The difference in temperature between the Arctic and areas to the south is what drives the jet stream, a fast-moving river of air that encircles the northern hemisphere. As the Arctic warms faster, this temperature difference weakens, as does the west-to-east wind of the jet stream. Just as a river of water tends to meander when it reaches the gentle slopes of coastal plains, a weaker jet stream tends to have steeper north-south waves. Arctic amplification also stretches the northern tips of the waves farther northward, which favors further meandering. Meteorologists know that steeper waves are slower to shift westward.
The weather we experience at mid-latitudes is largely dictated by these waves in the jet stream. The slower the waves move, the longer the weather associated with them will persist. Essentially, “hot,” “dry,” “cold,” and “rainy” are all terms to describe very normal weather conditions. It’s only when those conditions persist in one area for too long that they are dubbed with the names of their extreme alter egos: heat waves, drought, cold spells, and floods. And these kinds of extreme events are precisely what we’ve seen more of in recent years.
"Over the last 20 years we have used satellites to monitor ice losses from Antarctica, and we have witnessed consistent and substantial ice losses from around much of its coastline," said Robert Bingham, a glaciologist working in the University of Aberdeen's School of Geosciences and lead author of the study.
"For some of the glaciers, including Ferrigno Ice Stream, the losses are especially pronounced, and, to understand why, we needed to acquire data about conditions beneath the ice surface.
Using a skidoo towing an ice-penetrating radar system, a scan was done over a distance of 2400 kilometres. Examining the results, researchers were able to discover the previously hidden valley."
The Southern Ocean is warming faster than the average for the global ocean.
The warming extends to greater depth in the Southern Ocean than it does in low latitudesbecause of the unique ocean currents there that carry heat deep in the ocean. The large amount of heat stored in the ocean makes it expand, raising sea levels.
Originally published in Science Express on 19 June 2008
Science 1 August 2008:
Vol. 321. no. 5889, pp. 680 - 684
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High-Resolution Greenland Ice Core Data Show Abrupt Climate Change Happens in Few Years
Jørgen Peder Steffensen,1* Katrine K. Andersen,1 Matthias Bigler,1,2 Henrik B. Clausen,1 Dorthe Dahl-Jensen,1 Hubertus Fischer,2,3 Kumiko Goto-Azuma,4 Margareta Hansson,5 Sigfús J. Johnsen,1 Jean Jouzel,6 Valérie Masson-Delmotte,6 Trevor Popp,7 Sune O. Rasmussen,1 Regine Röthlisberger,2,8 Urs Ruth,3 Bernhard Stauffer,2 Marie-Louise Siggaard-Andersen,1 Árn E. Sveinbjörnsdóttir,9 Anders Svensson,1 James W. C. White7
The last two abrupt warmings at the onset of our present warm interglacial period, interrupted by the Younger Dryas cooling event, were investigated at high temporal resolution from the North Greenland Ice Core Project ice core. The deuterium excess, a proxy of Greenland precipitation moisture source, switched mode within 1 to 3 years over these transitions and initiated a more gradual change (over 50 years) of the Greenland air temperature, as recorded by stable water isotopes. The onsets of both abrupt Greenland warmings were slightly preceded by decreasing Greenland dust deposition, reflecting the wetting of Asian deserts. A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next.
Current warmth seems to be occurring nearly everywhere at the same time and is largest at high latitudes in the Northern Hemisphere. Over the last 50 years, the largest annual and seasonal warmings have occurred in Alaska, Siberia and the Antarctic Peninsula. Most ocean areas have warmed. Because these areas are remote and far away from major cities, it is clear to climatologists that the warming is not due to the influence of pollution from urban areas.
Extreme Nile floods and famines in Medieval Egypt AD 930–1500 and their climatic implications
by: F. Hassan
In: Quaternary International, Vol. 173-174 (October 2007) , p. 101--112.
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Nile gauge records of variations in Nile floods from the 9th century to the 15th century AD reveal pronounced episodes of low Nile and high Nile flood discharge. Historical data reveal that this period was also characterized by the worst known famines on record. Exploratory comparisons of variations in Nile flood discharge with high-resolution data on sea surface temperature of the North Atlantic climate from three case studies suggest that rainfall at the source of the Nile was influenced by the North Atlantic Oscillation. However, there are apparently flip-flop reversals from periods when variations in Nile flood discharge are positively related to North Atlantic warming to periods where the opposite takes place. The key transitions occur at AD 900, 1010, 1070, 1180, 1350 and 1400. The putative flip-flop junctures, which require further confirmation, appear to be quite rapid and some seem to have had dramatic effects on Nile flood discharge, especially if they recurred at short intervals, characteristic of the period from the 9th to the 14th century, coincident with the so-called Medieval Warm Period. The transition from one state to the other was characterized by incidents of low, high or a succession of both low and high extreme floods. The cluster of extreme floods was detrimental causing famines and economic disasters that are unmatched over the last 2000 years.
The earth's magnetic field impacts climate: Danish study
(AFP) – Jan 12, 2009
COPENHAGEN (AFP) — The earths climate has been significantly affected by the planets magnetic field, according to a Danish study published Monday that could challenge the notion that human emissions are responsible for global warming.
A Giant Breach in Earth's Magnetic Field
Dec. 16, 2008: NASAs five THEMIS spacecraft have discovered a breach in Earths magnetic field ten times larger than anything previously thought to exist. Solar wind can flow in through the opening to "load up" the magnetosphere for powerful geomagnetic storms. But the breach itself is not the biggest surprise. Researchers are even more amazed at the strange and unexpected way it forms, overturning long-held ideas of space physics.
"At first I didn't believe it," says THEMIS project scientist David Sibeck of the Goddard Space Flight Center. "This finding fundamentally alters our understanding of the solar wind-magnetosphere interaction."
Is the solar system entering a nearby interstellar cloud
Vidal-Madjar, A.; Laurent, C.; Bruston, P.; Audouze, J.
AA(CNRS, Laboratoire de Physique Stellaire et Planetaire, Verrieres-le-Buisson, Essonne, France), AB(CNRS, Laboratoire de Physique Stellaire et Planetaire, Verrieres-le-Buisson, Essonne, France), AC(CNRS, Laboratoire de Physique Stellaire et Planetaire, Verrieres-le-Buisson, Essonne, France), AD(Meudon Observatoire, Hauts-de-Seine; Paris XI, Universite, Orsay, Essonne, France)
Astrophysical Journal, Part 1, vol. 223, July 15, 1978, p. 589-600. (ApJ Homepage)
Observational arguments in favor of such a cloud are presented, and implications of the presence of a nearby cloud are discussed, including possible changes in terrestrial climate. It is suggested that the postulated interstellar cloud should encounter the solar system at some unspecified time in the near future and might have a drastic influence on terrestrial climate in the next 10,000 years.
December 23, 2009: The solar system is passing through an interstellar cloud that physics says should not exist. In the Dec. 24th issue of Nature, a team of scientists reveal how NASAs Voyager spacecraft have solved the mystery.
Like a wounded Starship Enterprise, our solar system's natural shields are faltering, letting in a flood of cosmic rays. The sun's recent listlessness is resulting in record-high radiation levels that pose a hazard to both human and robotic space missions.
Galactic cosmic rays are speeding charged particles that include protons and heavier atomic nuclei. They come from outside the solar system, though their exact sources are still being debated.
Originally posted by poet1b
Religious lunatics! You should look up JCs story on the vineyard, he was another well known lunatic in his day.
At least you are using decent sources now, but they still don't refute my opening sources.
Originally posted by nixie_nox
The little ice age wasn't an ice age at all, just a three century cooling period in Europe, that also has half a dozen other causes considered, including volcanic activity.
If the sun was "heating up", there would of been climate events all over the world, not just Europe.
Common sense would tell you that if the climate was driven by a moody sun, lt would be so turbulant that life couldn't exist.
Former NASA Scientists Say Climate Change Is Not Settled Science
Group Of 49 Issues A Letter To Administrator Charles Bolden Protesting Such Assertions
Nearly 50 former employees of NASA have sent a letter to administrator Charles Bolden asking that the agency stop saying that human-caused global warming is scientific fact. The 49 scientists say that such claims are "unproven and unsupported remarks."
The letter come soon after the head of the agency's Goddard Institute for Space Studies Jim Hansen made a speech calling global warming caused by man a "great moral issue" like "slavery," according to a report appearing in "The Blaze" online.
In the letter, the scientists say that "We believe the claims by NASA and GISS, that man-made carbon dioxide is having a catastrophic impact on global climate change are not substantiated, especially when considering thousands of years of empirical data.
Originally posted by nixie_nox
the new york times
Originally posted by nixie_nox
Climate in northern Europe reconstructed for the past 2,000 years: Cooling trend calculated precisely for the first time
Calculations prepared by Mainz scientists will also influence the way current climate change is perceived / Publication of results in Nature Climate Change
An international team including scientists from Johannes Gutenberg University Mainz (JGU) has published a reconstruction of the climate in northern Europe over the last 2,000 years based on the information provided by tree-rings. Professor Dr. Jan Esper's group at the Institute of Geography at JGU used tree-ring density measurements from sub-fossil pine trees originating from Finnish Lapland to produce a reconstruction reaching back to 138 BC. In so doing, the researchers have been able for the first time to precisely demonstrate that the long-term trend over the past two millennia has been towards climatic cooling. "We found that previous estimates of historical temperatures during the Roman era and the Middle Ages were too low," says Esper. "Such findings are also significant with regard to climate policy, as they will influence the way today's climate changes are seen in context of historical warm periods." The new study has been published in the journal Nature Climate Change.
Researchers from Germany, Finland, Scotland, and Switzerland examined tree-ring density profiles in trees from Finnish Lapland. In this cold environment, trees often collapse into one of the numerous lakes, where they remain well preserved for thousands of years.
The international research team used these density measurements from sub-fossil pine trees in northern Scandinavia to create a sequence reaching back to 138 BC. The density measurements correlate closely with the summer temperatures in this area on the edge of the Nordic taiga. The researchers were thus able to create a temperature reconstruction of unprecedented quality. The reconstruction provides a high-resolution representation of temperature patterns in the Roman and Medieval Warm periods, but also shows the cold phases that occurred during the Migration Period and the later Little Ice Age.
In addition to the cold and warm phases, the new climate curve also exhibits a phenomenon that was not expected in this form. For the first time, researchers have now been able to use the data derived from tree-rings to precisely calculate a much longer-term cooling trend that has been playing out over the past 2,000 years. Their findings demonstrate that this trend involves a cooling of -0.3°C per millennium due to gradual changes to the position of the sun and an increase in the distance between the Earth and the sun.
"This figure we calculated may not seem particularly significant," says Esper. "However, it is also not negligible when compared to global warming, which up to now has been less than 1°C. Our results suggest that the large-scale climate reconstruction shown by the Intergovernmental Panel on Climate Change (IPCC) likely underestimate this long-term cooling trend over the past few millennia."
Oh, and let's not forget what scientists have been able to demonstrate recently...
However, the study actually does none of the above. "Our study doesn't go against anthropogenic global warming in any way," said Robert Wilson, a paleoclimatologist at the University of St. Andrews in Scotland and a co-author of the study, which appeared July 8 in the journal Nature Climate Change.
That Scandinavia may have been slightly warmer in the 11th century than today also doesn't change the fact that the world, as a whole, is warmer now. "This data is spatially specific. You would expect to see this trend in northern Scandinavia, but not in the Alps," Wilson said. "Almost all models show that the current global warming is probably warmer overall than that warming."
But Wilson, Schmidt and the vast majority of climate scientists agree: human-caused warming of the entire globe now overwhelms those subtle, regional heat redistributions. World temperatures are now pushing in only one direction: up.
Originally posted by poet1b
Your sources are mainly second hand evaluations citing articles by real scientists who are peered reviewed. This has been pointed out many times. Or else your sources do not back up your claim.
From sources on the 1st page, soil frozen for millions of years is now thawed
Global Warming is happening so fast, that science is unable to keep up.
Those who want to hide under their beds can do so if they choose.
This thread is about discussing what most clearly see.