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

Term:

Settings

Beginner Intermediate Advanced No Definitions Definition Life:

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.

Recent Comments

Comments 5351 to 5400:

wilddouglascounty at 00:10 AM on 14 July 2021

The making of a one-of-a-kind climate change PR professional

This self review of a book is intriguing and shares many of the insights it sounds like is expanded upon between the covers of that book. I plan to check it out: I believe that the transition of our governing process from a bipartisan to a bipolar political process has been engineered through the processes discussed in this book, and as such examination of these dynamics will hopefully aid in dismantling the polarization of the public commons where differences can be shared and ways forward can be developed.

Bob Loblaw at 22:21 PM on 13 July 2021

Climate's changed before

A follow-up to the "sea level was higher in past interglacials" claim.

Is this person claiming that sea level is indeed rising to dangerous levels, but it's natural?

Is this person claiming that sea level has risen naturally in the past, so rising CO2 and rising temperatures cannot change this previous pattern?

The part TVC15 has quoted is the usualy mishmash of vague, unspecific claims. Good luck trying to pin the denier down to a specific claim or statement that can be examined by evidence - my experience is that such individuals often are incapable of expressing themselves clearly enough.

Eclectic at 17:35 PM on 13 July 2021

Climate's changed before

TVC15 , from experience, you know how anything & everything is grist for the deniers' mill, in their attempts to minimize and/or deny the climate science. It's always ABCD ~ Anything But Carbon Dioxide.

And their excuses come in cycles of excuse ~ first: It's Not Warming . . . then: It's only warming a bit . . . then: Yes, it's warming a lot, but it's Not caused by humans . . . then: Well yes it's half-caused by humans, but the Warming is really very very good for us and is saving us from disastrous cooling.

Then it's back to: the Warming has Stopped and it's cooling now (for at least 6 years' cooling, says the deluded Monckton) . . . and a Colossal Grand Solar Minimum will have all of Canada under a mile-thick ice sheet by 2050 or somesuch date.

For millennia, the US Southwest has been arid - the opposite of the Northeast. And you can find other regions of the world likewise arid. All it needs is a slight variation in climate, and you've got a mega-drought (a drought defined as >20 years) or a super-mega-drought (for centuries). Nothing very new about that ~ except that now our Anthropogenic global warming is exacerbating the droughty tendency. (The exacerbation being the point your denier wishes to deny.)

I haven't studied past Interglacials w.r.t. aridity & droughts. Presumably similar overall conditions in the past have caused rather similar episodes. But that's all rather irrelevant to the current situation, which must be dealt with on its own terms. And the current droughty tendency doesn't disprove the climate science, nor does it fail to point to more of the same trouble in future, as AGW worsens.

Of course, as we look back in time, the proxy evidence (in past Interglacials) gets fuzzier & fuzzier ~ so conclusions of any sort get more difficult to make.

The "Anthropocene" is a semi-humorous label. Not official. But the label does get up the deniers' noses. Still, it does rhetorically emphasize that the Holocene is transitioning into something significantly different from the "natural".

TVC15 at 16:09 PM on 13 July 2021

Climate's changed before

Bob Loblaw@876

[Sea levels are normally 4 meters to 14 meters higher than they are now during Inter-Glacial Periods.]

Thanks so much for responding to this deiners claim and providing that graph!

TVC15 at 16:07 PM on 13 July 2021

Climate's changed before

Eclectic @874, 875

Hi Electric,

Thanks for the responses!

I don’t understand why this denier is trying to make it a fact that the Western half of the US always undergoes a drought during Inter-Glacial Periods when I don’t think we really know, or do we?

They mention the other 11 interglacial periods, during which modern humans did not exist until the Holocene. I’ve also head a new epoch called the Anthropocene, with the start date of this new epoch still in debate. Not sure if this is recognized as the most current epoch.

Since humans did not occupy most of those interglacial cycles, I don’t understand the deniers argument. There is nothing to connect the dots between past interglacials and our current situation.

Now instead of saying climate always changes, deniers are claiming that what we are witnessing all over the globe today is typical during an interglacial cycle.

How can we know the conditions of ancient interglacials? Did they all cause drought in the Western half of the US?

Thanks!

Bob Loblaw at 11:17 AM on 13 July 2021

Climate's changed before

TVC15.

Your interlocutor seems to be using a combination of "Climate has changed before" (this thread) and "we're coming out of an ice age", which is an odd twist on "we're going into an ice age". Maybe he's confused with "we're coming out of the Little Ice Age".

There is a post here at SkS that talks about sea level over the past 150,000 years. It includes the following graph of sea level, covering the last glaclal/interglacial cycle:

Sea level past 150000 years

I do not see anything on that graph to support his claim that sea level is normally 4 to 14m higher than now during interglacials. The peaks of that graph may be a touch higher, but there sure isn't a steady period of higher sea levels in the last interglacial. I suspect his claim is completely bogus, but you could always try to get him to provide his source of data.

On very long time periods, ocean basin size/shape changes have dramatic effects on relative sea level. On short time scales (glacial/interglacial cycles), local sea level in areas subject to the weight of ice have serous effects due to isostatic depression and rebound.

Of course, the answer to "why should this interglacial be different?" is "because we're adding CO2 to higher levels than seen in hundreds of thousands of years, and we're looking at rising temperatures and conditions not seen in past interglacials".

Eclectic at 10:49 AM on 13 July 2021

Climate's changed before

. . . 2

TVC15 , a recent high-resolution sea-shore study [ IIRC - Kulp and Strauss 2019 ] indicates that a 1 meter SLR would displace approx 230 million people from their houses and farmlands. And factoring saline inundation by storm surge, there would be many millions of refugees displaced well before the "average" 1 meter rise is reached. So that's likely to be getting underway before 2100 even though the full 1m rise won't come until after 2100. And doubtless, some of these many refugees will need to settle in the neighbourhood of this denier's great-grandchildren. No social disruption at all !

And for a 2m rise in sea level, you can add a few hundred million more refugees . . . all wanting to go to higher ground . . . like Colorado, or wherever this unworried denier has been living.

Western droughts come and go - and sometimes stay for centuries, judging by the history of the last 2000 years. ( I'm sure your denier friend will tell the farmers and townsfolk, that they simply need to wait patiently, for a few generations or so.)

Note that the PAGES12k proxy studies show that world temperature is currently same or slightly higher than the peak of the Holocene - though many deniers still falsely claim that we are "colder than the Medieval Warm Period". Go figure !

Eclectic at 10:21 AM on 13 July 2021

Climate's changed before

TVC15 @873 ~ yes, it's marvellous to observe the shameless rhetorical mendacity of some of these deniers. Hard to say whether they believe their own nonsense, or whether they simply aim to score Debating Club points by playing any arguments (arguments 100% true or 95% false). But .... it is what it is, with these trolls.

I love their dismissive style of argument - "It's stupid to worry about a few extra degrees of warming, when only 4 billion years ago the Earth's surface temperature has been 200 degrees hotter." And so on.

As you know, TVC15, each glacial cycle is somewhat different from each of the others - but what we have to face up to is to deal with modern problems : not the problems of a million years before humankind arrived. So why is he himself running away from facing up to the present situation?

Perhaps your denier friend would be unfazed by having a sea level 3 meters deep in his own house's living room? Or is it only *other* people's houses he is unworried about.

. . . 2

TVC15 at 07:46 AM on 13 July 2021

Climate's changed before

My favoirite hubris spewing climate denier is at it again.

He was smarting of to a person in Colorado who was discussing the current drought in the Westen half of the US.

[What a coincidence.

The same thing happened in the previous Inter-Glacial Period, and the one before that and the one before that and the other 5 before before that.

Are you foolishly blind enough not to see the pattern?

The West always undergoes a drought during Inter-Glacial Periods.

Tell us why this Inter-Glacial Period should be different.

Ice sheets and glaciers always melt during Inter-Glacial Periods.

Tell us why this Inter-Glacial Period should be different.

Sea levels are normally 4 meters to 14 meters higher than they are now during Inter-Glacial Periods.

Tell us why this Inter-Glacial Period should be different.

Tell us why the sea level should not rise at least another 4 meters like it did in the other 8 previous Inter-Glacial Periods.

Global temperatures in the other 8 previous Inter-Glacial Periods were at least 7°F warmer than present.

Tell us why this Inter-Glacial Period should be different.

Tell us why this Inter-Glacial Period should be a statistical anomaly and be colder with lower sea levels and no melting and no drought.

Can you do that?]

This denier is so hostile and over the top smug and arrogant in his replies it's hard to take them seriously.

Is it accurate that the west always undergoes drough during interglacials?

Also I don't think it's correct that Sea levels are normally 4 meters to 14 meters higher than they are now during Inter-Glacial Periods.

How can this denier make this claim? Global temperatures in the other 8 previous Inter-Glacial Periods were at least 7°F warmer than present.

Tell us why this Inter-Glacial Period should be different.
Tell us why this Inter-Glacial Period should be a statistical anomaly and be colder with lower sea levels and no melting and no drought.

My response to the above bullets would be that this interglacial is nearning it's end and we should be seeing a global cooling effect, but we are seeing a warming effect due to human activity. Not sure what more I could add to my response to the bulleted statements made by this denier.

Bob Loblaw at 06:33 AM on 13 July 2021

The making of a one-of-a-kind climate change PR professional

I lived throught he Harper government pushback on many of these issues, and watched colleagues (and myself) lose jobs as climate-related programs were shut down. I remember Peter Kent, as Environment Minister, making a public announcement of of an extensive oil sands environmental monitoring program that he claimed would demonstrate that Canada was producing petroleum products in an environmentally friendly way.

Silly me: I thought that scientists were supposed to draw their conclusions after the data was collected, not before. [To the credit of the scientists that had to set up the monitoring, they did do a good job of it.]

The politicans that are going after environmental groups over "foreign funding" never seem to worry about groups such as The Fraser Institute and their sources of funding. (Hey, there's that Desmog database at work again!) The Kenny government in Alberta (Kenney was in Harper's federal cabinet) has continued the "investigation", starting in 2019 and continuing today.

https://www.cbc.ca/news/canada/calgary/alberta-war-room-public-inquiry-1.5200549

https://www.theglobeandmail.com/canada/alberta/article-alberta-inquiry-into-environmental-advocacy-funding-to-receive-fourth/

Bob Loblaw at 06:14 AM on 13 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Yes, Eric. distributions bring in a lot more data and make it a lot easier to evaluate the "how probable?" question. It really is a question of probabilities - asking "how much is cause A, vs. how much is cause B?" is very difficult when both cause A and cause B have built-in variation.

As a simple thought experiment, let's take the hypothetical case of a location with a mean high temperature of 30 for July, and with a normally-distributed variation that gives us a standard deviation of 5. Based on the characteristics of a normal distribution:

We would expect 95.45% of the values for July high temperature to be within 2 SD (so, in the range 20 to 40).
We would expect 99.73% of the values for July high temperature to be within 2 SD (so, in the range 15 to 45).
If we only look at hot extremes, temperatures >40 would happen 2.3% of the time, and temperatures above 45 would happen 0.14% of the time.

The latter case (>45) is about a 1:1000 return interval. That does not mean that we'd only see one such event in 1000 tries, though: random variation could mean it happens 0, 1, 2, 3, or more times (with it being increasingly unlikely as that number increases).

Let's look at two scenarios where conditions change.

In the first, the average does not change, but conditions get more variable. The SD increases to 7.5. Now, the upper limit of 45 is only 2 SD away from the mean, so it will be exceeded 2.3% of the time instead of 0.14% of the time. That is much more frequent.
In the second, the SD does not change, but the mean increases from 30 to 35. Again, the upper limit of 45 is only 2 SD from the mean, so it will be exceeded 2.3% of the time.

In reality, both the mean and variation can change - and need to be evaluated.

To add to the difficulty, the 2.3% figure is a long-term statistic. Try generating a sequence of 100 random values (normally distributed) and count how many are more than 2 SD above the mean. Repeat it several times, and watch the count change. (In my quick check, I can get it to vary from 0 to 7 over a few dozen tries.) It is that variation that makes it difficult to use just the extreme values to assess whether there is a shift in the regime. The count of how many values exceed the chosen extreme, in a random sample of the variable, is given by the Binomial Distribution.

Getting away from statistics, yes any region will have links to other regions. And yes, as soil dries out and both soil and vegetation respond with reduced evaporation more of the energy received from the sun will go into heating the soil and the air. So it gets hotter, and things dry out more, etc.

nigelj at 18:11 PM on 12 July 2021

The making of a one-of-a-kind climate change PR professional

What truly excellent commentary!

A couple of comments on a few aspects. I have found De Smog blog most useful for finding information on people. So thanks for this often very detailed and revealing work.

It's so sad when people abuse public relations skills to do bad things and promote disinformation.

This really resonates: "The goal of argument and public debate should not be to crush someone who disagrees with you, but to bring forward the truth. Argument is necessary and people should be encouraged to hold different opinions, to challenge issues, to question motivations and points of view, and to take part in passionate discussion. Paralysis is what’s bad......Empathy and evidence need to replace disinformation and division"

The commetary says "I became preoccupied with a question. Why, despite all the alarming scientific evidence, are we doing so little to address the big environmental challenges?"

While the disinformation campaign is obviously part of this it doesn't entitely explain it for me because many people who accept climate science and the need to do something don't appear to do much to change their own behaviour or change laws etcetera. This commentary is probably part of the answer:

"Harvard psychology professor Daniel Gilbert argues that humans are exquisitely adapted to respond to immediate problems, such as terrorism, but not so good at more probable, but distant dangers, like global warming. He talks about his op-ed piece which appeared in Sunday's Los Angeles Times......"

Eric (skeptic) at 12:23 PM on 11 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

...it is better to look at all the data and apply a frequency distribution, then use the fitted distribution to assess extreme values.

Thanks for the added feedback Bob. Initially I thought my question was simpler: how much of the recent event was weather and how much was global warming using the trend of monthly maximums. Then your frequency distribution suggestion led me to this paper:

The changing shape of Northern Hemisphere summer temperature distributions (the Wiley link may not work, so I included the title)

They are doing what you suggested, a frequency distribution of all Tmax values. Then they trend the percentiles. That seems very sensible. My trend of the maximum value of the month does not capture the nature of global warming because global warming affects averages.

That's of course using my assumption from the discussion in the rapid response paper: that the weather was not affected by global warming, just the temperature. So I have to go back and redo my work.

It seems reasonable that a warmer Gulf of Mexico could pump out more moisture and temper Tmax in the central and eastern US. Out west there may be a "desert amplification" effect in dry locations, but there's a lot of variability and that could be Tmax cooling from reforestation (e.g. Nevada City CA), Tmax warming from draining the delta (Sacramento around 1920), and some weather amplification. Soden and Held said the wet get wetter and dry get drier, and I think that applies to weather and seasons more than locations.

Drought is natural but amplification of any drought is part of global warming, and that clearly contributed to Tmax in Portland with 14% RH and Lytton, which I believe went all the way down to 9%. I'll have to leave that for later.

Finally, thanks for the Canada info. I drilled into a directory and found gridded anomalies. That could provide a global warming trend but probably for Tavg, rather than Tmax. I could compare the trend to the raw Tmax values for the recent event. But I'll probably stick with USA for now.

Bob Loblaw at 23:54 PM on 10 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Now, regarding the brief description you give of your methodology, Eric. If I go directly to the image you provided in comment #5, it is a little easier to read the text than it is here on the narrow SkS web page.

https://followthedata.dev/wx/temp/trends/LILLOOET.png

You also say a few words on your use of monthly maxima in comment #7.

The distrbution of temperature involves a lot more than just the extreme values, so you are not looking at the full picture when you restrict the data set that way. Restricting it to monthly maxima is even further limiting. In examining climatological data, it is better to look at all the data and apply a frequency distribution, then use the fitted distribution to assess extreme values. That distribution may be a normal gaussian curve in the case of temperature, but will be something else for other parameters. For instance, precipitation events are not at all described by a normal distribution, so other statistical distributions are used.

In comment #7, you finish with:

The bottom line is with the 98% criteria I can usually get 100 or more years of data. I consider that a minimum for rare events but obviously inadequate for very rare events. We will never see those.

It is erroneous to assume that an extreme temperature with a 100-year return interval is the highest temperature in a 100-year period of record, and it is erroneous to think that a shorter record will not contain these extreme values. A 100-year record may not include a 100-year return interval event, or it may contain several, and it may contain a 1000-year event. These are probabilities, not certainties.

Take the case of Lytton. Is the extreme measure in June 2021 (which is an all-time Canadiane record) a 100 year event? A 1000 year event? Neither? Even if the Lytton station only had data available starting in 2021, that temperature would be an extreme event even though the period of record is short. The classification "extreme event" is essentially independent of the length or record. Our abiity to assess that classification does require more data - but we need to keep a clear distinction between "is it extreme?" and "how do we know it is extreme?". If an event is extreme, it is extreme whether we know it or not.

In order to assess the 100-year/1000-year question, what is needed is enough data to properly assess the distribution of temperatures, which can be done with a lot less than 100 years of data, and involves including more than just the extreme data. In particular, the dsitribution within a region can be assessed using many different stations throughout the region, and determining that the behaviour is similar across the region.

In short, assessing the likelhood of extreme events is a little more complicated than it initially looks.

Bob Loblaw at 23:47 PM on 10 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Thanks for the links, Eric.

I will first comment on the Canadian sources of data, which I have more than a passing knowledge of. You have found the main public archive of data available from Environment and Climate Change Canada (Meteorological Service of Canada). The web site (https://climate.weather.gc.ca/historical_data/search_historic_data_e.html) has its limitations in search functions - in particular it's a bit hard to determine sources of data, whether data are available on hourly, daily, or monthly periods, etc. It takes a bit of manual labour to try all the drop-downs and see what shows up.

In my comment #6, the source of information I was using for station listings and observation programs was the old "Station Data Catalog". For decades, it was published on paper by MSC, and for a while in the elctronic age the catalog was available electronically, but they seems to have stopped providing it publicly. The last electronic copy I have is from 2017. The Catalog lists all observing programs/time periods for each station, including some that are not available electronically. MSC still has records that have not been transferred from paper to electronic form, and the public archive at the web site you used also does not cover every station and observing program that exists electroncially. That web site is probably as complete as it gets for public records, though.

The station catalog I refer to tells you when a measuremnt program was active at a station, but it does not tell you when there are gaps in the observations. For example, the one period I mentioned in comment #6 is based on this entry:

1114620 LILLOOET BC | 50 42 121 56 | 0290| 1948-03-01 1970-02-01

but the data do not appear to be avaiable on the web. As you have discovered, even if the web page provides you with a download, you may find missing values.

Yes, a change in station identifiers usually means a significant change in location, but it is not always so. Over many decades, it is hard to maintain a standard policy on when a new identifier should be used. The same identifier may be used when a station undergoes major changes in instrumentation, too - even though this can mean a discontinuity in methodology that may require homogenization. Station names may also change, making it hard to find other stations that might fill a gap. Once you have selected a specific station and are viewing data, there is a "Nearby Stations with Data" link.

A useful link to additional sources of MSC data is this one: https://climate.weather.gc.ca/links/index_e.html. It includes a link to gridded data based on adjusted and homogenized data.

The MSC web site provides data from a variety of sources. both in terms of who originally collects the data, and the type of observations that performed. Data can come from MSC-operated stations, or partners such as Nav Canada, DND, Parks, or provincial agencies. Observations can be done manually, or through a variety of automatic systems. Manual observations can be detailed hourly meteterological measurements by trained ovservers, or simple once-per-day temperature (max/min) and precipitation measurements by volunteers (although the equipment is provided by MSC).

You can find more information on the observation and processing methods in the Techncial Documentation and Glossary links on this web page: https://climate.weather.gc.ca/about_the_data_index_e.html.

A few key points:

Daily mean temperature is calculated as (Max+Min)/2 regardless of the level of detail available in the original observations. This provides consitency across many different data sources.
When manual observations of Max/Min are done once or twice per day, there are specific rules on how these are assigned to calendar dates, to maintain consistency. A high temperature will not be used twice on two days or two months.
When manual or automatic readings are available on an hourly basis, all Canadian data use a "climatological day" from 0601Z to 0600Z, regardless of time zone.

For the archived data, hourly, daily, and monthly reports are stored independently, so you are not looking at daily or monthly values that are calcualted on the fly when you request them. Until recently, only selected stations were being processed into daily and monthly results. For monthly results, the MSC folows WMO rules for completeness of records: monthly value are not computed if more than a few days are missing. As a result, monthly data may not be provided for a lot of stations that do report daily data.

I will comment on your methodology in the next response.

Reuben Fraser at 21:06 PM on 10 July 2021

Why the Miocene Matters (and doesn’t) Today

As 'this is' my 'first post' on 'Skeptical Science', I have decided to 'respectfully' introduce myself, even though I don't expect anyone to reply. 'Thank You!' That is, to the providers s of this website, and more specifically for howardlee, whose post back on 12 Feb. 2015 has introduced me to this website: Why the Miocene Matters (and doesn’t) Today.

I am accustomed to writing comments for the New York Times, and that is what has led me via a roundabout route to this website. It began when someone's comment informed me about something which I was unaware:

"Concentrations of CO2 in the atmosphere were as high as 4,000 parts per million (ppm, on a molar basis) during the Cambrian period about 500 million years ago to as low as 180 ppm during the Quaternary glaciation of the last two million years."

In the above I am quoting Wikipedia, rather than the person who made the comment, because that is my everday routine: turning to Wikipedia for further information about something which I have read in the NY Times; or otherwise, because there is a new artist about whom I am unfamiliar in the top 10 on the Apple Music charts for the U.S., U.K., South Korea or Spain, the four that I am happy to follow, it being routine to turn to their Artist Discography to download their most commercially successful songs.

The specific Wikipedia article about Climate Change that I am quoting above is Carbon dioxide in Earth's atmosphere; and their reference for what I have quoted is the Australian National University's Professor Tony Eggleton (2013) A Short Introduction to Climate Change, Cambridge University Press, p. 52. However, his text then redirects the reader to his chapter 8 for his references. Via many further such steps, I eventually found the following key reference: Hansen J, Sato M, Russell G, Kharecha P. 2013 Climate sensitivity, sea level and atmospheric carbon dioxide. Phil Trans R Soc A 371: 20120294; as this provides an excellent graph of relatively recent Climate Change, most notably the mid-miocene climatic optimum (MMCO).

Thermal Maximum and Climatic Optimum in the Mid-Eocene and Mid-Miocene

prove we are smart at 11:05 AM on 9 July 2021

Skeptical Science New Research for Week #27, 2021

Extract from 1 of the 107 articles from this weeks new research

"A rapid low-carbon transition is central to achieving the well below 2 °C goals of the Paris Agreement1. In addition to current policies and plans, meeting current NDC pledges is estimated to require US$130 billion per year of further investment in low-carbon technologies to 2030—an amount which could double or even triple for 1.5-2 degree consistency.

For the full article from Climate Change & Economics,week 27 here www.nature.com/articles/s41467-021-24305-3

Yes I know the bulk of that article is mainly concerned with the problems with financing green solutions in third world counties. Well maybe I am proving how smart I'm not but to me a big part of the slow response to new investment in green solutions is this?....

This probably also extends to our govt leaders, media and many more..

The extent of polluting affiliations exposed by the analysis underscore the need for closer scrutiny of board members, said Molly Scott Cato, Professor of Green Economics at the University of Roehampton and a former Green Party MEP."

“It’s shocking to see the very close links between banks and fossil fuel and other heavily polluting industries and helps to explain why, even in the middle of a climate emergency, it has been so difficult to undertake the rapid defunding of the very industries that are driving us to climate destruction,” she told DeSmog.

“This research needs to become a lesson for banks to conduct audits of their staff, not only to understand their potential biases, but also to ensure that they have undertaken mandatory sustainability education.”

Adam McGibbon of Market Forces, a group campaigning to prevent investment in environmentally-damaging projects, agreed that the extent of the connections that fossil fuel companies had to bank boardrooms presented a potentially concerning conflict of interest. He told DeSmog:

“Financial institutions are critical to driving the transition to clean energy, so it’s terrifying that their directors’ views are being shaped by the fossil fuel industry.”

“How can banks reasonably claim to support the Paris Agreement when their directors are linked to an industry with a vested interest in the Paris Agreement failing?”

For the full 11minute read see here www.desmog.com/2021/04/06/revealed-climate-conflicted-directors-leading-the-worlds-top-banks/

Eric (skeptic) at 10:37 AM on 9 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Bob, I used this link climate.weather.gc.ca/historical_data/search_historic_data_e.htmland then type a town. I noticed in most cases observation locations have changed. When I used NCDC, these are my steps: followthedata.dev/wx/temp/trends.html Although the US stations that result from that search may show as complete from 18XX to present, there may in fact be observation location changes over that stated time period.

My impression with the Canada search results is that location changes are all explicit. Elevation changes are obviously likely in the terrain in the parts of BC I looked at which can create obvious discontinuities.

The main reason I used the highest temperature for each month in the trend is to avoid having to homogenize. The highest temperature for the month has a very low chance of being double counted from the previous month (high temp on last day of previous month counted on first day of next month). I basically avoid one problem (observation time with min/max reset) that homogenization may solve.

As for Lillooet it is actually missing the temperature data but has some precipitation, e.g.

"-121.93","50.70","LILLOOET","1114620","1958-01-21","1958","01",

"21","","","","","","","","","","","","0.0","","13.2","","13.2","","","","","","",""

So I assumed the temperature was not recorded and those particular gaps (all with the same station ID) are not resulting from station moves which would have completely missing data. I believe I used 955 and 27388 but I no longer have the shell script in my shell history so I don't know for sure. Here is a line from the recent data:

"-121.93","50.68","LILLOOET","1114619","2021-01-13","2021","01","13","","5.5","","-0.2","","2.6","","15.4","","0.0","","","\
","","","","M","","","","M","","M"

On my US maps I used a 90 year minimum to include the 1930's (source code is linked). My station selection process (described at the link) is to download the first 3-4 stations with 98% or more completeness with current data and earliest start date. Some states have limited records so I settled for as low as 96% in some cases. But I also am downloading any long-record station that achieve new all-time highs. I have not done past mid-June so I do not have all of the PNW heat wave stations (started this before the PNW heat wave).

The bottom line is with the 98% criteria I can usually get 100 or more years of data. I consider that a minimum for rare events but obviously inadequate for very rare events. We will never see those.

Moderator Response:

[BL] Added a line break to try to fix page formatting issue.

Bob Loblaw at 07:48 AM on 9 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Thank you for providing additional information, Eric.

Regarding Lillooet. What is your source of data, and are you going by name, or the Climate ID used by the Meteorological Service of Canada? The information sources I have contain 29 entries for Lillooet, starting in 1878. Each entry indicates small changes in observing programs.Although there are gaps (as suggested by your graph), I see information that suggest a station was active in the period 1948-1970, and other stations in the 1970s and 1980s.

There are nine Climate ID values associated with those 29 station information records - a few have additional information in the names, such as "Lillooet A', which indicates an airport location. The nine Climate IDs are associated with slight variations in location, which would indicate a need for homogenization if records are joined.

You may be looking at a very incomplete record for the Lillooet area.

You may wish to look at the recent discussion where several of us talked about the Lytton location (record all-time Canadian high temperature) and fire:

https://skepticalscience.com/pacific-northwest-death-valley-like.html

In the information I have access to, the current Lytton RCS station (Climate ID 1114746) has been operating since 2006, but there are other records in Lytton going back to 1966. Lytton also has nine different Climate IDs associated with the name (incuding variations such as "Lytton", "Lytton RCS", "Lytton 2"). Again, homogenization would be required to join these together, but the current Lytton RCS station is within one arc-minute of the 1966 location (and 50m higher in altitude).

A great many weather observing locations in Canada (and throughout the world) have undergone many changes over the years, and it takes a lot of work to collect all the different bits and pieces. That's why people do homogenization, and they do tend to know what they are doing.

Although you mention "that web site", you did not actually provide a link.

You also state "Homogenization may or may not be a factor..." and "...that doesn't guarantee that extreme temperatures were not moderated by homgenization in prior years".

That is a very weak argument. Maybe it is? Maybe it isn't? Maybe you don't really know?

What do you consider to be a "short record station? How many years? On what basis do you decide that this is too short?

rpnman at 07:04 AM on 9 July 2021

Welcome to Skeptical Science

Thank you so much for a valuable site. I rely on it for educational purposes and will support it (to the limited extent I can) financially.
...
My comment and question has to do with the intersection of climate change activism and other avenues of effort to bring about a more just and sustainable world. I have phrased that introductory sentence very carefully, because I am deeply concerned with getting to the root of what ails humanity that gives rise to ongoing crises in so many aspects of our living at once. I'll mention just a few that I claim are (beneath the surface) related: climate change; the cruel distorting injustice of a racialized social, economic, and political order; and widespread alientation from science and a flourishing of irrational contrarianism.

So think it may not just be a meaningless fluke or that your public-facing, friendly, 'volunteers' shot is, roughly 3/4 male and overwhelmingly white. It would take an effort to delve beneath the statistics (yes, the costs of climate change are visited disproportionately on the poor and on people of color) and come to grips with the worldview that links these imbalances into a pattern.

This long prolog boils down to a series of questions. Is there a part of the website that I missed that addresses this issue? If not is there any fellow interest in pursuing it? And where would it land? If there is not any interest I am left wondering why, and would welcome any thoughts in response.

My perspective is not one of an atheistic skeptic, but I do recognize that much of the world's religion has become mired down in outdated ways of discussing things that borders on superstitious narrow-mindedness. What I'm saying is that the discussion of human values is also essential to understanding how we got in to this climate mess and will be key to finding a way forward. Inevitably, that discussion entails a host of other issues as well. I fear that to ignore this critically important part of the picture is a Procrustean, and potentially fatal, oversimplification.

Eric (skeptic) at 06:45 AM on 9 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Thanks for fixing my link, and thanks for the questions. I found one long record station that continues to the present in SW Canada:

Lillooett, Canada highest temperature by month

The trend is clearly up but due to the lack of data lacks statistical significance. I have the code on that website and can provide data if anyone wants to validate. The bottom line is that the first possibility in the top line of the paper is the most likely:

There are two possible sources of this extreme jump in peak temperatures. The first is that this is a very low probability event, even in the current climate which already includes about 1.2°C of global warming — the statistical equivalent of really bad luck, albeit aggravated by climate change. [versus climate nonlinearity]

They also point out the possibility of a combination. But charts from the US PNW are clear, a mostly flat trend in the highest monthly temperature followed by an extreme outlier. Bob, short record stations can't show the trend. Homogenization may or may not be a factor, and only in the single Canadian example, New Westminster. They said the 2020 homogenized and raw matched exactly. But that doesn't guarantee that extreme temperatures were not moderated by homgenization in prior years.

Phillippe said: "For Portland, OR in 1872. For Seattle, WA in 1891" They used Portland Int AP which starts in 1938 and SeaTac AP which starts in 1948.

John Hartz at 03:21 AM on 9 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Hot off the press:

The deadly heatwave that hit north-western US and Canada in late June would have been “virtually impossible” without human-caused global warming, a new “rapid-attribution” study finds.

The event, which saw temperature records shattered by as much as 5C, has been linked to hundreds of deaths in the Pacific north-west region.

The heatwave was “so extreme” that the observed temperatures “lie far outside the range” of historical observations, the researchers say. Their assessment suggests that the heatwave was around a one-in-1,000-year event in today’s climate – and was made at least 150-times more likely because of climate change.

The analysis also finds that, if global warming were to hit 2C, a heatwave as extreme as seen last month would “occur roughly every five to 10 years” in the region.

Pacific north-west heatwave shows climate is heading into ‘uncharted territory’ by Robert McSweeney, Carbon Brief, July 7, 2021

https://www.carbonbrief.org/pacific-north-west-heatwave-shows-climate-is-heading-into-uncharted-territory

Philippe Chantreau at 02:44 AM on 9 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Like Bob, I would like to know more about why exactly Eric has a problem with the World Weather Attribution Group method.

There is a discussion at RC about this and they link to the preprint, where this can be found in section 2.1 (Observational data):

"The main dataset used to represent the heatwave is the ERA5 reanalysis (Hersbach et al., 2020), extended to the time of the heatwave by ECMWF operational analyses produced using a later version of the same model. All fields were downloaded at 0.25º resolution from the ECMWF. Both products are the optimal combination of observations, including near-surface temperature observations from meteorological stations, and the high-resolution ECMWF weather forecast model IFS. Due to the constraints of the surface temperature observations, we expect no large biases between the main dataset and the extension, although some differences may be possible under these extreme conditions."

It would be nice to propose a potential better methodology before condemning this one to the Gemonies.

https://www.worldweatherattribution.org/wp-content/uploads/NW-US-extreme-heat-2021-scientific-report-WWA.pdf

Per NOAA, the period of record for Vancouver, WA starts in 1872. For Portland, OR in 1872. For Seattle, WA in 1891. For Vancouver BC in 1877. Etc, etc...

Bob Loblaw at 23:38 PM on 8 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Eric:

You state "they are comparing adjusted, homogenized data from prior years to unhomogenized data from this year which exaggerates the current event. "

Please explain your reasoning as to why recent unhomogenized data causes this problem.

Please also explain/support your assertions regarding "very short record stations" and "no long term data".

Eric (skeptic) at 20:10 PM on 8 July 2021

Analysts dissect historic Pacific Northwest ‘heat dome’

Link to study is on this page, and please read "main findings" bullets. https://www.worldweatherattribution.org/western-north-american-extreme-heat-virtually-impossible-without-human-caused-climate-change/ The bullets are sensible.

I'm not sure if they are intent on showing the event was mostly weather. But they are comparing adjusted, homogenized data from prior years to unhomogenized data from this year which exaggerates the current event. That makes it even more likely to be weather. They are comparing ERA to the euro model in the bounded area box. The 5C outlier extreme temperature in the bounded box is not verified by any station other than very short record stations, which I suspect is the problem with the analysis of the box.

In any case they are showing an event with an extreme outlier temperature without showing an increase in similar extremes. They claim an increase but have no long term data to show an increase.

Moderator Response:

[BL] Link activated.

The web software here does not automatically create links. You can do this when posting a comment by selecting the "insert" tab, selecting the text you want to use for the link, and clicking on the icon that looks like a chain link. Add the URL in the dialog box.

MA Rodger at 10:17 AM on 8 July 2021

CO2 is not increasing

the Inspector @41,

I'm not at all convinced by your 'China' theory or even that there is a convincing 'dip' in MLO CO2 levels (or perhaps best described as "less of a February CO2 rise relative to consecutive months").

But I would draw your attention to a definite error in your argument. The reason the windy.com graphics are showing sky-high levels over China and very low levels elsewhere is because this is CO (carbon monoxide) being plotted in parts per billion. It is not showing CO2 (carbon dioxide).

the Inspector at 09:00 AM on 8 July 2021

CO2 is not increasing

As this is your first post, Skeptical Science respectfully reminds you to please follow our comments policy. Thank You!

Thank you for the membership, i have followed the mauna loa curve for years and wondered what the yearly dip in co2 increase is caused by.

This year the curve is straight up for the first time ever and i found a correlation; China.

Since 2020 i have taken dayly screenshots of the "windy" website which monitors the co2 levels globally and focussed on china's dayly output, in short it showed increased activity just before the chinese new year celebration ( 12 feb to 26 feb ) and continues during the celebrations because of the pandemic demand for products.

Mauna loa is directly downwind of china by some days and is in effect monitoring China's co2 output.

You can check this out for yourselves on the "windy.com" and the noaa mauna loa co2 graph websites.

Here is a link to my 3 youtube video's titled; "co2 levels explained"on youtube, it has all the info combined to show the relationship in detail on a day by day basis;

https://www.youtube.com/watch?v=kbjnbw_npY8

https://www.youtube.com/watch?v=2IYQZu-XwOc

https://www.youtube.com/watch?v=7szFJD9nAFM

Another significant indicator is the dip in 2008 which stopped China's output for two months in the mauna loa graph.

Thank you; the Inspector.

Daniel Bailey at 04:10 AM on 8 July 2021

Deciphering the rise and fall of Antarctic sea ice extent

Global sea ice, showing both Arctic and Antarctic sea ice extent changes over time in the satellite observational record:

Arctic sea ice extent continues its multidecadal decline and Antarctic sea ice extent is currently at normal, average values.

Source: NSIDC

MA Rodger at 23:07 PM on 7 July 2021

Deciphering the rise and fall of Antarctic sea ice extent

gerontocrat @1/2,

For clarity, I have snatched your 'graphic of JAXA's VISHOP Antarctic SIE 1980-to-date' from Neven's Forum and installed it below.

Antarctic SIE 1980-2021

gerontocrat at 21:16 PM on 7 July 2021

Deciphering the rise and fall of Antarctic sea ice extent

Whoops - address is

https://forum.arctic-sea-ice.net/index.php/topic,1759.msg314913.html#msg314913

Moderator Response:

[BL] Link activated.

gerontocrat at 21:15 PM on 7 July 2021

Deciphering the rise and fall of Antarctic sea ice extent

As of now, 365 day trailing average of sea ice extent is now above the (meaningless) linear trend by 60k km2. You can see the image here...

Arctic Sea Ice Forum - Antarctic Sea Ice

Moderator Response:

[BL] Link edited per following comment.

Bob Loblaw at 00:54 AM on 7 July 2021

Models are unreliable

MAR:

This all hinges on what is meant by "calibration", and whether or not the parameters in a model are arbitrary.

Wiktionary defines "calibrate" as "To check or adjust by comparison with a standard." When discussing climate models, this implies that there is some adjustable parameter (or seven) or input that can be varied at will to create a desired output.

There are many problems with this argument [that climate models are "calibrated" to create a result]:

What are we calibrating for? A global 3-d climate model has thousands (if not millions) of outputs. Global mean surface temperature is one simple statistical summary of model output, but the model has temperatures that vary spatially (in 3-d) and temporally. It also has precipitation, humidity, wind speed, pressure, cloud cover, surface evaporation rates, etc. There are seasonal patterns, and patterns over longer periods of time such as El Nino. All of these are inter-related, and they cannot be "calibrated" independently. Analyzing the output of a GCM is as complex as analyzing weather observations to determine climate.
How many input parameters are devoid of physical meaning and can be changed arbitrariiy? The more physcially-based the model is, the fewer arbitrary parameters there are. You can't simply decide that fresh snow will have an albedo of 0.4, or open water will evaporate at 30% of the potential evapotranspiration rate, just because it makes one output look better. So much of the input information is highly constrained by the need to use realistic values. All these have uncertainties, and part of the modelling process is to look at the effect of those uncertainties, but the value to use can be determined independently through measurement. It is not a case of choosing whatever you want.

So, robnyc987's claim that you can achieve 100% accuracy by "calibrating" a small set of parameters is bunkum. If climate models are so easy to "calibrate", then why do they show variations depending on who's model it is? Or depending on what the initial conditions are? That variability amongst models and model runs indicates uncertainty in the parameters, physics, and independent measurements of input variables - not "calibration".

Perhaps robnyc987 will return to provide more explanation of his claim, but I somehow doubt it.

MA Rodger at 21:00 PM on 6 July 2021

Models are unreliable

Bob Loblaw @1289,

The paper that fuelled the 2011 Scientific American item linked @1288 is presumably Carter et al (2005) 'Our calibrated model has poor predictive value: An example from the petroleum industry' [ABSTRACT] which may provide the argument for "6 or 7 in interdependant variables" preventing model calibration although likely this is no more than a different version of the famous Fermi quote:-

“I remember my friend Johnny von Neumann used to say, with four parameters I can fit an elephant, and with five I can make him wiggle his trunk.”

However, this Fermi quote concerns "arbitrary parameters" and what Carter had in mind when he says "As far as I can tell, you'd have exactly the same situation with any model that has to be calibrated," isn't defined. But this 2011 Scientific American quote of Carter (I don't see an earlier statement of it) has occasionally been used by denialists to suggest the same calibration situation affects climate models. Of course GCMs do have a big challenge with calibration but I don't think it is down to the number of independent variables. There are many physical measures that can be used to callibrate the processes within GCMs, which is probably why they can (collectively) demonstrate useful predictive qualities. (The graphic is from this 2021 RealClimate post.)

RealClimate GCM performance 2020

Bob Loblaw at 22:36 PM on 5 July 2021

Models are unreliable

robnyc987:

You have made several empty assertions without evidence.

All models require some level examination between model outputs and observations, and all models undergo modification to improve their ability to match observations. That is good science.

You will need to provide some sort of definition for what you call "calibration" before anyone will take your criticism seriously.

Where do you get "6 or 7" from, and what is the basis for your claim that 6 or 7 variables is enough for "100% correlation"? It sounds like you think all models are purely statistical fits to data. If this is what you think, you are wrong. If you think that hind-casting models can be 100% accurate with only a few variables, you are wrong.

Your assertions of nonsense, working without calbration, bias and "no idea" are all just rhetorical waffling.

Of what relevance is a link to economic models to a discussion about climate models? The link refers to one case of a geophysical oil field model. Over-fitting a model - even one that is physically-based - is poor science, but that does not mean that every model is over-fitted and suffers the same problems. You will need to come up with an example of a climate model that is over-fitted if you want to be taken seriously.

If you do not understand the difference between statistical models and physically-based models, then you are woefully uninformed.

By the way, we know all models are "wrong" in that they are incomplete - but they can be useful.

You may have no idea, but the science of climatology does. Try reading and learning. Start with the blog post you are supposedly commenting on. If you continue to comment, I suggest that you actually respond to specifics in the blog post at hand. Comments need to be on topic, not just meaningless rants.

robnyc987 at 21:17 PM on 5 July 2021

Models are unreliable

Any model that requires calibration is wrong; there are an infinite number of models for a system with more than 6 or 7 in interdependant variables can be backtested with 100% coorelation yet differ in future predictions. So, all the models show is the bias of the modeler. It's non-sense to claim any model of the climate is accurate. Basically, the model must work without any calibration or the results simply reflect the bias of the modeler. Humanity may have increased the amount of CO2 in the atmoshere; but, humanity has simply no idea what the impact will be.

https://www.scientificamerican.com/article/finance-why-economic-models-are-always-wrong/

Moderator Response:

amhartley at 11:19 AM on 5 July 2021

Human Fingerprints on Climate Change Rule Out Natural Cycles

I wonder whether the "nights warming faster than days" fingerprint should be more nuanced? This page

https://news.yahoo.com/summer-swelter-trend-west-gets-134723813.html

says days, in the American west, are warming faster than nights.

John Hartz at 02:01 AM on 5 July 2021

Antarctica is gaining ice