Why companies like Google and Walmart are buying so much wind power
▻https://www.washingtonpost.com/news/energy-environment/wp/2016/04/12/why-companies-like-google-and-walmart-are-buying-so-much-wind-power
Why companies like Google and Walmart are buying so much wind power
▻https://www.washingtonpost.com/news/energy-environment/wp/2016/04/12/why-companies-like-google-and-walmart-are-buying-so-much-wind-power
Scientists are floored by what’s happening in the Arctic right now - The Washington Post
►https://www.washingtonpost.com/news/energy-environment/wp/2016/02/18/scientists-are-floored-by-whats-happening-in-the-arctic-right-now
New data from NASA and the National Oceanic and Atmospheric Administration suggest that January of 2016 was, for the globe, a truly extraordinary month. Coming off the hottest year ever recorded (2015), January saw the greatest departure from average of any month on record, according to data provided by NASA.
Concept of the day: “Arctic amplification”
►https://www.washingtonpost.com/news/energy-environment/wp/2016/02/18/scientists-are-floored-by-whats-happening-in-the-arctic-right-now #climate_change #arctic
Why Obama wants to spend millions relocating entire U.S. communities - The Washington Post
►https://www.washingtonpost.com/news/energy-environment/wp/2016/02/09/why-obama-wants-to-spend-millions-relocating-entire-u-s-communities
The island village of Kivalina, an Alaska Native community of 400 people the White House chose to highlight as a community at risk from rising sea levels, can be seen from Air Force One as U.S. President Barack Obama flies to Kotzebue, Alaska September 2, 2015. REUTERS/Jonathan Ernst
Why Obama wants to spend millions relocating entire U.S. communities
►https://www.washingtonpost.com/news/energy-environment/wp/2016/02/09/why-obama-wants-to-spend-millions-relocating-entire-u-s-communities
Obama’s budget request to Congress includes a proposed $ 400 million “to cover the unique circumstances confronting vulnerable Alaskan communities, including relocation expenses for Alaska Native villages threatened by rising seas, coastal erosion, and storm surges.”
[...] “When Kivalina voted to relocate decades ago, they found there was no government agency in charge of #relocation, and that most funding was available only after disaster struck,” said Christine Shearer, a researcher who wrote a book on Kivalina and now works for the NGO CoalSwarm.
[...] In the U.S., the problem with #climate-related relocations is that while funding may now be emerging, there still isn’t a process in place to determine when communities should try to obtain it or how they should recognize that it is time for them to move, said Robin Bronen, executive director of the Alaska Institute for Justice, who is working on a NOAA-funded project on relocations.
A Wrenching Choice for Alaska Towns in the Path of Climate Change
▻http://www.nytimes.com/interactive/2016/11/29/science/alaska-global-warming.html
At least two villages farther up the western coast, Shishmaref and Kivalina, have voted to relocate when and if they can find a suitable site and the money to do so. A third, Newtok, in the soggy Yukon-Kuskokwim Delta farther south, has taken the first steps toward a move.
But, after years of meetings that led nowhere and pleas for government financing that remained unmet, Shaktoolik has decided it will “stay and defend,” at least for the time being, the mayor, Eugene Asicksik, said.
This is what happens when the Arctic warms twice as fast as the rest of the planet - The Washington Post
▻https://www.washingtonpost.com/news/energy-environment/wp/2015/12/15/this-is-what-happens-when-the-arctic-warms-twice-as-fast-as-the-rest-of-the-planet/?wpisrc=nl_draw2
For a second straight year, the Arctic is warming faster than any other place in the world, and walrus populations in the area’s Pacific and Atlantic ocean regions are thinning along with the ice sheets that are critical for their survival, researchers reported Tuesday.
D’après la NASA la circulation thermohaline pourrait bien être en train de s’arrêter…
There has been growing concern, of late, that one predicted consequence of a changing climate — the slowing of the great “overturning” circulation in the Atlantic Ocean — is already starting to happen.
Et s’il s’arrêtent vraiment, chez nous, on pourra faire du patin à glace toute l’année !
If the circulation weakens too much it can even completely break down – the #AMOC has a well-known “tipping point” (Lenton et al., 2008). The latest IPCC report (just like the previous one) estimates a probability of up to 10% that this could happen as early as this century. However, this assessment is based on models that may underestimate the risk, as mentioned above. Expert surveys indicate that many researchers assess the risk higher than the (generally conservative) IPCC, as is the case for sea level. In a detailed survey (Kriegler et al 2009), the 16 experts interviewed saw already at moderate global warming (2-4 °C) a probability of a ‘tipping’ (major reorganisation) of the flow between 5 and 40 percent. With strong global warming (4-8 °C) this probability was even estimated as between 20 and 65 percent.
►http://www.realclimate.org/index.php/archives/2015/03/whats-going-on-in-the-north-atlantic
L’article de parle pas de Gulf Stream mais de circulation thermohaline. Le moteur du Gulf Stream c’est l’Anticyclone des Açores, qui a peu de chances de disparaître. Par contre pour la circulation thermohaline on peut effectivement être préoccupé d’après ce lien ▻http://www.clubdesargonautes.org/faq/gscourant.php
voir en revanche ▻http://www.ldeo.columbia.edu/res/div/ocp/gs qui relativise l’importance relative ces courants océaniques dans le climat européen, par rapport à l’importance de la dynamique de l’atmosphère.
Sur le Washington Post toujours, un article avec interview d’un certain Rahmstorf (Potsdam Institute for Climate Impact Research) qui a sorti un papier sur la modification de la circulation thermohaline dans un scénario de changement climatique.
One thing that will not happen from a shutdown of the circulation is a sudden, dramatic freezing of Europe. It will certainly cool, relative to a world in which the circulation remains robust — but that will be offset by rising average temperatures due to global warming, says Rahmstorf. The “Day After Tomorrow” scenario will not come to pass.
▻https://www.washingtonpost.com/news/energy-environment/wp/2015/03/23/global-warming-is-now-slowing-down-the-circulation-of-the-oceans-wit
Bref a priori conséquences minimes sur la météo en Europe mais conséquences lourdes sur l’océan.
Dans l’article Arrêt de la circulation thermohaline de WP, le graphique de 2004 montre déjà le phénomène de façon tout aussi impressionnante.
▻https://fr.wikipedia.org/wiki/Arrêt_de_la_circulation_thermohaline
Remarque que dans ce même article, la distinction entre circulation thermohaline et Gulf Stream n’est pas aussi nette.
Circulation thermohaline et eau douce
La chaleur est transportée de l’équateur vers les pôles essentiellement par l’atmosphère mais aussi par les courants marins, l’eau étant plus chaude en surface et plus froide vers le fond. Le segment le plus connu de cette circulation est le Gulf Stream, une branche de la gyre nord atlantique, qui transporte l’eau chaude des Caraïbes vers le nord. La dérive nord atlantique prend le relais plus au nord, où elle contribue à réchauffer l’atmosphère et le climat européen.
Lotka-Volterra c’est fini
▻http://www.sciencemag.org/content/349/6252/aac6284
Across ecosystems globally, pyramid structure becomes consistently more bottom-heavy, and per capita production declines with increasing biomass. These two ecosystem-level patterns both follow power laws with near ¾ exponents and are shown to be robust to different methods and assumptions.
#recherche #écologie #écosystèmes #proie-prédateur #loi_de_puissance
(une version plus digeste (?) ici ▻https://www.washingtonpost.com/news/energy-environment/wp/2015/09/03/researchers-may-have-just-stumbled-upon-a-mathematical-secret-to-how)
Plus le système croît, plus il ralenti...
C’est fondamentalement anticapitaliste ça ;)
j’ai pas pigé en quoi ça remet en question les équations de Lotka-Volterra
Oui mais il peut aussi y avoir une situation de biomasse stable des prédateurs et des proies, dans laquelle ni la biomasse de l’un ni celle de l’autre groupe n’oscillent, sans pour autant invalider l’équation en question. La proportionnalité différée ne s’observe que dans les cas où ça oscille mais ce ne sont pas les seuls cas existants (heureusement, j’ai envie de dire, sinon quel bordel ce serait :-))
Pour le dire autrement : l’état d’équilibre d’un système L-V est un certain ratio (prédateurs = ratio x proies). Et ça ne peut pas être autrement, car il n’y a pas de dimension dans ces équations. Mais ce qu’observe cet article (sous réserve que les résumés soient fiables et que je les ai bien compris), c’est que la dimension compte.