Climate Science Glossary

Term Lookup

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

Settings

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

Settings


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 Donate

Twitter Facebook YouTube Pinterest

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...



Username
Password
Keep me logged in
New? Register here
Forgot your password?

Latest Posts

Archives

Climate Hustle

Do the IPCC use alarmist language?

Posted on 14 October 2010 by James Wight

Graham Wayne has recently written rebuttals to “The IPCC consensus is phony” and “IPCC is alarmist”. But, you might say, that’s only half the story – do the IPCC present their conclusions in an alarmist way? There are many different ways you might look at this, but one of the more important ones is how the IPCC present probabilities (or “likelihoods”).

Thinking about probability does not come intuitively to the human mind. Our assessment of a risk often depends on how the probability is presented.

Suppose you are about to get on a plane and a reliable source tells you that there is a 1% chance that the plane will crash during your flight. Do you still want to get on the plane? I’m guessing you’d be having second thoughts about it.

What if the probability of a crash is 1 in 20? 1 in 10? 1 in 3? You’d probably run away screaming.

I’ll get to the point of all this shortly, but please bear with me and consider the following quote from the IPCC’s Fourth Assessment Report (AR4):

“It is very unlikely that [Atlantic Ocean circulation] will undergo a large abrupt transition during the 21st century.” [Source]

Are you alarmed yet? Is this an example of the IPCC using alarmist language in reporting its conclusions?

To answer this question, you first have to understand what the IPCC are trying to say. In the introduction to the AR4 Synthesis Report, there is a detailed description of how uncertainty is treated in IPCC reports, and I don’t think the public appreciates just how un-alarmist it is. A 1% chance scarcely rates a mention: anything with such a low probability is described as “exceptionally unlikely”. A probability of 1 in 20 is considered to be “extremely unlikely”; 1 in 10 is “very unlikely”, and even 1 in 3 is still “unlikely”. Conversely, 2 in 3 is “likely”, 9 in 10 is “very likely”, 19 in 20 is “extremely likely”, and 99% is “virtually certain”.

So if you asked the IPCC to do a report on your plane trip, and the probability of a crash was smaller than 1 in 10, about half a decade later they’d get back to you with something like: “It is very unlikely that this plane will crash.” (Except that it would probably be a lot wordier than that.)

And when the IPCC says an abrupt transition in Atlantic Ocean circulation is “very unlikely”, they mean the same thing: the chance is less than 1 in 10. Yet you’re probably not running away screaming.

Most of the IPCC’s main conclusions are given a high degree of likelihood. Probably the most quoted sentence from the entire AR4 is:

“Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” [Source]

Translation: the likelihood that humanity’s greenhouse gas emissions are causing global warming is greater than 9 in 10.

Another important conclusion (though not particularly new to the AR4) is this:

“[T]he equilibrium global mean [surface air temperature] warming for a doubling of atmospheric carbon dioxide (CO2), or ‘equilibrium climate sensitivity’, is likely to lie in the range 2°C to 4.5°C, with a most likely value of about 3°C. Equilibrium climate sensitivity is very likely larger than 1.5°C.” [Source]

Translation: the chances are 2 out of 3 that a doubling of atmospheric CO2 will warm the planet by between 2 and 4.5 degrees; 9 out of 10 that it will be more than 1.5 degrees.

One more IPCC quote:

“It is very likely that hot extremes, heat waves and heavy precipitation events will continue to become more frequent.” [Source]

That is, the chances of more extreme weather are higher than 9 in 10. If you’re thinking that wilder weather is not exactly as serious as a plane crash, then consider that over 20 million people have been affected by the 2010 Pakistan floods. This sort of extreme weather event will become more frequent with global warming. Do we, does humanity, really want to get on this plane?

The IPCC are not alarmist in their conclusions, and they are no more alarmist in the way they report their conclusions.

0 0

Bookmark and Share Printable Version  |  Link to this page

Comments

Comments 1 to 46:

  1. ...and, on top of that, observations show the reality has been at least as dire as IPCC projections. Hardly a sign of "alarmism".
    0 0
  2. Not to nitpick but with over 50,000 commercial airline flights per day I think the IPCC would more likely rate the chances of your plane crashing as “exceptionally unlikely.”

    Other than that, great post! :-)
    0 0
  3. James,

    Interesting post. Just to place the cost of these natural disasters in context. Putting the tragic and painful loss of life aside for a second, the cost of the floods in Pakistan is estimated at almost 10 billion dollars (World Bank).

    It is also noteworthy that the IPCC in AR4 (their most recent report released in 2007) underestimated the loss of Arctic sea ice and increase in global sea levels. GHG emissions are currently running along the upper edge of their uncertainty range. So much for them being "alarmist"....

    Re the plane analogy. I personally think that we have all purchased our tickets and are barreling sown the runway knowing that there is something wrong with one of the engines. Yet, the 'skeptics' on the plane are arguing about what could be making that disturbing noise, or what natural cause might be responsible for the smoke spewing from engine number 2. Meanwhile, the pilots (and flight attendants) are taking action to mitigate the damage and avert disaster.

    Not I perfect analogy I know, but I'm in a rush ;)
    0 0
  4. Amazing that Skeptical Science's James Wight betters the Royal Society when it comes to dealing with this. In the mind of the public one of the central problems in dealing with this affair is thinking about risk. While the RS failed to lend sufficient emphasis to explanations of probability and hence risk in their most recent attempt at a statement, here's a useful elaboration of the IPCC's own acknowledgments. Thanks, James.

    On a broader note, a lot of skeptic infection depends on people never actually looking at the IPCC report. James linked it above, here it is again just in case somebody missed it.

    Speaking of alarmists, perhaps it ought to go in the "incoherence thread" but reading this I was immediately struck by how frequently skeptics refer to our lamented warming as quite possibly helping us avert another Ice Age. I've never seen these claims bracketed with language on uncertainty...
    0 0
  5. Very nice explanation, James. Well done.
    0 0
  6. It's OK to be alarmed when facing extinction
    0 0
  7. I suppose IPCC have not heard of six sigma.

    The area under one tail of the normal curve 6 sigma out is approximately 10^-9, which corresponds to a probability of 1 in a billion. The area under one tail of the normal curve 4.5 sigma out is approximately 10^-6, which corresponds to a probability of about 1 in a million. Manufacturing strives for a failure rate of less than 1 in a million.

    Now some food for thought. The space shuttle has more than one billion parts. What is the probability that the shuttle will fail if each part has a probability of 1 in a million of failing?

    So where would IPCC come up with their numbers? A dart board? Or let's see; nine papers out of ten said that a doubling of atmospheric CO2 will warm the planet by more than 1.5 degrees, so the probability is 9 out of 10 that it will be more than 1.5 degrees.

    So which would be more useful to the reader, 9 out of 10, where the numbers were pulled from their butts, or "very" and (un)"likely", which were also pulled from their butts and mean nothing. I claim that the second option is closer to reflecting what the IPCC really knows about their probabilities.

    $Billions have been spent on computing the space shuttle's probability of failure and probability of catastrophic failure. Here is a little discussion. How well did they do? Miserably. Probably about the same as the old Indian who held up a piece of rope to predict the weather. If it's wet it's raining and if it wiggles the wind is blowing.

    Probability is all relative. I wouldn't rely on any of their "Three different approaches are used to describe uncertainties..." Astronauts are reckless and know they have a much greater probability of blowing up than passengers in James' airplane. But I'm not, and I won't get on board, especially if he is relying on other sources for his information. How many important inputs were "estimated" (scientific wild ass guesses or SWAGs?) or ignored or left out for simplicity or cost reduction or just overlooked? Back in my college days I computed numbers to three digits with my trusty old Post slide rule. Today, students compute answers to sixteen or more digits and write them all down. Which answer is more accurate? Precise?

    My advice is, read the information and study the charts and graphs. If something is "very important" to you, then don't take their word for it, but dig deeper into the subject.
    0 0
  8. Robert - You could read the papers on estimating uncertainty and probability in various aspects of climate instead of making unsubstantiated suggestions about dart boards. eg Annan and Hargreaves. Montecarlo methods are more common in complex model uncertainty estimation.
    0 0
  9. In one of my many former life, I did used to calculate failure risk in space mission. This is not that difficult. All you need is decent estimate of the component reliability. Those have to be crossverified when possible.

    As for probability assesment, IPCC language has been used to translate scientific uncertainties in layman language. In my mind, this is a combinaison of reported uncertainties (combined pdf) and expert assesment. This is not different of what you see in other field like risk management where similar approach is used.
    0 0
  10. It's OK to be alarmed when facing extinction


    What does that have to do with climate change or airplanes?
    0 0
  11. #7: "more than one billion parts. What is the probability that the shuttle will fail if each part has a probability of 1 in a million of failing?" That's not food for thought, its nonsense. The independent probabilities of multiple events don't add.

    But we should ask: What is the really alarmist language? The 'very likelys' or 'most likelys' described above? Compare those mild-mannered phrases to 'scam', 'fraud', 'big lie', 'propaganda', 'deceitful', 'snowmageddon', and the like.

    0 0
  12. "Montecarlo methods are more common in complex model uncertainty estimation."

    I have been in the computer-based modeling and simulation business for over thirty years. I invented the acronym GIGOSIM, which stands for Garbage In, Garbage Out SIMulation. When using computer-based models to analyze highly complex, nonlinear systems whose accurate response predictions depend on many nonlinear topological relationships, parameters, and input data, it is absolutely necessary to identify and include all significant topological, parametric, and boundary data. Montecarlo methods may have some utility if a model's topological and boundary relationships are fairly well established, otherwise they could "verify" erroneous models whose output may appear to give the expected results. Nonlinear systems can do that.

    Yvan Dutil said, "I did used to calculate failure risk in space mission. This is not that difficult. All you need is decent estimate of the component reliability."

    If it is not so difficult, then why has NASA spent $Billions on it and failed? Because the space shuttle is a nightmare. A little O-ring failure here a little insulation impacting a tile there. A gas leak here a stuck valve there. I've a feeling Earth's climate is no different. Just as one can't model part of a space shuttle without knowing thousands of boundary conditions, one can't model part of Earth's environment without knowing thousands of boundary conditions. Too many scientists zoom in on one or a few critical factors while ignoring others in the name of simplifying down to manageable levels at the risk of biased or even incorrect projections. This could lead to GIGOSM, and let the reader beware.
    0 0
    Moderator Response: If you want to discuss the specific topic of climate models' validity, please do so on the thread Models are unreliable.
  13. Roger Wehage, you will be surprised to learn that there is more to decision theory than "six sigma." Many decades more to it. There are societies, journals, academic departments, technologies, and successful commercial consultancies specializing in application of those technologies. Just type "decision theory" into your internet search engine.

    Specifically regarding the IPCC, you could read the relevant sections of the IPCC reports that describe how the IPCC decided on their published probability estimates.

    But if that's too technical, then you might be interested in a good poster that was presented at the American Geophysical Union in 2009. It was by a PhD student in philosophy, rather than by a statistician, so it is a good, comprehensible, basic, explanation. It does not seem to be online except for its abstract ("A Defence of the AR4's Bayesian Approach to Quantifying Uncertainty"), but perhaps if you contact the author he will send you the contents.
    0 0
  14. "That's not food for thought, its nonsense. The independent probabilities of multiple events don't add."

    You are absolutely correct. They don't just add or subtract or multiply or divide; they do all these plus thousands or millions of others.

    Try this: You have a rectangle whose length and width are each described by a normal distribution with a different mean and standard deviation. How would you describe the rectangle's area, length time width? What if opposite sides weren't parallel, and the angles were described by normal distributions with different means and standard deviations? What if the sides weren't even straight lines? What if the distributions weren't normal, but skewed or lognormal or something else?

    The algebra of probabilistic distributions is extremely complex and a danger in the hands of people who don't understand it or who pretend to. Extrapolating complex environmental data described by complex statistical relationships into the future is indeed a difficult process and subject to many hazards in the hands of those who don't have the prerequisite background or tools.

    I know enough to know that I have neither the prerequisite background nor the tools to predict the probabilistic distribution of anything more than simple statistical examples.
    0 0
  15. Well I would have to agree with you on need to explore all parameter uncertainty, and I think (but dont know for sure) that they dont have computer power to explore full model. Annan has paper coming out on model ensemble determination. However, note the approach in climate sensitivity estimation.
    0 0
  16. #14: "The algebra of probabilistic distributions is extremely complex" Switching to Models are unreliable as per Mod request.
    0 0
  17. Good to see this covered properly - thanks James. Understanding the nature of predictive science, which can only deal with probabilities, is key to appreciating the nature of the problems we face and the overwhelming likelihood that our actions are storing up great and disruptive problems for the future.
    0 0
  18. As a "truth seeker" (that's a person who is attacked and criticised by people at both extremes :-))I found that comment reasonably OK. I'd have minor quibbles but they are not enough to be worth raising. The addition at the end re Pakistan was unfortunate as it doesn't make the overall point at all well and the argument would have been better with the example excluded. While events such as the Pakistan flooding are complex and cannot be simplistically categorised, a major point is that this disaster was NOT driven by an especially extreme weather event. The overall rainfall is reported to have been in the 20 year flood to 30 year flood range. High - but within the range that people reasonably expect to have to deal with in a sensible manner. Damage would be expected, but not catastophe. In this case other factors appear to have been responsible for turning what should have been a modest disaster into a major one. The biggest apparent factor is a change in land use and irrigation practices in relatively recent times, so that drainage has been routed much more efficiently into areas requiring irrigation, and water which was previously wasted for this purpose is now channelled to where it is most wanted. Usually. Alas, as with many man-made optimisations, when the 25 year flood comes the drainage system does not drain as it did before and instead places the water where it is most unwanted, on this occasion, and fails to "waste" it by sending it to sea as it used to do. Lack of planning and foresight by authorities thus seems to be a major factor. A fine example of Murphy at work.

    SME
    0 0
  19. I must admit I have been frustrated by the conservatism of this projection, not so much now, but particularly when it appeared in earlier IPCC reports with a lower degree of certainty.

    “Most of the observed increase in global average temperatures since the mid-20th century is very likely (greater than 9 in 10) due to the observed increase in anthropogenic greenhouse gas concentrations.”

    With the mechanism for heat capture by greenhouse gases proven in the laboratory and confirmed by satellite measurements; with no other mechanism demonstrating sufficient forcing to account for the observed rise in temperature; with temperature and CO2 tightly coupled in paleo-climate data - what other explanation justifies the remaining 1 in 10 uncertainty? An alien secret weapon perhaps?

    I get annoyed that scientists are expected to prove that the warming is outside the bounds of “natural variation”, as if the latter were an independent phenomenon. It is clear that the natural variation in average temperature in both paleo and human history is predominantly driven by changes in CO2, even if initially triggered by smaller forcings such as variation in solar radiance. Yet the skeptics use the term as if it provides a valid alternate explanation. The rise in CO2 in the second half of the 20th century is obviously anthropogenic because we can make fairly accurate estimates of the oil, coal, peat and wood that has been burnt. When you have a proven relationship between cause and effect, and clear evidence for the cause, denying the effect is pure folly.
    0 0
  20. Roger A. Wehage

    "Because the space shuttle is a nightmare. A little O-ring failure here a little insulation impacting a tile there. A gas leak here a stuck valve there. I've a feeling Earth's climate is no different."

    Well said.

    A very good motivation why we should be careful not to change the composition of the atmosphere while we are in the dark about what the exact consequences are.

    Humanity at the controls of the climate feels about as safe as Homer Simpson at the controls of a nuclear power plant.

    ----------------------------------

    Since you are an expert on models, that is the subject you concentrate on. That is a pitfall. The predictions are based on more than just models. Ice cores for example are another line of evidence that point in the same direction wrt climate sensitivity. Look at the full body of evidence.
    0 0
  21. The Pakistani floods had multiple causes such as:

    '...unprecedented monsoon rain... attributed to La Niña... Some of the discharge levels recorded are comparable to those seen during the floods of 1988, 1995, and 1997... An article in the New Scientist attributed the cause of the exceptional rainfall to "freezing" of the jet stream, a phenomenon that reportedly also caused unprecedented heat waves and wildfires in Russia as well as the 2007 United Kingdom floods.'

    Other factors:

    'The Pakistani government was blamed for sluggish and disorganized response to the floods... President Asif Ali Zardari was also criticized for going ahead with visits to meet leaders in Britain and France at a time when his nation was facing catastrophe. In Sindh, the ruling Pakistan People's Party ministers were accused of using their influence to direct flood waters off their crops while risking densely populated areas. Pakistani ambassador for UN Abdullah Hussain Haroon called for an inquiry into allegations about rich landowners diverting water into unprotected villages to save their own crops.'

    Pakistan is no stranger to extreme weather events though these are the worst in its recorded history.

    The 1931 China floods
    are arguably the worst in world history with a death toll ranging from 1.3 – 4 million.

    Not an argument for complacency - mother nature is indeed an angry beast however we understand the recent tragedy.
    0 0
  22. SME wrote : "Lack of planning and foresight by authorities thus seems to be a major factor. A fine example of Murphy at work."


    It wasn't me, honest !

    Anyway, looking at lists of natural disasters, it's curious how most of those involving heatwaves are since 1980. Or is it ?
    0 0
  23. Heatwaves go back well before the 1980s but this may be purely coincidental:

    ‘The record for the longest heat wave in the world is generally accepted to have been set in Marble Bar in Australia, where from October 31, 1923 to April 7, 1924 the temperature broke the 37.8 °C (100.0 °F) benchmark, setting the heat wave record at 160 days... The 1936 North American heat wave during the Dust Bowl, followed the one of the coldest winters on record—the 1936 North American cold wave. Massive Heat waves across North America were persistent in the 1930s, many mid-Atlantic/Ohio valley states recorded their highest temperatures during July 1934. The longest continuous string of 100 °F (38 °C) or higher temperatures was reached for 101 days in Yuma, Arizona during 1937 and the highest temperatures ever reached in Canada were recorded in two locations in Saskatchewan in July 1937.’
    0 0
  24. chriscanaris
    yes, there has been heat waves, cold spells, floods, forest fire, etc., in the past. Then what? You're completely missing the meaning of probability, which is what James Wight is talking about. Your pedantic list of extreme events is useless as far as the probability of these events is concerned.
    0 0
  25. It is redundant to say something is very possible. A thing can either be or not be,... it is either possible or impossible. If it is possible, you can then move on to consider its likelihood (i.e., probability).

    We know that global warming, for instance is 100% possible, however the probability is indeterminant as the sample space is one.
    0 0
  26. Come off it, chriscanaris. You start off on natural disasters and then move on to some early heatwave records, posting some material from WIKIPEDIA but ignoring everything that followed on from the bits you liked - 10 to 15 times more information from the 1970s onwards with lots more records.
    0 0
  27. RSVP, in the words of my father, "Your guess is as good as mine."
    0 0
  28. JMurphy @22: I believe that one should not use the severity or lack thereof in individual events as arguments for or against global warming or climate change. For example, about two hundred years ago the mid Mississippi valley had a powerful earthquake that changed the course of the river. Only a few people died then because only a few people lived in the area. If that same quake were to occur today, hundreds of thousands could die.

    The same goes for floods and heat waves. Their frequency and severity certainly appear to be increasing. At the same time their impacts on the human population are becoming more severe because of artificial changes we've made to the environment and because of increased population density.

    For example, heat waves are most severe in paved-over cities that consume hugh amounts of energy to run millions of air conditioners. The unlucky ones are the poor and elderly who cannot afford air conditioners. Many flood disasters are similar. Man has destroyed most of the world's hummus and forest cover and built giant levees to hold back the surging water, only to worsen the situation. Over many decades the U.S. has naively spent many billions of dollars through the Corps Of Engineers to mess with nature; now it is spending many more billions to fix their first mistakes.
    0 0
  29. Roger @22: Indeed, if the population of the planet was only 7 million, instead of billion, and was projected to rise to 9 million then the imperative to act on the projected change in climate would be less. There would be plenty of space and resources to deal with, at best, a 2C change in temperature. But our population is so great, our use of resources so profligate that to continue on the present path is reckless.
    0 0
  30. Roger A. Wehage,

    RSVP, in the words of my father, "Your guess is as good as mine."

    Then I'll take an educated guess over yours or RSVP's. I prefer to use the best available information instead of willfully keeping myself in the dark and pretending the world is just a big blob of unknowable uncertainties.
    0 0
  31. This is getting off-topic, but since comment #7 is still there... Roger Wehage says NASA spent billions of USD on reliability analysis for the shuttle and still couldn't get an answer that was in the ballpark.

    First of all, as for the claim of billions spent on risk assessment, [citation needed]. A billion dollars will buy you 4000 years of full-time work from senior engineers; that's a lot of Probabilistic Risk Assessment.

    But more to the point, he provides a link which destroys his own argument. Follow the link he gives in comment #7 to see that the median reliability of the STS, across numerous studies, ranges from about 1/80 to 1/130. Huh, pretty much exactly the observed reliability. So whence the claim that PRA is impossible, Roger?

    Yes that's right, the risk assessment by the experts was correct. Remember, in the case of Challenger, all the engineers said "don't launch" until they were overruled by management. Seems to me this whole story does nothing but support the notion that the experts are quite capable of risk analysis of even complex systems, and are to be ignored at your own peril.
    0 0
  32. #30, #31
    There are no risk-free alternatives.
    0 0
  33. Roger A. Wehage,

    Your exemple about the rectangle is the typical calculation we do when we calculate error tree and Monte-Carlo methos can catch it very easily. By the way, you confuse risk management with quality control, which are quite different beast.


    When doing risk management, you put your brain in the paranoid mode. Your exemple from NASA are typical case of how exactely NOT doing risk management. For both Challenger and Columbia, the risk was identified but dismiss because it was annoying to adress it. Hum, looks like climate change debate for me. Also, NASA estimate for risks were too low. In the beguining of the program the estimate was 1/300 failure, while observe rate is more like 1/66. But administrators, put it at 1/10000 but it has to be that way.
    0 0
  34. Let me point out the obvious, RSVP and Robert. We act in life and death situations every day with a pitifully tiny amount of information. We walk, run, drive, and ride, for example, with only guesswork and little hard data. We constantly use the well-it-worked-before logic, even though the conditions have changed. In short, we bet our lives--and the lives of others--on what are often totally unscientific leaps of cheap reasoning. A great many of us, in fact, bet our time, money, and happiness (and the time, money, and happiness of others) on the idea that there is a supernatural being that has ordered the universe in some detailed way, according to a book written some thousand or thousands of years ago or according to someone who clearly has a vested interest in having us believe such a thing. And yet that's ok.

    Then we have the IPCC, which has collected the research and input of thousands of scientists, carefully weighed the significance of the data, modeled it in several different ways, checked and re-checked and re-checked the results, and published the information complete with error bars, recognition of weaknesses, and a host of caveats. If the IPCC had simply collected the data and published it all together without providing any models, people would be beating down the doors demanding models--with all their weaknesses.

    Do we have to stick our hand in the fire to know that doing so will hurt? Not as adults, we don't. We could stick our hand closer and closer to the fire, but we never know that the feeling of heat will not plateau at a certain point. We have theories, and we use the proxy of a stick, noting that the stick is destroyed (as a stick, not as matter) and that the same will likely happen to us. Children have a hard time understanding proxies, and so they stick their hands in the fire, get burned, cry, and get angry (and then end up projecting that anger on the people who warned them not to do it).
    0 0
  35. Checking with the grammar police - 'panel' is singular, so shouldn't the title be "Does the IPCC use alarmist language?"
    0 0
  36. Key term in Chris' post:

    ...The 1936 North American heat wave...

    Here on SkS the topic is planetary-scale, secular change.
    0 0
  37. Roger A. Wehage wrote : "JMurphy @22: I believe that one should not use the severity or lack thereof in individual events as arguments for or against global warming or climate change.
    The same goes for floods and heat waves. Their frequency and severity certainly appear to be increasing. At the same time their impacts on the human population are becoming more severe because of artificial changes we've made to the environment and because of increased population density."



    All true enough but the problem is that the so-called skeptics try to pretend that things are not really that bad because such things have happened a few times in the past, while failing to realise that such things are happening more regularly now and are affecting more and more people, now and in the future. It's similar to suggesting that people, animals and plants, etc. will be able to cope by migrating, as they have done in the past when necessary - forgetting about those big populations, behind their political and national boundaries, who won't be so keen on helping others to mitigate global warming in their backyards.
    0 0
  38. There are other threads here to discuss particular weather events, but SME's comment caught my eye:

    While events such as the Pakistan flooding are complex and cannot be simplistically categorised, a major point is that this disaster was NOT driven by an especially extreme weather event. The overall rainfall is reported to have been in the 20 year flood to 30 year flood range.

    Really? How about a reality check from the World Meteorological Organization?

    We don't have to guess at these things, there are people on the planet who know what they're talking about.

    For more circular discussion on the topic of weather extremes and their relationship to climate change, I'll tout this thread: NASA-GISS: July 2010-- What global warming looks like
    0 0
  39. Roger Wipage said "I know enough to know that I have neither the prerequisite background nor the tools to predict the probabilistic distribution of anything more than simple statistical examples." and then goes on to tell us that the IPCC cannot calculate probabilistic distributions. Why do these deniers always tell us about stuff they admit they do not understand?

    Alan Marshall: Many of the IPCC final conclusions were LOWERED by the government reviews before the report was approved. Remember that the Bush administration, Saudi Arabia and Australia all had to accept the conclusions. The lawers from countries who cause the most warming changed many of the risk levels.
    0 0
  40. barry writes: Checking with the grammar police - 'panel' is singular, so shouldn't the title be "Does the IPCC use alarmist language?"

    "Panel" is a group noun or collective noun, and different English-speaking countries have different usage. In the US, collective nouns are generally treated as singular, whereas in the UK they're often treated as plural.
    0 0
  41. It's important to point out that the IPCC is tasked with the job of assessing the risks and likelihoods. So, really Roger A. Wehage's complaints that it's too complex to assess a rather moot point.

    The issue at hand (the point of the main blog post) is whether the IPCC use alarmist language. I have to agree that they do the best job they can to address all sides of the issue in a way that... well, ultimately is not going to please anyone. In my mind that probably means they're doing a good job (i.e, the best job possible given the circumstances).

    If you think about it, the IPCC's assessment of climate sensitivity is probably the very best overall indicator for the entire issue of climate change.

    1) Climate sensitivity of 2C to 4.5C with 3C as best fit.
    2) Sensitivity below 2C is very unlikely.
    3) Sensitivity higher than 4.5C is also unlikely but can not yet be ruled out.

    (Hope I have that right.)

    Is this alarmist? Some alarm bells should be going off in everyone's head for sure. But they mitigate that alarm by saying we have a pretty strong inclination of about where things stand.
    0 0
  42. A recent set of articles comment about how you can now circumnavigate the Artic in one season (without sailing in an ice breaker.)

    For example - http://www.physorg.com/news/2010-10-crew-circles-north-pole-summer.html .
    A quote from this article " Less than 10 years ago the first steel-hulled sailboat managed to get through just one of the passages, and 100 years ago, a circumnavigation would have taken six years," the "Northern Passage" crew said in a statement. "

    How did the IPPC reports define the probability of this being possible in 2010 ?
    0 0
  43. Many scientists find the IPCC too timid in its conclusions. One of them is Andy Lacis.

    Human-induced warming of the climate system is established fact.

    “My earlier criticism had been that the IPCC AR4 report was equivocating in not stating clearly and forcefully enough that human-induced warming of the climate system is established fact, and not something to be labeled as “very likely” at the 90 percent probability level.”


    http://dotearth.blogs.nytimes.com/2010/02/17/lacis-at-nasa-on-role-of-co2-in-warming/
    0 0
  44. The IPCC are not alarmist in their conclusions, and they are no more alarmist in the way they report their conclusions.
    Yet their conclusions are alarming and quite possibly understated.
    0 0
  45. Byron Smith... Exactly.

    The IPCC are sounding the alarm bell but they've wrapped the clapper with rags so as to not hurt anyone's ears.
    0 0
  46. Ned, my understanding of the usage here is that 'panel' refers to the institute as a whole, rather than a group of individuals. To expand the sentence with the current verb usage, it reads "Do the members of the IPCC use alarmist language?" Some of them may at times, but the what they produce as a collective (ie, AR4) does not.

    (Last post on grammar, I promise. :-)
    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

THE ESCALATOR

(free to republish)

Smartphone Apps

iPhone
Android
Nokia

© Copyright 2018 John Cook
Home | Links | Translations | About Us | Contact Us