Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

New? Register here
Forgot your password?

Latest Posts


SkS Analogy 8 - I'll take the specialist

Posted on 15 June 2017 by Evan

Tag Line

I’ll take the specialist, please.

Elevator Statement

Your child has an eye injury and needs a doctor. Who are you going to call?

A Ph.D. in chemistry? No, you need a medical doctor.
A family-practice medical doctor? No, you need an eye doctor.
Any eye doctor? No, you need an eye doctor who does surgery.
Any eye surgeon? No, an experienced eye surgeon.

Because this is your child’s eye, you decide to take your child to two, experienced eye surgeons to make sure they agree on the course of action. You want consensus from at least two recognized experts in their field of specialty before messing with something as precious as the eye of your child. You care about your child and are using common sense.

Climate Science

You’ve heard that there is a global emergency on the planet on which your child is living, which is getting more and more severe, has already reached critical levels for some, and is increasingly threatening the lives of more and more people. You are concerned about the future your child faces, you want to get the facts, want to learn how to respond, and how to prepare. You want to know if this hype surrounding global warming, climate change, and ocean acidification is fact or fiction.

How will you get the facts? A lot of your friends have said they’ve “read this”, “seen that”, or “heard something else.” In the age of the Internet, you can find passionate views on all sides of any topic. Who do you believe?

There is a petition of over 30,000 “scientists” (the requirement is that the signatories have some kind of science-related degree) in the US who say that global warming is not a problem. 30,000 sounds like a lot, but actually this represents only about 0.3% of the people in the US who qualify to sign this petition, and they do not need to be studying climate science.

Would you trust the opinion of any 10 "doctors" to recommend the eye surgery needed for your child if they were a mixture of gynecologists, orthopedic surgeons, general practitioners, and chemical engineers with Ph.D.s? You would probably prefer to rely on the opinion of just 2 or maybe 3 qualified, experienced, eye surgeons.

So if this is how you approach the care of your child’s eye, why not use the same approach for the care of your child’s entire life, and the life of others on Earth you care about. Let’s see what real experts are saying.

We’ve all heard of Albert Einstein. In his day he was a geeky rock star with his theory of relativity, E=MC2, stretchy fabric of space with planets and stars warping here and there. He belonged to an exclusive group of people called the US National Academy of Sciences, which was set up by Abraham Lincoln in 1863 to advise the US Congress on matters of science. These are the Top Guns of the scientific community, and include many of the people responsible for the scientific miracles that we take for granted, like cell phones, computers, implantable medical devices, etc. They are the cream of the crop, individuals who think outside the box, challenge traditional thinking, and create scientific miracles that have transformed society. Periodically this group of Top Gun scientists put out publications on matters of interest to let us know what the consensus view is of the top scientists in the US. So let’s see what they say about global warming, climate change, and ocean acidification. The National Academy of Sciences published a book that you can download for free, called “Climate Change, Evidence & Causes.” Here are a couple of excerpts. When reading the following, substitute “over the coming century” with “in the lifetime of your children and grand-children.”

How confident are scientists that Earth will warm further over the coming century?
Very confident. If emissions continue on their present trajectory, without either technological or regulatory abatement, then warming of 2.6 to 4.8 °C (4.7 to 8.6 °F) in addition to that which has already occurred would be expected by the end of the 21st century.

Are climate changes of a few degrees a cause for concern?
Yes. Even though an increase of a few degrees in global average temperature does not sound like much, global average temperature during the last ice age was only about 4 to 5°C (7 to 9°F) colder than now. Global warming of just a few degrees will be associated with widespread changes in regional and local temperature and precipitation as well as with increases in some types of extreme weather events. These and other changes (such as sea level rise and storm surge) will have serious impacts on human societies and the natural world.

So who will you trust? 0.3% of Americans with some kind of science degree, or the Top Guns of the US science community?

Although the US NAS includes both climate and non-climate scientists, a separate study found that over 97% of current, practicing climate scientists endorse the consensus position of the US National Academy of Sciences.

In addition, the science academies from over 80 countries as well as the Vatican (Pontifical Academy of Science) endorse this position.

Humans are causing global warming, the problem is caused by greenhouse-gas emissions, mainly CO2, global warming is creating huge stresses on society that may cause irreversible degradation to our way of life, and the only sure way to stop the damage is to reduce the emissions of greenhouse gases to near zero.

The scientific evidence for CO2-induced warming dates from the 1800’s, the evidence is monumental, and yet the US Republican party continues to insist their own National Science Foundation is wrong. Perhaps the reason for their resistance to accepting the science can be summed up as follows.

Regarding global warming, a leading US Senator said “Do you realize I was actually on your side of this issue when I was chairing that committee [Environment and Public Works Committee] and I first heard about this, I thought it [referring to global warming] must be true, until I found out what it cost.” (See the Rachael Maddow show, about 4 minutes into an interview with Senator James Inhofe).

What does the cost of mitigation have to do with the accuracy of the diagnosis by the US National Science Foundation?

Typically a medical doctor will provide a diagnosis followed by multiple options for treatment. We don’t reject the diagnosis if the recommended treatment is expensive, but we might be forced to choose a treatment plan that fits our budget.

Doctors typically provide multiple options for treatment, and with global warming as well, we have multiple mitigation options. But failure to act is not one of the options. Taking action on Global Warming will be painful for us, but will mean a brighter future for our children. Failure to act will simply allow the problem to grow, shifting more of the burden and the pain to our children’s generation.

Acting now will mean a brighter future for our children.

Download the US National Academy of Sciences book called Climate Change, Evidence & Causes.”, read it, and make sure your children read it as well. This is an issue that is just as important as their immediate health ... it is about their future health.

3 0

Printable Version  |  Link to this page


Comments 1 to 22:

  1. Excellent analogy.  I have a similar analogy regarding eyesight.  It occurred to me that the climate debate can be simplified to determining just one number: the ECS (equilibrium climate sensitivity to doubled CO2).  If the ECS is greater than 2 C, then we need to take action.  If it is less than 2 C, then we can relax.  

    Can the public use its science-eyes to 'see' the ECS?  No.  The public's right eye definitely sees something: Climate science has been calculating the same ECS for over a century, and today converges on this average value, 3 C, from at least twenty different directions.  But there is a problem.  The public cannot trust what it's right eye sees because an entire fossil-funded doubt-industry has dedicated itself to throwing shade at the Climate scientists.  

    The public is thus blind in its right eye.  To make policy, however, it still needs to 'see' the ECS.  Lets ask the left eye, the eye of the Skeptics.  What do Skeptics 'see' for ECS, and can they please show their work?  But, there's a problem: the left eye is closed.  It turns out the only purpose of the left eye is to invent reasons why the right eye can't be trusted, not to see anything on its own.  There will always be a reason why they cannot calculate the ECS, or cannot show their work, but 'just know', intuitively, that ECS is less than 2 C  (Rarely someone like Christopher Monckton will calculate ECS, and show his work, and people will find the error in that work usually on the same day).

    Thus the public is blind in both eyes.  One eye cannot be trusted, and the other eye is closed.  So, until our vision improves, we'll just stumble along blindly in the same direction, hoping for the best.  Which is the entire reason a powerful industry funded the left eye in the first place.

    1 0
  2. Yes  clearly you need to ask the real experts, namely climate research scientists. Science has become so specialised these days, in fact all occupations have, and simply hiving a chemistry or physics degree isn't going to be able to tell you what's really happening with climate.

    In fact I would go further. It appears to me as an educated lay person, that the case that we are warming the climate rests on quite a wide range of evidence, unlike other theories which might rely on more limited labortatory experiments. This is because we cannot put the entire planet in a laboratory, so inferences and deductions are made from laboratory tests of carbon dioxide, paleo climate research, observations of changes in the atmosphere, modelling etc. Its very complex, and a monumental global exercise in research.

    The important point is it's hard for even one expert to see the full picture, and thus draw accurate conclusions. So only bodies of scientists like the IPCC or science academies can really get their heads around the full picture, and what it means. This means the consensus is particularly significant. This review by committee may be frustrating, but it is the only way of comprehending the full nature of the issue.

    And yes, the sceptical community are spreading doubt, but refuse to come up with a valid alternative theory, or anything convincing on climate sensitivity. It just seems they are driven by political ideology, vested interests and anger, because if they were really sincere, they would put all cards on the table,

    2 1
  3. Here is a perfect example of so called experts. Dr Gaiver has a mechanical engineering degree, plus a PHd in physics (something to do with semiconductor electronics) and has a nobel prize for physics, so clearly a bright guy with scientific credentials.

    He is also a well known climate sceptic. But he has never studied climate, and based much of his scepticism on one days worth of google searches on climate denial websites. His sceptical views are also on issues that have long since been genuinely debunked. Yet because he has a phd he gets peoples attention, and gets endlessly quoted by sceptics  (although selectively on what he says) even though his phd is not even remotely connected to the climate.

    Read his bio on wikipedia and also this article:

    "Shortly after Dr. Giaever delivered his speech, his comments about President Obama began appearing on conservative web sites, cited as proof that global warming is a “hoax” and a “conspiracy.” However, Dr. Giaever (a physicist, not a climatologist) has given the same type of global warming speech in the same setting before, and by his own admission he doesn’t know much about the subject:

    I am not really terribly interested in global warming. Like most physicists I don’t think much about it. But in 2008 I was in a panel here about global warming and I had to learn something about it. And I spent a day or so — half a day maybe on Google, and I was horrified by what I learned. And I’m going to try to explain to you why that was the case.
    Skeptical Science noted of Dr. Giaever back in 2012 that:

    While Giaever is certainly a highly accomplished physicist, that does not automatically make him a climate expert as well. As Giaever himself has admitted, he has spent very little time researching the subject, and it shows. He simply bounces from one climate myth to the next, demonstrating a lack of understanding of Climate Science 101, and then insults the entire scientific field by comparing it to a religion."

    2 0
  4. nigelj@3. What is also surprising about Dr. Giaever's comment that 0.8C warming is only about 0.3% of 288K ("From 1880 to 2015, the temperature has increased from 288 K [degrees Kelvin] to 288.8 K - 0.3 percent. I think the temperature has been amazingly stable."), is that any kind of trained engineer, scientist, or technical person knows that the scale you use depends on the question being asked. To do such simple math is really surprising, because just from the consideration of ice melting, a much more logical reference point is 0C, and not 0K. Relative to 0C a warming of 0.8C from 15C to 15.8C is something to worry about. But on the other hand, not even James Hansen has made a big deal of 0.8C warming, if that was what we were limited to. Apparently Giaever also does not realize that we are talking about warming of 2-4C. If you are ice, that is a really big deal.

    He should know this. But this is why we need to look for consensus opinioins, because such simple oversights get caught in a group of experts.

    0 0
  5. I note that the NAS states that global temperatures were 4 to 5 degrees lower during the last ice age than "now".  But we've warmed about one degree since the start of the Industrial Age.  So does that mean that Ice-Age temperatures were actually 5 to 6 degrees lower than the pre-industrial temperatures?  Or is that really 4 to 5 degrees lower than pre-industrial?

    0 0
  6. Digby Scorgie@5:  I've been wondering myself.  This graph says an 'ice age' (actually: glacial period) is about 4F to 8F colder than preindustrial.  

    420kyears of CO2, temp, and sea level, john englander

    8F is 4.5 C, so maybe that's what NAS means.  But I've been calling, in my personal correspondence, that an 'ice age' is, on average, 6F colder than preindustrial (average of 4F and 8F).  6F is about 3 C.  

    It's important to call attention not to the overall rise, but to the rise rate.  For example, the rise from the last glacial period was 3 C to preindustrial.  However, it took 10,000 years to accomplish.  That's a rise rate of 0.03 C/century, for one of the most radical natural climate changes recorded in prehistory (or, at least, the last 420,000 years).  By way of comparison, the rise rate in the 20th century was 25 times that value.  Natural?  I don't think so.  Worse: if the last 25 years is any guide about the 21st century, then this centuries rise rate is 75 times that natural value.  The people (Trump etc) who keep calling this climate change an example of 'natural' change, really need to explain why we are currently rising at a rate 75 times what a Milankovich Cycle would demand of Earth, naturally.

    0 0
  7. Evan @5, yes you would think Dr Giaver would realise small changes can have substantial effects, depending on the issue and context. He is an expert in  semiconductors, and these devices can amplify small currents into larger currents,so if anyone should appreciate this he should.

    However he might be thinking that these devices can also work with and remain stable with small fluctuations  in power supply voltage (I emphasise very small, I was investigating this to see if a smartphone power supply could work with my older spare mobile phone), and so thinks of the planet in those terms.

    However clearly humans have become adapted to a stable climate and face several degrees of change and this has to have consequences, and we know this from basic biology and the potential pressure on our infrastructure, communities, cities and agriculture.

    People see things from their learned perspectives, understandably enough, and I probably have my own biases.  He is probably applying analogies from his own specialist field, and has reaced a sceptical and flawed conclusion.

    0 0
  8. Digby Scorgie @5, Annan and Hargraves (2013) find a temperature difference between the preindustrial and the Last Glacial Maximum of 4.0 +/- 0.8o C.  The IPCC AR5 show a range of estimates as follows (Table 5.2):

    4.4–7.2; Single-EMIC ensemble with microfossil-
    assemblage derived tropical Atlantic SST; Schneider von Deimling et al. (2006)
    4.6–8.3; Single-EMIC ensemble with multi-proxy derived tropical SST;
    Holden et al. (2010a)
    1.7–3.7; Single-EMIC ensemble with global multi-proxy data; Schmittner et al. (2011)
    3.9–4.6; Multi-proxy; Shakun et al. (2012), for the interval 17.5–9.5 ka
    3.4–4.6; Multi-AOGCM ensemble with global multi-proxy data; Annan and Hargreaves (2013)
    3.1–5.9; Multi-AOGCM ensemble; PMIP2 and PMIP3/CMIP5

    The same table shows the East Antarctic temperature difference to be 7-10o C.  Any graph which shows a lesser temperature range using the Vostock ice core data has scaled the temperature to reflect the difference between the polar and global temperature.

    In any event, that suggests the NAS is claiming LGM temperatures 4-5o C below preindustrial temperatures, and hence 5-6o C below current temperatures.

    0 0
  9. It's a safe bet that virtually all physicists accept stochastic approaches like the "Monte Carlo Method" to studying the subatomic realm, because they have been undeniably successful in making discoveries that are backed up by experimental evidence. I sometimes wonder however, whether many in the physical sciences do not yearn, deep down, for the deterministic universe of pre-quantum days. One that does not require the troubling concept of randomness.

    For example, some of you may have encounterd an individual with a good grasp of meteorology who nonetheless finds climatology rather difficult to understand and essentially untrustworthy. Common misunderstandings of climate science occur to some extent because it is possible to negotiate a successful career in physics or engineering without the need for probability theory and statistical methods, let alone an understanding of complex global systems. In fact it is possible for the stochastically squeamish to earn an advanced degree without taking courses that addresses complexity of the sort the so called "soft" sciences routinely deal with.

    The days when a university education was comprehensive and initiated a lifelong process of keeping up with all fields of "Natural Science" are past (l-o-n-g past). Specialization is now essential, but the limitations of specialization require trust in the professionalism of other scientists. Unfortunately trust has all but evaporated in large segments of society. The concept of Professionalism itself is diminished by confusing it with obnoxious forms of elitism.

    By the way, I hope is not overly "political" to point out that the current mess we find ourselves in is an example of science applied by persons ignorant of how complex systems operate. We are literally witnessing uncontrolled "blowback" caused by unscrupulous social engineers who abused behavioral science. They employed sophisticated propaganda in pursuit of a certain limited result...... and got far more than they ever bargained for.

    I hope it was more. I'm not quite prepared to view our opponents in this debate(?) as being that derranged. Not yet.

    1 0
  10. What are the talents and experiences of the 3% of current, practicing climate scientists who do not endorse the consensus position of the US National Academy of Sciences? Historically, minority opinions about controversial subjects have often eventually prevailed while the majority opinions were found to be without merit. For example, apparently a significant percentage of legitimate scientists believed the "Piltdown Man" hoax for over 40 years:

    0 0
    Moderator Response:

    [DB]  Sloganeering and off-topic snipped.

  11. nigelj@3 said: "Giaever is... a highly accomplished physicist... not... a climate expert"   I've noticed Giaever also committed a fallacy I've started calling 'heads I win, tails you lose'.  In this case, no amount of temperature sensors covering the Earth, carefully adjusted to remove local effects like the urban heat island effect, and integrated together on an area basis will satisfy Dr Giaever that the climate scientists have done an adequate job calculating Earth's temperature... Tails You Lose.   A few minutes later, Dr Giaever casually points to a single temperature sensor, at the South Pole, which has cooled in recent decades, and declares this proves his point about Earth not warming... Heads I Win.

    As Donald Trump would say: "There's a real winner!"

    0 0
  12. dfwlms @ 10. The experience, talent and expertise of the researchers involved is completely irrelevant. First, one would have to quantify these according to objective criteria, an undertaking in its own right.

    Regardless of their "ranking" in these matters, they are only still 3%. Most people choosing the consensus as their favorite denmial target attempts to depict it as a consensus of opinion, while it is in fact a consensus of research results. 97% of scientists actively researching climate find that their research supports the current model of Earth climate and the influence of greenhouse gases, that's what matters.

    0 0
  13. Dfwlms @10 says:

    "What are the talents and experiences of the 3% of current, practicing climate scientists who do not endorse the consensus position of the US National Academy of Sciences? "

    Where are you going with that? Climate scientists all tend to have advanced degrees from what I have seen.

    And what would it matter? Having a poor qualification does not mean you are wrong, and having an exceptional qualification does not prove your assertions to be correct. This is the "argument from authority" fallacy as below. Qualifications are worthy of our respect, but they do not prove an argument or theory to be true or false, and only experiment and so on can prove that.


    "Historically, minority opinions about controversial subjects have often eventually prevailed while the majority opinions were found to be without merit."

    Sometimes this has been the case. Please quantify and prove what you mean by "often". 

    And what is your point? Its like you are implying some theories have been wrong in the past therefore climate science is by definition wrong. This is a pretty illogical claim, if you are making it. The scientific consensus has been wrong on some things, but that does not mean it is wrong on everything. All we can really say is scepticism has its place - but obviously has to be based on something compelling.

    And what is your alternative to scientific theory and consensus? Should the public just listen to whoever shouts loudest?

    I can at least say the large consensus views of physics and biology of this and last century have proven to be very durable, eg evolution, quantum theory, plate techtonics  etc.

    Some smaller consensus positions have proven to be only partly correct, eg dangers of saturated fats. In fact consensus positions sometimes evolve, rather than radically and completely change.

    "For example, apparently a significant percentage of legitimate scientists believed the "Piltdown Man" hoax for over 40 years: "

    That was a long time ago, when anthropology was in its infancy.   More modern scientific theories are much better scrutinised than piltdown man, because science itself has progressed, we have more scientists in the planet, communication systems have improved, science education has spread, and so on.

    0 0
  14. Ubrew12 @11, yes Giaver is like that.

    I recall Giaver complaining that the Antarctic or Arctic (I can't remember which) "only" had 10 weather stations, but he seems singularly unable to define exactly how many weather stations he want's, and why. It's like there would never be enough for him, and he is possibly saying "you cannot prove you have enough therefore, I'm going to say climate change is a fallacy". 

    In fact it's really hard to say exactly how many weather stations you ideally need globally. It's hard to quantify this.

    But the planet has thousands of weather stations through most countries, with gaps mainly in central africa. Even 10 in the Antaractic is obviously a lot better than just one or two, and they are reasonably dispersed.

    I suggest we intuitively know the thousands of weather stations across the planet that are at least reasonably widely dispersed, gives a good idea of global average temperatures that is pretty accurate, and accurate enough for our purposes. And its possible to look at areas with poor cover, and ask the question of whether it's likely temperatures in those areas whould be higher or lower, based on adjacent areas, and knowledge of their geography etc. We cant be 100% certain, but we can be pretty certain.

    Basically I feel people like Giaver are demanding 100% coverage and 100% certainty, yet as a scientist he should know things dont work like that and generally aren't possible. Maybe he has some hidden ideological agenda but I dont want to speculate. I just think he is being unreasonable.

    1 0
  15. While it's obvious to most, "sceptics" like Giaever, and many others, totally miss the point when they talk about problems with measuring the global average temperature. What anomalies measure is trend at a location. The global set of anomalies is the global sample of trends not the global sample of temperatures. Nowhere in there is any attempt to measure global mean temperature, nor should there be. Sampling issues remain, but the issue is whether there is sufficient coverage to infer trends averaged globally not whether there is sufficient coverage to measure global average temperature. While more coverage is good, what reasons do we have to assume that unsampled areas are systematically different from already sampled areas in ways not already identified and corrected for (e.g., urbanization at sampling sites)? 

    Giaever's critique focuses on showing the difficulties involved in measuring a completely irrelevant variable.

    1 0
  16. Tom Curtis @8


    0 0
  17. Dr. Giaever, President Trump and the rest of them are simply standing in the way, so we'll just have to walk around them.

    0 0
  18. Climate change is more like a cancer than an injury though, taking a long time to present definite symptoms and requiring a variety of invasive treatments over a long period of time.

    There are many cancer sufferers who decide not to undertake the treatments due to the high costs and known painful side-effects, particularly if a successful outcome has a low probability. 

    Similarly, with climate change mitigation, people will only be encouraged to pay for the treatments if there's a high probability that they will cure the disease, and they need to be confident that the treatments themselves don't create many years of misery.  I have a brother with a rare form of Leukemia that could be treated today with highly invasive and high risk treatments, but he's chosen a path of non invasive and low risk measures that will hopefully buy him enough time to still be alive when better and safer treatments that offer a cure are available.   

    0 0
  19. Fortunately most cancer treatments dont have do-nothing advocates exaggerating the cost of the treatment so they dont lose market share. In your brothers case another interesting analogy comes up. Suppose instead it was your 3 year old son. What route would take and whose advice would you trust about likelihood of surviving till a better treatment comes? Mostly we are making decisions about what a future generation would face.

    0 0
  20. Conversely, cancer treatments also don't have advocates that overstate the effectiveness and avoid mentioning potential down-sides. So it cuts both ways.

    I agree though, with the exception of people in their 20's or younger, most of us will probably avoid the dire consequences of climate change. Speaking only for myself here, but I think the best thing that I can do for my children and future grandchildren is to leave enough money to help them live as comfortably as possible and in the best place possible, though I accept that that's a selfish motivation. But I guess that's my point anyway. Most people will act out of self interest before collective interest, and most people will plan for the short term before they plan for the medium or long term.

    0 0
  21. "Conversely, cancer treatments also don't have advocates that overstate the effectiveness and avoid mentioning potential down-sides. So it cuts both ways."

    I think you will many to dispute that, but rather offtopic.

    I find your view of humanity depressing. Glad I dont live where you live.

    0 0
  22. Art Vandelay,

    Billions of dollars are wasted in the USA screening for prostrate cancer.  Doctors make billions of dollars treating the poor souls who screen positive.  Millions of American men have been rendered inpotent or incontinent by this treatment.  Studies show that few deaths are prevented by all this treatment.  In Europe, where the health system focuses on patient outcomes and not the profit of doctors, they have made much less use of the PSA screening test and have better overall health outcomes.  The surgeons do not make as much money.

    The fossil fuel industry has cried wolf many times during my lifetime over environmental regulations causing economic damage. You need to find a new analogy.

    0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

The Consensus Project Website


(free to republish)

© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us