The surprising bias in climate satellites (and models)

[@briannjoroge2344]

As a Kenyan and a Scientist, I appreciate the amazing science Tom is doing. We, as a species need to get out act together before its too late for our only home planet

[@blakewilson9691]

"Over 500 bald eagles wide" Ah yes of course.

[@figarybka1393]

Imperial shaming, You scoundrel :)

[@Razercat]

I fucking DIED. Am from US, am using this now.

[@Hiraghm]

Laden or unladen? Would they grasp the coconuts by their husks, or would they carry them strung on a line?

[@orkstuff5635]

From which we can work out that a bald eagle is ('a few kilometres' x 1000/'over 500') metres wide - don't you just love the metric system.

[@derradfahrer5029]

Anything to avoid using metric :D

[@dragonflycn]

Thanks so much for this Simon. I've been doing some soil surface temperature measurements for a site in Jamaica for my research and found the values from satellites much lower than what I got from my loggers. I was assuming the satellites were accurate for my region. Now I know why the data do not match up and I can look more into it to add to my thesis.

[@stanflo63]

So how did the thesis defence go ? I'd be interested in reading it (or at least parts of it ahah) Where can I find it ? Regards from France :)

[@Hi_Brien]

Hey, an American here. I really appreciate your conversion from kilometers to bald eagles. We're all about inclusivity here!

[@jackriley8759]

Yes we Americans measure in bald eagles now 🤣

[@matthewgraham7423]

5 Bald Eagles = 1 Freedum Unit

[@DerShermanator]

@@matthewgraham7423 I like measuring in FUs ;-)

[@bcwbcw7649]

yeah, and unless the election goes well, that unit will be subdivided into MAGA hat brims and AK57 bullet lengths.

[@bartroberts1514]

Canada measures in beavers.

[@mydroid2791]

@@bartroberts1514 Actually we measure in bald beavers. The hairless beavers allows for a more accurate interger ratio to the metric system.

[@andyg5059]

In the video you mentioned "air temperature", but the satellites will presumably be measuring the temperature of the ground that is emitting? In the validation tests, which air temperature is being used? Is it the usual air temperature as measured in a Stevenson screen (1.4 - 2 m above the ground), or the temperature at the surface, inside the super-adiabatic (heat haze) layer"? The temperature right at the surface could easily be 20 K hotter than the air temperature at 2 m. In order to calibrate the emitted radiation in the satellite, you need to know what the effect of the heat haze layer is at the ground don't you?

[@ryanmaxwelll2730]

American to British unit conversion, for reference: 1 bald eagle ≈ 37 dormouse

[@xorizontal2372]

you sir are a genius. but call them glis glis to confuse the yankees more.

[@heinoobermeyer7566]

@@johnperic6860 Because aliens do not wear hats

[@filanfyretracker]

@@xorizontal2372 I mean confusing an overrated New York baseball team shouldnt be too hard. ;)

[@lordsamich755]

Is that a measure of surface area, or volume? Do we have fluid Bald Eagles?

[@lordsamich755]

@@johnperic6860 How do you specify between eagle displacement, and eagle surface?

[@playgroundchooser]

Fun fact: if you were to put 500 balls eagles next to each other, they would collapse into a Singularity and create a black hole from the shear amount of Freedom. 🦅 #Murica

[@abhigyanchakraborty5563]

LoL..

[@stevejordan7275]

Don't omit the part about how they first form an Eagle Event Horizon.

[@NathanAMeyers]

Where's the freedom in fearing that you won't get healthcare?

[@playgroundchooser]

@@frogmorely hahaha! Think I'd better leave it that way 😆

[@playgroundchooser]

@@NathanAMeyers There's no fear. We just know we don't get it.

[@JoeeOSullivan]

Simon trying to get the sweet views from those climate change deniers - love the tact

[@joshuahillerup4290]

I suspect it's more about tricking a few of them to learn something

[@0xCAFEF00D]

Sadly their fact selection is such that they'll only grow 'stronger' in their argument. Not more correct. Because they ignore anything that disagrees with their ideas. You'll see how everything conspires to support them. They never seem to actually look balanced and just weigh towards the wrong conclusions overall by some error.

[@joshuahillerup4290]

@@0xCAFEF00D I know what you're referring to, but there have been difficulties in replicating those results. The actuality is probably more complicated

[@obrnenydrevokocur9344]

@@0xCAFEF00D Sure man, everyone who disagrees with you is thickheaded and ignorant. I mean, that is the only possible explanationof how they can arrive at conclusions that are different from yours, and therefore incorrect.

[@0xCAFEF00D]

@@joshuahillerup4290 I'm not referring to anything specific.

[@bisdak96]

5:17 “I’m not a biologist, it’s dead” 😂

[@jezzbanger]

To make the next generation of scientific instruments we need to validate one key parameter: Just how randy are giraffes?

[@arpitdas4263]

Very

[@akaviral5476]

It's amazing how complex and consequential data can be. I'm glad that you're able to clarify such subjects like you have. I'll be coming back to this video a lot, I'm certain

[@MT-gv8ns]

Excellent - too often science and the methods used to support studies are presumed to be "magical" when in fact they require a lots of nuts and bolts and dirty hands - and a squirt of giraffe repellent.

[@monad_tcp]

and then someone turns the knobs to apply a slight bias, and there we are. another watergate

[@notlessgrossman163]

That's collaboration with engineers and technologists is essential: they get these details correct before construction .

[@cornbreadcuban5456]

They’re only presumed to be magical by those who believe in magic and not science.

[@philobetto5106]

Funny how ice core samples show real facts recorded over millions of years and nobody brings that out in the open people need to wake up... make no mistake globalist are coming for us . we will witness the opening of the 7 seals the four horsemen

[@gordonrichardson2972]

At 10:02 there is an error. MODIS is not a satellite but a sensor suite, carried on the Terra and Aqua satellites.

[@leion1594]

3:22 There is now coffee all over my desk, keyboard and screen.

[@PapaFlammy69]

Hey Simon! :3

[@Bruno_Noobador]

Grand Flammy!!

[@PapaFlammy69]

@@Bruno_Noobador

[@robertstuckey6407]

Hi flammable maths

[@Bruno_Noobador]

@@PapaFlammy69 guten tag Mr. Maths

[@kawaichanx3]

Papa flammy's here

[@kevintumbo2882]

Watching this from kenya 😁😁

[@jeffreylebowski4927]

Shouldnt the spectrum of the emitted radiation give away the temperature? - I understand, that more emissive surfaces will emit more photons, but what about the spectrum/wavelengths of those photons? Wouldnt they be the same for the same temperature? TY

[@fee8422]

I'm fairly sure vegetation would have a spectrum bias, the earth doesn't radiate perfect black body radiation

[@fredturk6447]

This issue of measuring surface temperature on land and ocean is much more difficult than described in the video. The land surface emissivity is a function of viewing angle and to measure surface temperature you also need to remove the effect of radiance from the atmosphere including aerosols. The surface emissivity will also change with season as soil moisture levels and vegetation changes. However, satellites do accurately measure the amount of radiance (heat and light) being emitted and reflected by the Earth. Those measurements are not subject to bias from emissivity although there can be instrumental considerations. So climate models can include radiation data from satellites directly. I think the ECMWF is doing this. There is a mission called CLARREO to try to cross calibrate other satellite sensors to allow retrieval of long term changes in the atmospheric radiation balance. The complexity of retrieving land surface temperature is high because of the surface emissivity issue. Certainly ground measurements help calibrate data but you cannot cover every different spot on the planet every day and ground truth every satellite measurement. So you might use a number of different satellite instruments to measure the colour of the surface, include soil and vegetation information, measure general atmospheric conditions and correct with a model which includes viewing angle to get surface temperature. If there are clouds in the way you can’t do much so in fact the surface might be colder than when there were no clouds so a hot bias. Climate satellite instruments like MODIS only measured down to about a kilometre so that limits the detail in the measurement anyway. Sea surface temperature (SST) can be measured more accurately and there are huge number of buoys in the ocean reporting temperature profiles from the surface to depth. The emissivity issue is easier to deal with over the ocean but still requires a lot of data processing to retrieve a believable SST. I believe the trend is rather than try to derive things like surface temperature weather prediction models models rather take in satellite radiance measures. I think this also applies to climate models. This makes sense because the model includes the atmospheric and surface physics to assimilate the satellite radiance measurements with all other available data including a time sequence of model data. The bottom line here is that this is a difficult problem and there are all sorts of places where bias can creep in. However, satellite measurements will show long term climate trends (changes) even if derived parameters like land surface temperature can suffer from bias.

[@cakeinparadise]

I've worked with experts in the technical field in Namibia. I can personally attest to just how difficult it is building a relationship and convincing the people in power on both sides to cough up the money to build that relationship

[@SpenserRoger]

Just have to grease some palms. With palm oil. Lol

[@bazzmond]

In Thailand its only $5 for a relationship, I cant see why Namibians would cost more?

[@willmungas8964]

Bazzmond Why lmao

[@rjlooker]

disgusting responses

[@M0nu5]

Videos like these are exactly why I am subbed to your channel. Besides your oxford times

[@LionheartedDan]

Let’s be true to science - a consistent bias in temperature, whether “hot” or “cool” doesn’t imply a temperature gradient over time. Arbitrarily adjusting emissivity CONSTANTS in 2020 to get more accurate (higher) temperature readings is bad science if the adjustment is not applied to the whole period of record.

[@Arimaquinador]

That's true, normally I would focus on the variation and assume the observations are done in a consistent way and the variation is correct even if the actual temperature is wrong.

[@auspiciouslywild]

@LionheartedDan: " bad science if the adjustment is not applied to the whole period of record." - Don't you think that's *exactly* what they're doing? What makes you think they wouldn't? There's nothing in the video that implied that. It's plausible that it has been getting warmer faster than anticipated though, because if you tend to underestimate only the hottest days, then the more hot days it is, the more you'll underestimate. But the main point in the video was that some areas would be hit harder by climate change than previously anticipated, which is absolutely true regardless of how you apply adjustments. If some areas have more very hot days than anticipated, they have less of a margin before the land becomes so hot that it can't support life.

[@tylerpedigo2938]

Depends on whether the bias is in percentage terms or absolute terms. In percentage terms that does imply a gradient over time.

[@Alistair]

plus the system of measuring temp via satellite just sounds almost completely worthless if it's that sensitive to reflectiveness and that can change so dramatically during the day depending on if it's been raining recently or whatever. Stick to ground based sensors which can be calibrated accurately

[@Alistair]

@@auspiciouslywild "Don't you think that's exactly what they're doing? What makes you think they wouldn't?" hahahahah clearly you haven't spent much time around humans. Also the adjustments wouldn't actually be valid for the whole period of record, you'd have to measure the reflectivity accurately every time since areas can change depending on plant growth, building projects, drought, rain season, etc etc..

[@NickTrouble]

Wing tip to wing tip, or head to tail?

[@riccardoorlando2262]

Dorso to feet

[@Hiraghm]

IF the recent estimates are off by being too cold... then all the measurements in the past will be likewise wrong. you can't just say, "oh, well, this shows that measurements are 20 degrees too low, so we'll up them for 2020... Oh look! There's a 20 degree temperature increase from 1998!"

[@donjindra]

Exactly.

[@tobiaswilhelmi4819]

True ... As long as you don't take into account that former measurements are very likely not taken by satellites. I'm astound every time a youtube commenter shows up and think he can prove experts wrong who are doing this stuff for a living.

[@andrewsmith1735]

Question. If the planet gets hotter do we get more or less water vapor in the atmosphere? Do you get more or less precipitation?

[@donjindra]

@@tobiaswilhelmi4819 If anyone, including an 'expert', compares measurements taken between two radically different technologies then he's guessing too much.

[@rjlkc4668]

@@tobiaswilhelmi4819 I'm astounded every time a scientist comes out with a new model proving the old one wrong yet none of the climate alarmists never admit that climate science isn't actually definite but actually an educated guess(and usually Biased to one side or another).

[@baloofilmschannel]

Underestimating how hot it is becoming is worrying. Thanks for the video Simon. Great work Tom and video should be shared!!

[@Scrogan]

Question: how does emissivity make a difference? Assuming the emissivity is equal in both the two thermal IR bands being measured, then regardless of the intensity you should still get enough of a differential measurement to tell the temperature of the ground, right? If the ground is really dark, then the amplitude of the signal will increase, but the signal from IR band A will still be X times that of IR band B, and that X is what tells you where along the boltzmann distribution you are. Or is it that the reflection of solar IR is interfering? I’d thought that solar IR would be insignificant around the 0.1eV / 10μm realm, due to its peak being around 2eV / 500nm.

[@afonsorafael2728]

I’m from Portugal, I took geoespatial engineering as my degree and because of a course in remote sensing, (and my curiosity as well) I went to the validation station in Évora!

[@afonsorafael2728]

@Tom Dowling That's really, really cool! I hope we do get to make and build more stations around the world, In collaboration with all the countries obviously!

[@terrellworrell8005]

What a cool video! Thanks for the info and I’m glad people realize we should be working with all the brilliant scientists in the global south

[@theosphilusthistler712]

Almost clicked "do not recommend channel" on this. From the title and thumbnail I expected this to be some Tony Hellerish crap. Glad I took the time to check.

[@Drew-de7ey]

Could one say that while temperature numbers may be inaccurate, they are precise - and therefore monitoring any CHANGE is still accurate?

[@reddragon3132]

My guess would be to an extent. These systems are not linear so these inaccuracies will still affect the change just not drastically

[@peterblackmore7560]

Being Australian, I am bemused by journalists etc from the Northern hemisphere making assumptions the Southern hemisphere. In particular, assuming that what may or may not be happening in the Arctic icecap being mirrored in the Antarctic.

[@MrSmith-ve6yo]

Too much modeling; not enough getting out into the field.

[@infertagul]

Could this satellite data still be used to determine temperature differences over time? I'm guessing this would only work if the error in absolute temperature is fairly consistent and doesn't wildly vary over time.

[@CitizenSniiiips]

It absolutely can, but that error will factor into the change over time so that is why you will often see it reported as a temperature range e.g. 2.5 - 3.5 C. That range is factoring in the instrument and analytical error and depending on good we are at constraining that error, the range could be quite large. This was pretty common in the early days of modelling AND which is why we are finding a lot of models underestimated impacts of climate change as normally we would report the mean value... but we are finding that a lot of upper ends of the predictions are holding true. The other problem is comparing change over time with seasonality and veg changes like they discussed here. We will often compare change over time from a certain month usually Jan and July (summer/winter).

[@andrewsmith1735]

@@CitizenSniiiips if the planet is getting hotter is that primarily from water vapor or co2?

[@CitizenSniiiips]

@@andrewsmith1735 That's a good question, but unfortunately it doesn't have an easy answer. We know that CO2 rises and falls over glacial time periods and researchers still debate over whether temperature rise leads or lags CO2 rise (the general consensus is that it lags). It's a tricky area of research as getting the timing well constrained has lots of issues. Water vapour is a different story though. The amount of H2O in the atmosphere relates to temperature - higher temps = more H20 and vice versa. The problem is we don't really have a way to reconstruct how water vapour has changed in the past like we do with CO2 Rather than looking at it like "which one is worse" consider that they both have an impact and they reinforce one another in a positive feedback loop. We do know that CO2 now is much higher than it has been naturally over 1 million + years. We know that increased CO2 in the atmosphere increases the green house effect. This in turn leads to higher temperatures and will increase water vapour in the atmosphere. More water vapour will also lead to an increased greenhouse effect. The problem is that before the industrial revolution H2O and CO2 levels have stayed relatively constant over glacial periods, during glacials it is ~180ppm and during interglacials it is ~280ppm. We can safely assume that H2O has also followed a constant trend. But now we have injected so much more CO2 into the atmosphere AND reduced the natural environments ability to store CO2 e.g. forests, oceans, wetlands so in the grand scheme of things you can consider CO2 to be the most important greenhouse gas to consider

[@afriedrich1452]

​@@CitizenSniiiips CO2 both lags and leads. CO2 lags at the beginning of normal temperature increase cycles, but then the higher temperature induces more CO2. That CO2 then leads and causes more temperature increases. However, like you said, the CO2 we have now is much higher than any natural temperature cycle.

[@Alistair]

@@CitizenSniiiips that's incorrect. He explained in the video how the error is due to the current reflectivity of the surface. That could change in a matter of hours depending on if it was just raining or not. It could change year to year depending on if there's been drought or flood affecting how much foliage there is. This clearly isn't something where you can just look at the delta and assume it's due to actual temperature change and nothing else

[@venceremosallende422]

I was like: Oh yeah I hope the scientists are wrong, it isn’t as bad as it looks. Then you come and tell us and it’s even worse than what we think. Thanks man, more bad news, awesome...

[@andrewsmith1735]

It's not that bad. They need the fear to get funding which in the end is good for everyone. Funding went from thousands to trillions over the past few years to improve our understanding of the world.

[@geraldfrost4710]

@@andrewsmith1735 "We need fear to get funding." How about logic? There were three validation points for the continent of Africa (two of which were ten miles apart). Apply the engineering axiom: "What could possibly go wrong?" We were underestimating the temperature by 4 degrees C, and we know this is because of adding one (count 'em, one) new verification location. There was never an error bar on the temperature reported. The confidence that displays is amazing. You knew this was the temperature without the slightest hint of doubt; someone did an experiment showing that the temperature was 4C off. Now you know something different, and still no error bar on the temperature reading.

[@Alistair]

@@geraldfrost4710 it is kind of dumb that they're noticing how inaccurate all the measurements have been so far, but still trying to pretend like the original data sets they assumed warming from (despite also a couple of periods with significant cooling since the industrial age started) is valid. The level of intellectual dishonesty is staggering :/

[@Mosern1977]

This is great news, because it basically means - even with the state of the art technology of 2020, we have not the slightest idea what the actual temperature of the surface of earth really is. And we can be damn sure we had absolutely no idea what it was in 1920, when there was one termometer in all of Africa. Therefore we have no idea if the temperature has gone up, down, sideways or around in circles over the last 100 years. But stating that fact doesn't give us much funding now, does it?

[@geraldfrost4710]

@@Mosern1977

[@omeryehezkely3096]

How exactly can you draw a conclusion about all Africa from a single measurement station?

[@jamescaley9942]

That is grossly unfair. They had two measurement stations.

[@Mosern1977]

What number do you need for more funding and exotic trips to far away locations. Think hard on that number, and you have your answer.

[@builder3654]

This is so good! I'm taking a remote sensing class for my geography major and I'm very interested in how bands are interpreted in satellite imagery.

[@sarthakuprety7457]

hey simon,whats your thought on Bjørn Lomborg ?

[@simonbean3774]

Which is why predictions combine data from all satellites to produce a curve. Have to take into account the effect of cloud cover on ocean surface, etc etc.

[@ameebhatt3588]

3:19 That drone footage reminds me of Icraus Mark-2 or 3...

[@tsehayenegash8394]

Doctor, really you have deep knowledge, if you can please help me how retrieve temperature data from COSMIC satellite?

[@craigjones8558]

A) The temperature data collected, is subject to large degrees of inaccuracy = True B) The temperatures are probably much higher = Assumed True Were we also talking about heat islands before (ie validation stations built close to universities) ? I guess I'm confused about the scientific message here.

[@Mosern1977]

Science doesn't have a message, politicians have. Actual science is about trying to figure out what is going on.

[@lhaviland8602]

The more you learn about this stuff, the more you come to the realization.... we are already 100% boned.

[@Alistair]

more like the more you come to the realisation the way they gather and interpret data is ridiculously error prone and that most people seem much more concerned about confirming a political narrative than finding the truth

[@alephkasai9384]

@@Alistair Well yeah we're boned.

[@RBEmpathy]

@@Alistair many things are error prone - that's why we make corrections to our data. This just shows how uninformed you are on this topic.

[@mve6182]

I recently saw a presentation by prof. John Christy, and he pointed out that the CMIP5-models have 'projected' a warming of 0,44C/decade over the period 1975-2020, while the actual warming in the same period was about 0,16C/decade. So the models are about 175% off. The CMIP6-models perform slightly better, because they produced a warming of only 0,40C/decade and are therefor only 150% off. So indeed there seems to be a bias in the models, but it is not the bias that you refer to!

[@mve6182]

@grindupBaker Why don't you google it and find out for yourself?

[@mve6182]

@grindupBaker If you had taken the effort to actually google it, you would have found out that John Christy is referring to the tropical hot spot, which warms up a lot more than the the average surface temperature.

[@mve6182]

@grindupBaker I assume you still haven't seen the presentation by prof. Christy?

[@mve6182]

@grindupBaker If you were a bit less activistic and a bit more curious for facts, you would watch the presentation by prof. Christy I mentioned and you could hear and see the explanation by yourself. I do not lie, and if you don't believe me, watch it for yourself!

[@mve6182]

@grindupBaker You read what you want to read, good luck!

[@henrikgiese6316]

More of a technical question: While these measurement problems certainly has an impact on long-term climate models, how large is the impact on measurements of current temperature changes? If the error is consistent there shouldn't be much impact, but I guess deforestation and similar things might impact this?

[@johnpiccolini3305]

OK - I don't know how many comments reacted to this, but your inclusion of the Bob Ross T-shirt was brilliant (if for no other reason than the "Happy little Tree")

[@gnesterif5783]

Unbelievably good video!!!

[@Flyguy779]

ok this is for ground temperature measurement, but does this issue affect atmosphere temperature measurement from satellites as well?

[@dnomyarnostaw]

We use meteorological stations for air temps at the surface, and weather balloons for higher atmospheric temps.

[@derrickpang3680]

"Giraffes...quite tall" Choked on my coffee laughing 🤣🤣

[@RicardoPetrazzi]

What about the night time temperatures? Are these hotter too or colder?

[@mondotv4216]

So the interesting thing for climare modelling is the trajecotry may still be correct because the baseline measurements had the same inbuilt errors

[@JudeFurr]

Music around 8:23 is Dancing with the Devil

[@elsiegel84]

It is temperature change over time rather than any immediate temperature that is of interest. Systemic errors such as described here would be far less significant in a time series.

[@FloatingOer]

Doesn't that become a problem though when temperature readings become more accurate? If you are going to use it to look at the change over time then the error in measurement needs to be consistent over the whole measurement, but if the temperature is hotter in reality and the more accurate the readings become (due to technology and funding over time) the data will erroneously show a temperature increase over time even if none have actually taken place. So you do need the "immediate temperature" to be accurate and the errors can be very significant in a time series.

[@elsiegel84]

@@FloatingOer I strongly disagree. Errors in measure have a normal distribution and thus center on means that are sufficient for time series. Only the confidence level really changes with improved accuracy. I also disagree regarding an immediate temperature. Without an associated time series or other reference point it is just an irrelevant number, like 42.

[@FloatingOer]

@@elsiegel84 Sorry for the wall of text. Sure, if the error remains over the whole time series, for the sake of argument lets say we are measuring the temperature at the same location over a period of 50 years. And the initial error in measurement is -3 degrees Celsius, as time goes on better technology and more measurement stations is built will result in more accurate data, lets say the error is decreased to -1 degrees over that 50 year time span. Even thou the actual temperature in this example is consistent throughout it will be displayed as a temperature increase of 2 degrees which is significant. Now add actual global warming on top of this, without knowing what the actual initial error was (we can't know since the global temperature may have changed since then) we also can't say how much the global temperatures have increased or if they have increased much at all since the initial inaccuracies are "poisoning" the data. And more importantly is how many people are going to question the whole global warming theory because of this, even if you are satisfied with using incorrect data very many other people in general population won't be, and subsequently deny the whole thing, which we can already see happening. These people will vote for those who also deny global warming, slowing/hampering any progress to stop co2 emissions because they think it's a scam. This is the real danger of using incorrect data.

[@elsiegel84]

@@FloatingOer You begin by making the erroneous assumption that the error in measurement is signed. It is not: the error will not be e.g. - 3 degrees, it will be +/- 3 degrees. Your argument goes downhill from there because you fail in discerning the critical difference between accuracy and precision, Modern measurements are not more precise, they are more accurate. Where do you draw your statistical modeling from? Certainly not a textbook of statistics. I'm sorry, dude, but your argument is just very sophomoric and silly.

[@FloatingOer]

@@elsiegel84 The video literally say that the temperature is being underestimated from reality due to not having good data on the ground in africa, south america, and asia, so it wouldn't be +/-, it would more likely be something like -2 - -4 (these are just random numbers but the point is that the temperature fluctuations would be underestimating reality at all times, not overestimating). If it becomes more accurate in the future it will be hard to tell just by how much temperatures have changed. And as I said, the biggest problem isn't just about the data but how people will perceive it afterwards, if some part of it is inaccurate there will be people that will believe it's all fake, weather the actual scientists consider any of this as a problem or not.

[@thesteve4235]

One issue, if you say x problem will occur at a certain temperature, then later find your initial scale was 20 Kelvin off, wouldn't you have to then adjust your model since that area is already past your models threshold temperature for "problem" but is clearly not as dead or in crisis as you expected.

[@peterh5165]

Thank you for getting this information out to the general public!

[@antistory3771]

This is your best video yet! Wow just WOW

[@sleepiestgf]

comments for the algorithm gods woooooo give simon engagement

[@abhigyanchakraborty5563]

Simon : 1 km = 500 bald eagles. American : Oh! That makes sense.

[@willkersey7340]

Thank God he knows how to do bald eagle conversions, I had no idea what a kilometer was.

[@davidramsay6142]

Satellites as far as I am informed are measuring temperature indirectly in the troposphere the first 10kms or 35,000 ft and above the clouds (upper lower). I was under the impression that the sensors measure microwave emissions from oxygen that are used to determine temperature. To calibrate the satellite reading weather balloons are used as calibration points which to my mind makes eminent Sense a physical point with a high resolution thermometer tied to the satellite pass. One great think about satellites is they sample a very large volume of the atmosphere every day not a handful of points on the ground. For clarification 80% to 90% of the atmospheres mass is in the troposphere so this is really where it all happens. Clearly not ideal but I have more faith in a calibrated satellite data set than a station being humped by a giraffe.

[@vivienh4851]

New physics video from Simon yay!!!! (I look forward to videos about your precious kitty too🥰)

[@Dave5843-d9m]

If these temperatures have always been higher than we thought they should be, it affects the models (1) the start point was set too low potentially skews the model into seeing warming that never happened. (2) the current temperatures are higher than expected but are they abnormal compared to 100 years ago? I mean a reading that 20C low today is bad. But is the information we have (or have calculated) from 100 years ago also 20 C low? Apples,, pears and limes come to mind.

[@Mosern1977]

Short answer is: We have no f*** idea if there has been any measurable change over the last century. Because there were no data points to speak of, a century ago - and even today's best devices are not capable of giving precise enough measurements.

[@professormawillett4297]

You draw a very grandiose conclusion here. You spend the entire video pointing out the errors in the models and then rejoice that they are in error in your biased favor. I understand this modeling is difficult but you cannot say it is wrong and right in the same breath.

[@jenda386]

Exactly. What I took away from this video is that we do not know the reality _at all_ and want to use models based on these guestimates to make sweeping changes to global economy. Add into that ignorant politicians who say crazy nonsense like "climate is not changing" and "in 12 years the world is gonna end" and one can see how screwed we are.

[@professormawillett4297]

jan386 : I think you said it more succinctly than I did. If these folks would just report the science and refrain from interjecting their opinions and biases into the conversation, we could all take them much more seriously.

[@jenda386]

​@@professormawillett4297 I agree. Present the data. Be honest about corrections made and present uncorrected data also. Run your models. Describe their limitations. Make predictions. If your model fails to predict, it is incorrect. Admit it. Climate is incredibly complex -- we will understand. Improve your model and try again. And I would also like the rulers of this world to exercise extreme caution before implementing (hopefully) well-intentioned policies, because human society is complex and unintended consequences with catastrophic results can surface where least expected.

[@mattw9764]

Just what we were hoping to hear: a cold bias.

[@Alistair]

if there's always been a cold bias to the data, then I wonder what would happen as they gradually make it more accurate.. hmm..

[@alephkasai9384]

Honestly if it had been a hot bias I'd feel way better. Like phew we ain't gonna die so early. But uh, we're going to die way earlier

[@wesbaumguardner8829]

I wonder how he can claim with so much certainty that the error is one way or the other if the verification measurements simply have not been performed for the vast majority of the earth's surface. Even if the errors tend to lean a certain direction on what has been verified, it does not necessarily hold for all of the other measurements that have not been verified.

[@gilmanouellettejr.1925]

Because the measurements have been verified using multiple independent methods.

[@wesbaumguardner8829]

@@gilmanouellettejr.1925 He just went through how all of those satellite measurements were not correct and how actual measurements must be taken on the ground by humans to correct the errors and these ground based measurements have not been performed for the vast majority of locations on the planet. So essentially he is claiming to know with certainty that a majority of the corrections will increase the temperature that is recorded by the satellites before the corrective measurements are even taken. That is not how science is performed. In real science, the measurements come before the conclusions.

[@gilmanouellettejr.1925]

@@wesbaumguardner8829Um, I'm an actual Ph.D. scientist who has actually conducted assessments of satellite derived data. ui.adsabs.harvard.edu/abs/2016AGUOSPC54A2222O/abstract

[@wesbaumguardner8829]

@@gilmanouellettejr.1925 So are you saying that what this guy is saying is incorrect?

[@gilmanouellettejr.1925]

@Wes Baumguardner I mean, you could read my work. But in general the biases that do exist are generally in the "colder than reality" direction. But the data sets based on remote senses data are quite accurate globally (bias is more or less balanced) and for certain applications (like measuring temperature thresholds for coral bleaching) satellite data are actually better than in-situ measurements.

[@ellafw2944]

This is such good science communication!

[@georgedereck6525]

When determining accuracy of satellite measurements, wouldn't you also have to consider the effect of the atmosphere? What the satellite is seeing is mixture of emissions from all kinds of sources. It seems the whole raditation picture is quite complex and there is lots of room for interpretations and assumptions.

[@jackimo22]

Does this not mean the initial measurements years ago were also cold biased? And this need to be adjusted?

[@Ron_the_Skeptic]

Warmth is better than cold and regardless of what the satellites say, the North American growing season seems to be becoming shorter -- the opposite of warming.

[@jacobdaniels3246]

lol

[@jeffgold3091]

"local temp data and models are not as good as people think they are" ..a nugget of truth

[@frederikvdh]

Those witty comments on the stockvideo's simply deserve all my likes!

[@alessandrotrucchi8338]

Hell hath no fury like a giraffe scorned

[@christinearmington]

Thanks for not letting the family down. Had me worried. Glad I checked. 😁👍😎

[@tossancuyota7848]

this what ive been talkin bout before on a thread satellites doesnt accurately measure temp by a huge number unlike the one done on ground

[@anthonym3546]

I’m sorry, how many football fields long is a bald eagle? We use bald eagles for volume here.

[@peterfireflylund]

Anthony M just divide by square bananas.

[@malcolmanon4762]

Is that pure blend Eagle, or is it a condor - Eagle road side mash up?

[@Mosern1977]

Football fields? Real men measure distances in F-150 trucks.

[@kibrika]

Thank you for the lovely video! I was afraid the title was just a clickbeit, but it turns out to (unfortunately) be true. And lovely to see Tom Dowling in the comments answering people and such. Really cool.

[@svenweihusen57]

I am not sure if this is a real problem for climate modeling and satellite observation. It is really hard to pin down the changing emessivity but it is way easier to use correction data. A simple climate station with just a thermometer will give you very precise correction data. And there are many of these. Additionally we often forget that 70% aka the majority of the planet doesn't undergo these changes due to being water surfaces. So if you calculate that the temperature on 30% of the land mass is wrong, aka 10% of earth surface, by 20% it globally breaks down to an overall error of 2%.

[@Dragrath1]

Excellent video yeah it bothers me that people get the mistaken notion that science is some fixed body of knowledge rather than an iteratively and good to see this issue addressed with some extra nuance from the ground. The title is full clickbait though are you trying to hopefully get some of them to switch their tune? Has that ever worked?

[@danielmarbella1197]

Satellite measurement like UAHv6 is not on the surface, but low troposphere, an average between 0 and 12km. Those measurements are validated with independent measurements like low troposphere balloons stations, airplanes, etc. So yes, there are satellite projects that can give a decent measurability.

[@maherhussein1999]

I’m American and the bald eagle analogy helped me understand what you were saying so thank you

[@jimmyjohn8008]

I like the discussion of the propagation of error in measurements and calculations.

[@Number_Free]

A serious question: can't the satellites measure the emissivity directly? I am thinking of bouncing suitable laser light off the surface. That will take energy of course, but solar should be enough. Better still perhaps, modulate a beam of sunlight in some way, so that its reflection can be detected. Changing the refractive index of a 'bendy' material may work, for example. There may well be fancier ways of marking light beams of course, that work in the satellite context.

[@ParallelLogic]

- Sounds like you're describing LiDAR. I'm not too certain how common this is for Earth weather missions, but I believe there are reconnaissance missions that use this technology. Other techniques involve looking at the relative intensities of different wavelengths of light: a kind of emissivity fingerprint for different surface types. - "energy" is likely on the order of hundred of Watts and up depending on the spacial resolution you want - Emissivity is a function of frequency. If you want to model emissivity, you'd want data from every frequency you're measuring it at - FCC and international regulations still apply (limits on transmit powers) to objects in space - A simple sun mirror assumes a clear view of the sun. Presumably works if you're in a 6 AM polar orbit, but anything with a lower inclination (ex. ISS) or different right assention will have ~30% of every orbit on the dark side of the Earth - Using a mirror of sunlight seems dubious to me: it pre-supposes the sun is stable enough that a microscopic (on a cosmic scale) shining light on the planet will produce a measurable difference in the returned brightness. Even with processing gain, it seems like your signal would be swamped by noise (any variations in the instantaneous brightness of the sun).

[@simonabunker]

What sort of sensors do you need for a validation station? Some sort of thermometer? Humidity? If you can get something useful from an Arduino and some sensors then this would be great to crowd source. Even better would be an option to buy a box and donate one to a country that needs it. Of course that would be a non starter if it absolutely needs a giant pole!

[@simonabunker]

Although I guess there must be something special if they can't use the more extensive weather station network.

[@marthinwurer]

I'm glad you're getting back to climate model stuff! That was always my favorite topic of yours. I'd love it if you could do a deep dive into how something like the GFS or ECWMF work!

[@alpheusmadsen8485]

I have been aware of many of the anomalies of surface weather stations; I had assumed that satellites would be able to even those anomalies out! I didn't expect that satellites would need surface stations to calibrate things. *Sigh*. Measuring things right is *really* hard.

[@Mosern1977]

No problem for Climate Scientist. They have the temperature anomalies down to 0.1 degrees over the last 100 years. Who needs real accurate data, when computers can give you all the numbers you ever need.

[@noether9447]

1:16 "o no I'm pregnant" 1:21 "tell me where the money is"

[@roderickbraganca]

english person talking about units of measures. feel the pain in pounds.

[@ax14pz107]

Roughly four stone worth of pain.

[@MrPetertclarke]

English people (UK) use kg, Americans use pounds and various other heritage units.

[@roderickbraganca]

@@MrPetertclarke yeah, i joked about pounts but UK still uses miles, right?

[@MrPetertclarke]

@@roderickbraganca Yes, I think it was just the enormous cost of replacing all the road signs that meant we still use miles for travel.

[@roderickbraganca]

@@MrPetertclarke i see

[@drmadjdsadjadi]

It also shows that we might be really wrong to think that the warming of the Earth may be more consistent than we’d realize as opposed to being much greater outside the tropics than inside it, which is what we hear from a lot of the popular media. This is why we need to care about global warming around the equator just as much as we care about it in colder regions.

[@PremierCCGuyMMXVI]

Does this also mean the global warming trend is much more extreme than what we currently see? I really hope we can get better data to measure this planet’s temperature

[@jeffbenton6183]

I remeber reading something about a decade ago (maybe more) about how satellite data was used to account for the fact that many ground-based detectors were overestimating climate change since they were situated near cities (not that climate change wasn't happening, only that warming was slightly slower than previously thought). Well, now I'm learning that sat data is underestimating it. So, I guess it's somewhere in the middle.

[@dabay200]

Haven't fully understood why they can't use local weather stations to get temperature data and compare that to satellite pixel data for the same time period/location to infer emissivity instead of building special validation stations? Surely there is more 2 local weather stations in Africa?

[@symbioticcoherence8435]

Confirmation bias is stronger than a 16 min video that slowly unravels a complicated argument as to why the title is misleading. I fear you are doing more harm than good (i.e. spreading more misinformation than information) overall.

[@VikingTeddy]

Yeah, I'm not a fan of the title. And it isn't as if scientists don't know about this. Nitpicking one small issue which you don't really understand completely is just wrong. This really is just spreading misinformation and encouraging anti science sentiments which is a HUGE issue. I fear the net result of this video is very negative.

[@masterchef1174]

What could the video possibly have been titled that wouldn't result in hordes of deniers claiming the video as proof? Are we really at the stage where education itself must be carefully reviewed and gatekept? The point where information must be censored for some kind of greater good?

[@symbioticcoherence8435]

I think the title has since changed. I remember the title contained 'climate models are wrong'. The current title is IMO much much better. (the current title is, as of 2020-10-15-0800 UTC 'The Suprising Bias in Climate Satellites (and Models)' )

[@dereckhasken9055]

Just love the image at 1:16 of the lady putting a rectal thermometer in her mouth to measure her body temperature🤣

[@noisycarlos]

So 1km = 500 bald eagles, and 2.5 tons = 2 full land rovers. Got it.

[@stuffandnonsense8528]

Good work! .... Eldar forever!

[@klaudelu18]

Here's an idea: lions. 3 to 4 lion statues, 2 to 3 times bigger than lions normally are, made out of the cheapest materials one can make lion statues in the Savannah, and have them guard Tom's masts.

[@renchesandsords]

Part of me was scared that the wrong would be in the too alarmist direction and that deniers would use this as their foundational proof, but the other part of me was thinking, Oh crap, I'm not gonna be able to out-unhealthy this issue in my lifetime

[@Mosern1977]

Huh? Want to hide the truth because it doesn't fit your agenda. Sounds like you have a political career in front of you.

[@renchesandsords]

@@Mosern1977 No, it was just my reaction reading the title.

[@stvp68]

Nice job making your presentation seem spontaneous and not rehearsed

[@AndyRRR0791]

Interesting presentation. It seems odd you'd leap to the conclusion that underestimating the daytime temperature via satellite surface temperature sensing means global warming will be worse than it is currently predicted though.

[@AndyRRR0791]

@Tom Dowling but won't this have hitherto unknown effects on estimating the CO2 and general GHG forcing function coefficients in the GCMs? These are the things that are playing large roles in predicting long term climate trends, no? The whole climate thing is complex enough to be wary of making such linear assumptions, IMHO.

[@willb.nimble6749]

I came in expecting it to be that we were underestimating just how badly the climate is messed up, not disappointed.

[@francocarrieri1988]

Brilliant! I am subscribed.

[@nicholasmills6489]

These are the honest videos that discuss the accuracy of climate science. Models are hindcasted off adjusted temp data. I understand they only hindcast so far back. They then extrapolated forward. Can you discuss this process and the accuracy of the models on this basis. Thank you.