Month: August 2024

Being Properly Skeptical of Expert Consensus

Solvay conference 1927, probably the most intelligence ever photographed. 17 of the 29 attendees were or became Nobel Prize winners.

Miriam Solomon writes at  iai news Scientific consensus needs dissent.  Excerpts in italics with my bolds and added images

We place high epistemic value on expert opinion and when it reaches a consensus, we may view this as settled science. But, writes Miriam Solomon, we should not equate expert opinion with certainty. While expertise is a valuable guide to decision-making, experts can be prone to human error too. Laypeople can, and should, critically evaluate how expert consensus is reached.

We live in an immense, complex world, and frequently benefit from guidance from those with more information and experience—people we regard as experts—to make sense of it. Along these lines, we often use expert consensus as an indicator of what is known, and expert disagreement as an indicator of what is uncertain. So, for example, earth scientist and historian Naomi Oreskes appeals to the record of peer-reviewed scientific publications on climate change to argue that the public should listen to the expert consensus that there is anthropogenic climate change. Oreskes identified that those who publicly disagree with this consensus have not contributed to the peer-reviewed scientific literature on climate science, and in this way they are not experts with regard to the relevant subject matter, although they may have PhDs and even university positions in unrelated sciences.[Note that position ignores many expert climatologists who disagree, but who are dismissed as “deniers” because they dissent.]

Survey starting the narrative “97% consensus of experts agree humans are causing global warming.”

Oreskes dissuades us from taking such non-expert disagreement seriously, especially since she also finds that it is politically motivated. The appeal to expertise encourages us to trust those who know more than we do about a particular matter and invites us to pay attention to reliable markers of expertise, such as publication in relevant peer-refereed journals. In traditional epistemological terms, it recommends deference to epistemic authority (or authorities).

However, even experts are fallible. Expert consensus
should not be equated with certainty or truth.

But experts are more likely to be correct than non-experts, and the agreement of experts with one another can provide additional evidence for the robustness of their conclusions.  Oreskes’ approach implicitly relies on the trustability of the relevant experts, not only on their expertise. We need to know not only that experts are knowledgeable but that they are acting in the best interests of furthering knowledge. The integrity of science—its commitment to norms such as openness of inquiry, responsiveness to criticism, disinterestedness, etc. (see Merton (1942) and Longino (1990))—is vital for its trustability.

Sometimes, this trust can be eroded. Philosopher of medicine Maya Goldenberg has explored what is needed for laypersons to build justified trust in vaccine research, mentioning concerns about Big Pharma producing biased research and concerns about the historical record of medical, scientific, and governmental communities’ willingness to use untested medical technologies on marginalized groups.

When experts disagree—a common occurrence in science—deference to expertise yields conflicting results. Laypersons are apt to respond to such disagreements, such as which sorts of diets are best for long-term health, or which vaccines should be mandated and for whom, with statements such as “even the experts don’t know.”

Knowing this, experts are aware of the need for a public
face of consensus on matters they wish to influence
.

They have become savvy about disseminating any publicly relevant consensus that is achieved. This thinking is behind established institutions such as the United States’ NIH Consensus Development Conference Program (1977-2013), which issued regular reports on new clinical interventions, and the Intergovernmental Panel on Climate Change (1988-present), which issues regular updates on climate science.

Forcing a consensus when the science is not there rarely works.

Deferring to the consensus of trustable experts is one of the best kinds of argument based on epistemic authority. It is certainly better than the Scholastic practice of referring to the writings of just one “great man,” such as Aristotle or Aquinas. Several experts coming to the same conclusion about a matter is usually more convincing than one expert coming to that conclusion. However, as many have pointed out, the strength of the argument depends on:

(1) the degree of independence of these experts from each other, and
(2) the individual and collective interests of these experts.

Scientists, like the rest of us, come to their knowledge in social context and, generally speaking, scientists are neither independent of each other nor completely interest-free. They are often trained similarly—by the same schools, people, and educational materials—and feel pressured towards group conformity as well as towards deference to uber-experts. Scientists have individual biases, such as confirmation bias, that can be magnified when one scientist influences another. There are many well-known cases in the history of science and medicine in which expert consensus has turned out to be incorrect and harmful. Some examples in medicine are the traditional practice of blood-letting as a general cure-all, the use of surgery and antacids for stomach ulcers, and the practice of radical mastectomy for early stage breast cancer.

Thus, while deferring to the consensus of experts is often a good practice, it is defeasible: there are circumstances in which that deference is not ultimately justified. It is worth spelling out what those circumstances are. Here are some questions to ask of any purported expert consensus.

♦  Who agrees? Is there any dissent—if so, is it between particular groups of experts (say, family medicine practitioners disagreeing with radiologists about the effectiveness of screening mammography) or between experts and non-experts?

♦  What do the dissenters say? It is necessary to get at least a little “into the weeds” of dissent to decide whether or not dissenters are worth taking seriously.

♦  How long has there been agreement? If agreement is new, what brought it about? In particular, how much of a role did new evidence play?

♦  If agreement is longstanding, would counterevidence be sought, noticed and responded to?

These kinds of questions are a check on the processes that led to consensus. There will always be some social processes such as peer pressure and graduate school training that are unrelated to relevant evidence yet play a role in expert belief formation. This does not mean that we should distrust all consensus that has any sources in “bias.” That is too idealistic. Instead, we should look at the complete picture of what played a role in consensus formation and try to assess whether new evidence had a deciding role.

It is also worth reflecting that consensus is not the general end goal of science. Scientific communities tolerate—even benefit from—lack of consensus. Already in the nineteenth century, the philosopher John Stuart Mill put things especially well in On Liberty (1859) when he argued that consensus is an obstacle to progress, rationality and truth because it eliminates points of view that may turn out to be partially or wholly correct, or at least useful for criticism and consequent refinement of the correct view.

 

Dissent is strategically valuable when it leads to the distribution of cognitive labour over a variety of perspectives, hypotheses, and methods. While individual experts are often over-confident about their own views, this does little harm when it does not get in the way of other experts exploring alternatives. It is best to have the scientific community pursue all promising lines of inquiry.

Achieving consensus on a scientific matter becomes important only when there is a need for cooperative communal action and there needs to be agreement on steps to take to achieve a policy goal, such as health or sustainability. Even in such cases, there need not be agreement on all issues. The publications of the Intergovernmental Panel on Climate Change are quite clear that there is plenty of disagreement between scientists on some of the details of climate science. What is emphasized is that there is sufficient consensus on basic matters to guide important policy decisions. 

Expert consensus is an important, but not infallible, guide for laypeople and decision-makers. The strength of a consensus depends on the independence of the experts involved and the processes that shaped their agreement. While deference to experts is often justified, it should be accompanied by critical scrutiny, particularly when consensus is used to guide public policy. Dissent within the scientific community remains essential, not only for advancing knowledge but also for ensuring that consensus, when achieved, is robust and reliable.

 

via Science Matters

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August 24, 2024 at 12:45PM

Claim: A Trump Victory Would Set the Planet On Fire

Essay by Eric Worrall

The Trump obsessed media is still talking about Trump and Elon Musk dissing climate tropes.

The new wave of climate claptrap

Misleading, misinformed or just plain baffling utterances continue to gush forth in the face of an increasingly evident problem.

Pilita Clark Columnist

You can sum up the world in just one word today: hot.

Powerful heatwaves have struck every continent over the past year. At least 10 countries have recorded daily temperatures above 50 degrees in more than one place. Wildfires are scorching unusually large areas of the globe and coral reefs have been hit by the fourth global bleaching event on record.

But last week, in a conversation on his X platform with Donald Trump, Musk said the climate risk wasn’t actually as high as many thought before launching into a mystifying explanation for why there was loads of time left to tackle it.

If the accumulation of carbon dioxide in the atmosphere keeps rising from today’s average levels of around 420 parts per million to above 1000 ppm, “you start getting headaches and nausea”, he told Trump. But since we’re only adding about 2 ppm of CO₂ a year, “we still have quite a bit of time” and “we don’t need to rush”.

This is claptrap of the highest order. The heat, flooding and fire disasters we’re seeing with the amount of warming that accumulated CO₂ has already driven will be paltry compared to what would happen if levels rose to anything like 1000 ppm.

Read more: https://www.afr.com/policy/energy-and-climate/even-musk-has-got-caught-up-in-the-new-wave-of-climate-claptrap-20240821-p5k46j

Thankfully we have proof the claim a 1000ppm CO2 world would be a fire ravaged disaster zone is utter nonsense. From the hothouse world of the PETM, 5-8C hotter than today, estimated CO2 levels around 1500ppm

Fire and ecosystem change in the Arctic across the Paleocene–Eocene Thermal Maximum

Author links open overlay panelElizabeth H. Denis a1, Nikolai Pedentchouk b, Stefan Schouten cd, Mark Pagani e2, Katherine H. Freeman a

Volume 467, 1 June 2017, Pages 149-156

Highlights

  • •Increased PAH abundances relative to plant biomarkers suggests increased fire.
  • •Angiosperms increased relative to gymnosperms based on pollen and plant biomarkers.
  • •Wetter and hotter conditions preceded increased angiosperms and greater fire.
  • •During the PETM in the Arctic, climate-driven changes in ecology increased fire.
  • •Fire may have attenuated the effects of increases in plant biomass on carbon cycle.

Abstract

Fire has been an important component of ecosystems on a range of spatial and temporal scales. Fire can affect vegetation distribution, the carbon cycle, and climate. The relationship between climate and fire is complex, in large part because of a key role of vegetation type. Here, we evaluate regional scale fire–climate relationships during a past global warming event, the Paleocene–Eocene Thermal Maximum (PETM), in order to understand how vegetation influenced the links between climate and fire occurrence in the Arctic region. To document concurrent changes in climate, vegetation, and fire occurrence, we evaluated biomarkers, including polycyclic aromatic hydrocarbons(PAHs), terpenoids, and alkanes, from the PETM interval at a marine depositional site (IODP site 302, the Lomonosov Ridge) in the Arctic Ocean.

Biomarker, fossil, and isotope evidence from site 302 indicates that terrestrial vegetation changed during the PETM. The abundance of the C29 n-alkanes, pollen, and the ratio of leaf-wax n-alkanes relative to diterpenoids all indicate that proportional contributions from angiosperm vegetation increased relative to that from gymnosperms. These changes accompanied increased moisture transport to the Arctic and higher temperatures, as recorded by previously published proxy records. We find that PAH abundances were elevated relative to total plant biomarkers throughout the PETM, and suggest that fire occurrence increased relative to plant productivity. The fact that fire frequency or prevalence may have increased during wetter Arctic conditions suggests that changes in fire occurrence were not a simple function of aridity, as is commonly conceived. Instead, we suggest that the climate-driven ecological shift to angiosperm-dominated vegetation was what led to increased fire occurrence. Potential increases in terrestrial plant biomass that arose from warm, wet, and high CO2 conditions were possibly attenuated by biomass burning associated with compositional changes in the plant community.

Read more: https://www.sciencedirect.com/science/article/abs/pii/S0012821X17301577

Hangon, didn’t that study just say fires increased in the PETM?

Yes, but read it again. The fires increased, but only in proportion to changes in vegetation. The change of fire risk was because the warmth and elevated CO2 of the PETM changed the type of vegetation growing in the Arctic.

Angiosperms = trees, and other woody flowering plants. In place of today’s Arctic tundra, the Arctic of the PETM was covered in trees.

The point is, even if a temperature excursion as extreme as the PETM were to occur, the fire risk could be managed by adopting the fire mitigation policies of the state to to the south of your current home. There will be no CO2 driven fiery apocalypse, even if CO2 levels hit 1000ppm or higher. The only changes to fire risk would be driven by alterations to the types of plants which are growing, and improvements in growing conditions – all of which could be mitigated by adopting the fire management practices of places which already enjoy such conditions.

Pilita Clark, you are supposed to be a journalist for a responsible financial paper. You owe it to your readers to do a little research, before publishing wild, “claptrap” claims about global warming.


The Trump / Musk interview is available here

via Watts Up With That?

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August 24, 2024 at 12:05PM

WHAT IS THE COST OF CARBON CAPTURE UTILISATION AND STORAGE?

 CCUS applications do not all have the same cost. Looking specifically at carbon capture, the cost can vary greatly by CO2 source, from a range of USD 15-25/t CO2 for industrial processes producing “pure” or highly concentrated CO2 streams (such as ethanol production or natural gas processing) to USD 40-120/t CO2 for processes with “dilute” gas streams, such as cement production and power generation. Capturing CO2 directly from the air is currently the most expensive approach.

Moving on to the cost of transport and storage, this can also vary greatly on a case-by-case basis, depending mainly on CO2 volumes, transport distances and storage conditions. In the United States, for example, the cost of onshore pipeline transport is in the range of USD 2-14/t CO2, while the cost of onshore storage shows an even wider spread. However, more than half of onshore storage capacity is estimated to be available below USD 10/t CO2

Is carbon capture too expensive? – Analysis – IEA

The following video looks at the problems with this as well as stating its importance, assuming that capturing and storing CO2 is necessary.

How does carbon capture and storage actually work? | ABC News (youtube.com)

All this begs the question – do we need to do this at all? The answer to that depends on whether you believe the planet is facing a looming disaster caused by CO2. If we don’t ( and I believe the evidence is very doubtful) then we certainly do not have to spend billions of dollars capturing and burying it.

via climate science

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August 24, 2024 at 09:46AM

Sunday

10 out of 10 based on 1 rating

via JoNova

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August 24, 2024 at 09:35AM