why that’s no comfort.

By Brad Plumer, vox.com Jan 13, 2017

Randall Munroe, the author of the webcomic XKCD, has a habit of making wonderfully lucid infographics on otherwise difficult scientific topics. Everyone should check his take on global warming. It’s a stunning graphic showing Earth’s recent climate history. Take some time with it. Stroll through the events like the domestication of dogs and the construction of Stonehenge. And then ponder the upshot here.

There’s a common line among climate skeptics that “[t]he climate has always changed, so why worry if it’s changing now?” The first half of that sentence is undeniably true. Due to orbital wobbles, volcanic activity, rock weathering, and changes in solar activity, the Earth’s temperature has waxed and waned over the past 4.5 billion years. During the Paleocene it was so warm that crocodiles swam above the Arctic Circle. And 20,000 years ago it was cold enough that multi-kilometer-thick glaciers covered Montreal.

But Munroe’s comic below hits at the “why worry.” What’s most relevant to us humans, living in the present day, is that the climate has been remarkably stable for the past 12,000 years. That period encompasses all of human civilization — from the pyramids to the Industrial Revolution to Facebook and beyond. We’ve benefited greatly from that stability. It’s allowed us to build farms and coastal cities and thrive without worrying about overly wild fluctuations in the climate.

And now we’re losing that stable climate. Thanks to the burning of fossil fuels and land use changes, the Earth is heating up at the fastest rate in millions of years, a pace that could prove difficult to adapt to. Sea level rise, heat waves, droughts, and floods threaten to make many of our habitats and infrastructure obsolete. Given that, it’s hardly a comfort to know that things were much, much hotter when dinosaurs roamed the Earth.

XKCD A timeline of Earth's average history

Randall Munroe



Climate ‘Skeptics’ are not like Galileo

The following article is from https://www.skepticalscience.com/climate-skeptics-are-like-galileo.htm. Skeptical Science was created and maintained by John Cook, the Climate Communication Fellow for the Global Change Institute at the University of Queensland.


Some climate change skeptics compare themselves to Galileo, who in the early 17th century challenged the Church’s view that the sun revolves around the earth and was later vindicated.

“I mean, it — I mean — and I tell somebody, I said, just because you have a group of scientists that have stood up and said here is the fact, Galileo got outvoted for a spell” – Texas Governor Rick Perry

The comparison to Galileo is not only flawed; the very opposite is true.

1.   Galileo was suppressed by religious/political authority, not scientists.     Galileo was not suppressed or “outvoted” by other early scientists.   Many scientific contemporaries agreed with his observations[2], and were appalled by his trial.[3]

Galileo was persecuted by the religious-political establishment – the Catholic Church, which in 1616 ordered him to stop defending his view of the solar system, which contradicted church dogma.  After Galileo published his famous Dialogue, the Roman Inquisition tried him in 1633 for defying Church authority, and found him guilty of suspected religious heresy, forced him to recant, banned his books and sentenced him to house arrest for life.[4]   Galileo died eight years later.[5]

2.   Science is evidence-based; the most vocal skeptics are belief-based.  The key difference between Galileo and the Church concerned Galileo’s “way of knowing,” or epistemology.  How is knowledge attained?

Medieval scholarship and Catholic Church dogma relied on the authority of Aristotle and a literal interpretation of the Bible to place earth at the center of the universe.

In contrast, Galileo’s views were not based on an infallible authority.   His conclusions flowed from observations and logic.  Galileo’s evidence- and logic-based method of inquiry later became known as the scientific method.

The vast majority of vocal skeptics are not engaged in climate research.   The common bond uniting them, observers note, is an ideological belief system:   Government regulation is bad, so problems that may require regulation must be resisted.[6]   From there, they search for ways to cast doubt on the science.[7]   Unlike Galileo and modern scientists, they do not change their view when presented with new evidence, because their position derives not from open-ended scientific inquiry, but from strongly-held ideological convictions.

In contrast, climate science applies the scientific method pioneered by Galileo.    Scientists make observations, form logical hypotheses, then test their hypotheses through experiments and further observations.   They follow the evidence wherever it leads.

The Church’s attack on Galileo and the skeptical assault on climate science are far from unique.   History is full of examples where new scientific findings threatened powerful vested interests – whether religious, financial or ideological — and provoked a furious backlash.

3.  The discovery of global warming overturned an age-old belief; the skeptics seek to restore it.   In arguing that the planets revolve around the sun, Galileo was challenging an idea that had dominated Western thought for over 1400 years.    Ever since Ptolemy (90-168 AD) codified Aristotle’s “geocentrism,” most philosopher/scientists had accepted the common sense view that the earth is the center of the universe, with the sun and planets revolving around us.

Similarly, the prevailing view throughout history was that people, through our own actions, could not possibly alter earth’s climate on a global scale.   Even into the 20th century, the overwhelming majority of scientists maintained, in science historian Spencer Weart’s words,

the widespread conviction that the atmosphere was a stable, automatically self-regulated system. The notion that humanity could permanently change global climate was implausible on the face of it, hardly worth a scientist’s attention.[8]

Some say climate science’s first “Galileo moment” came in 1896, when Swedish scientists Svante Arrhenius, after years of laborious hand calculations, predicted eventual global warming due to CO2 emissions.[9]    Others point to 1938, when a British steam engineer named Guy Stewart Callendar, after poring over old CO2 and temperature records, stood alone before the Royal Meteorological Society to argue that global warming was already happening.[10]

Arrhenius and Callendar were ahead of their time, and failed to persuade others.   In both cases, the scientific establishment found their calculations oversimplified and their evidence incomplete, certainly not convincing enough to overturn the ancient view that global climate was impervious to human acts.

Mainstream scientific opinion was slow to change.  During the post-war science boom in the 1950’s, early computers and advanced methods allowed scientists to directly investigate objections to Arrhenius’ and Callendar’s view.[11]

Using the new digital computers, Gilbert Plass found that more CO2 could indeed block more heat.[12]

Hans Suess analyzed radioactive isotopes to detect ancient carbon in the air, presumably from fossil fuels.[13]

Roger Revelle and Suess discovered that the oceans could not quickly take up additional CO2.

David Keeling built the first sensor capable of accurately measuring atmospheric CO2 – just as Galileo had invented a more advanced telescope – and found that the CO2 level was indeed rising.

From 1960 to 1990, the evidence kept accumulating, from areas of study as far afield as geology, astronomy and biology.   As the gaps in knowledge were filled, one-by-one, most scientists changed their views and gradually formed a new consensus:  significant anthropogenic (human caused) global warming was likely.[14]

By 2000, the evidence was overwhelming.

The hypothesis proposed by Arrhenius in 1896—denied by almost every expert through the first half of the twentieth century and steadily advancing through the second half—was now as well accepted as any scientific proposal of its nature could ever be.[15]

The climate pioneers were vindicated.

climate timeline IPCC emissions

Critics of climate science, backed by the alarmed fossil fuel industry,[16] sprang into action in the late 1980s, when the mounting evidence led to calls for international action to limitCO2 emissions.   They did not argue, like Galileo, for a revolutionary hypothesis based on new evidence, because they could not agree on one among themselves.[17]    They produced little new evidence.   Instead, they searched for flaws in others’ research, and launched a public relations campaign to sow public doubt.

Unlike Galileo, climate skeptics were not trying to overturn an ancient view. Their goal was the opposite:   to restore the  age-old conventional wisdom, that, by itself, “human activity was too feeble to sway natural systems”[18].     In clinging to this old view, the skeptics’ stance more closely resembles that of the Catholic Church, which fought Galileo’s views for another 100 years after the scientific establishment had embraced him.

No Slow Down In Global Warming NOAA National Centers for Environmental Information

4.  Climate scientists, not skeptics, are being dragged into court     Armed with ideological certainty, backed by powerful financial and political interests, skeptics have sought to not only discredit the science but impugn the researchers’ honesty.   Unfounded accusations of deception and conspiracy fly freely,[19] and some climate scientists even receive death threats.[20]   These attacks, according Dr. Naomi Oreskes, “have had a chilling effect…   Intimidation works.”[21]

In April 2011, personal attacks on scientists took a more ominous turn, when Virginia’s Attorney General Ken Cuccinelli, a fierce climate skeptic, launched a criminal fraud investigation of a prominent climate scientist, Dr. Michael Mann.[22]   Multiple investigations by independent scientific bodies have found no trace of wrongdoing  in Mann’s work, and a Virginia judge dismissed Attorney General’s subpoena request for lack of evidence.    Yet, as of September 2011, Cuccinellis’ crusade continues.[23]

If Galileo were alive today, watching climate scientists being dragged into court on baseless charges, is there any doubt whose side he would take?

Global warming GIF

[1]  On Sept 7, 2011, at the Republican presidential debate in Simi Valley, Texas Gov.. Rick Perry, became the highest level politician to invoke the Galileo comparison.

Well, I do agree that there is — the science is — is not settled on this. The idea that we would put Americans’ economy at — at — at jeopardy based on scientific theory that’s not settled yet, to me, is just — is nonsense. I mean, it — I mean — and I tell somebody, I said, just because you have a group of scientists that have stood up and said here is the fact, Galileo got outvoted for a spell.http://www.nytimes.com/2011/09/08/us/politics/08republican-debate-text.html?pagewanted=all

The founders of Australia’s “Galileo Movement” claim that global warming is a “fabrication,” and

 cite as inspiration Galileo Galilei, the 17th century astronomer and father of modern science, who challenged the dogma of the Roman Catholic Church to report the Earth orbited around the sun. http://www.scientificamerican.com/article.cfm?id=galileo-movement-fuels-australia-climate-change-divide

[3] personal communication, Spencer Weart, 9-17-2011.

[4] Wooton, David.   Galileo: Watcher of the Skies, Yale University Press, New Haven (2010), p. 224-5.

[5] Galileo died on January 8, 1642 at age 77.

[7] See Oreskes, Naomi and Erik M. Conway.  Merchants of Doubt, Bloomsbury Press, New York (2010)

[12] Dr. Spencer Weart’s excellent history of this period can be found in overview at http://www.aip.org/history/climate/summary.htm, with more details athttp://www.aip.org/history/climate/co2.htm, the linked timeline and other articles.

[13] Weart, Spencer.   The Discovery of Global Warming, Harvard University Press, New York (2004), p. 26

[14] Weart, p. 164.

[15] Weart, p. 191.

[18] http://www.aip.org/history/climate/summary.htm

[19] Oreskes and Conway, page 4, 198-213. 264.

[20] http://www.theaustralian.com.au/news/nation/climate-scientists-angered-by-deniers-death-threat-campaign/story-e6frg6nf-1226079058193

[21] Oreskes and Conway, p. 264-5.

[23]http://voices.washingtonpost.com/virginiapolitics/2010/07/the_university_of_virginia_hol.html    Also see the Climate Science Legal Defense Fund:  http://profmandia.wordpress.com/2011/09/09/donation/

Last updated on 3 February 2014 by dana1981.




Trying to replicate climate contrarian papers

Here’s what happens when you try to replicate climate contrarian papers:
A new paper finds common errors among the 3% of climate papers that reject the global warming consensus

Dana Nuccitelli, Aug 25, 2015, The Guardian

Here’s what happens when you try to replicate climate contrarian papers

Those who reject the 97% expert consensus on human-caused global warmingoften invoke Galileo as an example of when the scientific minority overturned the majority view. In reality, climate contrarians have almost nothing in common with Galileo, whose conclusions were based on empirical scientific evidence, supported by many scientific contemporaries, and persecuted by the religious-political establishment. Nevertheless, there’s a slim chance that the 2–3% minority is correct and the 97% climate consensus is wrong.

To evaluate that possibility, a new paper published in the journal of Theoretical and Applied Climatology examines a selection of contrarian climate science research and attempts to replicate their results. The idea is that accurate scientific research should be replicable, and through replication we can also identify any methodological flaws in that research. The study also seeks to answer the question, why do these contrarian papers come to a different conclusion than 97% of the climate science literature?

This new study was authored by Rasmus Benestad, myself (Dana Nuccitelli), Stephan Lewandowsky, Katharine Hayhoe, Hans Olav Hygen, Rob van Dorland, and John Cook. Benestad (who did the lion’s share of the work for this paper) created a tool using the R programming language to replicate the results and methods used in a number of frequently-referenced research papers that reject the expert consensus on human-caused global warming. In using this tool, we discovered some common themes among the contrarian research papers.

Cherry picking was the most common characteristic they shared. We found that many contrarian research papers omitted important contextual information or ignored key data that did not fit the research conclusions. For example, in the discussion of a 2011 paper by Humlum et al. in our supplementary material, we note,

The core of the analysis carried out by [Humlum et al.] involved wavelet-based curve-fitting, with a vague idea that the moon and solar cycles somehow can affect the Earth’s climate. The most severe problem with the paper, however, was that it had discarded a large fraction of data for the Holocene which did not fit their claims.

When we tried to reproduce their model of the lunar and solar influence on the climate, we found that the model only simulated their temperature data reasonably accurately for the 4,000-year period they considered. However, for the 6,000 years’ worth of earlier data they threw out, their model couldn’t reproduce the temperature changes. The authors argued that their model could be used to forecast future climate changes, but there’s no reason to trust a model forecast if it can’t accurately reproduce the past.

We found that the ‘curve fitting’ approach also used in the Humlum paper is another common theme in contrarian climate research. ‘Curve fitting’ describes taking several different variables, usually with regular cycles, and stretching them out until the combination fits a given curve (in this case, temperature data). It’s a practice I discuss in my book, about which mathematician John von Neumann once said,

With four parameters I can fit an elephant, and with five I can make him wiggle his trunk.

Good modeling will constrain the possible values of the parameters being used so that they reflect known physics, but bad ‘curve fitting’ doesn’t limit itself to physical realities. For example, we discuss research by Nicola Scafetta and Craig Loehle, who often publish papers trying to blame global warming on the orbital cycles of Jupiter and Saturn.

This particular argument also displays a clear lack of plausible physics, which was another common theme we identified among contrarian climate research. In another example, Ferenc Miskolczi argued in 2007 and 2010 papers that the greenhouse effect has become saturated, but as I also discussin my book, the ‘saturated greenhouse effect’ myth was debunked in the early 20th century. As we note in the supplementary material to our paper, Miskolczi left out some important known physics in order to revive this century-old myth.

This represents just a small sampling of the contrarian studies and flawed methodologies that we identified in our paper; we examined 38 papers in all. As we note, the same replication approach could be applied to papers that are consistent with the expert consensus on human-caused global warming, and undoubtedly some methodological errors would be uncovered. However, these types of flaws were the norm, not the exception, among the contrarian papers that we examined. As lead author Rasmus Benestad wrote,

we specifically chose a targeted selection to find out why they got different answers, and the easiest way to do so was to select the most visible contrarian papers … Our hypothesis was that the chosen contrarian paper was valid, and our approach was to try to falsify this hypothesis by repeating the work with a critical eye.

If we could find flaws or weaknesses, then we would be able to explain why the results were different from the mainstream. Otherwise, the differences would be a result of genuine uncertainty.

After all this, the conclusions were surprisingly unsurprising in my mind. The replication revealed a wide range of types of errors, shortcomings, and flaws involving both statistics and physics.

You may have noticed another characteristic of contrarian climate research – there is no cohesive, consistent alternative theory to human-caused global warming. Some blame global warming on the sun, others on orbital cycles of other planets, others on ocean cycles, and so on. There is a 97% expert consensus on a cohesive theory that’s overwhelmingly supported by the scientific evidence, but the 2–3% of papers that reject that consensus are all over the map, even contradicting each other. The one thing they seem to have in common is methodological flaws like cherry picking, curve fitting, ignoring inconvenient data, and disregarding known physics.

If any of the contrarians were a modern-day Galileo, he would present a theory that’s supported by the scientific evidence and that’s not based on methodological errors. Such a sound theory would convince scientific experts, and a consensus would begin to form. Instead, as our paper shows, the contrarians have presented a variety of contradictory alternatives based on methodological flaws, which therefore have failed to convince scientific experts.

Human-caused global warming is the only exception. It’s based on overwhelming, consistent scientific evidence and has therefore convinced over 97% of scientific experts that it’s correct.

The contradictory nature of global warming skepticism. By John Cook, Climate Communication Fellow for the Global Change Institute at the University of Queensland

A major challenge in conversing with anthropogenic global warming (AGW) skeptics is that they constantly seem to move the goalposts and change their arguments. As a consequence, they also frequently contradict themselves. One day they’ll argue the current global warming is caused by the Sun, the next that it’s “natural cycles”, the next that the planet is actually cooling, and the next day they’ll say the surface temperature record is unreliable, so we don’t even know what the global temperature is. This is why Skeptical Science has such an extensive skeptic argument list.

It should be obvious that the arguments listed above all contradict each other, yet they’re often made by the same skeptics. As one prominent example, in 2003 physicist and skeptic Fred Singer was arguing that the planet wasn’t warming, yet in 2007 he published a book arguing that the planet is warming due to a 1,500-year natural cycle. You can’t have it both ways!

It’s a testament to the robustness of the AGW theory that skeptics can’t seem to decide what their objection to it is. If there were a flaw in the theory, then every skeptic would pounce on it and make a consistent argument, rather than the current philosophy which seems to be “throw everything at the wall and see what sticks.” It would behoove AGW skeptics to decide exactly what their objection to the scientific theory is, because then it would be easier to engage in a serious discussion. . .

The contradictory nature of global warming skepticism

Table of global warming skeptic contradictions (click the link below for the full article)


Some climate change skeptics compare themselves to Galileo, who in the early 17th century challenged the Church’s view that the sun revolves around the earth, and was later vindicated. However, most scientists hold that this view is flawed; and in fact the opposite is true. Climate skeptics are not like Galileo.



Exxon knew of climate change in 1981, email says – but it funded deniers for 27 more years

Exxon knew of climate change in 1981, email says – but it funded deniers for 27 more years: A newly unearthed missive from Lenny Bernstein, a climate expert with the oil firm for 30 years, shows concerns over high presence of carbon dioxide in enormous gas field in south-east Asia factored into decision not to tap it.

ExxonMobil, the world’s biggest oil company, knew as early as 1981 of climate change – seven years before it became a public issue, according to a newly discovered email from one of the firm’s own scientists. Despite this the firm spent millions over the next 27 years to promote climate denial.

The email from Exxon’s in-house climate expert provides evidence the company was aware of the connection between fossil fuels and climate change, and the potential for carbon-cutting regulations that could hurt its bottom line, over a generation ago – factoring that knowledge into its decision about an enormous gas field in south-east Asia. The field, off the coast of Indonesia, would have been the single largest source of global warming pollution at the time.

“Exxon first got interested in climate change in 1981 because it was seeking to develop the Natuna gas field off Indonesia,” Lenny Bernstein, a 30-year industry veteran and Exxon’s former in-house climate expert, wrote in the email. “This is an immense reserve of natural gas, but it is 70% CO2,” or carbon dioxide, the main driver of climate change.

However, Exxon’s public position was marked by continued refusal to acknowledge the dangers of climate change, even in response to appeals from the Rockefellers, its founding family, and its continued financial support for climate denial. Over the years, Exxon spent more than $30m on thinktanks and researchers that promoted climate denial, according to Greenpeace.

Exxon said on Wednesday that it now acknowledges the risk of climate change and does not fund climate change denial groups.

Some climate campaigners have likened the industry to the conduct of the tobacco industry which for decades resisted the evidence that smoking causes cancer….

Exxon knew of climate change in 1981, email says – but it funded deniers for 27 more years