2015 was hottest year on record, say some scientists

[Chicog]

A temperature anomaly graph is a simple temperature graph. That's why they are used.

No it's not. It's a simple temperature anomaly graph.

You *know* what I'm asking you to post.

Why are you avoiding doing it?

[RickBradford]

Meanwhile, do you agree that 2015 is the hottest year on record ?

According to NASA GISS data, it is. According to RSS/UAH data, it isn't.

This is ground that has been gone over repeatedly already, and I think everyone else has got it......

[Chicog]

Well it seems the interpretation of the data is flawed. What is your response to this?

John Christy and Roy Spencer of the University of Alabama published a series of papers starting about 1990 that implied the troposphere was warming at a much slower rate than the surface temperature record and climate models indicated Spencer and Christy (1992).One early version of their data even showed a cooling trend (Christy et al. 1995).

<snip>

Several groups of scientists began looking closely at this discrepancy. With so many other pieces of evidence indicating warming, it seemed unlikely that the troposphere would not be warming. Errors were discovered in the methods the UAH group used to adjust the data.

<snip>

When the correct adjustments to the data were applied the data matched much more closely the trends expected by climate models. It was also more consistent with the historical record of troposphere temperatures obtained from weather balloons. As better methods to adjust for biases in instruments and orbital changes have been developed, the differences between the surface temperature record and the troposphere have steadily decreased.

And

All three groups measuring temperatures of the troposphere show a warming trend. The U.S. Climate Change Science Program produced a study (pdf) in April 2006 on this topic.Lead authors included John Christy of UAH and Ben Santer of Lawrence Livermore National Labs. The first page has this quote:

Previously reported discrepancies between the amount of warming near the surface and higher in the atmosphere have been used to challenge the reliability of climate models and the reality of human-induced global warming... This significant discrepancy no longer exists because errors in the satellite and radiosonde data have been identified and corrected. New data sets have also been developed that do not show such discrepancies."

Full link here:

https://www.skepticalscience.com/satellite-measurements-warming-troposphere.htm

[RickBradford]

NOAA Fiddles With Climate Data To Erase The 15-Year Global Warming ‘Hiatus'

National Oceanic and Atmospheric Administration scientists have found a solution to the 15-year “pause” in global warming: They “adjusted” the hiatus in warming out of the temperature record.

New climate data by NOAA scientists doubles the warming trend since the late 1990s by adjusting pre-hiatus temperatures downward and inflating temperatures in more recent years.

http://dailycaller.com/2015/06/04/noaa-fiddles-with-climate-data-to-erase-the-15-year-global-warming-hiatus/

[i claudius]

You all go on and on ,but records have only been kept for 100 or so years , what about 200 ,300 1000 years ago , they used to grow grapes in Britain hundreds of years ago because it was so warm , and in the 1800s the river Thames used to freeze over and the held fairs on it , its just nature ,anything else is guesswork and a way to tax you .

[Chicog]

NOAA Fiddles With Climate Data To Erase The 15-Year Global Warming ‘Hiatus'

National Oceanic and Atmospheric Administration scientists have found a solution to the 15-year “pause” in global warming: They “adjusted” the hiatus in warming out of the temperature record.

New climate data by NOAA scientists doubles the warming trend since the late 1990s by adjusting pre-hiatus temperatures downward and inflating temperatures in more recent years.

http://dailycaller.com/2015/06/04/noaa-fiddles-with-climate-data-to-erase-the-15-year-global-warming-hiatus/

And that has what to do with 2015?

Or are you implying that because they did something in the '90's, that they and every other party around that globe that has reported 2015 as the hottest ever have falsified their data?

[up2u2]

I don't think you have spent much time looking at the data in the slightest.

With a due sense of foreboding, I will make just one more effort to explain what is going on here.

If you have an acquaintance who completed a high school education, ask them about this graph, and here is what they will say:

"This is a graph of absolute temperature anomalies, that is, how much hotter a particular year was than 1979, which was the baseline year. It is not a trend graph, as can be seen by looking at the original graph from RSS itself."

http://images.remss.com/msu/msu_time_series.html

"As you will see, it says temperature anomaly, and even supplies the actual trend line so you can see what is happening."

"The satellite (RSS) data diverges somewhat from the ground station data (NASA/NOAA) for various technical reasons. In particular, the RSS data records rather less warming than the NASA data, to the extent that the RSS data still has 1998 as the hottest year in the satellite record."

"This is why people who like to downplay the extent of global warming (such as Jo Nova) like to quote the RSS data, while those who like to up-play the extent of global warming typically cite the ground station data of NOAA/NASA."

It has long been known that the global warming narrative relies on extreme ignorance to further its aims, but to see it in the raw is still quite eye-opening.

Okay now you have changed your graph. The previous graph had been manipulated using RSS data. That is why it is so flat as it uses a very small sample average of 6 months on a year to year comparison and a baseline set at 1979.

The graph above is indeed run using RSS data and is published by Remote Sensing Systems. However it has NOTHING to do with the SURFACE TEMPERATURE of the Earth. It is measuring (inaccurately) the ENTIRE Lower Troposphere (TLT). WE do not live in the TLT we live on the surface of the Earth. That is why we monitor the SURFACE TEMPERATURE.

So if you live 12 Kilometres above Sea Level use the RSS data to decide your hottest year, the rest of the human population living on the surface of the Earth are stuck with living in the temperatures that are measured where we actually live.

You will need to wait about six months before the satellites begin picking up the heat from El Nino there is a 'lag time' as it moves into the higher troposphere.

A good article that also includes the UAH satellite data is here. Even they don't agree with each other. UAH shows more heating.

So on the surface of the Earth 2015 was the hottest year on record. 7-20 kilometres above the Earth who cares. Well unless you live on the top of Mt Everest lol It is always freezing cold there at 7.2 klms above sea level but to my knowledge not many people live there.

[RickBradford]

Or are you implying that because they did something in the '90's, that they and every other party around that globe that has reported 2015 as the hottest ever have falsified their data?

Every other party around that globe that has reported 2015 as the hottest ever has been using the NASA GISS data (or their press release, anyway)

NASA GISS doesn't "falsify" data, heaven forbid. They "adjust" it and "homogenise it". It just happens that every time they "adjust" or "homogenise" the data, it goes in one direction -- to make warming seem more rapid than the raw data would suggest..

[RickBradford]

7-20 kilometres above the Earth who cares

Oh dear.

Meteorologists care greatly, because it's at that level where most weather systems develop.

Climate scientists care greatly, because predictions of temperatures at that level of the atmosphere are central to their climate models.

[up2u2]

Or are you implying that because they did something in the '90's, that they and every other party around that globe that has reported 2015 as the hottest ever have falsified their data?

Every other party around that globe that has reported 2015 as the hottest ever has been using the NASA GISS data (or their press release, anyway)

NASA GISS doesn't "falsify" data, heaven forbid. They "adjust" it and "homogenise it". It just happens that every time they "adjust" or "homogenise" the data, it goes in one direction -- to make warming seem more rapid than the raw data would suggest..

Not true often the data is adjusted down. Homogenising surface temperature data is just merging it so you get an overall coverage concept of temperature flow. Otherwise you would just see 6300 dots on the Earth. If you just used raw data it would give you inaccurate results. If a weather station is surrounded by concrete it has to be adjusted to account for that. A perfect example of when raw temperature data is adjusted to show less warming. Also low altitudes are adjusted down.

If you saw the adjustments required on satellite data you wouldn't even mention it. Raw satellite data is the most adjusted data known.

[up2u2]

7-20 kilometres above the Earth who cares

Oh dear.

Meteorologists care greatly, because it's at that level where most weather systems develop.

Climate scientists care greatly, because predictions of temperatures at that level of the atmosphere are central to their climate models.

So we should measure the temperature 7 kilometres above New York city and publish that as the temperature for that day in New York City?

[RickBradford]

7-20 kilometres above the Earth who cares

Oh dear.

Meteorologists care greatly, because it's at that level where most weather systems develop.

Climate scientists care greatly, because predictions of temperatures at that level of the atmosphere are central to their climate models.

So we should measure the temperature 7 kilometres above New York city and publish that as the temperature for that day in New York City?

If you want.

The fact is, that for both practical and theoretical purposes, the troposphere is the most important part of our planetary climate system.

[Chicog]

If you want.

The fact is, that for both practical and theoretical purposes, the troposphere is the most important part of our planetary climate system.

Not in isolation it isn't.

Unless you ignore the oceans' role in heat absorption and weather.

[up2u2]

7-20 kilometres above the Earth who cares

Oh dear.

Meteorologists care greatly, because it's at that level where most weather systems develop.

Climate scientists care greatly, because predictions of temperatures at that level of the atmosphere are central to their climate models.

So we should measure the temperature 7 kilometres above New York city and publish that as the temperature for that day in New York City?

If you want.

The fact is, that for both practical and theoretical purposes, the troposphere is the most important part of our planetary climate system.

Yes but we don't live in the Troposphere. We live on the surface. That is why we monitor SURFACE temperature. I was chatting to a Climate Scientists in the UK. The Remote Sensing System satellites will not pick up the Global heat from 2015 till it heads into the mid troposphere. The same thing occurred in 1997/1998 where the surface temperatures showed 0.54 warming and RSS only picked up 0,1 warming the following year 1998 RSS went of the scale showing the 1997/1998 El Nino at +0.55 increase. The Surface Temperature data isn't going to show up until maybe 2016/2017. I didn't know there was such a long lag time. I may back off my statement 2016 may be hotter than 2015 as a lot of that heat may turn up in 2016 as well. Makes sense El Nino kicked off very late 2015 so that heat is really going to carry over into 2016 and satellites aren't going to begin detecting it till its gets into the mid troposphere. So RSS data should start detecting the rise over the next few months and through 2016. The RSS graph will look very different in 2016. It should exceed 1998 peak. That is the problem with satellite data it cannot measure surface temperatures it just takes a large chunk of troposphere and tries to work it out from there and it doesn't measure actual temperature so it actually has to adjust and model the data.

[up2u2]

If you want.

The fact is, that for both practical and theoretical purposes, the troposphere is the most important part of our planetary climate system.

Not in isolation it isn't.

Unless you ignore the oceans' role in heat absorption and weather.

That is true only 3% of heat stays in the atmosphere. 97% is absorbed into the oceans.

[boomerangutang]

Interesting that Bradford likes added CO2 and smog pumped into the air.

Where did I say I wanted more smog pumped into the air? Or did you just make that up, as usual?

However, the Paris "agreement" will have exactly that effect, as it has given a free pass to countries such as China and India to massively expand their coal-fired power generation for at least the next 15 years, with essentially no oversight of how clean those power plants are.

Getting China and India to sign an agreement was tough and took a lot of negotiating. Yes, they want to continue to expand coal use. Yet some agreement (to lessen CO2 and dirty air) is better than no agreement. Plus, amendments/adjustments can be made over time. It's not carved in stone.

Bet those East Coasters wish they had some of that heat about now.

Snow does not necessarily = colder weather. Snow is precipitation. BTW, I've resided nearly 20 yrs in northernmost Thailand, and this winter has been the warmest thus far in those years.

You all go on and on ,but records have only been kept for 100 or so years , what about 200 ,300 1000 years ago , they used to grow grapes in Britain hundreds of years ago because it was so warm , and in the 1800s the river Thames used to freeze over and the held fairs on it , its just nature ,anything else is guesswork and a way to tax you .

No one believes climate hasn't changed profoundly in earlier epochs. Frankly, I don't like the term 'climate change' because it too easily enables posts like Claudius' above. One big reason a warming climate over recent decades is important is because of the type of 'footprint' which humans have. You've seen the hockey stick graph of human population - and how it's exploded in the past 100 years - now well over 6 billion. Who knows where it will level off at: 9 billion? 14 billion? .....whatever, the number is already way to high for the carrying capacity of the planet. There are myriad proofs: mass migrations, loss of natural habitat, death of oceans, increased desertification, dearth of fresh water, Pacific Trash Vortex, ....the list is long and sad. A related reason why the debate needs to focus on a scale of decades and not centuries/millenia: People have adapted somewhat to particularly places. Most of the largest cities in the world are along coastlines or otherwise in places which will be adversely affected by rising seas. If half the largest cities in the world become seriously flooded year 'round, that obviously affects many people. Where do they go? Similarly, increased desertification compels people to migrate in desperation. That's half the reason there is a flood of immigrants from N. Africa and the M.East. On and on.

[Grouse]

There's none so blind as them that won't see....

Especially the ones who can't tell the difference between "temperature" and "change in temperature".

Great stuff as always!

BTW, there's a great new documentary on Einstein's general theory of relativity. It's coming out two months ago.....

[goatfarmer]

a strong el nino year, Just like 1997-98. We all knew this year would be a spike. I would love to see if the official amount it surpassed the last high is over the amount of uncertainty they have in the calculation of the average. It usually isn't.

Whatever happens we can be sure the alarmists will ride this insignificant piece of data like a Prius.

It's more than just a year, the past decade was the warmest on record. From 2014 (which also set a record):

http://www.theguardian.com/environment/2014/mar/24/warmest-years-record-un-global-warming

13 of the 14 warmest years on record occurred this century, according to the UN.

...................

2001-2010 was the warmest decade on record, the WMO noted, and added that the last three decades had been warmer than the previous one.

The WMO reiterated its earlier finding that 2013 was the sixth warmest on record, with temperatures 0.5C above the long-term average (1961-1990).

Great chart. Impossible to argue with the data. Though we can argue about why the earth is warming. Though evidence strongly points to man made sources.

https://www.nasa.gov/press/2015/january/nasa-determines-2014-warmest-year-in-modern-record

The year 2014 ranks as Earths warmest since 1880, according to two separate analyses by NASA and National Oceanic and Atmospheric Administration (NOAA) scientists.

The 10 warmest years in the instrumental record, with the exception of 1998, have now occurred since 2000. This trend continues a long-term warming of the planet, according to an analysis of surface temperature measurements by scientists at NASAs Goddard Institute of Space Studies (GISS) in New York.

In an independent analysis of the raw data, also released Friday, NOAA scientists also found 2014 to be the warmest on record.

Well of course all the hottest years were in the last 20 years or so. Since 1940 the avg temp has gone up by half a degree. So all of the years currently will be hotter than years gone by. But in the last 20 years we are looking at temperature increases in the 0.0x degrees. Really unmeasurable differences, unless you disregard the level of accuracy there is in determining the actual global temperature for the year. Which I believe is around 0.1 degree. What is alarming is the lack of warming predicted by all of the models, And if the models are all wrong then why are we investing in the hysteria?

Because the problems of measurement are too sophisticated for the average, inumerate punter who is merely satisfied with a good story.

[canuckamuck]

Well of course all the hottest years were in the last 20 years or so. Since 1940 the avg temp has gone up by half a degree. So all of the years currently will be hotter than years gone by. But in the last 20 years we are looking at temperature increases in the 0.0x degrees. Really unmeasurable differences, unless you disregard the level of accuracy there is in determining the actual global temperature for the year. Which I believe is around 0.1 degree. What is alarming is the lack of warming predicted by all of the models, And if the models are all wrong then why are we investing in the hysteria?

Because the problems of measurement are too sophisticated for the average, inumerate punter who is merely satisfied with a good story.

Ah the Wizard of Oz response. Pay no attention to the man behind the curtain, the great and powerful Oz has it all under control. Yes calculating the temperature of the entire planet for an entire year to .00 degrees is phenomenally complex. In fact it is so complex that they don't believe they can do it with certainty. Which is why there is a degree of accuracy involved, a plus or minus .1 degrees. So when they say it is .01 degrees hotter this year than last, they fail to explain that this sort of accuracy is not reliable. But they can't resist showing all the digits from their calculators when it fits the agenda.

[sirineou]

Well of course all the hottest years were in the last 20 years or so. Since 1940 the avg temp has gone up by half a degree. So all of the years currently will be hotter than years gone by. But in the last 20 years we are looking at temperature increases in the 0.0x degrees. Really unmeasurable differences, unless you disregard the level of accuracy there is in determining the actual global temperature for the year. Which I believe is around 0.1 degree. What is alarming is the lack of warming predicted by all of the models, And if the models are all wrong then why are we investing in the hysteria?

Because the problems of measurement are too sophisticated for the average, inumerate punter who is merely satisfied with a good story.

Ah the Wizard of Oz response. Pay no attention to the man behind the curtain, the great and powerful Oz has it all under control. Yes calculating the temperature of the entire planet for an entire year to .00 degrees is phenomenally complex. In fact it is so complex that they don't believe they can do it with certainty. Which is why there is a degree of accuracy involved, a plus or minus .1 degrees. So when they say it is .01 degrees hotter this year than last, they fail to explain that this sort of accuracy is not reliable. But they can't resist showing all the digits from their calculators when it fits the agenda.

if the deviation was consistently ±.1 degree then it can attributed to random deviation, with in the margin of error, if it is consistently +.01 degrees, then there is a trend.

a number of ,01 degrees change in any direction have an accumulative affect

Edited January 25, 2016 by sirineou

[goatfarmer]

Well of course all the hottest years were in the last 20 years or so. Since 1940 the avg temp has gone up by half a degree. So all of the years currently will be hotter than years gone by. But in the last 20 years we are looking at temperature increases in the 0.0x degrees. Really unmeasurable differences, unless you disregard the level of accuracy there is in determining the actual global temperature for the year. Which I believe is around 0.1 degree. What is alarming is the lack of warming predicted by all of the models, And if the models are all wrong then why are we investing in the hysteria?

Because the problems of measurement are too sophisticated for the average, inumerate punter who is merely satisfied with a good story.

Ah the Wizard of Oz response. Pay no attention to the man behind the curtain, the great and powerful Oz has it all under control. Yes calculating the temperature of the entire planet for an entire year to .00 degrees is phenomenally complex. In fact it is so complex that they don't believe they can do it with certainty. Which is why there is a degree of accuracy involved, a plus or minus .1 degrees. So when they say it is .01 degrees hotter this year than last, they fail to explain that this sort of accuracy is not reliable. But they can't resist showing all the digits from their calculators when it fits the agenda.

Exactly. The admitted margin of error is greater than the claimed increment. But even the claimed margin of error involves a guess.

There is no contention with the science - only with its numerical representation, which is in the realm of fantasy.

[up2u2]

Well of course all the hottest years were in the last 20 years or so. Since 1940 the avg temp has gone up by half a degree. So all of the years currently will be hotter than years gone by. But in the last 20 years we are looking at temperature increases in the 0.0x degrees. Really unmeasurable differences, unless you disregard the level of accuracy there is in determining the actual global temperature for the year. Which I believe is around 0.1 degree. What is alarming is the lack of warming predicted by all of the models, And if the models are all wrong then why are we investing in the hysteria?

Because the problems of measurement are too sophisticated for the average, inumerate punter who is merely satisfied with a good story.

Ah the Wizard of Oz response. Pay no attention to the man behind the curtain, the great and powerful Oz has it all under control. Yes calculating the temperature of the entire planet for an entire year to .00 degrees is phenomenally complex. In fact it is so complex that they don't believe they can do it with certainty. Which is why there is a degree of accuracy involved, a plus or minus .1 degrees. So when they say it is .01 degrees hotter this year than last, they fail to explain that this sort of accuracy is not reliable. But they can't resist showing all the digits from their calculators when it fits the agenda.

Exactly. The admitted margin of error is greater than the claimed increment. But even the claimed margin of error involves a guess.

There is no contention with the science - only with its numerical representation, which is in the realm of fantasy.

Which margin of error in what data set?

[up2u2]

No you didn't, and if you look at the scale on the left that should explain it to you.

Oh, I see, you don't even understand the concept of a temperature anomaly. I truly am gobsmacked, now. That's about the first thing everybody in this field learns about.

Here you go.

https://www.ncdc.noaa.gov/monitoring-references/faq/anomalies.php

Instead of drawing 59, 60, 61F on the left-hand scale, we say "let 59F be our reference point, we'll designate that as our zero." From that basis, we write 0,1,2 rather than 59, 60, 61.

It's not that complicated to master.

In the case of Surface Temperature the average temperature is calculated between the years of 1951 - 1980 a total of 30 years. The average temperature for each year is calculated and compared to the 30 year average giving a plus or minus deviation from the 29 year average The Surface Temperature Anomaly that quickly shows the underlying Trend.

[goatfarmer]

Well of course all the hottest years were in the last 20 years or so. Since 1940 the avg temp has gone up by half a degree. So all of the years currently will be hotter than years gone by. But in the last 20 years we are looking at temperature increases in the 0.0x degrees. Really unmeasurable differences, unless you disregard the level of accuracy there is in determining the actual global temperature for the year. Which I believe is around 0.1 degree. What is alarming is the lack of warming predicted by all of the models, And if the models are all wrong then why are we investing in the hysteria?

Because the problems of measurement are too sophisticated for the average, inumerate punter who is merely satisfied with a good story.

Ah the Wizard of Oz response. Pay no attention to the man behind the curtain, the great and powerful Oz has it all under control. Yes calculating the temperature of the entire planet for an entire year to .00 degrees is phenomenally complex. In fact it is so complex that they don't believe they can do it with certainty. Which is why there is a degree of accuracy involved, a plus or minus .1 degrees. So when they say it is .01 degrees hotter this year than last, they fail to explain that this sort of accuracy is not reliable. But they can't resist showing all the digits from their calculators when it fits the agenda.

Exactly. The admitted margin of error is greater than the claimed increment. But even the claimed margin of error involves a guess.

There is no contention with the science - only with its numerical representation, which is in the realm of fantasy.

Which margin of error in what data set?

I was not referring to any particular dataset; rather, the idea of measuring the earth's temperature to 0.1 degrees, extrapolating back to 1850 and projecting to the end of the century strikes me as a flight of fancy.

[up2u2]

I was not referring to any particular dataset; rather, the idea of measuring the earth's temperature to 0.1 degrees, extrapolating back to 1850 and projecting to the end of the century strikes me as a flight of fancy.

It does sound a complex task but they do.

[i claudius]

Interesting that Bradford likes added CO2 and smog pumped into the air.

Where did I say I wanted more smog pumped into the air? Or did you just make that up, as usual?

However, the Paris "agreement" will have exactly that effect, as it has given a free pass to countries such as China and India to massively expand their coal-fired power generation for at least the next 15 years, with essentially no oversight of how clean those power plants are.

Getting China and India to sign an agreement was tough and took a lot of negotiating. Yes, they want to continue to expand coal use. Yet some agreement (to lessen CO2 and dirty air) is better than no agreement. Plus, amendments/adjustments can be made over time. It's not carved in stone.

Bet those East Coasters wish they had some of that heat about now.

Snow does not necessarily = colder weather. Snow is precipitation. BTW, I've resided nearly 20 yrs in northernmost Thailand, and this winter has been the warmest thus far in those years.

You all go on and on ,but records have only been kept for 100 or so years , what about 200 ,300 1000 years ago , they used to grow grapes in Britain hundreds of years ago because it was so warm , and in the 1800s the river Thames used to freeze over and the held fairs on it , its just nature ,anything else is guesswork and a way to tax you .

No one believes climate hasn't changed profoundly in earlier epochs. Frankly, I don't like the term 'climate change' because it too easily enables posts like Claudius' above. One big reason a warming climate over recent decades is important is because of the type of 'footprint' which humans have. You've seen the hockey stick graph of human population - and how it's exploded in the past 100 years - now well over 6 billion. Who knows where it will level off at: 9 billion? 14 billion? .....whatever, the number is already way to high for the carrying capacity of the planet. There are myriad proofs: mass migrations, loss of natural habitat, death of oceans, increased desertification, dearth of fresh water, Pacific Trash Vortex, ....the list is long and sad. A related reason why the debate needs to focus on a scale of decades and not centuries/millenia: People have adapted somewhat to particularly places. Most of the largest cities in the world are along coastlines or otherwise in places which will be adversely affected by rising seas. If half the largest cities in the world become seriously flooded year 'round, that obviously affects many people. Where do they go? Similarly, increased desertification compels people to migrate in desperation. That's half the reason there is a flood of immigrants from N. Africa and the M.East. On and on.

Actually I believe the flood of migrants had nothing to do with climate change,more the benefits that they can get in the west,free food and housing etc

[goatfarmer]

I was not referring to any particular dataset; rather, the idea of measuring the earth's temperature to 0.1 degrees, extrapolating back to 1850 and projecting to the end of the century strikes me as a flight of fancy.

It does sound a complex task but they do.

I am not disputing the fact that 'they do'. I am disputing the credibility of the result. There is a difference between precision and accuracy. They may be able to make precise measurements, but it does not follow that the measurements, precise to 0.1 degrees celsius, are an accurate assessment of the average global temperature to 0.1 degrees celsius.

[up2u2]

I was not referring to any particular dataset; rather, the idea of measuring the earth's temperature to 0.1 degrees, extrapolating back to 1850 and projecting to the end of the century strikes me as a flight of fancy.

It does sound a complex task but they do.

I am not disputing the fact that 'they do'. I am disputing the credibility of the result. There is a difference between precision and accuracy. They may be able to make precise measurements, but it does not follow that the measurements, precise to 0.1 degrees celsius, are an accurate assessment of the average global temperature to 0.1 degrees celsius.

Why?

[goatfarmer]

I was not referring to any particular dataset; rather, the idea of measuring the earth's temperature to 0.1 degrees, extrapolating back to 1850 and projecting to the end of the century strikes me as a flight of fancy.

It does sound a complex task but they do.

I am not disputing the fact that 'they do'. I am disputing the credibility of the result. There is a difference between precision and accuracy. They may be able to make precise measurements, but it does not follow that the measurements, precise to 0.1 degrees celsius, are an accurate assessment of the average global temperature to 0.1 degrees celsius.

Why?

Because there are too many biases involved in the process and biases reduce accuracy:

differences in time of taking temperatures from one station to another and at the same weather station over time.

different procedures for taking sea temperatures: (canvas buckets, rubber buckets, stationary buoys, satellite images, infrared remote sensing, to name a few)

distribution of land temperature weather stations, biased to the northern hemisphere.

- all of these biases create compound uncertainties.

And because compound uncertainties are combined.

[up2u2]

I am not disputing the fact that 'they do'. I am disputing the credibility of the result. There is a difference between precision and accuracy. They may be able to make precise measurements, but it does not follow that the measurements, precise to 0.1 degrees celsius, are an accurate assessment of the average global temperature to 0.1 degrees celsius.

Why?

Because there are too many biases involved in the process and biases reduce accuracy:

differences in time of taking temperatures from one station to another and at the same weather station over time.

different procedures for taking sea temperatures: (canvas buckets, rubber buckets, stationary buoys, satellite images, infrared remote sensing, to name a few)

distribution of land temperature weather stations, biased to the northern hemisphere.

- all of these biases create compound uncertainties.

And because compound uncertainties are combined.

What weather station, sea temperature data have you looked at and found errors in managing adjustments to potential inaccuracies, biases and uncertainties?