Oceanography

Researchers from the U.S. Geological Survey and McGill University have found here is new permafrost forming around Twelvemile Lake in the interior of Alaska. 

Twelvemile Lake, and many others like it, have been shrinking over the past thirty years, now being 15 feet shallower than three decades ago. 

As the lake recedes, bands of willow shrubs have grown up on the newly exposed lake shores over the past twenty years. What Martin Briggs from the U.S. Geological Survey and Prof. Jeffrey McKenzie from McGill's Dept. of Earth and Planetary Science have just discovered is that the extra shade provided by these willow shrubs has both cooled and dried the surrounding soil, allowing new permafrost to expand beneath them.


Deep sea fish help keep more than one million tons of CO2 from UK and Irish surface waters every year - that's worth £10 million per year in carbon credits, if anyone actually paid full price for those. Those fish living in deep waters on the continental slope around the UK may play an important role in carrying carbon from the surface to the seafloor, but they do it solely for free. 


Evidence for massive and abrupt iceberg calving in Antarctica dating back 19,000 to 9,000 years ago is based on an analysis of new, long deep sea sediment cores extracted from the region between the Falkland Islands and the Antarctic Peninsula. 

The study in Nature documents that the Antarctic ice sheet is unstable and can abruptly reorganize Southern Hemisphere climate and cause rapid global sea level rise. 


Two new shipping routes have opened in the Arctic: the Northwest Passage through Canada, and the Northern Sea Route, a 3,000-mile stretch along the coasts of Russia and Norway connecting the Barents and Bering seas.

Overall, it means for the first time in perhaps 2 million years, the north Pacific and north Atlantic oceans are navigable, and that means new opportunities for Arctic natural resources and interoceanic trade with lower environmental impact, but commercial ships often inadvertently carry invasive species. Organisms from previous ports can cling to the undersides of their hulls or be pumped in the enormous tanks of ballast water inside their hulls.


Between 1889 and 2012, the Greenland sheet saw large-scale surface melting, according to the best available evidence. But claims that the melt events were driven by warming alone are incorrect, according to a new study. Ash from  northern hemisphere forest fires contributed to an extent not previously recognized.

Continued climate change could result in nearly annual widespread melting of the ice sheet's surface by the year 2100 and a positive feedback mechanism may be set in motion. Melting in the dry snow region does not contribute to sea level rise; instead, the meltwater percolates into the snowpack and refreezes, causing lower albedo and leaving the ice sheet surface even more susceptible to future melting. Albedo is the surface's ability to reflect sunlight.


The West Antarctic Ice Sheet, which holds enough water to raise global seas by several feet, is thinning and computer models predict that the collapse may already have begun. The Thwaites Glacier could disappear in a few hundred years, raising sea levels by nearly 2 feet. That glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet of global sea level rise. 


Multiple lines of evidence incorporating 40 years of observations that six massive glaciers in the Amundsen Sea sector "have passed the point of no return", a worrisome sign for melting of the West Antarctic Ice Sheet.

Those glaciers already contribute to sea level rise, releasing as much ice into the ocean each year as the entire Greenland Ice Sheet does. They contain enough ice to boost the global sea level by 4 feet (1.2 meters) and are melting faster than most scientists had expected. Rignot said the findings will require that current predictions of sea level rise be revised upward.

Is it The Day After Tomorrow imagery that environmentalists and a lot of journalists like to create?


Sea levels are always changing, they always have. We can't count how many glaciers there are because the number is different every year. But the big question is if sea level rise is inceasing or, worse, accelerating.

A new model may help figure out if sea levels might rise around the world throughout the 21st century and if the rate of sea level rise is currently increasing.

An international team of researchers analyzed data from 10 long-term sea level monitoring stations located around the world. They looked into the future to identify the timing at which sea level accelerations might first be recognized in a significant manner. 


We know some glaciers are growing and we know some glaciers are receding. What we did not know until recently is how many glaciers there are, where they are, and what their extents and volumes are.

That has changed - for the first time reliable calculations of the future development of glaciers and their contributions to regional hydrology and global sea-level rise can be derived from an accurate measurement.

The international team mapped all of the world’s glaciers so all glaciologists can study the impacts of a changing climate on glaciers worldwide, and determine their total extent and volume on a glacier-by-glacier basis. Overall, glaciers cover an area of about 730,000 km2 and have a volume of about 170,000 km3.

The melting of a rather small ice volume on East Antarctica's shore could trigger a persistent ice discharge into the ocean, resulting in unstoppable sea-level rise for thousands of years to come, according to computer simulations of the Antarctic ice flow by scientists at the Potsdam Institute for Climate Impact Research (PIK).

They detail their estimates in Nature Climate Change.