Global Warming...New Report...and it ain't happy news

While recent studies have shown that on the whole Arctic sea ice has decreased since the late 1970s, satellite records of sea ice around Antarctica reveal an overall increase in the southern hemisphere ice over the same period. Continued decreases or increases could have substantial impacts on polar climates, because sea ice spreads over a vast area, reflects solar radiation away from the Earth's surface, and insulates the oceans from the atmosphere.

In a study just published in the Annals of Glaciology, Claire Parkinson of NASA's Goddard Space Flight Center analyzed the length of the sea ice season throughout the Southern Ocean to obtain trends in sea ice coverage. Parkinson examined 21 years (1979-1999) of Antarctic sea ice satellite records and discovered that, on average, the area where southern sea ice seasons have lengthened by at least one day per year is roughly twice as large as the area where sea ice seasons have shortened by at least one day per year. One day per year equals three weeks over the 21-year period.

The NASA quote, from the cite, is from 2002, I suspect. Which makes it kinda old news in a very fluid (in several senses) situation. And I also suspect, from the dates on those stories, that most of them are from the denialists' PR releases based on complete misinterpretations of research and dismissed as bullsh*t, rather more politely phrased, by the researcher involved, who said his data showed nothing like what they were claiming. As widely discussed several hundred pages ago in this topic.

Why is Antarctica getting colder in the middle when it's warming up around the edge? One possible explanation is that the warmer temperatures in the surrounding ocean have produced more precipitation in the continent's interior, and this increased snowfall has cooled the high-altitude region around the pole. Another possible explanation involves ozone. Ozone in the Earth's stratosphere absorbs ultraviolet radiation, and absorbing this energy warms the stratosphere. Loss of UV-absorbing ozone may have cooled the stratosphere and strengthened the polar vortex, a pattern of spinning winds around the South Pole. The vortex acts like an atmospheric barrier, preventing warmer, coastal air from moving in to the continent's interior. A stronger polar vortex might explain the cooling trend in the interior of Antarctica.

NASA Researchers Find Snowmelt in Antarctica Creeping Inland

On the world's coldest continent of Antarctica, the landscape is so vast and varied that only satellites can fully capture the extent of changes in the snow melting across its valleys, mountains, glaciers and ice shelves. In a new NASA study, researchers using 20 years of data from space-based sensors have confirmed that Antarctic snow is melting farther inland from the coast over time, melting at higher altitudes than ever and increasingly melting on Antarctica's largest ice shelf.

[...]

Nevertheless, NASA researchers using data collected from 1987 to 2006 found snow melting in unlikely places in 2005: as far inland as 500 miles away from the Antarctic coast and as high as 1.2 miles above sea level in the Transantarctic Mountains. The 20-year data record was three times longer than previous studies and reaffirmed the extreme melting irregularity observed in 2005. During the same period, they also found that melting had increased on the Ross Ice Shelf, both in terms of the geographic area affected and the duration of increased melting across affected areas.

"Snow melting is very connected to surface temperature change, so it's likely warmer temperatures are at the root of what we've observed in Antarctica," said lead author Marco Tedesco, a research scientist at the Joint Center for Earth Systems Technology cooperatively managed by NASA's Goddard Space Flight Center, Greenbelt, Md., and the University of Maryland at Baltimore County, Baltimore. The study will be published on Sept. 22 in the American Geophysical Union's Geophysical Research Letters.

A map of Antarctica indicates first time persistent melting detected within the study period from 1987-2006. Areas where persistent melting took place are shown in darker shades of green.

Reliable satellite readings date to only 1979.

To reconstruct the Antarctic's precipitation over the last half-century, the OSU-led team used computer weather models and measurements of past snow amounts, especially ice cores. The cores, extracted by hollow drills, are like a Jell-O parfait, containing many layers corresponding to each year's snowfall.

Whether the Antarctic ice sheet is in or out of balance -- whether, overall, it is gaining or losing mass, with repercussions for sea levels -- is up for debate.

Earlier this year, University of Colorado researchers using satellite data determined that Antarctica had lost up to 36 cubic miles of ice annually since 2002.

But last year, using different satellite readings, the University of Missouri's Curt Davis and colleagues reported that the interior of the East Antarctic ice sheet -- the larger of the continent's two frozen regions --
appeared to have gained 45 billion tons per year between 1992 and 2003, probably from snowfall.

Since the ice sheet's balance is a combination of what's happening to its various regions, thickening in one area and melting in another is possible.
The OSU-led team doesn't doubt that the East Antarctic region is thickening, only that it's due to greater snowfall. The cause might be a slow-motion traffic jam, as glaciers moving to the melting coasts temporarily pile up.

"There are only two explanations" for the ice sheet's thickening, Davis said. "Either this is snowfall-driven, which [the OSU] data suggests it's not. Or there is a long-term imbalance in East Antarctica left over from
the last glacial period. We don't know enough to say one way or the other."

That's the one thing Antarctic scientists can agree on: they need more information.
http://bprc.osu.edu/news/press/cleveland_antarctic_snowfall_20060811.pdf

Seriously though guys, doesn't it give anybody pause for thought when there can be such a 180 switch in scientific opinion within five years or even within one month as in 2002?

Foxfyre wrote:

Seriously though guys, doesn't it give anybody pause for thought when there can be such a 180 switch in scientific opinion within five years or even within one month as in 2002?

What "180 switch in scientific opinion within five years" exactly?

Compare the NASA article I posted a little while ago with the more recent one posted.

Compare those headlines I posted a little while ago showing the 180 shift within a one month period.

NASA Finds Vast Regions of West Antarctica Melted in Recent Past

A team of NASA and university scientists has found clear evidence that extensive areas of snow melted in west Antarctica in January 2005 in response to warm temperatures. This was the first widespread Antarctic melting ever detected with NASA's QuikScat satellite and the most significant melt observed using satellites during the past three decades. Combined, the affected regions encompassed an area as big as California.

Son Nghiem of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Konrad Steffen, director of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder, led the team. Using data from QuikScat, they measured snowfall accumulation and melt in Antarctica and Greenland from July 1999 through July 2005.

"Antarctica has shown little to no warming in the recent past with the exception of the Antarctic Peninsula, but now large regions are showing the first signs of the impacts of warming as interpreted by this satellite analysis," said Steffen. "Increases in snowmelt, such as this in 2005, definitely could have an impact on larger-scale melting of Antarctica's ice sheets if they were severe or sustained over time."

old europe wrote:

Foxfyre wrote:

Seriously though guys, doesn't it give anybody pause for thought when there can be such a 180 switch in scientific opinion within five years or even within one month as in 2002?

What "180 switch in scientific opinion within five years" exactly?

Compare the NASA article I posted a little while ago with the more recent one posted.

Compare those headlines I posted a little while ago showing the 180 shift within a one month period.

IMO, the idea that climate change can be adequately measured in 100 year increments, let alone five or six year increments, is absurd.

Then, in the very recent past, vast areas of Antarctica (admittedly still mostly around the edges) that have previously been continuously frozen start melting.

Quote:

Climatic changes appear to be destabilizing vast ice sheets of western Antarctica that had previously seemed relatively protected from global warming, researchers reported yesterday, raising the prospect of faster sea-level rise than current estimates.

http://www.washingtonpost.com/wp-dyn/content/article/2008/01/13/AR2008011302753.html?hpid=topnews

Escalating Ice Loss Found in Antarctica
Sheets Melting in an Area Once Thought to Be Unaffected by Global Warming

Part of the Larsen B ice shelf in Antarctica is shown after its rapid collapse in early 2002, which was attributed to global warming. Ice sheets elsewhere on the continent that were considered stable are melting, scientists have found. At right, satellite images show the Sheldon Glacier in western Antarctica in, from top, 1986, 2001 and last October. (Kpa/mediacolors)

While the overall loss is a tiny fraction of the miles-deep ice that covers much of Antarctica, scientists said the new finding is important because the continent holds about 90 percent of Earth's ice, and until now, large-scale ice loss there had been limited to the peninsula that juts out toward the tip of South America. In addition, researchers found that the rate of ice loss in the affected areas has accelerated over the past 10 years -- as it has on most glaciers and ice sheets around the world.

"Without doubt, Antarctica as a whole is now losing ice yearly, and each year it's losing more," said Eric Rignot, lead author of a paper published online in the journal Nature Geoscience.
...

Foxfyre wrote:

IMO, the idea that climate change can be adequately measured in 100 year increments, let alone five or six year increments, is absurd.

Well, okay, that's your opinion.

I haven't even commented on whether or not the current trends or observations are adequate measurements.

---

I've commented on your contention that there has been "a 180 switch in scientific opinion within five years or even within one month."


But that simply doesn't seem to be the case. Rather, there are (admittedly somewhat puzzling) conditions to be observed in Antarctica: the ice sheet is thickening in one area and melting in another.

Does reporting this constitute a "switch in scientific opinion"? The answer seems to be 'no'.


Then, in the very recent past, vast areas of Antarctica (admittedly still mostly around the edges) that have previously been continuously frozen start melting.

Does reporting this constitute a "switch in scientific opinion"? The answer, again, seems to be 'no'.