Earlier observations showed that Arctic ice extents were low in the 1940s, grew thereafter up to a peak in 1977, before declining. That decline was gentle until 1994 which started a decade of multi-year ice loss through the Fram Strait. There was also a major earthquake under the north pole in that period. In any case, the effects and the decline ceased in 2007, 30 years after the previous peak. Now we have a plateau in ice extents, which could be the precursor of a growing phase of the quasi-60 year Arctic ice oscillation.
The average global temperature drop between October and November, 2017, tied for the fifth largest one-month-to-the-next drop in the 39-year satellite temperature record, according to Dr. John Christy, director of the Earth System Science Center (ESSC) at The University of Alabama in Huntsville. Compared to seasonal norms, the average temperature around the globe fell 0.27 C (almost 0.49 degrees F) between October and November. (The largest drop was from January to February 2013, when the global average temperature fell 0.32 C.)
by Rupert Darwall, November 28, 2017 in CompetitiveEnterpriseInstitut
This essay by Rupert Darwall explores the expressions of public certainty by climate scientists versus the private expressions of uncertainty, in context of a small Workshop on Climate organized by t he American Physical Society (APS). I was privileged to participate in this workshop, which included three climate scientists who support the climate change consensus and three climate scientists who do not — all of whom were questioned by a panel of disting uished physicists (…).
Les prévisions climatiques à très long terme (2100) sont établies à l’aide de modèles qui ne sont rien d’autre des logiciels très complexes, dont le but est de reproduire le comportement du climat terrestre.
Comme on ne peut pas décrire ce qui se passe en tous les points de la terre, celle-ci est découpée en mailles de quelques centaines de kilomètres de côté. Les modèles utilisés par le GIEC pour son cinquième rapport d’évaluation (2013) avaient des résolutions relativement grossières (supérieures à 100 km). La situation évolue toutefois rapidement et les modèles climatiques les plus récents auraient une résolution plus fine (de l’ordre de 20 km).
La Banque mondiale a présenté le 18 juillet une étude soulignant les énormes besoins de minerais et de métaux associés à la transition « bas carbone » dans le monde. Un aspect souvent ignoré de cette transition.
New research yields old result: Climate warming slow, steady. Observed value is half that of CMIP5 climate models.
The rate at which Earth’s atmosphere is warming has not significantly accelerated over the past 23 years, according to research at The University of Alabama in Huntsville (UAH).
If you take away the transient cooling in 1983 and 1992 caused by two major volcanic eruptions in the preceding years, the remaining underlying warming trend in the bottom eight kilometers (almost five miles) of the atmosphere was 0.096 C (about 0.17° Fahrenheit) per decade between January 1979 and June 2017.
That was unexpectedly close to the 0.09 C warming trend found when similar research was published in 1994 with only 15 years of data, said Dr. John Christy, director of UAH’s Earth System Science Center.
by P. Homewood, November 28, 2017 in NotaLotofpeopleKnowThat
We are all too familiar with graphs showing how much global temperatures have risen since the 19thC.
The HADCRUT version above is typical, and also very precise, with fairly tight error bars even in the early part of the record.
One wonders where they got the data to work all this out, because it certainly could not have come from thermometers.
All of the major global temperature datasets rely heavily on the Global Historical Climatology Network (GHCN). Yet as the “Overview of the Global Historical Climatology Network-Daily Database”, published by Matthew Menne et al in 2012, rather inconveniently showed, most of the world had little or no temperature data in the 19thC, and even up to 1950.
The statistical association between temperature and greenhouse gases over glacial cycles is well documented, but causality behind this correlation remains difficult to extract directly from the data.
We show that such variable time lags are typical for complex nonlinear systems such as the climate, prohibiting straightforward use of correlation lags to infer causation.
Figure 1 shows one example of data derived from such proxy sources. The top panel of the figure shows a declining temperature trend over the 8,000-year period from the Holocene Climate Optimum to the modern warm period (left-hand scale). It also shows that this location experienced numerous cycles of warming and cooling that involved temperature changes of the order of two degrees Celsius.
by Steve Penn, November 22, 2017 in ClimateChangeDispatch
(…) It seemed obvious to me that there was a climate change problem. I heard about it—and read about it—every day in the news. Eventually, I started to study the issue, thinking that I needed to understand it better to write informed articles on the subject (…)
Rapid expansion of the Arctic sea ice cover is the norm for October as solar input dwindles and the remaining heat in the upper ocean is released upwards, warming the lower atmosphere and escaping to space. Because of late season growth, the seasonal Antarctic maximum we previously reported as occurring on September 15 was exceeded, with a new maximum set on October 11 and 12. This is the second-lowest and second-latest seasonal maximum extent in the satellite record.
In recent years, researchers have identified a small group of stalactites that appear to have calcified underwater instead of in a dry cave. The Hells Bells in the El Zapote cave near Puerto Morelos on the Yucatán Peninsula are just such formations. Scientists have recently investigated how these bell-shaped, meter-long formations developed, assisted by bacteria and algae.
(…) However, as so often, the supposed “hockey stick” appeared only after the data had been severely adjusted. The difference is shown at the figure at right. Unadjusted (raw) relative sea level (i.e. how sea level appears locally – the concern of state planners and policy-makers) in North Carolina increased steadily through the last two millennia, with somewhat of an upward inflection in the 19th century; it is only after heavy adjustment that a HS shape appears.
by Paul Homewood, November 25, 2017 in NotaLotofPeopleKnowThat
“Science” is not a set of facts but a process or method that sets out a way for us to discover information and which attempts to determine the level of confidence we might have in that information. In the method, a “claim” or “hypothesis” is stated such that rigorous tests might be employed to test the claim to determine its credibility. If the claim fails a test, the claim is rejected or modified then tested again.
Let’s face it, global surface temperature histories measured by thermometers are a mess. Recording stations come on-and offline seemingly at random. The time of day when the high and low temperatures for the previous 24 hours are recorded varies, often changing at the same station. Local conditions can bias temperatures. And the “urban heat island” can artificially warm readings with population levels as low as 2500. Neighboring reporting stations can diverge significantly from each other.
According to the most basic precepts of anthropogenic global warming (AGW), variations in CO2 concentrations exert significant control on sea surface temperatures, glaciers, sea levels, and generalized climate dynamics (i.e., precipitation patterns).
In particular, high CO2 concentrations, driven by human activity, are presumed to cause dangerously warming ocean waters, rapid glacier melt and sea level rise, and overall disruption to the Earth’s biosphere.
Newly published scientific papers wholly undermine this popularized conceptualization.
In fact, according to Bertrand et al. (2017), there has been a “marked cooling” of sea surface temperatures in the southernmost South America region during the last ~800 years — 3°C to 4°C colder than during the Medieval and Roman warm periods — that has continued unabated into “the most recent decades”.
How deep can seawater penetrate through cracks and fissures into the seafloor? By applying a new analysis method, an international team of researchers has now discovered that the water can penetrate to depths of more than 10 kilometers below the seafloor. This result suggests a stronger cooling effect on the hot mantle.
Earth’s Moon had a rough start in life. Formed from a chunk of Earth that was lopped off during a planetary collision, it spent its early years covered by a roiling global ocean of molten magma before cooling and forming the serene surface we know today.
by P. Homewood, November 21, 2017 in NotaLotofPeopleKnowThat
A year ago the media was full of fake Arctic heatwave news (…)
And a year later?
Arctic sea ice extent this October was the third highest since 2006, and continues to track recent years. Most of the Arctic basin is full of 2 meter+ thick ice, in stark contrast to 2008.
For two weeks the whole world has been fretting about the petition “World Scientists’ Warning to Humanity: A Second Notice” with thousands of scientists stating that: (…)
There is only one slight problem: everybody can sign the petition, you, me, everybody. Where is the evidence? Well, simply go to their page and look for yourself:
Preboreal event was driven by contemporaneous methane from sources such as wetlands; our findings constrain the contribution from old carbon reservoirs (marine methane hydrates8, permafrost9 and methane trapped under ice10) to 19 per cent or less (95 per cent confidence). To the extent that the characteristics of the most recent deglaciation and the Younger Dryas–Preboreal warming are comparable to those of the current anthropogenic warming, our measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.
La géologie, une science plus que passionnante … et diverse
