New study sheds light on global warming trends
TALLAHASSEE, Fla. — New research by a team of Florida State University scientists shows the first detailed look at global land surface warming trends over the last 100 years, illustrating precisely when and where different areas of the world started to warm up or cool down.
The research indicates that the world is indeed getting warmer, but historical records show that it hasn’t happened everywhere at the same rate.
And that new information even took scientists by surprise.
“Global warming was not as understood as we thought,” said Zhaohua Wu, an assistant professor of meteorology at FSU.
Wu led a team of climate researchers including Fei Ji, a visiting doctoral student at FSU’s Center for Ocean-Atmospheric Prediction Studies (COAPS); Eric Chassignet, director of COAPS; and Jianping Huang, dean of the College of Atmospheric Sciences at Lanzhou University in China. The group, using an analysis method newly developed by Wu and his colleagues, examined land surface temperature trends from 1900 onward for the entire globe, minus Antarctica.
Previous work by scientists on global warming could not provide information of non-uniform warming in space and time due to limitations of previous analysis methods in climate research.
The research team found that noticeable warming first started around the regions circling the Arctic and subtropical regions in both hemispheres. But the largest accumulated warming to date is actually at the northern midlatitudes. They also found that in some areas of the world, cooling had actually occurred.
“The global warming is not uniform,” Chassignet said. “You have areas that have cooled and areas that have warmed.”
For example, from about 1910 to 1980, while the rest of the world was warming up, some areas south of the equator — near the Andes — were actually cooling down, and then had no change at all until the mid 1990s. Other areas near and south of the equator didn’t see significant changes comparable to the rest of the world at all.
The team’s work is featured in the May 4 edition of the journal Nature Climate Change.
The detailed picture of when and where the world has warmed or cooled will provide a greater context to global warming research overall, Wu said.
The paper: Fei Ji, Zhaohua Wu, Jianping Huang, Eric P. Chassignet. Evolution of land surface air temperature trend. Nature Climate Change, 2014; DOI: 10.1038/nclimate2223
Evolution of land surface air temperature trend
Fei Ji, Zhaohua Wu, Jianping Huang & Eric P. Chassignet
Abstract:
The global climate has been experiencing significant warming at an unprecedented pace in the past century1, 2. This warming is spatially and temporally non-uniform, and one needs to understand its evolution to better evaluate its potential societal and economic impact. Here, the evolution of global land surface air temperature trend in the past century is diagnosed using the spatial–temporally multidimensional ensemble empirical mode decomposition method3. We find that the noticeable warming (>0.5 K) started sporadically over the global land and accelerated until around 1980. Both the warming rate and spatial structure have changed little since. The fastest warming in recent decades (>0.4 K per decade) occurred in northern mid-latitudes. From a zonal average perspective, noticeable warming (>0.2 K since 1900) first took place in the subtropical and subpolar regions of the Northern Hemisphere, followed by subtropical warming in the Southern Hemisphere. The two bands of warming in the Northern Hemisphere expanded from 1950 to 1985 and merged to cover the entire Northern Hemisphere.
““Global warming was not as understood as we thought,” should suggest that those trillion-dollar policy decisions need to be reconsidered VERY carefully.
Exactly what I’ve been saying for years. And, this is the reason you can’t average temperatures over disparate areas; such a thing presents a false impression of uniformity.
“The global warming is not uniform…”
But…I thought “the global warming” was temporally correlated over large distances…isn’t that the basis for the NASA/GISS global temperature analysis (aka GISTEMP)? (LOL!).
http://data.giss.nasa.gov/gistemp/
“The analysis method was documented in Hansen and Lebedeff (1987), showing that the correlation of temperature change was reasonably strong for stations separated by up to 1200 km, especially at middle and high latitudes.“
HUH?
HUH? we’ve been showing this for three years.
REPLY: HUH? HUH? Another crypto comment from drive-by-Mosher with no context. For somebody who constantly bitches about showing your work, code, data, etc. you sure do leave lots of incomplete commentary that leave people scratching their heads.. Live up to your own expectations please by at least giving the SLIGHTEST hint of what you are talking about. -Anthony
In reply to: Peter Burmer says: May 5, 2014 at 12:41 am
I’m glad to see that WUWT it’s changing its editorial policy to include the publications in Nature, almost all of which it has previously ignored. Usually WUWT would also not mention anything that concludes “The global climate has been experiencing significant warming at an unprecedented pace in the past century”. Notice also how the paprler shows how there has been very fast warming in northern mid-latitudes in the past couple of decades.
I congratulate the WUWT team for a more balanced selection of posts that takes seriously the reality of manmade global warming!
William:
The observed warming in the last 70 years is not unprecedented and the WUWT does cover Nature climate ‘change’ related papers.
As this Nature submitted paper notes (see WUWT story for details concerning an interesting Nature editor firing incident related to this paper), there has been 342 warming cycles observed in the Antarctic peninsula in the last 250,000 years. (Antarctic peninsula ice cores provide a proxy for the Southern Ocean temperature as the peninsula is sufficient south that it is outside of the Antarctic polar vortex.)
http://wattsupwiththat.files.wordpress.com/2012/09/davis-and-taylor-wuwt-submission.pdf
Davis and Taylor: “Does the current global warming signal reflect a natural cycle”
…We found 342 natural warming events (NWEs) corresponding to this definition, distributed over the past 250,000 years …. …. The 342 NWEs contained in the Vostok ice core record are divided into low-rate warming events (LRWEs; < 0.74oC/century) and high rate warming events (HRWEs; ≥ 0.74oC /century) (Figure). … ….The current global warming signal is therefore the slowest and among the smallest in comparison with all HRWEs in the Vostok record, although the current warming signal could in the coming decades yet reach the level of past HRWEs for some parameters. The figure shows the most recent 16 HRWEs in the Vostok ice core data during the Holocene, interspersed with a number of LRWEs. …. ….We were delighted to see the paper published in Nature magazine online (August 22, 2012 issue) reporting past climate warming events in the Antarctic similar in amplitude and warming rate to the present global warming signal. The paper, entitled "Recent Antarctic Peninsula warming relative to Holocene climate and ice – shelf history" and authored by Robert Mulvaney and colleagues of the British Antarctic Survey ( Nature , 2012, doi:10.1038/nature11391),reports two recent natural warming cycles, one around 1500 AD and another around 400 AD, measured from isotope (deuterium) concentrations in ice cores bored adjacent to recent breaks in the ice shelf in northeast Antarctica. ….
Greenland ice temperature, last 11,000 years determined from ice core analysis, Richard Alley’s paper. William: As this paper shows there the Greenland Ice data shows that have been 9 warming and cooling periods in the last 11,000 years, interestingly the warming and cooling observed in the Northern hemisphere was the same periodicity as the warming and cooling in the Southern hemisphere.
http://www.climate4you.com/images/GISP2%20TemperatureSince10700%20BP%20with%20CO2%20from%20EPICA%20DomeC.gif
Curious that the Real Climate cabal have remained silent concerning the unprecedented increase in sea ice in the Antarctic. Surprise, surprise, surprise!, cyclic global warming is followed by cyclic global cooling.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png
P.S. Solar magnetic cycle changes causes the cyclic warming and cooling. The solar modulation of cloud cover's (there are four different mechanisms) affect is stronger at higher latitudes which explains why the warming in the last 70 years is primary at high latitudes. As the Antarctic ice sheet albedo is higher slightly greater than the albedo of low level clouds a decrease in cloud cover over the Antarctic ice sheet causes cooling rather than warming. The fact that the albedo of the Antarctic ice sheet is greater than low level clouds is the reason for what is called the polar see-saw (Antarctic ice sheet warms when the Greenland Ice sheet cools and vice verse. See Svenmark's linked paper for an explanation of the mechanism and ice core data that shows the cyclic warming and cooling.)
http://arxiv.org/abs/physics/0612145v1
The reason for the high albedo of the Antarctic ice sheet is the hurricane force winds on the Antarctic ice sheet break the snow crystals which then form an ice like substance. The Greenland ice sheet does not experience the same type of long term, seasonal, high velocity winds and hence has a lower albedo.
I think the conclusions of this paper will be very important for AGW supporters. Now, if anyone points to cooling in any region they just have to say, “Yes that’s what our research found, and that GW is unprecedented”. In other words, it gets them off the hook for any regional cooling, including lower-48 US and even Antarctica if they ever decide to admit that, while continuing with the warming meme overall. It’s very clever!
As I read the abstract and the supplimentary information (the paper itself is paywalled), the main claim is for the effectiveness of a new analysis method (Multi-dimensional Ensemble Empirical Mode Decomposition, or MEEMD), which is an improvement over Empirical Mode Decomposition, or EMD). I tried to get information on how many station records they used and covering what periods; I could not find it. So it is not clear to me whether this is a study based on primary data, or whether they simply re-analyzed the usual surface temperature data sets.
There is no point getting excited one way or the other until you know what their study actually examines and why their method produces different results from all the other studies.
For 30 years i have been told that Global warming is ‘spatially and temporally uniform’ and now it isn’t.
so in actual fact everything they have been telling me over the last 30 years is wrong, lordy what next.
Most of the warming seems constrained to areas where Hansen, Jones etc have had ample time to adjust the records to create that warming.
Hmm, what about small changes in the quasi-stationary long waves.
richardscourtney says:
May 5, 2014 at 1:12 am
Peter Burmer:
“Indeed, as the discussed paper reports there has not been global warming: there has only been local cooling and local warming.”
Careful, Richard. You do not want to cause a stroke. /sarc
http://www.freep.com/apps/pbcs.dll/article?AID=2014305010053
“Great Lakes ice cover from brutal winter could lead to a chilly summer”
another area not uniform, been quite a few this year.
well global warming is not global .
from http://www.merriam-webster.com/dictionary/global
glob·al adjective \ˈglō-bəl\
: involving the entire world
: involving all of something and especially a computer system, file, etc.
Full Definition of GLOBAL
1
: spherical
2
: of, relating to, or involving the entire world : worldwide ; also : of or relating to a celestial body (as the moon)
3
: of, relating to, or applying to a whole (as a mathematical function or a computer program) : universal
— glob·al·ly adverb
See global defined for English-language learners »
See global defined for kids »
Dear Professor Wu,
Because you acknowledge that “Global warming was not as understood as we thought,
how does your research showing warming “hasn’t happened everywhere at the same rate” apply
to the hypocrisy in the notion that the medieval warming period was regional yet modern warming is presumed to be global?
Can you at least acknowledge that there is not sufficient understanding of climate science to make such conflicting assertions?
From what I have read every rational used to call the MWP “regional” could more easily apply to modern warming.
Which makes the reverse plausible. That modern warming is regional and the MWP was global.
…..rationale…….
Okay, everyone who did not know this fact twenty years ago, please raise your hands.
Sheeeish. NCDC noted this fact way back when I was still young and skinny. This confirmation comes as a surprise to no scientists.
ftp://ftp.ncdc.noaa.gov/pub/data/cirs/
REPLY: Except to the scientists who are quoted in the press release who said:
– Anthony
“The research indicates that the world is indeed getting warmer, but historical records show that it hasn’t happened everywhere at the same rate.”
No scientist ever said otherwise.
Steve Oregon says:
May 5, 2014 at 9:45 am
Classic!
“But the largest accumulated warming to date is actually at the northern midlatitudes.”
ROFLMAO! Oh you mean the exact areas that have actual surface temperature data going back to 1900 that has conveniently been adjusted numerous times to make the past appear cooler? Those are the areas that warmed more than any other? Gollygee, I wonder why.
If evidence and ethics are optional can’t skeptics run around claiming that modern warming is regional and the MWP was global with the same certainty as alarmists in claiming the opposite?
Not me of course, but some other skeptics? 🙂
Also.
“And that new information even took scientists by surprise.”
That is like the Captain of the Titanic feigning surprise to learn icebergs were known to be in the area.
lemiere jacques says:
May 5, 2014 at 9:42 am
“well global warming is not global.”
Isn’t this little Mikey Mann’s reason for the MWP and LIA not being global in scope and why he claims everyone else’s paleotemperature reconstructions are false and his hockey stick is the correct reconstruction? Ironic, don’t you think?
This analysis should be a cautionary story for assuming globally well-mixed CO2 is the main mechanistic component of modern day global warming trends. Milankovitch cycles, natural ocean atmosphere heat cycles, and solar UV influences SHOULD loom larger now with this analysis. Sadly, it won’t, as the religion of global warming in single-mindedly centered on anthropogenic CO2 as its devil.
We are left to wonder how informative “global” statistics are. One “global” statistic I would like to see is a time-series plot of atmospheric pressure at sea level. There should be a shift in pressure correlated to any change in sea level and to global temperature as well.
Global Warming is a great theory, except it’s not Global and it’s not Warming.
The rising awareness among Alarmists that warming is not uniform but regional answers a question that I asked a few days ago. I had asked what benefits accrue to Alarmists from substituting the phrase “extreme weather events” for “global warming,” aside from the fact that it allows them to dodge the evident fact that warming stopped about seventeen years ago. Now the answer is clear. “Extreme weather events” are not global. The Alarmists have surrendered both the claim that there is warming and the claim that the effects of manmade CO2 are global. Retreat. Retreat. Retreat.
The good side of this is that maybe Alarmists will begin to focus on the regional rather than the global. Maybe they will begin to construct Correspondence Principles that connect the global phenomenon of rising CO2 to different effects in different regions. Lord knows that some empirical work would do them a world of good.