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


2015 SkS Weekly News Roundup #31C

Posted on 1 August 2015 by John Hartz

Climate pressures lead to rise in 'new-age orphans' in India's delta

Eleven-year old Srijita Bhangi sits in the waiting room of the jetty boat that connects her island home in Khulna to the mainland Sundarbans, near India's border with Bangladesh.

After spending a few days with her elderly grandparents - an effort to lift her most recent spell of depression - she is travelling back to the school hostel where she has lived since her parents left two years ago to find work in a garment factory 1,000 kilometres (620 miles) away, in Tamil Nadu.

Since then she has seen them only once, and the school lodging has effectively become her new home.

Climate pressures lead to rise in 'new-age orphans' in India's delta by Aditya Ghosh, Thomson Reuters Foundation, July 30, 2015

Earth now halfway to UN global warming limit

IT’S the outcome the world wants to avoid, but we are already halfway there. All but one of the main trackers of global surface temperature are now passing more than 1 °C of warming relative to the second half of the 19th century, according to an exclusive analysis done for New Scientist.

We could also be seeing the end of the much-discussed slowdown in surface warming since 1998, meaning this is just the start of a period of rapid warming. “There’s a good chance the hiatus is over,” says Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colorado.

Earth now halfway to UN global warming limit by Michael Le Page, New Scientist, Aug 1, 2015

Forests suck up less carbon after drought

Climate scientists forecast sea levels to rise anywhere from one to four feet by the end of the century. That's a pretty big range. And there's a good reason for that: there's a lot of uncertainty baked into climate models

Take, for example, the way climate models predict how trees respond to drought. "Drought in these models is treated as a light switch"—either on or off—“but in the real world we know that drought damages trees, and it can take a while for trees to repair this damage and recover." 

Forests suck up less carbon after drought by Christopher Intagliata, Scientific Amercian, July 31, 2015

Northern forests falter in combating climate change

The Earth relies on its vegetative cover to extract and hold onto carbon dioxide when a great deal of it finds its way into the atmosphere, as has happened with the burning of fossil fuels. The forests, which form the largest part of this land-based cover, are referred to as carbon sinks.

Now, new research shows that one of the planet’s largest and most important carbon sinks, the forests of northern Eurasia, may be pulling in carbon at a slower rate than in the past. What is even more worrying is the possibility that regions that were absorbing carbon may emerge as sources of carbon emissions as the permafrost melts.

In northern Eurasia, the annual net sink rate increased from the 1960s to the 2000s, but since then, the rate at which carbon is sequestered by the region has leveled and even showed signs of weakening, said Michael Rawlins, an assistant professor in the University of Massachusetts’ Department of Geosciences.

Northern Forests Falter in Combating Climate Change Malavika Vyawahare, ClimateWire/ Scientific American, July 28, 2015

People's Climate March: the revolution starts here

reating a world powered on clean energy to save ourselves from climate catastrophe is a central challenge of our time, and requires a revolutionary transition in our economies. We can’t wait for our leaders to solve this problem; unless they feel serious public pressure, they’ll never go far enough or fast enough. Revolutions start with people, not politicians.

To survive the 21st century, we must discover the sense of common purpose that has driven revolutionary change through history, building a mass movement to stretch what our politicians believe is possible. We must lead, not follow, and bring leaders with us.

In the years leading up to 2014, as the gap between what the science demanded and our politicians delivered widened, fatalism began to creep into parts of the climate movement. Then a handful of organisers took a major bet on the power of people – calling for the largest climate change mobilisation in history to kick-start political momentum.

People's Climate March: the revolution starts here by Rick Patel, The Guardian, July 29, 2015

The fossil fuel industry is still winning the investment war

There’s sobering news for campaigners trying to persuade investors to withdraw their funds from the fossil fuel industry: UK experts say their efforts are unlikely to achieve enough quickly enough.

One expert, using the term often applied to the global energy industry, told a meeting in London: “The incumbency is winning the cold war.”

Senior members of asset management firms and carbon risk specialists were invited this week by a prominent British charitable foundation, Sainsbury Family Charitable Trusts, to discuss the prospects for disinvestment and the attitudes in the City of London to attempts to match investment policies with avoidance of climate change risks.

They say the continued confidence of the industry in the long-term viability of coal, oil and gas—despite the plunging cost of many renewable fuels—means that the UN climate change summit in Paris at the end of the year will fall short of its aims.

The Fossil Fuel Industry Is Still Winning the Investment War by Alex Kirby, Climate News Network/Truthdig, July 29, 2015

The new economics of climate change

The twentieth century was a terrible time to be born a blue whale. After 1926, when seagoing factory vessels were introduced, the population plummeted, and by the early seventies only a few hundred remained. Attempts at conservation met with limited success, and it seemed that the whale’s days were numbered. The Japanese and Russians, in particular, continued to aggressively hunt the docile mammals, well aware that such rapacity would result in their extinction. In 1973, a creative economist named Colin W. Clark decided to take financial analysis to its logical conclusion. He posed the question of which method—hunting the whales to oblivion and investing the profits in stocks, or fishing the population sustainably—would yield the most money in the long term. The answer: hunt the whales to extinction and invest all the proceeds in the market.

The new economics of climate change by Katy Lederer, The New Yorker, July 30, 2015

Tomgram: Subhankar Banerjee, Fire at World's End

TomDispatch regular and award-winning photographer Subhankar Banerjee lives on the Olympic Peninsula in the state of Washington and has recently found himself on the frontlines of the present wildfire season and of climate change. In his latest piece, he takes us into perhaps the single place least likely to be ablaze in America and oh yes, if you haven’t already guessed, it’s on fire. Welcome to — if you’ll excuse my appropriation of a classic phrase from our past — the new world Tom

Tomgram: Subhankar Banerjee, Fire at World's End by Tom Englehardt, TomDispatch, July 30, 2015

Warming may boost wind energy in U.S. Plains states

Powerful winds are commonplace in the U.S. prairie states, which experienced walls of dirt swept into the air by these gusts during the Dust Bowl. While today's winds don't often carry the huge quantities of dust that they did in the 1930s, they’re stirring up something significantly more useful in states like Kansas, Oklahoma and Texas – energy.

A study published last month in the journal Renewable Energy suggests that climate change is likely to make these states windier than they've ever been before, which could be a boon to the nation’s renewable energy industry and the already thriving wind energy operations in those states.

Warming May Boost Wind Energy in Plains States by Chelsey B. Coombs, Climate Central, July 29, 2015

World Bank rejects energy industry notion that coal can cure poverty

The World Bank said coal was no cure for global poverty on Wednesday, rejecting a main industry argument for building new fossil fuel projects in developing countries.

In a rebuff to coal, oil and gas companies, Rachel Kyte, the World Bank climate change envoy, said continued use of coal was exacting a heavy cost on some of the world’s poorest countries, in local health impacts as well as climate change, which is imposing even graver consequences on the developing world.

“In general globally we need to wean ourselves off coal,” Kyte told an event in Washington hosted by the New Republic and the Center for American Progress. “There is a huge social cost to coal and a huge social cost to fossil fuels … if you want to be able to breathe clean air.”

World Bank rejects energy industry notion that coal can cure poverty by Suzanne Goldenberg, The Guardian, July 29, 2015

0 0

Printable Version  |  Link to this page


Comments 1 to 9:

  1. "Earth now halfway to UN global warming limit"

    Glad someone who could publish had the same idea I did a couple weeks ago here.

    0 0
  2. Please, can someone from this website write a debunking of the latest denier scam saying "the 97% Consensus is now 43%" ?

    That's all my denialist friends have been talking about lately, it's driving me nuts! 

    0 0
  3. jenna,

    You don't need to keep debunking something that has already been debunked.  See #4 of "most used climate myths" listed on this site. If you really want to, just ask them to provide the evidence for their claim and then it will be easy to show that it is nonsense.

    0 0
  4. Jenna... I believe that comes from JoNova. I would suggest locating the original research she's quoting and see if it agrees with what she's saying.

    1 0
  5. jenna @2, the claim echoes those made by Fabius Maximus, and echoed by Joanne Codling three days ago.  They relate to the release of additional data from Verhenger et al (2014).  (Note, the PDF document is a data release, not a new paper - contrary to the misrepresentation by Codling.)

    A couple of things are worth knowing about the data.

    First, the authors invited responses from a number of groups chosen for their having authored scientific papers on climate change plus a small group invited because they had signed "... public statements disapproving of mainstream climate science".  That group represented just 2.4% of invitees, but 4.7% of respondents.  We are told that "about half of [the respondents only invited because of public political statements against climate science] only published in the gray literature on climate change"; ie, that they are not climate scientists at all.  Further, even for the "about half" who are climate scientists, it is unlikely that that many of them would have been invited from a random sample of climate scientists.  Indeed, we know that they would not because there is not a 50% overlap between the "unconvinced" and those invited on their merits.

    Fairly obviously, because the rest of the respondents were invited based on their names appearing of authors on climate science related papers in the scientific literature, that introduces another bias into the group.  Those who have published fewer papers are less likely to have been invited.  Ergo, even ignoring the deliberately introduced bias in favour of the "unconvinced", the sample is also biased in favour of frequent publishers.  Ergo the the sample does not represent a random sample of climate scientists, and therefore it is impossible to infer from the sample frequencies the frequencies of particular beliefs among climate scientists in general.  The results are merely indicative, and when we look at patterns among subsamples, informative.

    Second, the survey explicity asked about the respondents breadth of knowledge in climate science.  That is very important because "climate science" is a multidisciplenary subject with a very complex field.  As a result, many climate scientists are very expert in a particular issue relating to climate science without therefore being expert in all, or even many aspects of climate science.  In fact, among respondents only 34% indicated that their "general knowledge of physical climate science" was "broad" or "quite broad", with another 31% indicating that their knowledge was only "slightly broad", or that it was "not broad" at all (Question 8a).

    A similar question was asked about depth of knowledge of even one aspect of climate science ("one or more aspects of physical climate science"), with only 38% indicating it was "very deep" or "quite deep" on even one aspect, while 35% indicated it was only "slightly deep", or "not deep" on even one aspect of climate science.  The low level of stated depth of knowledge would be a function of two factors.  One is the level of comparison.  Scientists would compare their depth of knowledge to the acknowledged experts in the specialist field (aspect), so that even "slightly deep" knowledge may well represent at least an undergraduate level of understanding of the topic.  Further, because climate science is multidisciplenary, coauthors of climate sciense papers may be authors because of their specialist knowledge in a related field, but not in how it applies to climate science.  A paper on dendroclimatology (determing past climates from tree rings) may include as an author an expert in tree rings who has not studied any aspect of climate science beyond the effects of temperature and precipitation on treering density and width.

    Given these stated limits on the knowledge of climate science by the respondents, it is absurd to argue (as Joanna Codling does) that:

    "Fabius Maximus suggests we exclude the “I don’t knows” which brings up the number to 47%. Since these are “climate scientists” I don’t see why those responses should be excluded. An expert saying “I don’t know” on the certainty question is an emphatic disagreement with the IPCC 95% certainty."

    Climate scientist is not the same as "expert on attribution of temperature increases", the latter being a distinct and very small subset of the former.  Therefore when a climate scientist says about an attribution question that "I don't know", it is safe to assume that is because attribution is not their area of expertise, and that they should not be included among the experts in that area.

    So, where does the 43% come from?  Essentially, Maximus takes the percentage of respondents who agreed that 50% or more of "global warming since the mid-twentieth century can be attributed to human induced changes in atmospheric greenhouse gas (GHG) concentrations" (question 1a), which is 65.9%.  He multiplied that by the percentage that agreed that the certainty was "extremely likely" or "virtually certain" (65.2%), thereby obtaining a percentage that agreed with the IPCC AR5 both with respect to the attribution level and certainty (43%).

    So, even on face value, the claim becomes that only 43% of a non-representative group of climate scientists and skeptics without necessarilly having detailed knowledge on attribution agree with experts in attribution who have spent more than a year in a detailed review of all the relevant data on attribution both on amount and certainty.  To that, I think, the appropriate response is, "so what".  Without a detailed study of attribution, climate scientists have no independent knowledge of the level of attribution, let alone the certainty of the attribution.  Do Maximus and Codling realy expect detailed study of (for example) ENSO, will magically confer the knowledge of not just the best estimate of the attribution percentage, but also the certainty of the estimate?  Perhaps they do.  Codling at least certainly seems to believe it is possible to make detailed and exact attribution statements by studying just the Sun - and may well carry a similar magical view of science across to other areas.  But just because they live in a fantasy land is no reason for us to take them seriously.

    Of course, many, including many who don't have an investment in "anything but CO2" being the cause of recent warming may find such a reponse unsatisfying.  For them it may be necessary to examine the numbers.

    If we do that, the first thing to notice is that the IPCC AR5 says that:

    "More than half of the observed increase in global mean surface temperature (GMST) from 1951 to 2010 is very likely due to the observed anthropogenic increase in greenhouse gas (GHG) concentrations."

    But that:

    "It is extremely likely that human activities caused more than
    half of the observed increase in GMST from 1951 to 2010."

    (My emphasis in both quotes)

    As the survey question relates to the effect of greenhouse gases, it is the first statement, not the second that is the relevant comparison.  That being the case, if you want to compare those who agree with both the attribution level and the certainty, it is the certainty of the first statement (not the second) that should be used.  That immediately lifts the percentage to 65.9% (attribution) * 89.3% (certainty), or 59%.  Puting it simply, Maximus fudged the issue by using an incorrect comparison.  Without that fudge he could not have claimed a minority of scientists agreed with the IPCC.

    The second thing to notice is that the percentage increases significantly if we eliminate the non-climate scientists and the overrepresented "skeptics" from the sample.  This is a necessary step if we want to interpret the result as anything meaningful with relation to climate scientists.

    As it happens, 14 (15.9%) of those "unconvinced" respondents agreed with the concensus that more than 50% of recent warming is due to changes in GHG concentration.  Removing those 14 from those agreeing on attribution, and the other 74 "unconvinced" from those 'disagreeing' lifts the attribution percentage to 68.4%, and hence the total agreeing on both attribution and certainty is lifted to 61%.

    The third thing is that not only the "I don't knows" but also the "others" should be excluded from the response.  The first because (as note above) "climate scientist" is not the same as "expert on attribution" so that when they say that they do not know, that response should be taken as a statement of personal ignorance, not (as Maximus and Codling would have it) just a variant formulation of "it is unknown".  That is, a statement of personal ignorance is not a conclusion that the experts are wrong in stating that they know something.  

    The "other" category needs to be excluded because it is logically incoherent.  The available responses allowed you to respond that there was "no warming", or that the cause of the warming was "unknown".  It also allowed you to respond that GHG was responsible for "less than 0%" of the warming.  That is, it covered all logical bases.  For something to be "other" you have to agree that warming was greater than zero (to exclude the "no warming response").  You further have to agree that the answer to the attribution question is known (to exclude the "unknown" response), known by you (to exclude the "I don't know" response, and that GHG caused neither less than nor more than 0% of the warming (to exclude all other possible responses).  Having done that, you are at least a sixth of the way to dining at Milliways.  Put simply, the "other" responses are inchorent and therefore should be excluded.

    Excluding these two cagegories excludes 222 responses from all responses, and 7 responses from the "unconvinced".  That means excluding them raises the attribution level to 74%, and the 66%.

    To summarize, if we did a valid comparison with the IPCC AR5, and did not pad out the survey numbers with known "skeptics" and by including explicity statements of ignorance and incoherent results to pad out the denominator, the proportion we would obtain would be, not 43%, but 66% agreeing on attribution and certainty, and 74% agreeing on attribution.  That is, Maximus has deflated the agreement to fit his narrative by 35% at minimum.  (Given that the survey is of climate scientists in general, not of researchers into attribution in particular, I would say he has deflated it by 58%.

    Having said that, I would still not call 74%, let alone 66% a consensus.  It is a supermajority.  This should bring some caution in the over interpretation of studies like Cook et al (2013), which showed a 97% concensus in published literature - not among climate scientists.  That however, has been evident for a while.  What is known, however, is that the more expert climate scientists are on the topic, the more likely it is that climate scientists will agree with the IPCC consensus.  The same is shown with Verheggen et al, with 84.5% of respondents having published 30 papers or more (and exlcuding those who express personal ignorance or have an incoherent response) agree with the IPCC on attribution.  Only 8.5% think GHG concentrations are reponsible for less than 50% of warming, or think there has been no warming; and only 7% think the answer unknown.  (Percentages calculated by pixel count, and are only accurate withing approx 0.5%).  No doubt the percentage would be even greater among climate scientists with experience in attribution studies. 

    0 0
  6. Jenna, if Tom Curtis' answer is too much detail for your friends, you can ask them why they're so intent on denying the existence of a consensus, while at same time arguing that science is not done "by consensus." Most deniers have forgotten by now that it was originally their myth that the science was ambiguous. As Tom points out above, the consensus really is a convergence of research results in published papers. There is no doubt as to where the weight of the evidence is pointing

    0 0
  7. ..this, in turn, will lead to a convergence in the form of nomenclature, will it not!??!

    0 0
  8. If anyone is interested, "The editor of Fabius Maximus" has participated in a discussion of this topic at And Then There's Physics.  As part of his participation, he tried to indicate why he thought his mathematical prestidigitation was significant.  I responded:

    "Editor of the Fabius Maximus website:

    “Yes, I agree with this formulation. I believe that’s what I said. The dimensions of climate scientists’ consensus is a vital input to the public policy process. These surveys provide a valuable check on the IPCC.
    I don’t see much value in examining these things under a microscope. The headline result (combining 1a and 1b) is what it is, providing a direct comparison to the keynote finding of WG1 of AR4 and AR5 — and for comparison with the many other similar surveys (which this improves upon).”

    Complete nonsense.

    The IPCC result is the work of specialists in attribution studies surveying the relevant literature over a 12 month period, and distilling the results of that literature into a report. It is not, and is not intended to be a survey of the consensus opinion of all ‘climate scientists’, where the later is so loosely defined that a geologist being a coauthor of a single paper discussing paleoclimate counts as a “climate scientist”, ie, the effective definition for the Verheegen survey (once the “unconvinced”, ie, those invited to respond solely because of their expression of a political opinion on the web, and without regard to actual study of, or publication in regard to climate science).

    If you wanted a double check on the IPCC on attribution, the proper method is an independent literature survey on attribution. As an approximate alternative, you could survey the opinion of climate scientists who specialize in attribution studies asking them as to:

    1) Central estimate of the percentage contribution of anthropogenic (and/or GHG) to recent warming;
    2) Their upper and lower bounds at 90 and 95% confidence on the attribution;
    3) Their estimate as to the proportion of attribution experts whose central estimate lies within the IPCC value; and
    4) Their estimate of robustness of the evidence in favour of their opinion (ie, how likely they think it is that their view of the central estimate will have changed significantly with 10 more years of information).

    A general survey of climate scientists and deniers without regard their expertise in attribution is not a check on the IPCC.

    What the Verheggen survey is a check on is not the literature surveys such as Cook et al, but on the misinterpretation of the literature surveys which treats them as surveys of scientists rather than of papers. It is also an update and check on Doran et al 2009, which found that:

    “Results show that overall, 90% of participants answered “risen” to question1 and 82% answered yes to question 2.In general, as the level of active research and specialization in climate science increases, so does agreement with the two primary questions (Figure1). In our survey, the most specialized and knowledge-able respondents (with regard to climate change) are those who listed climate science as their area of expertise and who also have published more than 50% of their recent peer- reviewed papers on the subject of climate change (79individuals in total). Of these specialists, 96.2% (76 of 79) answered “risen” to question1 and 97.4% (75 of 77) answered yes to question2.”

    Note that the finding of Doran et al that agreement with the consensus rise with both specialist knowledge of climate science and with increased publication (as a proxy of greater expertise). The appropriately corrected percentage of agreement (74% among climate scientists; 84.5% among those having published 30 or more papers) are less than the nearest corresponding result from Doran et al. That may be because of the more precise nature of the questions, or may be due to a decline in certainty. The first is almost certainly the case, but the second cannot be excluded from the data available."


    I also included a summary of my post above, for those who want a shorter version.

    0 0
  9. I wrote a detailed reply to the claims made by Fabius Maximus regarding our PBL survey. It comes down to the first question having an effective plateau value at 78% if you include all respondents, since so many answered "don't know", "unknown", or "other". We have good reasons to believe that this was because the question was difficult to answer to the level of precision required by the answer options. Talking that into account, and looking at responses from both Q1 and Q3 leads to the conclusion that indeed there is a strong consensus.

    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