Global temperature records in close agreement, despite subtle differences

Jan 14, 2011 By Adam Voiland
Multiple institutions monitor global surface temperatures. Despite subtle differences in the ways the scientists perform their analyses, these four widely referenced records show remarkable agreement. Credit: NASA Earth Observatory/Robert Simmon

Groups of scientists from several major institutions – NASA’s Goddard Institute for Space Studies (GISS), NOAA's National Climatic Data Center (NCDC), the Japanese Meteorological Agency and the Met Office Hadley Centre in the United Kingdom – tally data collected by temperature monitoring stations spread around the world and make an announcement about whether the previous year was a comparatively warm or cool year.

NASA’s announcement this year – that 2010 ties 2005 as the in the 131-year instrumental record – made headlines. But, how much does the ranking of a single year matter?

Not all that much, emphasizes James Hansen, the director of NASA’s Goddard Institute for Space Studies (GISS) in New York City. In the GISS analysis, for example, 2010 differed from 2005 by less than 0.01°C (0.018 °F), a difference so small that the temperatures of these two years are indistinguishable, given the uncertainty of the calculation.

Meanwhile, the third warmest year -- 2009 -- is so close to 1998, 2002, 2003, 2006, and 2007, with the maximum difference between the years being a mere 0.03°C, that all six years are virtually tied.

Even for a near record-breaking year like 2010 the broader context is more important than a single year. “Certainly, it is interesting that 2010 was so warm despite the presence of a La Niña and a remarkably inactive sun, two factors that have a cooling influence on the planet, but far more important than any particular year’s ranking are the decadal trends,” Hansen said.

There are large areas in the Arctic without weather stations. NASA GISS approaches the problem by filling in gaps with data from the nearest land stations. The Climatic Research Unit at the University of East Anglia, which works jointly with the Met Office Hadley Centre, leaves much of the region out of its global temperature analysis. Credit: NASA Earth Observatory/Robert Simmon

One of the problems with focusing on annual rankings, rather than the longer trend, is that the rankings of individual years often differ in the most closely watched temperature analyses – from GISS, NCDC, and the Met Office – a situation that can generate confusion.

For example, while GISS previously ranked 2005 warmest, the Met Office listed 1998 warmest. The discrepancy helped fuel the misperception that findings from the three groups vary sharply or contain large amounts of uncertainty. It also fueled the misperception that global warming stopped in 1998.

“In reality, nothing could be further from the truth,” said Hansen. have continued to rise steadily. “The three official records vary slightly because of subtle differences in the way we analyze the data, but they agree extraordinarily well,” said Reto Ruedy, one of Hansen’s colleagues at GISS who helps analyze global surface temperatures.

All three records show peaks and valleys that vary in virtual sync with each other since 1880. All three show particularly rapid warming in the last few decades. And all three show the last decade is the warmest in the instrumental record.

Handling the Arctic

There are several reasons for the small discrepancies that exist between the three records. Most important, subtleties in the way the scientists from each institution handle regions of the world where temperature-monitoring stations are scarce produce differences.

While developed areas have a dense network of weather stations, temperature monitoring equipment is sparse in some parts of the Amazon, Africa, Antarctica, and Arctic. In the Arctic, particularly, the absence of solid land means there are large areas without weather stations.

The Met Office and the NCDC leave areas of the Arctic Ocean without stations out of their analyses, while GISS approaches the problem by filling in the gaps with data from the nearest land stations, up to a distance of 1200 kilometers (746 miles) away. In this way, the GISS analysis achieves near total coverage in the Arctic.

Both approaches pose problems. By not inferring data, the Met Office assumes that areas without stations have a warming equal to that experienced by the entire Northern Hemisphere, a value that satellite and field measurements suggest is too low given the rate of Arctic sea ice loss.

On the other hand, GISS’s approach may either overestimate or underestimate Arctic warming. “There’s no doubt that estimates of Arctic warming are uncertain, and should be regarded with caution,” Hansen said. “Still, the rapid pace of Arctic ice retreat leaves little question that temperatures in the region are rising fast, perhaps faster than we assume in our analysis.”

Choosing a Base Period

Another reason that the three records differ relates to the “base period” that each group uses to calculate global temperature changes. It is not possible to calculate absolute global average surface temperatures for the GISS analysis because weather stations aren’t spread evenly enough across the globe to offer meaningful measurements. Scientists instead calculate a relative measure called a “temperature anomaly” to track whether global temperatures are changing.

To calculate temperature anomalies scientists compare average temperatures over any given time period -- a month or year, for example -- to a long-term average, or base period. The base period serves as a point of reference against which can be tracked.

All three groups use this same approach, but they do not all use the same base period. GISS uses a base period of 1951 to 1980. The Met Office uses 1961 to 1990. And NCDC uses the entire 20th century. Average temperatures during the GISS and NCDC base periods are about the same, but the base period the Met Office uses is slightly warmer than the period the other two groups use.

This means that numerical values of the temperature anomalies differ for the three analyses. However, the choice of base period should have no effect on the ranking of different years or on the magnitude of global warming over the past century.

Invariably, a great deal of attention centers on each year’s ranking, but it is critical to focus on the decade-long trends that matter more, the GISS scientists emphasize. On that time scale, the three records are unequivocal: the last decade has been the warmest on record. “It’s not particularly important whether 2010, 2005, or 1998 was the hottest year on record,” said Hansen. "It is the underlying trend that is important."

Explore further: Quakes destroy or damage 83 houses in Philippines

More information: Read the associated article published Jan. 12 announcing the GISS data: www.physorg.com/news/2011-01-t… -year-worldwide.html

add to favorites email to friend print save as pdf

Related Stories

2007 was tied as Earth's second warmest year

Jan 16, 2008

Climatologists at the NASA Goddard Institute for Space Studies (GISS) in New York City have found that 2007 tied with 1998 for Earth’s second warmest year in a century.

2008 Was Earth's Coolest Year Since 2000

Feb 23, 2009

(PhysOrg.com) -- Climatologists at the NASA Goddard Institute for Space Studies (GISS) in New York City have found that 2008 was the coolest year since 2000. The GISS analysis also showed that 2008 is the ...

Determining how warm this summer really was

Oct 01, 2010

An unparalleled heat wave in eastern Europe, coupled with intense droughts and fires around Moscow, put Earth's temperatures in the headlines this summer. Likewise, a string of exceptionally warm days in July ...

NOAA: Global temperature ties for warmest on record

Oct 18, 2010

The first nine months of 2010 tied with the same period in 1998 for the warmest combined land and ocean surface temperature on record. The global average land surface temperature for January-September was ...

Climate is warming - despite 'ups and downs'

Dec 28, 2010

Periodic short-term cooling in global temperatures should not be misinterpreted as signalling an end to global warming, according to an Honorary Research Fellow with CSIRO Marine and Atmospheric Research, Barrie Hunt.

Recommended for you

Kiribati leader visits Arctic on climate mission

17 hours ago

Fearing that his Pacific island nation could be swallowed by a rising ocean, the president of Kiribati says a visit to the melting Arctic has helped him appreciate the scale of the threat.

NASA catches a weaker Edouard, headed toward Azores

Sep 19, 2014

NASA's Aqua satellite passed over the Atlantic Ocean and captured a picture of Tropical Storm Edouard as it continues to weaken. The National Hurricane Center expects Edouard to affect the western Azores ...

User comments : 31

Adjust slider to filter visible comments by rank

Display comments: newest first

Skepticus_Rex
1.8 / 5 (10) Jan 14, 2011
I actually liked this article. It presented the ideas and methodological differences behind the differences in statistical analysis used by three out of four of the institutions in a format ideal for the lay reader.

It would have been nice to see and compare that with the methodology of the Japanese Meteorological Agency as well. Of interest is that the latter group appears to be a degree lower in temperatures at places.

In addition, as the chart is laid out and while it overall shows a warming trend and that the last decade was the warmest decade therein within the shown range of observed temps with infilled data, it still looks as if it agrees that the trend of rising temps during this last decade from 1998 was statistically insignificant, just as Phil Jones stated for the public record.

Hmmm...
Quantum_Conundrum
1.8 / 5 (10) Jan 14, 2011
There are so many issues with this data set that it's completely ridiculous.

First, we're comparing satellite age and digital thermometer age data which is updated instantaneously by the minute, to pre-automobile, mercury thermometer data taken when temperature readings were all taken manually, involving anything from mis-reading the instrument, Human estimation of rounding up or down to the nearest degree or half-degree, forgetting to take a measurement, to errors of calibration, etc.

Additionally, this data starts conveniently at the end of the little ice age and with the eruption of Krakatoa, the largest volcanic eruption in the past 300 years, which was probably about as large as all stratovolcano eruptions since then combined, with a shockwave that circled the earth 7 times, by some reports.

It's impossible to control for all of this stuff: Instrumentation errors, human errors, volcanism, solar variation, and other unknowns, and unknown unknowns.
Quantum_Conundrum
1.5 / 5 (8) Jan 14, 2011
so anyway, sorting out all these unkowns to figure how much, if anything, is actually man made change is absurd.

Unknown error in instrumenation.
Unknown human error.
Unknown Little Ice Age rebound.
Unknown Krakatoa rebound.
Unknown due to lack of instruments.

In 1880 there were far, far fewer weather stations around the world and many entire regions had 1 or no instruments.

Unknown due to loss of data in some cases.
gunslingor1
3.9 / 5 (7) Jan 14, 2011
"There are so many issues with this data set that it's completely ridiculous."
-QC, you have no credibility, you challenge all science simply because it is not faith based. You need to be on a religious site, not a physics site.

Are you related to Sarah Palin or Bush? I've never met a more ignorant person.
Quantum_Conundrum
1.6 / 5 (7) Jan 14, 2011
"There are so many issues with this data set that it's completely ridiculous."
-QC, you have no credibility, you challenge all science simply because it is not faith based. You need to be on a religious site, not a physics site.

Are you related to Sarah Palin or Bush? I've never met a more ignorant person.


You have absolutely no idea what you're talking about.

I don't challenge "science" at all. I challenge "psuedo science" when there is no basis in fact, or when the "facts" are in fact flawed or not factual at all.

My opposition to this fake science of climate change has absolutely nothing to do with "religion". It's simple observation of the inconsistencies and unkowns in the data sets.

I'm actually banned from most of the major "religious" sites on the internet, because they don't like me pointing out their corruption and false doctrines.

It is in my very nature to point out inconsistencies, self contradictions, and fallacies. Get over it.
Quantum_Conundrum
1.6 / 5 (7) Jan 14, 2011
Anyway, people who post data like this and "neglect" to mention all the issues I listed above have no credibility.
ekim
5 / 5 (4) Jan 14, 2011
Anyway, people who post data like this and "neglect" to mention all the issues I listed above have no credibility.

All of your issues are with the unknown rather than the facts. There will always be a unknown. Deal with it.
Mira_Musiclab
3.7 / 5 (6) Jan 14, 2011
I'm still waiting to see if there's frankly any article published here that QC doesn't have some contrary opinion about..

If the articles here are as completely off-base as it seem you believe they are, then -

1. Why do you spend so much time commenting here, versus supporting some other site that has more accurate information?

2. Can you post links for other science news sites that you think are more accurate in their publishing of similar articles?

I'm genuinely interested, yeah there's a lot of fluff out here, so if you know of sources that will provide a more solid learning experience, please do share..
Howhot
5 / 5 (3) Jan 14, 2011
2010 Ties with 2005 as the warmest year ever. CO2 9levels are ~400ppm up roughtly 1C from 1970 temps (in 40 years). By 2100 it will be ~1000ppm and temps of like 16C (28.8F) over the 280ppm of the 70's. My prediction is that it will be hot, dry and dusty with 130F temps for in NY during a summer. Hummm, and the rightwing just Lie to you about it. Interesting.

Skepticus_Rex
1 / 5 (8) Jan 15, 2011
Howhot,

Are you intentionally clueless, as in a WWF shill, or are you just trying to make the AGW/AGCC proponents look bad? Seriously?

Since 2010 TIES with 2005, it means that it did not get warmer--yet. In other words, just as Phil Jones stated, both the cooling and the warming over the last decade is statistically insignificant. Let's see what the next decade reveals to us.

Current average atmospheric CO2 levels, based upon preliminary data as of January 7, 2011, are 389.69 ppm.

1970 saw average atmospheric CO2 levels of just over 325 ppm.

Guys over at MIT say that their simulations and calculations give a median prediction of just over ~866 ppmv CO2 for the year 2100. Other calculations with other variables give a range of between 716 and 1095 ppmv for the year 2095.

Looks like someone took the highest calculation and ran with it for purposes of propaganda.

I tried to provide links but the spam filter would not let the posts through with them in the text.
rgwalther
5 / 5 (1) Jan 15, 2011
"There are so many issues with this data set that it's completely ridiculous."
-QC, you have no credibility, you challenge all science simply because it is not faith based. You need to be on a religious site, not a physics site.

Are you related to Sarah Palin or Bush? I've never met a more ignorant person.


I don't think that you have met QC yet. You don't even know for sure if he is human or from Earth. All nameless posters are entertaining, but their opinions are just that, entertainment; on the level with street hustlers. If you play, you pay.
gvgoebel
5 / 5 (2) Jan 15, 2011
You don't even know for sure if he is human or from Earth.


Eh, we got that figured out. He's Mr. Myxzptlk.
Quantum_Conundrum
1 / 5 (3) Jan 15, 2011
2010 Ties with 2005 as the warmest year ever. CO2 9levels are ~400ppm up roughtly 1C from 1970 temps (in 40 years). By 2100 it will be ~1000ppm and temps of like 16C (28.8F) over the 280ppm of the 70's. My prediction is that it will be hot, dry and dusty with 130F temps for in NY during a summer. Hummm, and the rightwing just Lie to you about it. Interesting.


Do you realize that since venus has an "ideal" greenhouse effect, being in isothermal equilibrium, it's possible to use that to calculate the worst case scenario for the earth using the Kelvin temperature scale? Venus' atmosphere is 96.5% CO2, while Earth is only trace CO2. And Venus atmosphere is roughly 93 times as massive as earth's.

You can calculate what Venus' temperature would be if it were in earth's location, and it comes to 384.2K, or 111C.

However, we should remind the reader that Venus has roughly 236,000 times more CO2 in it's atmosphere, by mass, than does the Earth.
Quantum_Conundrum
1 / 5 (3) Jan 15, 2011
So the Earth is nowhere near achieving any runaway greenhouse effect.

You'd have to convert several feet of earth's soil to gas before you had enough CO2 to achieve a runaway greenhouse effect, and you could never do that, because the "real" greenhouse effect isn't strong enough to produce that much temperature increase that would be needed to accomplish this.

Boiling the oceans would make a runaway greenhouse effect, but you couldn't actually boil the oceans unless you already had a runaway greenhouse effect.
ekim
5 / 5 (3) Jan 15, 2011
However, we should remind the reader that Venus has roughly 236,000 times more CO2 in it's atmosphere, by mass, than does the Earth.

Venus also has a cloud layer many times thicker than earth. We could surround venus in a swarm of satellites to determine how much sunlight is being reflected and how much is absorbed. That would provide more facts. However I would rather stick to the facts as they pertain to Earth, rather than focus on the unknown climates of other planets.
eachus
5 / 5 (2) Jan 15, 2011
...this data starts conveniently at the end of the little ice age and with the eruption of Krakatoa, the largest volcanic eruption in the past 300 years...

Good point about where the record begins, but the Tambora eruption in 1815 (with a VEI of 7) was possibly the largest such eruption in recorded history. (The other contestants are Baekdu on the Chinese/Korean border in around 989, and the Taupo eruption in New Zealand around 180 AD. Before that you have to go back about 5000 years to find another VEI 7.)

However, eruptions near the equator have a much larger effect on global temperatures than those at higher latitudes. Krakatoa erupted from May until the final explosion in August, and created a lot of very fine ash that was visible in sunsets for years.

It is not clear whether Tambora or Krakatoa had the biggest effect on global temperatures. Since they occurred in the same century, the 19th century may hold a record for volcanic dust in the last million years or so.
eachus
5 / 5 (1) Jan 15, 2011
Oops! Sorry. Make that the last half-million years or so. There was an eruption of the Yellowstone caldara about 640,000 years ago that may have put more dust into the stratosphere. There are three other known VEI 8 eruptions between then and now. But as I say, the type of ash, and the latitude help determine the effect on climate. Tambora and Krakatoa were situated near the equator and both put dozens of cubic kilometers of fine ash in the stratosphere. (I'm only counting the fine ash which is why the numbers are so low. ;-)
AdamCC
3 / 5 (2) Jan 17, 2011
so anyway, sorting out all these unkowns to figure how much, if anything, is actually man made change is absurd.


Absolutely nowhere in this article anywhere does it say ANYTHING about man made changes. The question of whether global warming is in any way being influenced by man is an open one - not enough data, absolutely correct. The question of whether there *is* a global warming trend - regardless of the cause - is completely answered and incontrovertible. It is that which this article discusses - the agreement of multiple data sets / analysis to show that trend, debunking the claim that theses sources of information disagree.
ekim
5 / 5 (1) Jan 17, 2011
The question of whether global warming is in any way being influenced by man is an open one - not enough data, absolutely correct.

I agree that man made warming is a theory that needs more data. Most theories need more data. However it is the least crazy of all the theories presented and that makes it the most accepted. I'm open to hear any other crazy theories if they have data to back them up.
Nik_2213
5 / 5 (1) Jan 17, 2011
"First, we're comparing satellite age and digital thermometer age data which is updated instantaneously by the minute, to pre-automobile, mercury thermometer data taken when temperature readings were all taken manually, involving anything from mis-reading the instrument, Human estimation of rounding up or down to the nearest degree or half-degree, forgetting to take a measurement, to errors of calibration, etc."

IIRC, most weather stations are still equipped with 'traditional' thermometers. Regular observers can read repeatedly and reliably to small fractions of a degree, and all instrumentation is routinely recalibrated and traceable to 'National Standards'.

I'm sorry, QC, yet again you've shown you really don't know what you're talking about...
Skepticus_Rex_
1 / 5 (3) Jan 17, 2011
Don't forget climategate :) Showed that all the temperatures are fixed and we can't trust any of them. How can they say there was no medieval warm period when vikings where growing and eating pineapples in Greenland? I will find the link for this somewhere
Skepticus_Rex
1 / 5 (7) Jan 17, 2011
Don't forget climategate :) Showed that all the temperatures are fixed and we can't trust any of them. How can they say there was no medieval warm period when vikings where growing and eating pineapples in Greenland? I will find the link for this somewhere


Ignore the MikeyK/treemikey imitative sockpuppet, Skepticus_Rex_, behind the curtain. Watch that underscore or you will be fooled as well by the troll.
Truthforall
1 / 5 (1) Jan 18, 2011
This valid point of this article is that when looking at climate change in a statistically significant way one has to look at the tend in terms of decades. But what is decade compared with the history of Earth. Knowing that Earth has seen steep climate cycles in the past, may be we should also compare the significant of millenium and century trends and not just the decade trend. For all our worries, the next asteroid strike might end human civilization sooner than AGM.
Venus green house warming might not be solely due to solar heating. If Earth's core is to eventually cool, this implies that the energy buget is negative, losing heat to space despite the sun's rays, or else the Earth surface will cook. The thick blanket above Venues is an example. Has there been in depth study on geothermal heating? This have greater heating effect on the ocean, efficiency almost 100%, and unlike sun light has no reflection. If not then our current climate model is not complete.
Skepticus_Rex
1 / 5 (5) Jan 18, 2011
Venus green house warming might not be solely due to solar heating.


I believe you are correct--at least so far as various opinions and research go.

Some are of the opinion that the extra heating is in large part due to adiabatic compression caused by the high pressure and density of Venus' atmosphere.

I am inclined to lean that way as well.
Truthforall
not rated yet Jan 19, 2011
adiabatic compression
Venus has no moon, and its orbit is rather circular, is gravitational tidal effect apparant like Io? Or does solar wind has a big role?
With a think soup like atmosphere the core's heat will have no where to go too and a long way to space.
My view is that Earth's ocean is a big heat sink, but little was done on undersea thermal activity despite that the ocean covers 3/4 of Earth's service. It has to have some effect in climate but current Climate Science doesn't seem to care.
Skepticus_Rex
1 / 5 (4) Jan 19, 2011
None of these will have major effect on the atmosphere of Venus. However, the high pressure and density of its atmosphere does cause a compression effect on the lower atmosphere, raising temperatures much more highly than would be the case for Earth. Temperatures in the region of the atmosphere equal to earth pressure (1 bar) are not too much higher than those of Earth on the ground. Venus's atmospheric pressure at ground level is about 93 bars and that is the region around where most of the heat is to be found.

Consider also that Venus receives nearly twice the amount of solar insolation than does Earth and that Venus' atmosphere is on the order of around 965,000 ppmv CO2 as compared to Earth's paltry average CO2 level of 389.69 ppmv. Even though Venus has a small percentage of N2 in its atmosphere, it still has more N2 than does earth, also contributing to heating and holding of heat in the atmosphere by filling the 'holes' left by CO2 in its atmosphere like a 'fuzzy blanket.'
Truthforall
not rated yet Jan 19, 2011
Bear with me for I am no climate scientist. I was thinking about the thermal energey budget. The work done on gas must come from somewhere, physical work from solar wind, gravitational tidal effect on atmosphere, electromagnetic tidal effect on the ionsphere, sunlight, geothermal conduction, frictional lost on the angular momentum of Venus and the occassional meteor strike. Compression effect is a manifestation of the above without which the compression effect will have settled ages ago.
By saying Venus refelcts twice the amount of solar irradiation, do you mean Venus has twice the reflective index on the combined spectrum or twice the amount of radiation. The former is geometric to the radiation on Venus and the latter absolute.
Common sense led me to think that it must be radiating out more than it takes in otherwise it will be molten by now. Venus started of molten and has slowly cooled, despite GHE. It's surface is hot because its atmosophere has a steep thermal gradiant.
Skepticus_Rex
1 / 5 (4) Jan 20, 2011
I wrote 'receives' not 'reflected.' There are several reasons, all combined, that appear to cause the heating of the atmosphere of Venus to its current state.

However, greenhouse effect does not appear to be the cause of the most significant amount of heat retention. Remember, Venus' atmosphere is over 90 times denser than that of earth. While only about 3.5% nitrogen is to be found in the Venusian atmosphere, there still is more nitrogen in the atmosphere of Venus than on earth.

Nitrogen (N2) combined with CO2 has some very interesting thermal properties in combination. The density of Venus' atmosphere prevents more radiation of heat into space by its very density and composition. Dense clouds also help with that.

For the record, just about everything we have sent to Venus has melted down or otherwise had components melted. It is that hot on the surface--hot enough to melt lead. The Soviets (before becoming the Russian Federation) had a satellite survive 127 minutes in 1982.
Skepticus_Rex_
5 / 5 (1) Jan 20, 2011
I hope the above shows you why I believe that there is no such thing as a 'Greenhouse' effect. Look at Watts up and you find that greenhouses don't work and all the scientists in the world, with their "peer review" and their "qualifications" know shack Jit. I don't have any "experience" or "knowledge" on the subject, save what I can Google for each question, but I can spot an ecoweener a mile off. I believe Venus is so hot because it is the closest planet to the sun (mercury is a AGW myth, as seen in climategate) and the convection is what does it :)
Skepticus_Rex
1 / 5 (6) Jan 20, 2011
Idiot MikeyK and his rear-underscore sockpuppet (Skepticus_Rex_) notwithstanding, he clearly does not know what he is talking about so he has to go about spewing nonsense and "talking bullocks" (to quote him) rather than addressing the subject intelligently. I think his mother would be very angry if she caught him at her computer sitting the way he is.

That aside, run any number of calculations and greenhouse warming does not account for the warming of Venus on its own. There is some warming as a result but not enough to account for it all.

Venus' atmosphere is far denser and contains far more CO2 than does the atmosphere of earth. Even if we burnt everything organic on the planet we could never reach the levels on Venus. Venus even has more nitrogen than does Earth in its atmosphere even with its limited amounts of nitrogen by comparison to its CO2.

And, yes, I fully believe in the existence of Mercury, contrary to the sockpuppet king's fanciful assertions.
wranglerwayne
not rated yet Feb 26, 2011
GISS folks know their data is incorrectly warmer in certain spots, but refuse to correct it. Saying it fits other data is no justification not to do so. It presents a false and ridiculous alignment of other system's data that may not really exist.