Evolutions récentes du CO2 atmosphérique (1/3)

by J.C. Maurin, 16 septembre 2018, in Science,Climate,Energie

Dans les années 80, la découverte dans les archives glaciaires d’une corrélation entre température et taux de CO2 permit de soupçonner une influence anthropique sur le climat: les taux mesurés depuis 1958 étaient supérieurs aux taux des archives glaciaires.
L’IPPC (GIEC) fut créé en 1988 par 2 organismes: United Nations Environment Programme (UNEP) et  World Meteorological Organization (WMO). Le GIEC attribue l’intégralité de la hausse du taux de CO2 depuis un siècle à l’influence humaine.  Pour les dernières décennies, nous examinerons ici les mesures disponibles, les corrélations CO2 / température, enfin le modèle anthropique GIEC sera confronté à un modèle concurrent.

Hurricane Florence is not climate change or global warming. It’s just the weather.

by Roy W. Spencer, September 15, 2018 in USAToday

Even before Hurricane Florence made landfall somewhere near the border of North and South Carolina, predicted damage from potentially catastrophic flooding from the storm was already being blamed on global warming.

Writing for NBC News, Kristina Dahl contended, “With each new storm, we are forced to question whether this is our new, climate change-fueled reality, and to ask ourselves what we can do to minimize the toll from supercharged storms.”

The theory is that tropical cyclones have slowed down in their speed by about 10 percent over the past 70 years due to a retreat of the jet stream farther north, depriving storms of steering currents and making them stall and keep raining in one location. This is what happened with Hurricane Harvey in Houston last year.

But like most claims regarding global warming, the real effect is small, probably temporary, and most likely due to natural weather patterns …

Beyond Milankovitch

by Donald Rapp, September 8, 218 in Climate Etc.

On the terminations of Ice Ages.

Terminations occur on solar up-lobes

There is no doubt that there is merit in the widely accepted Milankovitch theory that Ice Ages and their terminations are controlled by solar input to the NH in mid-summer. It is also clear that relying on the solar input to the NH alone, does not adequately account for the occurrence of terminations of Ice Ages. The variation of solar input to high latitudes is modulated by precession, which produces continual up-lobes and down-lobes in solar input with a ~ 22,000-year period. While every termination is accompanied by the 5,500-year rising portion of an up-lobe in the solar input to high latitudes, many strong up-lobes do not produce a termination….

End of the Little Ice Age in the Alps forced by industrial black carbon

by Thomas H. Painter et al., September 17, 2018 in PNAS

The end of the Little Ice Age in the European Alps has long been a paradox to glaciology and climatology. Glaciers in the Alps began to retreat abruptly in the mid-19th century, but reconstructions of temperature and precipitation indicate that glaciers should have instead advanced into the 20th century. We observe that industrial black carbon in snow began to increase markedly in the mid-19th century and show with simulations that the associated increases in absorbed sunlight by black carbon in snow and snowmelt were of sufficient magnitude to cause this scale of glacier retreat. This hypothesis offers a physically based explanation for the glacier retreat that maintains consistency with the temperature and precipitation reconstructions.