Animation shows the temperature change by country from year 1880 to 2019 | Hacker News Reader

Animation shows the temperature change by country from year 1880 to 2019

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Very cool.

Also, see this: https://i.redd.it/h6annrws3qa41.png

Er, you meant, very warm?

...duh.

Very nice animation! Data is suspect, though -- US 1937 should be bright red, not pale yellow. 1937 had record heat wave in US.

It's probably ok but you could look at the source data and be more specific, averages and base indexes can play tricks on the visualization. From the video:

https://data.giss.nasa.gov/gisstemp

Data source NASA GISS, GISTEMP Land-Ocean Temprature Index (LOTI), ERSSTv5, 12000km square smoothing.

Average of monthly temprature anaomolies. GISTEMP base period 1951-1980.

...which followed one of the coldest winters on record, which brings the average down.

The visualization makes it look a little terrifying. Maybe that's an understatement...

You can make anything look terrifying with an appropriate choice of palette.

(That's not to say the data aren't also terrifying, of course.)

Is it practical to have giant nuclear powered facilities that either pump cooled air or artificially cool surface ocean water? Or just use the electricity to break down water for O2 production and use the hydrogen to power other things?

To create that cooled air you have to heat something else right? I'm not sure that's the right direction...

Something other than the atmosphere and surface ocean water? A mile or so under the earth crust, or 5k meter+ under ocean water heat release/transfer

> or artificially cool surface ocean water

Good curiosity, but they would have to put out atleast an equal amount of heat into the atmosphere! (2nd law of thermodynamics).

People are still trying to work out if we can make black bodies that are biased to radiate more heat in frequencies that the atmosphere is permeable to.

We have some materials that are much more thermally conductive in one direction than the other. Pair the two, and it might just be possible to shed some heat into space at night.

Entropy always wins. It’s the heat trapped in the atmosphere that’s killing us. The universe is a mighty big heat sink though.

Interesting. Do you have resources/keywords I can use to know more about such research?

Search for radiating heat into space. There were some reports about 8-10 years back. Occasionally you will see people working on materials that have narrow emissions spectra, but I think they may have other things in mind, like combining them with photovoltaics to make solid state heat engines. Which has the potential to be much more efficient than thermocouples. Thermocouples are so far from their theoretical limits that boosting the conversion rate by single digit percentage points is more than doubling efficiency, which is how we ended up with a new thromocouple material on the front page of HN a month ago.

> heat sink

Bad analogy and you cannot rely on conduction to transfer heat in space. The only means of heat transfer is radiation.

The question was why can’t we just make hot things cold.

The answer is “you can, if you have some place to put the heat”. What would you call the counterpart to a heat source?

Why the atmosphere? Deep ocean water is already super cold right? Plus water does a good job of absorbing heat.basically transfer the surface heat energy to deep waters,that way surface level glaciers are kept frozen?

Water is a good insulator, but not a perfect insulator. If the temperature difference between the bottom and top changes so does the heat transfer and given time the effects will spread. But most important is, warm water/moisture is less dense than cooler water, that means large heat transfer by convection currents in addition to the low conduction (inverse of insulation).

> Is it practical to have giant nuclear powered facilities that either pump cooled air or artificially cool surface ocean water?

That would be like opening your refrigerator to cool your room - more heat is emitted from the radiator on the back of the refrigerator than is removed and so the room as a whole gets hotter. (Because movement of the heat from the interior to the back cancels out, but the energy used to move it creates additional heat resulting in a nett increase.)

This would have the net effect of warming the atmosphere, unless you developed new technology to simultaneously beam significant heat energy into space.

Does it have to be space? Can't you send the excess heat to deep ocean waters or into the earth's mantle?

The "to space" method has the smallest probability of backfiring in surprising ways. For instance, heating deep ocean waters could disrupt the local ecosystem down there, and we don't fully understand yet how the deep ocean is connected to everything else on an ecological level.

True, the situation at the surface seems much more dire and urgent though.

Underground is generally warmer than the surface, and warming the ocean causes problems of its own. But really the problem is that the amount of heat you'd have to move is absolutely massive - the best we can do is alter the atmosphere to increase the amount of heat radiated to space, because we can't out-cool the sun.

If we have this level of surplus energy, we should be using it to first replace all fossil fuel consumption and then secondarily start drawing CO2 down from the air. We can't out-cool the sun.

You would have to find a way to move the heat away from the earth.

That would be a heat pump and say it worked at a COP of 3 which is typical you would need 1 watt of power to move 3 watts of heat to somewhere, probably deep underground.

Nuclear power is what maybe 40% efficient so 60% of the nuclear energy is waste heat, so for every watt of energy 1.5 watts of heat released.

So now your only netting 1.5 watts for every watt. To make a difference the numbers would be staggering as the earth receives on the order 170,000 terawatts of solar energy.

Solar power rather than nuclear would make more sense but again the scale to make a difference is staggering.

I think more "realistic" would be using energy to split CO2 back into C and O2 and sequestering the carbon in the ground which is basically what plants do through photosynthesis. If we could make machines that do that more efficiently on a large scale from solar power we might make a difference.

Thank you for the detailed explanation. Would the logistics still be the same if you're talking about cooling spcific subsets of the polar regions? For example, the "rim" of the arctic?

Perhaps the excess heat from nuclear can be used to clean up CO2, I remember reading a few articles that suggest CO2 cleaning plants are actually practical

I am a bit upset about all the downvotes,i know it's bad etiquette to complain about that but I just wanted to say how questions of curiosity shouldn't be looked down upon. This isn't my field but climate change is concerning, so I simply wanted to know why certain solutions (however naive) were not being pursued.

Cheers.

Don't let it worry you. Downvoting is essentially a thoughtless act so you can pretty much ignore them. It just means some people dislike what you wrote without considering the substance of it.

In reality it's a good question and it prompted some good answers.

Thank you, sorry for being so petty

Some companies are working on carbon scrubbing tech that removes CO2 from the atmosphere and converts into something else — a liquid fuel in one case, if I remember correctly. These processes, I believe, are energy intensive — so using something like nuclear to power them would make a lot of sense, if you can find a way to install new plants with less money, and less regulatory hurdles than today. (Bill Gates is funding a nuclear plant design that seems promising in this regard — Terra Nova, I think it’s called.)

In 28 August 1981, the mean surface temperature is 288K = 15 degree C:

http://climate-dynamics.org/wp-content/uploads/2016/06/hanse...

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In 1988, it was claimed that the global avg temperature was 59 deg F = 15 degree C

Multiple sources:

https://www.nytimes.com/1988/03/29/science/temperature-for-w...

https://news.google.com/newspapers?nid=1915&dat=19880705&id=...

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IPCC's First Assessment Report in 1990, table on page xxxvii of the report listed the "Observed Surface Temperature" of Earth as 15 degrees Celsius:

https://www.ipcc.ch/site/assets/uploads/2018/03/ipcc_far_wg_...

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In Jan 12 1992, it's 15 degree C:

https://news.google.com/newspapers?id=S2xGAAAAIBAJ&sjid=7ugM...

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############## SOMETHING CHANGED IN 1997:

"Global Temperature Down Slightly":

https://books.google.ca/books?id=VyFpAwAAQBAJ&pg=PA62&lpg=PA...

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December 14, 2002: They magically started using 14C as the long term average instead of 15C without any explanation:

https://www.smh.com.au/world/global-warming-blamed-for-heat-...

> This year the Earth's average temperature was 14.64C, compared with the long-term average of 14C, said James Hansen, of NASA's Goddard Institute for Space Studies, who analyses the data collected from thousands of weather stations around the world. The meteorological year runs from December to November. During that period, 2001 temperatures were 14.51C. The record remains with 1998, when global temperature rose to 14.67C - the highest since records were first compiled in the late 1800s. The warm temperatures of 2001 and 2002 are especially significant when they are considered in the light of El Nino weather patterns that alter global climate, Mr Hansen said. "The fact that 2002 is almost as warm as the unusual warmth of 1998 is confirmation that the underlying global warming trend is continuing," Mr Hansen said.

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August 25, 2011:

> But Hansen and colleagues have estimated that Earth's actual average surface air temperature between 1951 and 1980 was approximately 287 K (14 degrees Celsius) (Hansen et al. 2010). The difference in temperature is attributed to greenhouse gases that trap thermal radiation, warming Earth as depicted in figure 2.1.

https://www.gao.gov/assets/330/322216.html

##########

Sometime between 1997 and 1998, they magically started claiming the avg to be 14 degree C instead of 15.

18 January 1998's "Vital Signs 1998: The Environmental Trends that are Shaping Our Future" magazine made this magical change with a small footnote:

https://books.google.ca/books?id=EfZRAwAAQBAJ&pg=PA174&lpg=P...

> In earlier versions of Vital Signs, Worldwatch added the temperature change reported by the Goddard Institute to an estimated global temperature of 15 degrees Celsius, but the institute has since informed Worldwatch that a better base number would be 14 degrees Celsius. James Hansen, Goddard Institute for Space Studies, New York, email to author, 18 January 1998.”

Can someone please explain this unexplained change on how avg surface temperature between 1951 and 1980 went from claims that it was 15C to now being claimed it was 14C?

Edited: changed magic to unexplained change

Interesting observation. Changing by a whole degree celsius is quite a big change that needs a good reason.

If you wouldn't use the word "magic" in your post, I'd perceive it as neutral/curious.

I am curious but I have pointed out similar discrepancies quite a few times but never received a satisfactory response. Now a days, I am pretty much afraid to even point out such discrepancies in other data too. I can share another example if anyone's curious.

are you familiar with the blog made by tony heller (also on youtube) ? He regularely points out those exact same remark.

I am very careful to wait until other people confirms that there is indeed a methodological problem before jumping to conclusion, but it really sounds very interesting.

I read Heller's blog. I've also done a bit of double checking of his work because indeed, what he keeps uncovering is extremely interesting and should I feel really have been discussed in popular journalism about climate before now.

I want to check more of his claims in future. But for now, I only checked how many data points in the NOAA US temperature dataset are now the output of model simulations and not actual measurements:

https://realclimatescience.com/61-fake-data/

I verified the "Percent of USHCN Monthly Temperature Data which is fabricated" graph by downloading the source dataset and writing some scripts to process it. I was able to replicate his numbers. It's alarming that over half of reported temperature readings in the USA are actually not readings at all but rather estimates by a computer program.

I also spent some time reading the source code of the programs doing the temperature simulation but wasn't impressed. It's very old FORTRAN that has no unit tests of any sort. There are code comments giving the basic gist of what it's doing, but it's clear that the code has been grown and patched ad-hoc since the 1980s. There's nothing resembling real software engineering.

However there are also reasons to not be alarmed.

Some years ago climate skeptic bloggers started pointing out extensive problems with the network of weather stations used to calculate US temperatures. It had degraded over time as measuring stations dropped out, moved, had things built next to them etc. This in turn led to climatologists making extensive adjustments to the raw data, which is a very sketchy thing for scientists to be doing.

Congress agreed there was a problem and released funding to build a pristine new temperature network, which started operating some years ago. The skeptic bloggers agreed that the design of this new network was excellent, and the good news is the output of it matches the adjusted output of the old network (in fact, the adjusted old network measurements are still being used as canonical, which is a bit weird). So it seems that the current set of adjustments is not a problem even though it looks alarming.

The bad news is that this is partly because the adjustments made to modern measurements are quite small compared to the extent to which historical temperatures have been adjusted. Heller has been investigating the TOB adjustment in particular, which is near non-existent now but massively alters past readings. It's based on the belief that for most of the 20th century weather station operators didn't know how to properly use a min/max thermometer and that this methodological failure was never documented in primary sources, but has to be inferred from the recorded data.

I haven't made up my mind about these adjustments yet and remain in the neutral "they're probably OK" position. TOB is one but there are many others. The issue for Heller is not only methodological but also "where there's smoke there's fire", that is, the adjustments might be correct but everything around them is extremely suspicious, starting with the fact that - as this thread shows - climatologists keep adjusting even very recent data. How hard can it possibly be to read a thermometer and write down the numbers? Apparently, very hard.

There was this project but it seems to be not active any more. http://clearclimatecode.org/

Is is sad how much of very important software is so maintenance starved.

I really thank you for your comment, and the time you took to honestly assess the current situation. The one thing that i still have a hard time accepting is that a whole community of scientist accepts doing science on such a fragile basis (such as the fact that more than three quarter of the world wasn't recording temperature until 50 years ago).

It seems impossible that so many people keep doing their work on fragile data (and code, apparently), while at the same time seeing their work used by politicians all over the world to advocate massive policy changes.

I still haven't reached a personal conclusion, but i would be glad to read about the progress made by "hands deep in the dirt" people like you in their investigation.

Mmmm. Surely it's the other way around, this is the expected and indeed only possible outcome.

I was in a different HN thread this week where I pointed out that there are some conclusions that might be right but which some sections of academia institutionally cannot reach, conclusions like:

1. We don't know enough to make predictions in this field.

2. Our datasets are inadequate for use.

3. Our research is unimportant and doesn't need to be done.

Note that commercial research can easily reach any of these conclusions; that's the function of senior management who are motivated by some fundamental ground truth goal rather than research for the sake of it.

Climatology is almost entirely driven by academia and other government institutions. They cannot reach a conclusion like, "old temperature datasets are of too low quality to derive models from" because then they'd invalidate the basis of their own careers. My impression is that climatologists have few transferable skills. Perhaps it's just small sample sizes, but it seems like their maths skills aren't really "hard" enough to outcompete physicists, mathmos or CS profs for jobs in finance or other exit routes.

Given that climatology has a single main theory (global warming), and that theory is based primarily on a single dataset (temperature), problems with that dataset have to be addressed by adjusting the data. Otherwise what's left for the field to do?

But that’s the thing : there is definitely a science for climate modeling, but it’s probably at its infancy. Someone brave enough to correctly asses the limits of the field should be recognized in the field itself. It’s a bit similar in spirit to the « reproducability » issues in biology research.

It's because anyone who tries to point out holes in the claims gets demonized with a label (denier) and loses all grants and funding. Even IPCC (and therefore UN) no longer provides grants to anyone who points out skepticism.

> In honor of the late AUGIE AUER, Professor of Atmospheric Science at the University of Wyoming, Chief Meteorologist for the MetService, co-founder of the NZ Climate Science Coalition and much-loved scientist of the highest integrity, members of the Coalition have established a fund now totaling $10,000 to be granted to the first applicant to present real-world evidence showing that the man-made fraction of airborne carbon dioxide causes dangerous global warming. Professor Augie Auer was appalled that climate scientists should be denied funding and be branded ‘deniers’ unless they submitted to the political global warming narrative and renounced the ancient principle that science is never settled. Those refusing the NZCSC’s request for evidence of dangerous man-made global warming include the IPCC, the Royal Society, the Royal Society of New Zealand, the NZ Ministry for the Environment and Professor James Renwick. To the first person who proves what they cannot, we offer this prize in the name of our late, incorruptible colleague.

So far, no one has been able to win it.

I actually confirmed the Arctic Sea ice one too. Got the data from:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02186/

Used masie_4km_allyears_extent_sqkm.csv to plot it.

It looks like this:

https://i.imgur.com/9kNtYbI.png

Another source which confirms this too:

June 22, 2008:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE...

June 22, 2014:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE...

June 22, 2018:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE...

i think you and parent should create some kind of blog confirming all this. It makes a huge difference between having one guy ( tony heller ) blogging about this, and multiple independant people confirming the findings.

It also makes for different POV about the same issue ( data fixing methodology and code quality), and it’s always a good way to bring improved arguments in the debate.

Tony Heller is a well credentialed denier[1], been in the game since at least 2008, and is at least good friends with the deniers that get oil money to keep going [2]. I estimate his honesty as comparable to that of Giuliani post 2017.

[1] https://www.desmogblog.com/steven-goddard

[2] https://insideclimatenews.org/news/12032015/leaked-email-rev...

Simply coming up with a demonizing label for him (denier) and applying these label as a castigation to anyone who even tries to point out skepticism is not how you should make arguments.

> good friends with the deniers

What does that have to do with anything when he's pointing out with raw data which is provided by science and anybody has the ability to point out what he's doing wrong? If you don't have the ability to point out holes in his data, then I don't think you are acting in good faith.

Also political attacks in a civil debate about science isn't good.

This isn’t a debate about science, this is a political debate about who to trust as you really ought to know if you paid any attention to the climate debate.

It's ironical you think about Heller's work as "political", as one of the arguments he makes is that the climate science field became completely crippled once politicians started to put their nose in it.

It's also a huge problem that once a scientific theory (man-made climate change due to CO2) becomes "mainstream" and labelled as "official", you can't oppose it without immediately having all kinds of people with various interests supporting you for sometimes bad reasons. It's unfortunately inevitable.

Worth reading how Dr James Hansen and senator Timothy Wirth (who's the president of UN for many years now) sabotaged the air conditioner back in 1988 and opened the windows to make things appear worse for the cameras:

https://www.pbs.org/wgbh/pages/frontline/hotpolitics/intervi...

I didn't bring in politics, I simply states sources from scientific sources and old newspapers. If anyone can point out what's wrong with it, then I am okay for a debate. The problem is that people have made this into a political debate because there's a lot of money involved in climate change policy making.

I’d be very interested in another example. It’s not too often we can hear evidence against AGW so it’s worth the downvotes that it will inevitably bring.

One of the major claims Dr James Hansen made in his testimony in 1988 (which led to the creation of the IPCC) was that the arctic sea ice is melting and it would disappear. In 2008, he was asked about it and he said he was sure it would happen. Dr. James Hansen made his prediction on June 22 1988 and repeated them in 2008.

https://www.cbsnews.com/news/nasa-climate-scientist-says-wer...

So I looked at the actual data from the Danish Meteorological Institute:

http://ocean.dmi.dk/arctic/icethickness/thk.uk.php

June 22, 2008:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE...

June 22, 2014:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE...

June 22, 2018:

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE...

The data shows the exact opposite of the claims which were made and even made now a days by the media. It shows it has gotten thicker, more volume and area.

You can confirm this from another source by using the data provided here too:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02186/

It looks like this:

https://i.imgur.com/9kNtYbI.png

The research is done in terms of a temperature anomaly from a reference that is chosen. The absolute mean temperature is an estimate based on the specific technique chosen using the data as input. The delta values are more important because they are calculated with a consistent method for a given model, whereas from model to model the value may change.

from https://www.pnas.org/content/94/16/8314

""" The two main marine data sets are those of Jones et al. (ref. 9; see also ref. 11) and the U.K. Meteorological Office (UKMO) (12, 13). These two data sets have overlapping primary source material but differ in the way that they are corrected for instrumentation changes. """

https://pubs.giss.nasa.gov/docs/2007/2007_Hansen_ha09210n.pd... (mentions the particular model in section 1, along with a discussion of the data sources).

You basically want to be looking at the temperature anomaly not the absolute temperature.

That doesn't answer the sudden change from 15C claims to 14C for the 1950-1980 period.

For example, in the following data, for 2016, they say the average global temperature as 14.8C:

https://www.ncdc.noaa.gov/sotc/global/201613

If the average global temp used to be claimed to be 15C but since 2000, they claim it was 14C, then somebody is making false claims about the avg temp.

Sorry I don't see 14.8 in the URL you gave?

> The average global temperature across land and ocean surface areas for 2016 was 0.94°C (1.69°F) above the 20th century average of 13.9°C (57.0°F)

The larger point I'm trying to make is that average global temperature is something that is calculated as a result of the specific method the people doing the study use. It's not a simple average of a list of numbers. It tries to account for missing and spotty data, instrument biases, location biases, etc.

So if they find a better way to do it the calculated value will change.

That's a fair point and others have mentioned that before. However, all the sources I have used in my original comment are from the same person - Dr James Hansen who served as the director of NASA Goddard institute for 35 years. He used the 15C claim for many years until he suddenly decided to switch to 14C. In any scientific claim, especially when such small changes could impact major things, a scientist shouldn't simply be allowed to change their data claims without any explanation, especially when it suddenly doesn't fit their claim.

Also in this source:

https://books.google.ca/books?id=VyFpAwAAQBAJ&pg=PA62&lpg=PA...

in 1997, the scientific community knew that the temperature was actually going down and not up:

> "Global Temperature Down Slightly"

The claims Hansen made are contained in his research papers. So you'd have to cite them, though in most of the papers I've read they tend not quote absolute numbers.

In https://pubs.giss.nasa.gov/docs/2010/2010_Hansen_ha00510u.pd... paragraph 6:

""" 6] One consequence of working only with temperature change is that our analysis does not produce estimates of absolute temperature. For the sake of users who require anabsolute global mean temperature, we have estimated the 1951–1980 global mean surface air temperature as 14°C with uncertainty several tenths of a degree Celsius. That value was obtained by using a global climate model[Hansen et al., 2007] to fill in temperatures at grid points without observations, but it is consistent with results of Jones et al.[1999] based on observational data. The review paper of Jones et al.[1999] includes maps of absolute temperature as well as extensive background information on studies of both absolute temperature and surface temperature change. """

The 2007 paper is https://pubs.giss.nasa.gov/docs/2007/2007_Hansen_ha09210n.pd...

Jones' paper https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999...

Section 6 discusses the anomaly vs absolute temp.

https://core.ac.uk/download/pdf/19595636.pdf Introduction gives a brief history and list of the historically calculated values.

So he was probably using the best value they had at the time. I don't know why any specific number was printed in the popular press at any given time though.

The 90's "pause" is still reflected in the data (depending on how you long you want to average over), then temps started increasing again.

Fortunately there are an awful lot of other proxy variables which can be used to show a long-term change in climate. One example of thousands is the Japanese cherry blossom season: https://www.economist.com/graphic-detail/2017/04/07/japans-c...

And yes, there have been reversals in some years. But overall you can see the industrialisation "hockey stick" quite clearly in that calendar data.

That graph seems to have opposing data for the global Medieval Warm Period and Little Ice Age. Medieval Warm Period (MWP) from about 900 A.D. to 1300 A.D. and the Little Ice Age (LIA) from about 1300 A.D. to 1915 A.D.

The MWP was a local phenomenon; per wikipedia

> The Medieval Warm Period (MWP) also known as the Medieval Climate Optimum, or Medieval Climatic Anomaly was a time of warm climate in the North Atlantic region lasting from c. 950 to c. 1250.[1] It was likely[2] related to warming elsewhere[3][4][5] while some other regions were colder, such as the tropical Pacific

.. which implies that Japan may have been slightly colder at the time.

(Neatly illustrates that computing global average temperature from a set of local measurements is not as simple as it sounds, because there may also be local climate phenomena)

Wikipedia contradicts IPCC's reports from the past. Even the thing about Japan contradicts the IPCC report.

Until 2000, it was claimed that the MWP was global.

IPCC's 1990s report Page 8 of 44 (PDF page number, not the one on the text)

https://www.ipcc.ch/site/assets/uploads/2018/03/ipcc_far_wg_...

Look at the bottom graph and the text.

> Schematic diagrams of global temperature variations since the Pleistocene on three time scales > There is giowing evidence that worldwide temperatures were higher than at present during the mid-Holocene (especially 5 000-6 000 BP), at least in summer, though carbon dioxide levels appear to have been quite similar to those of the pre-mdustnal era at this time (Section 1 i Thus parts <si western Euiope China, Japan, the eastern USA were a few degrees warmer in July during the midHolocene than in recent decades (Yoshino and Urushibara, 1978, Webb ct al 1987, Huntley and Prentice, 1988, Zhang and Wang 1990) Parts of Australasia and Chile were also waimei The late tenth to early thirteenth centuries (about AD 950-1250) appear to have been exceptionally warm in western Europe, Iceland and Greenland (Alexandre 1987, Lamb, 1988) This period is known as the Medieval Climatic Optimum China was, however, cold at this time (mainly in winter) but South Japan was warm (Yoshino, 1978) This period of widespread warmth is notable in that there is no evidence that it was accompanied by an increase of greenhouse gases

Sorry about the spelling issues in the copied text, the PDF's OCR isn't the best.

-------

Also here in another report, graph b) on page 2/16 shows the same MWP and little ice age as "Global temperature trend for millennium"

https://web.archive.org/web/20070404001809/http://www.epa.go...

The graph c) also shows that in the past 25,000 years, it first used to be much colder, then got much hotter and then cooler and then warmer. It is pretty much impossible for it to be a local phenomenon if the variation was that much in that many areas.

-------

https://www.epw.senate.gov/public/index.cfm/hearings?Id=BFE4...

Dr. David Deming, geologist and geophysicist, College of Earth and Energy, University of Oklahoma, senate testimony from December 6, 2006:

> I had another interesting experience around the time my paper in Science was published. I received an astonishing email from a major researcher in the area of climate change. He said, "We have to get rid of the Medieval Warm Period." The Medieval Warm Period (MWP) was a time of unusually warm weather that began around 1000 AD and persisted until a cold period known as the "Little Ice Age" took hold in the 14th century. Warmer climate brought a remarkable flowering of prosperity, knowledge, and art to Europe during the High Middle Ages. The existence of the MWP had been recognized in the scientific literature for decades. But now it was a major embarrassment to those maintaining that the 20th century warming was truly anomalous. It had to be "gotten rid of."

--------

Edit:

I read the wikipedia citation:

https://en.wikipedia.org/wiki/Medieval_Warm_Period#cite_note...

The citation seems to contradict what's said in the wikipedia.

http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/Glacial....

> The first phase of the LIA began around the thirteenth century in all the regions for which there is evidence. The glacial phase preceding the MWP seems to have begun between the seventh and ninth centuries A.D. but is generally less securely dated and not dated at all in Canada. There are at least some indications of fluctuations in ice position in the course of the MWP in Norway, Alaska, and perhaps in extratropical South America and New Zealand, indicating that recession may have been interrupted by advances, perhaps of limited extent, as in the European Alps. The available evidence suggests that the MWP was global in extent and not uniform climatically. The glacial data needs to be considered in relation to that from other sources, but is of value in obtaining a more complete understanding of both the environment in the later medieval period and the possible causes of climatic change on the century time scale.

> The available evidence suggests that the MWP was global in extent and not uniform climatically.

Reading the wikipedia, every single citation they used contradicts what the wikipedia says:

https://en.wikipedia.org/wiki/Medieval_Warm_Period#cite_note...

http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/Glacial....

> The available evidence suggests that the MWP was global in extent and not uniform climatically.

https://link.springer.com/article/10.1007%2FBF01092411

> Dating of organic material closely associated with moraines in many montane regions has reached the point where it is possible to survey available information concerning the timing of the medieval warm period. The results suggest that it was a global event occurring between about 900 and 1250 A.D., possibly interrupted by a minor readvance of ice between about 1050 and 1150 A.D.

The other citation they used is:

https://en.wikipedia.org/wiki/Medieval_Warm_Period#cite_note...

https://science.sciencemag.org/content/342/6158/617

> The findings support the view that the Holocene Thermal Maximum, the Medieval Warm Period, and the Little Ice Age were global events, and they provide a long-term perspective for evaluating the role of ocean heat content in various warming scenarios for the future.

https://en.wikipedia.org/wiki/Medieval_Warm_Period#cite_ref-...

https://books.google.ca/books?id=z-BWE4iCrfYC&pg=PA134&redir...

> "They conclude that the Medieval Warm Period was a global event"

> If the average global temp used to be claimed to be 15C but since 2000, they claim it was 14C, then somebody is making false claims about the avg temp.

You get different baseline body temperatures depending on whether you use an oral thermometer or one of those infrared thermometers you put in the ear, but you'll both be able to detect a fever -- it's higher than it would normally be with that thermometer.

There are many ways of measuring the average temperature of the planet, and they will return different results today, tomorrow and yesterday -- but if you use the same method across time, all of them should agree on whether the planet is warming or cooling over all. One might say it was 15 in the 60s and 16 today, another might say that it was 14 in the 60s and 15 today -- they both agree the planet has warmed by a degree, though.

It's easy to go through several decades of stories on climate and cherry pick measurements from different news stories to make it look like the numbers are all over the place, but you have to compare measurements from a single source using a single method.

Your analogy with the thermometer does not work. If you use rectal or oral measurement you will be able to detect fever, because temperature fluctuation at these locations is low if the person is healthy. With global temperatures this is different. Fluctuation is very high (for example there was snow in Cairo in 2013, but we did not have an ice age then).

Therefore you need to cover many locations, and that's the problem. Global temperature data is not very good for the first half of the 20th century.

What's making me suspicious about the whole question is the lack of significant decimals on a number that's supposed to be the average of a very large number of measurements.

What's the average of [15, 15, 15, 15, 14, 14, 14]? 15.

What's the average of [15, 15, 15, 14, 14, 14, 14]? 14.

Is that a big difference?

In this paper from 1999 it is claimed that the global temperature between 1961 and 1990 was 14.0°C (14.6°C for the northern hemisphere and 13.4°C for the southern hemisphere). https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999...

In my original comment I pointed that out:

> Sometime between 1997 and 1998, they started claiming the avg to be 14 degree C instead of 15.

So far, I haven't read any valid reasoning on why this happened out of nowhere.

As you know, you're piggybacking talking points off of a minor conspiracy theory that has been floating around for a while. Here's a yahoo post from 7 years ago raising the same questions and citing much the same sources: https://ca.answers.yahoo.com/question/index?qid=201211281036...

I won't pretend to know anything in detail about climate science but these alleged discrepancies don't seem to have raised enough alarms at any point to have warranted a serious rebuttal from the scientific community. Perhaps citing a handful of random cherry-picked sources isn't really the smoking gun you think it is? However, fwiw, here's a comment from a couple of years ago responding to some of those points. https://skepticalscience.com/argument.php?p=11&t=521&&a=110#...

I pointed out with raw data and sources. Simply calling it a conspiracy theory without pointing anything wrong with my actual point or data isn't worth debating in good faith.

Is it fair to say the temperatures in tropical areas change slowly?

It is alarming to say that temperatures around polar areas increased a lot. That is where a couple of positive reinforcement loops are located (less reflective surface because ice melted, and the release of frozen greenhouse gases).

In fact, animations that show the average global temperature increase, or local, but by (alphabetically sorted) countries like this one don't let us see that trend.

Another mostly hidden temperature trend (that may have regional component too) is the sea temperature, as water is capturing most of the heat. And in part that is what is fueling extreme weather events.

So why are we to draw any conclusions one way or the other based off a data set that's statistically insignificant compared to the age of the earth?

If you got a fever tomorrow, would that be statistically insignificant?

Does the dataset before the dawn of agriculture and permanent settlements matter that much?

The conversation largely revolves around flooding and food production.

The earth will be fine, itll bounce back. Billions of people however, could be displaced from their homes as their land floods, or starve if food production and distribution is destroyed. The Earth had maybe 1 billion people 200 years ago. Now its at 7.5. Unprecedented doesnt begin to describe the migration that would occur if the Earth lost its coastal cities.

What I dont like about this animation is that giant land masses like the USA and Russia get the same treatment as tiny countries. The average temperature of the USA is a lot less useful than if it were broken down by region.

How do you compare a statistical significance to an age?

Like how does p<0.01 compare to my age (38 years)?

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