No one really knows what’s in the deep ocean in Antarctica. Now we have the technology to reach into the ocean depths, we accompanied scientist and deep-sea explorer Jon Copley and became the first to descend to 1000 meters underwater in Antarctica for Blue Planet II. The exotic creatures we found there will astonish you.
Under the Antarctic Ice Beauty of The Nature 720p Documentary & Life Discovery HD
Under the Antarctic Ice – Beauty of The Nature The Antarctic ice sheet is one of the two polar ice caps of the Earth. It covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth. It covers an area of almost 14 million square km and contains 26.5 million cubic km of ice. That is, approximately 61 percent of all fresh water on the Earth is held in the Antarctic ice sheet, an amount equivalent to 70 m of water in the world’s oceans. In East Antarctica, the ice sheet rests on a major land mass, but in West Antarctica the bed can extend to more than 2,500 m below sea level.
The land in this area would be seabed if the ice sheet were not there. The icing of Antarctica began with ice-rafting from middle Eocene times about 45.5 million years ago and escalated inland widely during the Eocene–Oligocene extinction event about 34 million years ago. CO2 levels were then about 760 ppm and had been decreasing from earlier levels in the thousands of ppm. Carbon dioxide decrease, with a tipping point of 600 ppm, was the primary agent forcing Antarctic glaciation. The glaciation was favored by an interval when the Earth’s orbit favored cool summers but Oxygen isotope ratio cycle marker changes were too large to be explained by Antarctic ice-sheet growth alone indicating an ice age of some size. The opening of the Drake Passage may have played a role as well though models of the changes suggest declining CO2 levels to have been more important.
Ice enters the sheet through precipitation as snow. This snow is then compacted to form glacier ice which moves under gravity towards the coast. Most of it is carried to the coast by fast moving ice streams. The ice then passes into the ocean, often forming vast floating ice shelves. These shelves then melt or calve off to give icebergs that eventually melt. If the transfer of the ice from the land to the sea is balanced by snow falling back on the land then there will be no net contribution to global sea levels. A 2002 analysis of NASA satellite data from 1979–1999 showed that while overall the land ice is decreasing, areas of Antarctica where sea ice was increasing outnumbered areas of decreasing sea ice roughly 2:1.
The general trend shows that a warming climate in the southern hemisphere would transport more moisture to Antarctica, causing the interior ice sheets to grow, while calving events along the coast will increase, causing these areas to shrink. A 2006 paper derived from satellite data, measures changes in the gravity of the ice mass, suggests that the total amount of ice in Antarctica has begun decreasing in the past few years. Another recent study compared the ice leaving the ice sheet, by measuring the ice velocity and thickness along the coast, to the amount of snow accumulation over the continent. This found that the East Antarctic Ice Sheet was in balance but the West Antarctic Ice Sheet was losing mass. This was largely due to acceleration of ice streams such as Pine Island Glacier. These results agree closely with the gravity changes. The estimate published in November 2012 and based on the GRACE data as well as on an improved glacial isostatic adjustment model indicates that an average yearly mass loss was 69 ± 18 Gt/y from 2002 to 2010. The West Antarctic Ice Sheet was approximately in balance while the East Antarctic Ice Sheet gained mass. The mass loss was mainly concentrated along the Amundsen Sea coast.
Discovery presents itself using the category “Science & Technology”. Clearly that is, at best, misleading.
Two More New Papers Document No Warming Trend In Antarctica
By Paul Homewood
Repost from NoTricksZone:
For several decades now, Antarctica has not been cooperating with the “global” warming narrative, as the continent as a whole has not been warming.
Several scientific papers have been published recently that document the lack of an anthropogenic warming signal for the Antarctic continent or the surrounding ocean, as well as the dominance of natural variability.
Smith and Polvani (2016) concluded that warming of West Antarctica or the Antarctic Peninsula are predominantly natural.
“[We] conclude that there is little evidence of anthropogenic SAM-induced driving of the recent temperature trends … compelling evidence pointing to natural climate variability as a key contributor to the recent warming of West Antarctica and of the Peninsula“
Turner et al., 2016, in a paper entitled “Absence of 21st century warming on Antarctic Peninsula consistent with natural variability,” documented a significant cooling trend for the Antarctic Peninsula since the late 1990s.
“The annual mean temperature has decreased at a statistically significant rate, with the most rapid cooling during the Austral summer.”
Jones et al. (2016) concluded that (a) there has been no overall warming trend for large portions of the continent in the past few hundred years, (b) the Southern Ocean has been cooling since 1979, and that (c), because of the cooling ocean, sea ice extent has been advancing. In other words, climate models that assume humans drive Antarctic climate are “not compatible with the observed trends.”
“Most observed trends [over the 36-year satellite data] are not unusual when compared with Antarctic palaeoclimate records of the past two centuries. … [C]limate model simulations that include anthropogenic forcing are not compatible with the observed trends. This suggests that natural variability overwhelms the forced response in the observations“
A 2,000-Year Cooling Trend For Antarctica, Uninterrupted By Rising CO2 Levels
Scientific documentation of the dominance of natural variability — and a glaring lack of an anthropogenic forcing signal for Antarctica — continues in 2017.
The PAGES 2k reconstruction crew has just published a comprehensive analysis of the surface temperature trends for the entire continent of Antarctica. The results do not advance the “global” warming narrative. Instead, over 20 contributing scientists find that modern Antarctic temperatures are still much colder than they were during first millennium, and the long-term cooling trend has not been reversed on a continent-wide scale even with the onset of an assumed anthropogenic influence within the last century.
In other words, natural variability is the dominant factor influencing the Antarctic climate, not anthropogenic CO2 emissions.
“Within this long-term cooling trend from 0-1900 CE we find that the warmest period occurs between 300 and 1000 CE, and the coldest interval from 1200 to 1900 CE.”
“Our new continental scale reconstructions, based on the extended database, corroborates previously published findings for Antarctica from the PAGES2k Consortium (2013): (1) Temperatures over the Antarctic continent show an overall cooling trend during the period from 0 to 1900 CE, which appears strongest in West Antarctica, and (2) no continent-scale warming of Antarctic temperature is evident in the last century.”
Read the full post here.