Anthropogenic Global Warming (1985 - 2009) Rest In Peace

[Jexiel]

Well, it seems the about-face concerning AGW has begun. Michael Mann, the infamous climate scientist author of the infamous "Hockey Stick" used by the IPCC and Al Gore and one of the leading characters in the ClimateGate scandal, has published a new paper in Science where he finally acknowledges (sort of) there was a Medieval Warm Period, among other things. The timing of this publication is excellent! Just in time to deflect some heat off Mr. Mann (to be honest, this paper was probably submitted for review a few months back).

First, the abstract.

Spoiler Alert, click show to read: 

Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly
Michael E. Mann,1,* Zhihua Zhang,1 Scott Rutherford,2 Raymond S. Bradley,3 Malcolm K. Hughes,4 Drew Shindell,5 Caspar Ammann,6 Greg Faluvegi,5 Fenbiao Ni4

Global temperatures are known to have varied over the past 1500 years, but the spatial patterns have remained poorly defined. We used a global climate proxy network to reconstruct surface temperature patterns over this interval. The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally. This period is marked by a tendency for La Niña–like conditions in the tropical Pacific. The coldest temperatures of the Little Ice Age are observed over the interval 1400 to 1700 C.E., with greatest cooling over the extratropical Northern Hemisphere continents. The patterns of temperature change imply dynamical responses of climate to natural radiative forcing changes involving El Niño and the North Atlantic Oscillation–Arctic Oscillation.

1 Department of Meteorology and Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, USA.
2 Department of Environmental Science, Roger Williams University, Bristol, RI 02809, USA.
3 Department of Geosciences, University of Massachusetts, Amherst, MA 01003–9298, USA.
4 Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA.
5 NASA Goddard Institute for Space Studies, New York, NY 10025, USA.
6 Climate Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80305, USA.

Second, the press release

Spoiler Alert, click show to read: 

Past regional cold and warm periods linked to natural climate drivers
Published: Thursday, November 26, 2009 - 14:39 in Earth & Climate

Intervals of regional warmth and cold in the past are linked to the El Niño phenomenon and the so-called "North Atlantic Oscillation" in the Northern hemisphere's jet stream, according to a team of climate scientists. These linkages may be important in assessing the regional effects of future climate change. "Studying the past can potentially inform our understanding of what the future may hold," said Michael Mann, Professor of meteorology, Penn State.

Mann stresses that an understanding of how past natural changes have influenced phenomena such as El Niño, can perhaps help to resolve current disparities between state-of the-art climate models regarding how human-caused climate change may impact this key climate pattern.

Mann and his team used a network of diverse climate proxies such as tree ring samples, ice cores, coral and sediments to reconstruct spatial patterns of ocean and land surface temperature over the past 1500 years. They found that the patterns of temperature change show dynamic connections to natural phenomena such as El Niño. They report their findings in today's issue (Nov. 27) of Science.

Mann and his colleagues reproduced the relatively cool interval from the 1400s to the 1800s known as the "Little Ice Age" and the relatively mild conditions of the 900s to 1300s sometimes termed the "Medieval Warm Period."

"However, these terms can be misleading," said Mann. "Though the medieval period appears modestly warmer globally in comparison with the later centuries of the Little Ice Age, some key regions were in fact colder. For this reason, we prefer to use 'Medieval Climate Anomaly' to underscore that, while there were significant climate anomalies at the time, they were highly variable from region to region."

The researchers found that 1,000 years ago, regions such as southern Greenland may have been as warm as today. However, a very large area covering much of the tropical Pacific was unusually cold at the same time, suggesting the cold La Niña phase of the El Niño phenomenon.

This regional cooling offset relative warmth in other locations, helping to explain previous observations that the globe and Northern hemisphere on average were not as warm as they are today.

Comparisons between the reconstructed temperature patterns and the results of theoretical climate model simulations suggest an important role for natural drivers of climate such as volcanoes and changes in solar output in explaining the past changes. The warmer conditions of the medieval era were tied to higher solar output and few volcanic eruptions, while the cooler conditions of the Little Ice Age resulted from lower solar output and frequent explosive volcanic eruptions.

These drivers had an even more important, though subtle, influence on regional temperature patterns through their impact on climate phenomena such as El Niño and the North Atlantic Oscillation. The modest increase in solar output during medieval times appears to have favored the tendency for the positive phase of the NAO associated with a more northerly jet stream over the North Atlantic. This brought greater warmth in winter to the North Atlantic and Eurasia. A tendency toward the opposite negative NAO phase helps to explain the enhanced winter cooling over a large part of Eurasia during the later Little Ice Age period.

The researchers also found that the model simulations failed to reproduce the medieval La Nina pattern seen in the temperature reconstructions. Other climate models focused more specifically on the mechanisms of El Niño do however reproduce that pattern. Those models favor the "Thermostat" mechanism, where the tropical Pacific counter-intuitively tends to the cold La Niña phase during periods of increased heating, such as provided by the increase in solar output and quiescent volcanism of the medieval era.

The researchers note that, if the thermostat response holds for the future human-caused climate change, it could have profound impacts on particular regions. It would, for example, make the projected tendency for increased drought in the Southwestern U.S. worse.

Source: Penn State

So Mr. Mann has finally discovered that Greenland was at least as warm as today (something historians and archaeologists have known for years), has finally discovered that natural phenomenon such as El Niño/La Niña influence global climate (something climatologists and meteorologists have known for years), and finally discovered that the Sun and volcanoes also influence global climate (something every scientists of any kind has known for years).

I love how he attempts to rename the MWP as the "Medieval Climate Anomaly" because "some areas were cooler than others." If this is the case, I hereby rename the current warming trend as the "Contemporary Warm Anomaly" because some areas are indeed cooler than others. A 400 year natural phenomenon is classified as an "anomaly" yet a 30 year warming trend is named catastrophic Anthropogenic Global Warming. Unbelievable.

Mr. Mann also points out that the Sun had a strong influence on past climate change. Therefore, it is very likely that the Sun is also influencing current climate change, Mr. Mann.

Mr. Mann, it is unlikely that humans caused global warming. It is likely that humans are contributing to the current trend. However, our contribution level has not been properly established. Our future sustainable energy lifestyle needs to be based on solid scientific evidence and not on junk-science and/or fear inducing mumbo-jumbo.

The AGW god is dead.

[removeduser_487563287433]

What bollocks. No serious scientist deniers the existance of the Medieval Warm Period or the Little Ice Age of Victorian times. You are massively and purposely misinterpreting the facts to fit your conspiracy theory.

[Jexiel]

What bollocks. No serious scientist deniers the existance of the Medieval Warm Period or the Little Ice Age of Victorian times. You are massively and purposely misinterpreting the facts to fit your conspiracy theory.

Are you sure about that? Because this infamous paper reconstructed the infamous "hockey stick" graph with no MWP. Also, this paper claimed at the time that Medieval warmth was not as high as today, in contradiction to what he currently claims.

Spoiler Alert, click show to read: 

I see no MWP here!

[removeduser_487563287433]

But what difference does that make? This graph of several studies (you are being grossly unscientific and purposefully misleading by using only one) shows the Medieval Warm period, and shows how much more significant the current rise in temperature is;

[Jexiel]

But what difference does that make? This graph of several studies (you are being grossly unscientific and purposefully misleading by using only one) shows the Medieval Warm period, and shows how much more significant the current rise in temperature is;

Spoiler Alert, click show to read: 

*Img spoilers added by me*

What difference does it make? You mean a manipulated graph that was used in the IPCC report does not make any difference? How can you be sure that the current temperature was not manipulated as well? Even the graph you showed displays a MWP cooler than today (despite Michael Mann himself just admitting that the MWP was at least as warm as today's current temperatures!)

If you claim I am being "grossly unscientific and purposefully misleading by using only one" then the IPCC is just as grossly unscientific and misleading since they used the graph I just posted.

time to face the facts, Mr.

[Razor]

But what difference does that make? This graph of several studies (you are being grossly unscientific and purposefully misleading by using only one) shows the Medieval Warm period, and shows how much more significant the current rise in temperature is;

Spoiler Alert, click show to read: 

I dunno. I like mine better:

Spoiler Alert, click show to read: 

Anyone can set up a graphic and claim things and support them in anyway they want. I dare not to automatically trust anything related to such heated and politically loaded subjects and take anything for granted.

The government has pushed the people for years to buy 'green energy', months to buy expensive LED lights to lower the consumption of energy (even launched an expensive campaign for it) which in turn would lead to a lower bill. Now with the prospect of people of saving money in the long term when buying LED lights etc. we hear on the new that we have to pay for more than 300 euros more per year and even more later on for energy because the government wants to invest in so-called 'green energy'.

Sorry but if that's not milking then I don't know what it is. After first trying to get people over to buy expensive lights which would save money in the long term, they're now already reclaiming the money people other wise would save for environmental projects "because we all (- supposedly -) don't want to have even more CO2 in the atmosphere causing an even higher temperature rise?" (roughly citing our Minister of Space and Environment IIRC).

[Jexiel]

For people that may not be understanding the huge implications behind Michael Mann's sudden about face allow me to state the facts.

Michael Mann is (was?) considered one of the world's top climate scientists, if not the top climate scientist today. Mr. Mann was the Lead Author "Observed Climate Variability and Change" chapter of the IPCC 3rd Scientific Assessment report as well as wielding strong influence in the National Academy of Sciences. This man is (was) widely respected and has received numerous awards.

Mr. Mann is also the creator of the infamous "hockey stick" graph that Al Gore used in "An Incovenient Truth" and that the IPCC utilized in the 2001 3rd Scientific Assessment. The "hockey stick" graph is the most famous graph in AGW since it was used as "proof" that humans "caused" global warming.

The recent ClimateGate scandal (the Climactic Research Unit emails/documents hacked or released recently) suggest that Mr. Mann was at the center of a scandal that may have involved scientific data manipulation, blocking FOI Act requests, deletion of scientific data, etc. Mr. Mann himself is alleged to have manipulated data to "hide a decline", presumably a temperature decline in recent times.

Now, pay attention to what Michael Mann's new study is suggesting: "The researchers found that 1,000 years ago, regions such as southern Greenland may have been as warm as today. Please remember that as of now, 2009, southern Greenland still has lots of ice over it; do not forget that historical and archaeological evidence suggests Vikings were farming in southern Greenland 1,000 years ago. Have you made the connection(s) yet?

These observations may suggest several things:

1) If souther Greenland was just as warm as is it today, then the current warming is not abnormal!
2) If 1,000 years ago, Vikings were able to farm in southern Greenland but today we cannot do the same, this suggests temperatures may have been higher back then than what they are now!
3) If 1,000 years ago temperatures were as high as today's but then dropped, this suggests today's temperatures may drop in the future as well!

Can anyone truly defend "Mann-made Global Warming" after these revelations?

[godol shmok]

Can anyone truly defend "Mann-made Global Warming" after these revelations?

see: http://www.springerlink.com/content/...ext.pdf?page=1

[Jexiel]

see: http://www.springerlink.com/content/...ext.pdf?page=1

Feel free to read the abstract for the paper you just cited

Spoiler Alert, click show to read: 

Klemens Hocke1 and Niklaus Kämpfer1(1) Institute of Applied Physics and Oeschger Centre for Climate Change Research, University of Bern, Sidlerstr. 5, 3012 Bern, Switzerland


Received: 21 May 2009 Accepted: 6 November 2009 Published online: 20 November 2009
Abstract Atmospheric and oceanic reanalysis data of the past 60 years are visualized by time–latitude cross sections which inform about temporal and latitudinal variability, changes, and meridional circulation of the climate system on time scales from years to decades. The diagrams ease the understanding of climate dynamics in a similar way as the Hovmöller diagram has clarified the zonal propagation of synoptic-scale waves in a latitude band. Thus the time–latitude cross sections are referred to as Hovmöller diagrams of climate anomalies. Various parameters are selected at the Earth’s surface level: air temperature, pressure, sea surface temperature, column-integrated atmospheric water vapour (IWV), surface relative humidity, and surface wind. Contour lines of one parameter are overlayed on the color image of the other parameter so that relations and coincidences of trends, oscillations, and sudden changes of the climate are revealed. Temporal variations of IWV and surface relative humidity appear to be related to the strength of the Southern polar front jet. In case of ENSO 1997/1998, the equatorial IWV enhancement is accompanied by acceleration of the meridional circulation cells of the Southern Hemisphere. Meridional surface wind data suggest the existence of double polar cells in both hemispheres. The Southern polar cells switched to a higher circulation speed in 1997, and surface relative humidity increased over Antarctica. A sudden and persistent decrease of surface pressure occurred in Antarctica around 1980. Since 2000, a rapid increase of surface air temperature, sea surface temperature, and IWV occurs in the Northern Hemisphere. These results of NCEP/NCAR reanalysis have to be cross-validated with other reanalyses, climate models, and pure observations which will be a major endeavour.

Keywords Climate - Diagnostics - Abrupt - Change - Variability

In other words, if the results cannot be replicated, they are false. But just to entertain you, read what other climate scientists have to say about current temperatures. The debate is not over.

[Erlinggra]

2) If 1,000 years ago, Vikings were able to farm in southern Greenland but today we cannot do the same,

if someone was dumb enough to try to farm on greenland they would get crops

also remember that said settlement died out because of food shortages

[removeduser_487563287433]

You are referring to an event several years ago. I have nothing to fear from scientific debate, and that's why I posted the graph, with several studies, including the Medieval Warm Period, which still debunks your theory.

[Jexiel]

You are referring to an event several years ago. I have nothing to fear from scientific debate, and that's why I posted the graph, with several studies, including the Medieval Warm Period, which still debunks your theory.

The hockey stick graph was published in 1998 by Mann et al. This same hockey graph was published by the IPCC in their 2001 assessment. The IPCC was forced to remove that graph from later assessments after other scientists pointed out it did not include the MWP. Michael Mann and the IPCC chose to ignore the MWP to promote their ideology. Mann himself calls it "Medieval Climate Anomaly" and not MWP. This proves my theory.

Now, since you do not fear scientific debate, please post the studies that published the graph you just posted (they should be at the bottom of the Wikipedia you got the graph from, reference section).

[removeduser_487563287433]

after other scientists pointed out it did not include the MWP.

So what's the scandal? A victory for scientific process and it happens the conclusions not being altered by the event.

[Mcgruder]

So what's the scandal? A victory for scientific process and it happens the conclusions not being altered by the event.

Manipulating data is not scientific.

[removeduser_487563287433]

Manipulating data is not scientific.

But other scientists pointed it out and it was corrected.

Almost ten years ago.

If this is the support for global warming not happening its not very convincing.

[Mcgruder]

You are referring to an event several years ago. I have nothing to fear from scientific debate, and that's why I posted the graph, with several studies, including the Medieval Warm Period, which still debunks your theory.

I think you are in denial mate. You talk about Jexiel miss interpreting facts, but this is exactly what the IPCC have been doing for years now, the leaked e mails and data from the CRU hack clearly shows this. There is even an e mail from Mann discussing how to 'get rid of' the MWP. These bastards at CRU were manipulating raw data to fit the graphs they had already published.

They have broke every "norm" when it comes to Peer Review, they rigged that process by using tame reviewers and then denying the data to anyone else.

What these people are doing is not science.

[godol shmok]

Global warming is just trash ... .

"Trash"



see: http://earthobservatory.nasa.gov/IOTD/view.php?id=5668

The retreat of mountain glaciers, on the other hand, is directly tied to increasing temperatures and melting. The Arapaho Glacier in the Rocky Mountains in Boulder County, Colorado, has shrunk dramatically since it was photographed in 1898. Measurements collected since 1960 suggest the glacier has thinned by at least 40 meters since then; thinning between 1898 and 1960 is unknown but is probably considerably greater than 40 meters. Compared to the contribution of tidewater glaciers, the volume of water added to the sea from melting alpine glaciers is very small.

[Razor]

"Trash"



see: http://earthobservatory.nasa.gov/IOTD/view.php?id=5668

I've read in another thread that some were saying that some glaciers weren't shrinking but in fact growing...
Just give it time. We'll have an ice age again sooner or later. I just don't want to throw money away to prevent the inevitable...

[godol shmok]

I've read in another thread that some were saying that some glaciers weren't shrinking but in fact growing...
Just give it time. We'll have an ice age again sooner or later. I just don't want to throw money away to prevent the inevitable...

It might be that we'll have both, a rising tendence and then a declining.

In other words, if the results cannot be replicated, they are false.

But that's not what the author says. Results in a science are always tendative and need to be connected to other results.

Anthropogenic emissions of greenhouse gases such as carbon dioxide and methane induce a warming of the troposphere and the oceans. The warming process changes the hydrological cycle and the circulation of the ocean–atmospheresystem (Held and Soden 2006). The evaporation rate of water is greater for a warmer sea surface, warmer air, and stronger surface winds. Since atmospheric water vapour absorbs the thermal radiation of the Earth, an amplification of human-induced global warming by natural processes is possible (Gillett et al. 2005; Shindell et al.1999; Trenberth et al. 2005; Willett et al. 2007). This example of a long interaction chain with influences on various atmospheric parameters motivates us to perform a combined analysis of trends and oscillations of surface air temperature, sea surface temperature, surface pressure, column-integrated water vapour (IWV), surface relative humidity, and surface wind based on meteorological and oceanic reanalysis data from January 1948 to July 2009. Climate change is analyzed by means of time–latitude cross sections which we like to call Hovmoeller diagrams of climate anomalies.

[G-Megas-Doux]

Global warming is just trash that has only recently been used by governments as a tool for controlling people.

We are in an ice age people; this is why there are polar caps. The water level will not rise when the ice melts because when it turns to water the mass is smaller. When the polar caps melt then we will not be in an ice age any more. The environment changing is part of nature’s constant way of challenging life to evolve to fit the environment. When you fight nature eventually you will lose.

Human beings had more of an effect on nature during the industrial revolution then now. Mostly co2 will not affect natures course one bit.

If we think that the amount of co2 is increasing to fast check it against the doubling time over the last millennium, there is no way to stop it without massacring human beings and changing the lifestyle back to an antiquity lifestyle, even then would it have an effect?

Ice age, non Ice age this is nature breathing.