Archives par mot-clé : Arctic

climate-debate

Skillful prediction of northern climate provided by the ocean

by M. Arthur et al., June 20, 2017, in Nature Communication

We show that variations in ocean temperature in the high latitude North Atlantic and Nordic Seas are reflected in the climate of northwestern Europe and in winter Arctic sea ice extent. Statistical regression models show that a significant part of northern climate variability thus can be skillfully predicted up to a decade in advance based on the state of the ocean. Particularly, we predict that Norwegian air temperature will decrease over the coming years, although staying above the long-term (1981–2010) average. Winter Arctic sea ice extent will remain low but with a general increase towards 2020.

energy and fields

Norway offers oil firms record number of Arctic blocks

by AFP/UKnews, June 21, 2017

Norway on Wednesday proposed to open up a record number of blocks in the Barents Sea to oil exploration despite protests from environmentalists and others fearing possible damage to the Arctic region.

The Norwegian oil and energy ministry offered oil companies 93 blocks in the Barents Sea and nine others in the Norwegian Sea, all located beyond the Arctic Circle.

climate and geology

Threshold in North Atlantic-Arctic Ocean circulation controlled by the subsidence of the Greenland-Scotland Ridge

by Michael Stars et al., June 5, 2017 in Nature Communication

High latitude ocean gateway changes are thought to play a key role in Cenozoic climate evolution. However, the underlying ocean dynamics are poorly understood. Here we use a fully coupled atmosphere-ocean model to investigate the effect of ocean gateway formation that is associated with the subsidence of the Greenland–Scotland Ridge. We find a threshold in sill depth (∼50 m) that is linked to the influence of wind mixing.

climate-debate

Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability

by Hiroki Tokinaga et al., PNAS, May 1, 2017

Arctic amplification is a robust feature of climate response to global warming, with large impacts on ecosystems and societies. A long-standing mystery is that a pronounced Arctic warming occurred during the early 20th century when the rate of interdecadal change in radiative forcing was much weaker than at present. Here, using observations and model experiments, we show that the combined effect of internally generated Pacific and Atlantic interdecadal variabilities intensified the Arctic land warming in the early 20th century.

climate-debate

Are methane seeps in the Arctic slowing global warming?

by Randall Hayman, May 8, 2017, in Science

Good news about climate change is especially rare in the Arctic. But now comes news that increases in one greenhouse gas—methane—lead to the dramatic decline of another. Research off the coast of Norway’s Svalbard archipelago suggests that where methane gas bubbles up from seafloor seeps, surface waters directly above absorb twice as much carbon dioxide (CO2) as surrounding waters. The findings suggest that methane seeps in isolated spots in the Arctic could lessen the impact of climate change.

climate and geology, climate-debate

Taking The Economist to Task for Unfounded Climate Catastrophe Fearmongering

by   Dr. John D. Harper, FGSA,FGAC, PGeol., former director of the Geological Survey of Canada © May 2017

I have recently been asked to comment on three articles published in The Economist. My background for such a response is as a Professor of Petroleum Geology and Sedimentology (ret.), a former Director-Energy for the Geological Survey of Canada, a former researcher in industry, and as an academic researcher on sea level changes and climate documentation through geologic time, Natural Resources of the Future and a couple of decades of studies in the Arctic.

1) Skating on thin ice: The thawing Arctic threatens an environmental catastrophe. Apr 27, 2017

2) The Arctic as it is known today is almost certainly gone. April 29, 2017

3) Thaw point: As the Arctic melts the world’s weather suffers. April 29, 2017

climate and geology

Methane seeps in the Canadian high Arctic

by Geological Society of America, April 13, 2017

in ScienceDaily

Cretaceous climate warming led to a significant methane release from the seafloor, indicating potential for similar destabilization of gas hydrates under modern global warming. A field campaign on the remote Ellef Ringnes Island, Canadian High Arctic, discovered an astounding number of methane seep mounds in Cretaceous age sediments.

climate-debate

Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice

by Q. Ding et al., March 13, 2017, Nature Climate Change

The Arctic has seen rapid sea-ice decline in the past three decades, whilst warming at about twice the global average rate. Yet the relationship between Arctic warming and sea-ice loss is not well understood. Here, we present evidence that trends in summertime atmospheric circulation may have contributed as much as 60% to the September sea-ice extent decline since 1979.

Egalement : Recul de la banquise arctique: 30% à 50% lié à la variabilité naturelle de l’atmosphère

climate-debate

Learning from the climate’s history: the Arctic heat waves of the 1930s and 40s

by Dr. Sebastian Lüning and Prof. Fritz Vahrenholt [German text translated/edited by P Gosselin] , April 1, 2017

Now let’s extend the time scale and look back 100 years. What a surprise: In the 1930s and 1940s there were two heat decades in the Arctic which were almost as warm as today (Fig. 2). This is just a small fact that went missing in the WMO press release and in the derwesten.de article.

climate-debate

Cette banquise Arctique qui n’en finit pas de fondre

Laisser un commentaire

Prof. Dr. Istvan Marko

Depuis des années, ils guettent, telle une nuée de médecins de Molière au chevet d’un agonisant, les moindres déviations de la quantité de glace en Arctique, son épaisseur et son âge. Nombreux sont ceux qui ont prétendu qu’elle allait disparaître en 2008, 2012, 2013, 2015 et même 2016. Hélas pour eux, la glace est toujours là et bien là. Damien Ernst a parlé de “tipping point”, un point de basculement, au-delà duquel les choses se dégraderaient inéluctablement. Et d’ajouter que l’on entre dans un domaine inconnu où tout – surtout le pire, évidemment – peut arriver. Alarmisme, quand tu nous tiens !

Mais qu’en est-il vraiment du triste sort de la banquise arctique ? Fond-elle de manière anormale ? Va-t-elle disparaître dans un proche avenir ? Et qu’adviendra-t-il des ours polaires ?

Signalons d’emblée que les mesures effectuées au cours de l’année 2016 montrent effectivement que, depuis la mi-octobre, l’étendue de la banquise arctique est inférieure à celle observée les années précédentes. Il semblerait donc que la glace se reconstitue moins vite. Cependant, si l’on examine attentivement les données, on observe que le regel, lent en octobre, s’accélère et que la quantité de glace devrait revenir à la normale avant la fin de l’hiver.

nb: janvier 2017. Finalement la banquise arctique a rejoint la courbe ‘moyenne’ de surface des glaces au cours du mois de décembre 2016.

 See alo : Arctic Heatwave? It Was Warmer in 1985!

La géologie, une science plus que passionnante … et diverse