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"We are seeing the global ocean store more heat than it gives off," said John Lyman, an oceanographer at NOAA's Joint Institute for Marine and Atmospheric Research, who led an international team of scientists


"The ocean is the biggest reservoir for heat in the climate system," said Josh Willis, an oceanographer at NASA's Jet Propulsion Laboratory and one of the scientists who contributed to the study. "So as the planet warms, we're finding that 80 to 90 percent of the increased heat ends up in the ocean."

A warming ocean is a direct cause of global sea level rise, since seawater expands and takes up more space as it heats up. The scientists say that this expansion accounts for about one-third to one-half of global sea level rise.

Combining multiple estimates of heat in the upper ocean -- from the surface to about 2,000 feet down -- the team found a strong multi-year warming trend throughout the world's ocean. According to measurements by an array of autonomous free-floating ocean floats called Argo as well as by earlier devices called expendable bathythermographs or XBTs that were dropped from ships to obtain temperature data, ocean heat content has increased over the last 16 years.

Combining multiple estimates of heat in the upper ocean -- from the surface to about 2,000 feet down -- the team found a strong multi-year warming trend throughout the world's ocean

I think that it is still premature to make claims about the Earth's energy imbalance based on satellite observations and ocean heat content data over ANY period. As with the satellite observations, the ocean heat content data continue to undergo refinement and removal of systematic errors. Since the satellite data are insensitive to the absolute value of the imbalance, they rely on ocean heat content data to estimate it. However, I personally belive that there is not a long enough common period between the satellite observations and the RELIABLE ocean heat content record to make any strong claims about the energy budget. Many people are working on both data sets, however, and I hope that a more reliable comparison will become available soon

[Greenland] has....a dense icecap up to 2 km thick that covers much of the island--pressing down the land beneath and lowering its elevation. Now, scientists at the University of Miami say Greenland's ice is melting so quickly that the land underneath is rising at an accelerated pace.

"It's been known for several years that climate change is contributing to the melting of Greenland's ice sheet," Dixon says. "What's surprising, and a bit worrisome, is that the ice is melting so fast that we can actually see the land uplift in response," he says. "Even more surprising, the rise seems to be accelerating, implying that melting is accelerating."

The same process is affecting the islands of Iceland and Svalbard...

"During ice ages and in times of ice accumulation, the ice suppresses the land....When the ice melts, the land rebounds upwards...Our study is consistent with a number of global warming indicators, confirming that ice melt and sea level rise are real and becoming significant."

Even more surprising, the rise seems to be accelerating, implying that melting is accelerating

The latest paper is a consensus effort from many of the people involved in the previous work and shows how robust the recent decades warming of the ocean has been. Indeed, the 'best estimate' for the changes in the top 700m seems to be a greater warming than seen in the NODC data and more than even the models were suggesting....

As usual, this is unlikely to be the very last word on the subject, but this is more evidence that the planet is basically behaving as the scientists think it is. And that isn't necessarily good news.

If Arctic warming continues at its current rate, the Arctic Ocean could have ice-free summers by 2040 or even earlier, modelling studies suggest. The last time the ocean may have had ice-free seasons was around 10,000 years ago, when the region was getting much more sunlight than today due to Earth's orbital fluctuations. By using geological records to piece together the history of Arctic sea ice over the last 50 million years, scientists have shown that the combined magnitude and abruptness of the recent ice loss is likely higher than ever before and can't be explained by any known natural variables.

For the last 11,000 years or so we have been enjoying a relatively warm, low-ice interglacial period, with a gentle cooling as we head towards the next glacial. "From orbital variations, we'd expect the Arctic to continue to slowly cool as it has done so for the past several thousand years, eventually slipping into a new ice age," said Mark Serreze director of the US National Snow and Ice Data Center at the University of Colorado.

But the last 100 years have bucked the trend in a big way. "We've lost about 30% of the summer ice extent and as much as 85% of the multi-year ice volume since the 1970s," Serreze told environmentalresearchweb. And this decrease can't be explained by natural variations alone. "If you ignored our recent atmospheric carbon dioxide rise, the recent reduction in sea ice in the Arctic would look highly anomalous, because it comes at a time when orbits favour extensive sea ice," said Richard Alley from Pennsylvania State University.

...on the Great Barrier Reef and in the central Pacific, scientists are drilling into coral and surfacing with a picture of the past.

Swing south-east, to the bottom end of New Zealand, and they are collecting samples of old tree rings.

Further south, in eastern Antarctica, century-old ice cores are being dug up, containing oxygen pockets frozen in time.

All of this disparate work will be brought together at the University of Melbourne during the next two days, at an international workshop on filling gaps in understanding of how the Australasian climate has shifted over the past 500 years.

The results will feed into the fifth report of the Intergovernmental Panel on Climate Change, due in 2014.

Recently published work...found a link between increased snowfall in Antarctica and the drought in south-west Western Australia over the past 30 years. The change in pressure systems causing the phenomenon was so far outside normal variations that Dr van Ommen concluded it was likely to have been caused by man-made climate change.

Analysis of cross-discipline research led to the conclusion that the warming could not be explained by natural variation alone and that, without skyrocketing emissions, changes in solar and volcanic activity over the past 50 years would probably have caused the globe to cool.

"The ice loss that we see today -- the ice loss that started in the early 20th Century and sped up during the last 30 years -- appears to be unmatched over at least the last few thousand years," said Leonid Polyak, a research scientist at Byrd Polar Research Center at Ohio State University. Polyak is lead author of the paper and a preceding report that he and his coauthors prepared for the U.S. Climate Change Science Program.

While knowing the loss of surface area of the ice is important, Polyak says that this work can't yet reveal an even more important fact: how the total volume of ice -- thickness as well as surface area -- has changed over time.

"Underneath the surface, the ice can be thick or thin. The newest satellite techniques and field observations allow us to see that the volume of ice is shrinking much faster than its area today. The picture is very troubling. We are losing ice very fast," he said.

Ocean temperature and heat content

Over the past 50 years, the oceans have absorbed more than 80% of the total heat added to the air/sea/land/cyrosphere climate system (Levitus et al, 2005). As the dominant reservoir for heat, the oceans are critical for measuring the radiation imbalance of the planet and the surface layer of the oceans plays the role of thermostat and heat source/sink for the lower atmosphere.

Domingues et al (2008) and Levitus et al (2009) have recently estimated the multi-decadal upper ocean heat content using best-known corrections to systematic errors in the fall rate of expendable bathythermographs (Wijffels et al, 2008). For the upper 700m, the increase in heat content was 16 x 1022 J since 1961. This is consistent with the comparison by Roemmich and Gilson (2009) of Argo data with the global temperature time-series of Levitus et al (2005), finding a warming of the 0 - 2000 m ocean by 0.06°C since the (pre-XBT) early 1960's.

The first comprehensive synthesis on the effects of climate change on the world's oceans has found they are now changing at a rate not seen for several million years.

In an article published June 18 in Science magazine, scientists reveal the growing atmospheric concentrations of man-made greenhouse gases are driving irreversible and dramatic changes to the way the ocean functions, with potentially dire impacts for hundreds of millions of people across the planet.

Professor Ove Hoegh-Guldberg, lead author of the report and Director of The University of Queensland's Global Change Institute, says the findings have enormous implications for mankind, particularly if the trend continues.

He said that the Earth's ocean, which produces half of the oxygen we breathe and absorbs 30% of human-generated CO2, is equivalent to its heart and lungs. "Quite plainly, the Earth cannot do without its ocean. This study, however, shows worrying signs of ill health

He warned that we may soon see "sudden, unexpected changes that have serious ramifications for the overall well-being of humans," including the capacity of the planet to support people. "This is further evidence that we are well on the way to the next great extinction event."

The "fundamental and comprehensive" changes to marine life identified in the report include rapidly warming and acidifying oceans, changes in water circulation and expansion of dead zones within the ocean depths.

The longest sequences of temperature and salinity data analyzed (from 1900 to present), have confirmed the gradual warming of the waters of the western Mediterranean. The warming has accelerated since the mid 1970's.

This work, published this May in the Journal of Marine Systems, has reconstructed the longest time series of temperature and salinity in the western Mediterranean, from 1900 to 2008.

In addition, the study shows that the way in which the temperature of the Western Mediterranean deep layer increases is well correlated with the air temperature in the northern hemisphere and with the heat absorbed by the Atlantic Ocean.

Thus, the Western Mediterranean is presented as an excellent indicator of the changes that are occurring in the Earth's climate on a larger scale, and, therefore, the observing systems developed by the IEO and the ICM become very useful tools in the study of climate change.

Temperaturen i Arktis har økt langt mer enn den globale middeltemperaturen de siste 30 år, mens det motsatte er tilfellet i Antarktis. Dette kan, i alle fall delvis, skyldes naturlige svingninger.

Figuren tyder på at menneskeskapt oppvarming i nord siden 1970-tallet er forsterket av den naturlige svingningen i temperaturen i dette området, mens disse effektene i sør har motvirket hverandre. Fortsetter dette mønsteret, vil forholdene om noen år bli motsatt, slik at menneskeskapt og naturlig temperaturendring vil motvirke hverandre i nord, men forsterke hverandre i sør.

Jakob tilknyttede følgende billede:...

Kosmos skrev:
- for det afbildede tidsinterval illustrerer dine grafer med fuld tydelighed, at vi stadig er under recovery fra lille istid, og gudskelov for dét!

Jakob skrev:
Nå ja, det er jo trist, hvis det bliver koldt. Så hellere en menneskeskabt "recovery", som kan ende med mere end 70 meter havstigning, eller hvad er din pointe..?

kulden-varmen skrev:
Hvordan smelter man Antarktisk selvom temperaturerne er langt under frysepunktet?

Jeg har søgt efter det, uden at kunne finde det, men husker jeg ikke rigtigt, at det er et spørgsmål, som du har funderet en del over...

Kosmos skrev:
- jeg er ikke helt sikker på, hvad du mener med 'det'!?

Jakob skrev:

kulden-varmen skrev:
Hvordan smelter man Antarktisk selvom temperaturerne er langt under frysepunktet?

Det ved jeg ikke lige helt, var det ikke mig, der spurgte først..?

Men selv langt under frysepunktet må en lille temperaturstigning i de øverste islag give anledning til overfladespændinger og revnedannelser.
Temperaturen på det flydende saltvand er måske under nul grader, men ikke meget.
Og det lidt varmere flydende saltvand kan måske smelte is og gnave sig ind under isbjerge, der står på havbunden, så de brækker af i kæmpe stykker, som flyder nordpå og smelter.

Lyder det sandsynligt..?

Og måske et ledende spørgsmål til din personlige omvendelse:
Anerkender du svingningerne mellem polerne, så du ikke mere er i tvivl om, at vi godt kan have global opvarmning, selvom det ikke er jævnt fordelt på de to klodehalvdele..?
Jeg har søgt efter det, uden at kunne finde det, men husker jeg ikke rigtigt, at det er et spørgsmål, som du har funderet en del over, og som der med rick_uk's indlæg nu er givet svar på..?

GLAR skrev:
Det skal du spørge Al Gore om ! I hans seneste bog 'Vores Valg' er der på en Phoshoppet illustration 1974 meters vandstandsstigninger.... Cuba og nærmeste omegn er blevet undersøisk og Panama er omdannet til Internationalt farvand.

kulden-varmen skrev:

Jakob skrev:

kulden-varmen skrev:
Hvordan smelter man Antarktisk selvom temperaturerne er langt under frysepunktet?

Det ved jeg ikke lige helt, var det ikke mig, der spurgte først..?

Men selv langt under frysepunktet må en lille temperaturstigning i de øverste islag give anledning til overfladespændinger og revnedannelser.
Temperaturen på det flydende saltvand er måske under nul grader, men ikke meget.
Og det lidt varmere flydende saltvand kan måske smelte is og gnave sig ind under isbjerge, der står på havbunden, så de brækker af i kæmpe stykker, som flyder nordpå og smelter.

Lyder det sandsynligt..?

næ!

Jakob skrev:
Hvor meget større isbjerg kan der ligge på Sydpolen, før det bryder sammen under sin egen vægt og smuldrer ud i havet..?

kulden-varmen skrev:
Der skete et større sammenbrud af Antarktis' is-kappe for nogen milioner år siden. Men der er sket mindre sammenbrud i den sene jernalder og igen omkring år 1100.

Nej der er ingen direkte forbindelse i sammenbrud af Antarktis' is-kappe og nogen som helst global opvarmning.

Du ville ønske at der var, men der er ingen sammenhæng.

Jakob skrev:
Mit personlige ønske til klimasammenhæng er næppe relevant i søgen efter en objektiv sandhed.

Men nej, jeg vil da ønske, at vi kan forårsage nogle graders global opvarmning, som du ønsker, men uden det får alvorlige konsekvenser.
Og det ville jo nok hjælpe, hvis vi bare kunne læsse havvandsstigninger af på sydpolen i form af sne.
Men det forstår jeg på dig, at vi ikke kan regne med, men nærmere til enhver tid må forvente at få det hele i hovedet igen.

kulden-varmen skrev:
Og pas på i trafikken.

What's changed in the last decade is that we've started to accumulate enough measurements to show there are widespread changes happening in the deep ocean. And those include really remarkably widespread warming of the deepest layers of the ocean

"The heat storage aspect is important because over the past 50 years, about 90 percent of the extra heat stored by the earth is now found in the ocean"...The deep ocean takes up 10 to 20 percent of this.

The memory of last winter's blizzards may be fading in this summer's searing heat, but scientists studying them have detected a perfect storm of converging weather patterns that had little relation to climate change. The extraordinarily cold, snowy weather that hit parts of the U.S. East Coast and Europe was the result of a collision of two periodic weather patterns in the Atlantic and Pacific Oceans, a new study in the journal Geophysical Research Letters finds.

After a blizzard shut down the nation's capital, skeptics of global warming used the frozen landscape to suggest that manmade climate change did not exist...

After analyzing 60 years of snowfall measurements, a team...found that the anomalous winter was caused by two colliding weather events. El Niño, the cyclic warming of the tropical Pacific, brought wet weather to the southeastern U.S. at the same time that a strong negative phase in a pressure cycle called the North Atlantic Oscillation pushed frigid air from the arctic down the East Coast and across northwest Europe. End result: more snow.

"Snowy winters will happen regardless of climate change," said Richard Seager, a climate scientist at Lamont-Doherty and lead author of the study. "A negative North Atlantic Oscillation this particular winter made the air colder over the eastern U.S., causing more precipitation to fall as snow. El Niño brought even more precipitation -- which also fell as snow."

David Robinson, a climate scientist at Rutgers University who was not involved in the research, said the study fills an important role in educating the public about the difference between freak weather events and human-induced climate change.

"When the public experiences abnormal weather, they want to know what's causing it," he said. "This paper explains what happened, and why global warming was not really involved. It helps build credibility in climate science."