Showing posts with label Atlantic. Show all posts
Showing posts with label Atlantic. Show all posts

Friday, March 22, 2024

Atlantic ocean heat threatens to unleash methane eruptions

The image below shows that the monthly Atlantic surface temperature anomaly in February 2024 was 1.176°C when compared to a 1951-1980 base.

[ click on images to enlarge ]

The image below shows that the monthly Atlantic surface temperature anomaly in February 2024 was 1.435°C when compared to a 1901-2000 base. 


The difference illustrates the importance of selecting a base to calculate anomalies from. The anomaly indicates how much heat has accumulated in the Atlantic, and it is even larger for February 2024 when using a genuinely pre-industrial base, as discussed earlier.

The images also highlight the potential for the slowing down of the Atlantic meridional overturning circulation (AMOC) to contribute to more heat accumulating at the surface of the Atlantic Ocean.

As temperatures rise, many feedbacks are kicking in with greater ferocity, including increased stratification of oceans, loss of sea ice, loss of reflectivity of clouds and increased freshwater due to stronger melting of sea ice and glacial ice, due to heavier runoff from land and rivers and due to changes in ocean circulation.

While this may look to cause less ocean heat to reach the Arctic Ocean at the moment, the result is that a huge amount of ocean heat is accumulating in the North Atlantic that threatens to abruptly move into the Arctic Ocean. The danger is that an influx of ocean heat can cause large amounts of methane to erupt from the seafloor of the Arctic Ocean. 

The inset on the top image illustrates that, as people's emissions raise the temperature, this rise can strengthen wind, evaporation, ocean currents and rainfall locally, resulting in greater potential for a lid to form and spread at the surface of the North Atlantic. As temperatures rise and winds strengthen, more evaporation can occur in one place and more rain can then fall further down the path of the Gulf Stream, i.e. an ocean current that extends into the Arctic Ocean, as part of AMOC. This rain further contributes to the freshwater accumulation at the surface of the North Atlantic.

In the video below, Guy McPherson discusses a recent study by Marilena Oltmanns et al. on some of these issues.


This page further discusses formation of a cool freshwater lid at the surface of the North Atlantic and the contribution to this of Jet Stream changes. The image below shows that the Jet Stream reached speeds as high as 455 km/h or 283 mph north of Washington on February 18, 2024 03:00 UTC, with Instantaneous Wind Power Density as high as 387.5 kW/m².

From earlier post Blue Ocean Event 2024?

A huge amount of ocean heat is accumulating in the North Atlantic and threatens to abruptly move into the Arctic Ocean. The danger is that, due to strong wind along the path of the Gulf Stream, huge amounts of ocean heat will abruptly get pushed into the Arctic Ocean, with the influx of ocean heat causing destabilization of hydrates contained in sediments at the seafloor of the Arctic Ocean, resulting in eruptions of huge amounts of methane. 

Strong hurricanes can significantly add to the danger. More hurricanes are forecast for the 2024 Atlantic hurricane season than during 1950-2020, as illustrated by the image below. 


Many of the dangers have been discussed before, e.g. the danger that sea currents in the Arctic Ocean will change direction, in this 2017 post

Arctic sea ice thickness warning

The compilation image below shows Arctic sea ice on March 28, 2024. The satellite image (left) may indicate extensive sea ice, but clouds can obscure things. The other image (right) indicates that sea ice in a large area from the Laptev Sea down to the North Pole may be very thin.


The image below illustrates the decline of Arctic sea ice volume over the years.


The images above and below show that Arctic sea ice volume has recently been the lowest on record for the time of year.


Given that Arctic sea ice currently is still relatively extensive, this low volume indicates that sea ice is indeed very thin, which must be caused by ocean heat melting sea ice from below, since little or no sunshine is yet reaching the Arctic at the moment and air temperatures are still far below freezing point, so where ocean heat may be melting sea ice away from below, a thin layer of ice will quickly be reestablished at the surface. 

This situation looks set to dramatically change over the next few months, as air temperatures will rise and as more ocean heat will reach the Arctic Ocean. Moreover, as illustrated by the map below, much of the thicker sea ice is located off the east coast of Greenland. This sea ice and the purple-colored sea ice can be expected to melt away quickly with the upcoming rise in temperatures over the next few months.


Climate Emergency Declaration

The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.


Links

• Climate Reanalyzer

• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.html

• Cold freshwater lid on North Atlantic
https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html

• European summer weather linked to North Atlantic freshwater anomalies in preceding years - by Marilena Oltmanns et al.
https://wcd.copernicus.org/articles/5/109/2024/wcd-5-109-2024-discussion.html
discussed at facebook at: 
https://www.facebook.com/groups/arcticnews/posts/10161330866254679

• Science Snippets: Arctic Sea Ice Affects European Summers, Marine Life, and All Life on Earth - by Guy McPherson
https://www.youtube.com/watch?v=X09vtWNDuDw

• nullschool 
https://earth.nullschool.net

• Jet Stream
https://arctic-news.blogspot.com/p/jet-stream.html

• Extended range forecast of Atlantic seasonal hurricane activity and landfall strike probability for 2024 - by Philip Klotzbach et al.
https://tropical.colostate.edu/forecasting.html
discussed on facebook at:
https://www.facebook.com/groups/arcticnews/posts/10161346323759679

• Arctic Ocean Feedbacks
https://arctic-news.blogspot.com/2017/01/arctic-ocean-feedbacks.html

• NASA Worldview satellite images
https://worldview.earthdata.nasa.gov

• University of Bremen - Arctic sea ice
https://seaice.uni-bremen.de/start

• Danish Meteorological Institute - Arctic sea ice volume and thickness


Friday, June 17, 2016

Ocean Heat Overwhelming North Atlantic

Arctic sea ice extent on June 19, 2016, was at a record low for the time of the year, as the (updated) image below shows.

[ image from JAXA ]
Not only is Arctic sea ice extent at record low for time of year, the sea ice is also rapidly getting thinner, more fractured, lower in concentration and darker in color. 

[ Cracks in sea ice north of Greenland on June 19, 2016, created with Arctic-io image ]
On the morning of June 20, 2016, strong methane releases were recorded over the water north of Greenland, as well as east of Greenland, as illustrated by the image below.

The image below shows that on the morning of June 20, 2016, mean global methane levels had increased be several parts per billion over a large altitude range, compared to the two previous days. Methane levels at selected altitudes on days in July 2015 and December 2015 are added for reference.
[ click on images to enlarge ]
Temperatures in the Arctic are rising, as illustrated by the image below, showing that on June 19, 2016, temperatures were as high as 31.4°C or 88.4°F over the Mackenzie River (green circle) which ends in
the Arctic Ocean (and thus warms up the Arctic Ocean there).


On June 20, 2016, the Sun will reach its highest point (Solstice), and the Arctic will have 24 hours sunlight, i.e. on the Arctic Circle (latitude 66.56° north) or higher. The Arctic is about 20,000,000 square km (7,700,000 square miles) in size and covers roughly 4% of Earth's surface. Insolation during the months June and July is higher in the Arctic than anywhere else on Earth, as illustrated by the image below, by Pidwirny (2006).


Sea surface temperature near Svalbard was as high as 55°F (or 12.8°C, at the green circle) on June 14, 2016, an anomaly of 19.6 °F (or 10.9°C) from 1981-2011, as illustrated by the image below.


[ click on images to enlarge ]
Above image, created with nullschool.net, further shows that the cold lid that had been growing so prominently in extent over the North Atlantic over the past few years, has shrunk substantially. By comparison, the cold area over the North Pacific has grown larger. This is further confirmed by the image on the right, created with NASA maps and showing ocean temperature anomalies for May 2016.

Plenty of meltwater has run off from Greenland in 2016, as illustrated by the NSIDC.gov image on the right. The run-off from Alaska and Siberia into the Pacific seems less by comparison than the run-off into the North Atlantic. So, how could it be that the cold area in the North Pacific has grown larger than the cold area in the North Atlantic?
[ click on images to enlarge ]

Could there be another factor influencing the size of these cold areas in the North Atlantic and the North Pacific?

The image below, created with NOAA images, gives a comparison between the situation on June 1, 2015 (top), and June 1, 2016 (bottom), showing anomalies from 1961-1990.


Friday, January 2, 2015

Strong winds threaten to push sea ice out of Arctic Ocean

By Albert Kallio


The lateral viscosity of the thin Arctic sea ice cover continues to lower. In November just one quarter of the high Arctic Ocean basin above 85° north was covered by a thin this winter's ice. This has now doubled, soon covering two quarters. The ice has been pushed away from Russia towards Canada and to the Fram Strait at phenomenal rates.
 
Animation by navy.mil showing 30 days of sea ice thickness, up to January 1, 2015
This is increasingly suggesting that the remaining half in front of the Fram Strait will be sucked into the Atlantic Ocean soon. The dark blue ice is newly formed crushed ice behind the North Pole (pack ice). We may well be in course to the first recorded ice free season in the Arctic Ocean. In addition, the rear is pushed from behind Canada to the Beaufort and Chukchi Seas.

Animation by navy.mil showing 30 days of sea ice speed and drift, up to January 1, 2015

We need to act, now. I think we need to monitor this development almost on daily basis. I am curious to see how the ice may behave after the last remainders of the second quarter are sucked into the Atlantic Ocean and the newly forming sea ice will face the force of the Atlantic waves. That could mean extremely highly fractured sea ice across the Russian side by the return of spring 2015 sunlight.

I think we are witnessing a historic transition right now with no ice in the summers.



Saturday, September 6, 2014

Antarctica linked to Arctic

Waters in the Arctic Ocean continue to warm up. Very warm waters from the North Atlantic and Pacific Ocean are invading the Arctic Ocean.



Waters in the North Atlantic and in the North Pacific are very warm, due to a number of reasons.

What is happening in the oceans is very important in this respect. As discussed in earlier posts, most of the extra heat caused by people's emissions goes into the oceans.

The great ocean conveyor belt (Thermohaline Circulation), brings warm water from the southern hemisphere to the northern hemisphere.

The Gulf Stream is the North Atlantic leg of the great ocean conveyor belt, and it brings dense, salty water from the North Atlantic into the Arctic Ocean.

Saltier water is denser than fresher water because the dissolved salts fill interstices between water molecules, resulting in more mass per unit volume.

Very dense ocean water can be found in the North Atlantic because the North Atlantic has high salinity, due to high evaporation rates, while salty water is also coming from the Mediterranean Sea.

As also discussed in an earlier post, this dense, saltier water sinks in the North Atlantic, accumulating in deeper water.

By contrast, much of the Arctic Ocean has low salinity, due to ice melt and river runoff.  As it enters the Arctic Ocean, the warm and dense water from the Atlantic thus dives under the under the sea ice and under the less salty surface water in the Arctic Ocean.

In conclusion, much of the heat resulting from people's emissions accumulates in the North Atlantic and also ends up in the Arctic. This partly explains why surface temperatures are rising much faster at the poles, as illustrated by the NOAA image below.


There are further reasons why surface air temperatures elsewhere (other than at the poles) are rising less rapidly than they did, say, a decade ago. As also discussed by Andrew Glikson in the post No Planet B, the increased amounts of sulphur emitted by the growing number of coal-fired power plants and by the burning of bunker fuel on sea is (temporarily) masking the full wrath of global warming.

Another reason is the growth of the sea ice around Antarctica, as illustrated by the CryosphereToday image on the left.

Melting takes place both in the Arctic and on Antarctica, but more so in the Arctic. Recent research of CryoSat-2 data reveals that Greenland alone is now losing about 375 cubic kilometers of ice annually, while in Antarctica the annual volume loss now is about 125 cubic kilometers.

Currents also distribute ocean heat in ways that make the Arctic warm up more than twice as rapidly as the Antarctic. In a recent paper, John Marshall et al. further suggest that ozone depletion also contributes to this.

All this makes that, while the jet streams on the northern hemisphere are circumnavigating the globe at a slower pace, jet streams on the southern hemisphere are getting stronger, making it more difficult for warm air to enter the atmosphere over Antarctica, while the stronger winds also speed up sea currents on the southern hemisphere. This makes the sea ice around Antarctica grow, and as the sea ice spreads further away from Antarctica, temperatures of surface waters around Antarctica are falling.

Growth of the sea ice around Antarctica makes that more sunlight is reflected back into space. There now is some 1.5 million square kilometers more sea ice around Antarctica than there used to be. The albedo change associated with sea ice growth on the southern hemisphere can be estimated at 1.7 W/sq m, i.e. more than the total RF of all CO2 emission caused by people from 1750 to 2011 (IPCC AR5).


The rapid growth of sea ice on the southern hemisphere alone goes a long way to explain why, over the past three months, surface air temperatures have not been much higher than they used to be, both globally and in the Arctic, as illustrated by above NOAA image. What has also contributed to warmer temperatures around latitude 60 on the northern hemisphere is the fact that methane has accumulated in the atmosphere at that latitude, as discussed in earlier posts.

Arctic SST far exceed anything ever seen in human history
So, does the sea ice on the southern hemisphere constitute a negative feedback that could hold back global warming? It doesn't.

It may temporarily keep surface temperatures close to what they used to be, as the sea ice reflects lots of sunlight back into space, but at the same time ocean temperatures are rising strongly, as the sea ice also prevents heat from radiating out of the waters around Antarctica.

The latter also helps explaining the colder surface temperatures over those waters.

Much of this additional ocean heat has meanwhile been transported by the great ocean conveyor belt to the northern hemisphere.

No time before in human history has such a huge amount of ocean heat accumulated in the North Atlantic and the North Pacific. This heat is now threatening to invade the Arctic Ocean and trigger huge temperature rises due to methane eruptions from the seafloor.


The situation is dire and calls for comprehensive and effective action, as dicussed at the Climate Plan blog.