Archives de catégorie : climate and geology

Novel hypothesis goes underground to predict future of Greenland ice sheet

by Penn State, February 2,  2019 in ScienceDaily


Paleoclimatic records indicate that most of Greenland was ice-free within the last 1.1 million years even though temperatures then were not much warmer than conditions today. To explain this, the researchers point to there being more heat beneath the ice sheet in the past than today.

Data show that when the Iceland hot spot — the heat source that feeds volcanoes on Iceland — passed under north-central Greenland 80 to 35 million years ago, it left molten rock deep underground but did not break through the upper mantle and crust to form volcanoes as it had in the west and east. The Earth’s climate then was too warm for Greenland to have an ice sheet, but once it cooled the ice sheet formed, growing and shrinking successive with ice ages.

Volcano In Scotland May Have Caused Prehistoric Global Warming prehistoric volcanic eruption

by S. Beech, January 25, 2019 in ClimateChangeDispatch


A massive volcanic eruption in Scotland on the same scale as the infamous Krakatoa blast may have contributed to prehistoric global warming.

Scientists say that global temperatures spiked around 56 million years ago.

And a new study suggests that a major explosive eruption from the Red Hills on the Isle of Skye may have been a contributing factor to the massive climate disturbance.

Large explosive volcanic eruptions can have lasting effects on climate and have been held responsible for severe climate effects in Earth’s history.

One such event occurred around 56 million years ago when global temperatures increased by up to 8 degrees Celcius (46 degrees Fahrenheit.)

The event has been named the Paleocene-Eocene Thermal Maximum (PETM).

 

New Paper: PETM Was Caused by Climate Change… Ancient Climate Change Caused Climate Change… AEUHHH????

by David Middleton, January 23, 2019 in WUWT


Note how the PETM (55 Ma) is about as far from a CO2 analog to modern times as it possibly could be… unless the PETM stomata data are correct, in which case AGW is even more insignificant than previously thought.

Regarding temperatures, the PETM is also about as far from being an analog to modern times as it possibly could be.

 

Figure 2.  High latitude SST (°C) From benthic foram δ18O.  Funny how the PETM is often cited as a nightmarish version of a real-world RCP8.5… While the warmer EECO is a climatic optimum. (Zachos et al., 2001). Note: Older is to the right.

 

 

 

Global-scale evaluation of role of soil minerals in carbon storage

by U. of California – Santa Barbara, January 2, 2019 in ScienceDaily


“We’ve known for quite a long time that the carbon stored on minerals is the carbon that sticks around for a long time,” said Chadwick, co-author of the paper, “Climate-driven thresholds in reactive mineral retention of soil carbon at the global scale,” published in the journal Nature Climate Change. How much carbon the soil can take and how much it can keep, he said, are dependent on factors including temperature and moisture.

“When plants photosynthesize, they draw carbon out of the atmosphere, then they die and their organic matter is incorporated in the soil,” Chadwick explained. “Bacteria decompose that organic matter, releasing carbon that can either go right back into the atmosphere as carbon dioxide or it can get held on the surface of soil minerals.”

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HOW CAN SO MANY SCIENTISTS BE SO WRONG ABOUT THE PAUSE?

by David Whitehouse, December 20, 2018 in GWPF


Using simple statistics it looked at and dismissed over 200 peer-reviewed papers that analysed the pause and concluded it was a real phenomenon. How did they, and the IPCC, get it all so wrong?

Source: Clive Best

Nobody who keeps an eye on climate research will be at all surprised by this “new” paper. Its conclusions were well aired in April 2018 at a meeting of the European Geophysical Union.

The authors must have been rather frustrated at the time as the paper describing their work had been submitted to the journal Environmental Research Letters over a year earlier, in February 2017 in fact, still had not been published. This was remedied a few days ago when it was finally published — one year and nine months after its submission!

Examples of How the Use of Temperature ANOMALY Data Instead of Temperature Data Can Result in WRONG Answers

by Bob Tisdale, December 13, 2018 in WUWT


This post comes a couple of weeks after the post EXAMPLES OF HOW AND WHY THE USE OF A “CLIMATE MODEL MEAN” AND THE USE OF ANOMALIES CAN BE MISLEADING(The WattsUpWithThat cross post is here.)

INTRO

I was preparing a post using Berkeley Earth Near-Surface Land Air Temperature data that included the highest-annual TMAX temperatures (not anomalies) for China…you know, the country with the highest population here on our wonder-filled planet Earth. The graph was for the period of 1900 to 2012 (FYI, 2012 is the last full year of the local TMAX and TMIN data from Berkeley Earth). Berkeley Earth’s China data can be found here, with the China TMAX data here. For a more-detailed explanation, referring to Figure 1, I was extracting the highest peak values for every year of the TMAX Data for China, but I hadn’t yet plotted the graph in Figure 1, so I had no idea what I was about to see.

Figure 1 The results are presented in Figure 2, and they were a little surprising, to say the least.

China’s Climate U-Turn

by P. Homewood, December 12, 2018 in NotaLotofPeopleKnowThat


A must read GWPF analysis of developments in China’s energy policy since the Paris Agreement:

China-U-Turn

Patricia Adams is an economist and the executive director of Probe International, a Toronto based NGO that has been involved in the Chinese environmental movement since its beginnings in the mid-1980s.

Her paper can be read here:

China-U-Turn

She is confirming much of what I have said in recent years. The only thing I would take issue with his her description of there being a U-Turn. In my view, China never had the slightest intention of being serious about cutting emissions.

Molecular fossils from phytoplankton reveal secular Pco2 trend over the Phanerozoic

by C.R. Witkowski et al., November28,  2018 in SciAdvances


Here, we reconstructed Phanerozoic PCO2 from a single proxy: the stable carbon isotopic fractionation associated with photosynthesis (Ɛp) that increases as PCO2 increases. This concept has been widely applied to alkenones, but here, we expand this concept both spatially and temporally by applying it to all marine phytoplankton via a diagenetic product of chlorophyll, phytane. We obtained data from 306 marine sediments and oils, which showed that Ɛp ranges from 11 to 24‰, agreeing with the observed range of maximum fractionation of Rubisco (i.e., 25 to 28‰). The observed secular PCO2 trend derived from phytane-based Ɛp mirrors the available compilations of PCO2over the past 420 Ma, except for two periods in which our higher estimates agree with the warm climate during those time periods. Our record currently provides the longest secular trend in PCO2 based on a single marine proxy, covering the past 500 Ma of Earth history

Fig. 2Ɛp calculated from phytane in Witkowski et al., 2018

See also here

Human ancestors not to blame for ancient mammal extinctions in Africa

by University of Utah, November23, 2018 in ScienceDaily


New research disputes a long-held view that our earliest tool-bearing ancestors contributed to the demise of large mammals in Africa over the last several million years. Instead, the researchers argue that long-term environmental change drove the extinctions, mainly in the form of grassland expansion likely caused by falling atmospheric carbon dioxide (CO2) levels.

The study is published today in the journal Science.

“Despite decades of literature asserting that early hominins impacted ancient African faunas, there have been few attempts to actually test this scenario or to explore alternatives,” Faith says. “We think our study is a major step towards understanding the depth of anthropogenic impacts on large mammal communities, and provides a convincing counter-argument to these long-held views about our early ancestors.”

To test for ancient hominin impacts, the researchers compiled a seven-million-year record of herbivore extinctions in eastern Africa, focusing on the very largest species, the so-called ‘megaherbivores’ (species over 2,000 lbs.) Though only five megaherbivores exist in Africa today, there was a much greater diversity in the past. For example, three-million-year-old ‘Lucy’ (Australopithecus afarensis) shared her woodland landscape with three giraffes, two rhinos, a hippo, and four elephant-like species at Hadar, Ethiopia.

See also here

Volcanoes and glaciers combine as powerful methane producers

by Lancaster University, November 20, 2018 in ScienceDaily


The Lancaster university-led research, which is featured in Scientific Reports, is the first published field study to show methane release from glaciers on this scale.

“This is a huge amount of methane lost from the glacial meltwater stream into the atmosphere,” said Dr Peter Wynn, a glacial biogeochemist from the Lancaster Environment Centre and corresponding author of the study. “It greatly exceeds average methane loss from non-glacial rivers to the atmosphere reported in the scientific literature. It rivals some of the world’s most methane-producing wetlands; and represents more than twenty times the known methane emissions of all Europe’s other volcanoes put together.”

‘True polar wander’ may have caused ice age

by Rice University, November 19, 2018 in ScienceDaily


Their study in the journal Geophysical Research Letters is based on an analysis of fossil signatures from deep ocean sediments, the magnetic signature of oceanic crust and the position of the mantle “hot spot” that created the Hawaiian Islands. Co-authors Richard Gordon and Daniel Woodworth said the evidence suggests Earth spun steadily for millions of years before shifting relative to its spin axis, an effect geophysicists refer to as “true polar wander.”

“The Hawaiian hot spot was fixed, relative to the spin axis, from about 48 million years ago to about 12 million years ago, but it was fixed at a latitude farther north than we find it today,” said Woodworth, a graduate student in Rice’s Department of Earth, Environmental and Planetary Sciences. “By comparing the Hawaiian hot spot to the rest of the Earth, we can see that that shift in location was reflected in the rest of the Earth and is superimposed on the motion of tectonic plates. That tells us that the entire Earth moved, relative to the spin axis, which we interpret to be true polar wander.”

Paleoclimatological Context and Reference Level of the 2°C and 1.5°C Paris Agreement Long-Term Temperature Limits

by S. Lüning & F. Vahrenholt, December12, 2017 in FrontEarthSci


The Paris Agreement adopted in December 2015 during the COP21 conference stipulates that the increase in the global average temperature is to be kept well below 2°C above “pre-industrial levels” and that efforts are pursued to limit the temperature increase to 1.5°C above “pre-industrial levels.” In order to further increase public acceptance of these limits it is important to transparently place the target levels and their baselines in a paleoclimatic context of the past 150,000 years (Last Interglacial, LIG) and in particular of the last 10,000 years (Holocene; Present Interglacial, PIG). Intense paleoclimatological research of the past decade has firmed up that pre-industrial temperatures have been highly variable which needs to be reflected in the pre-industrial climate baseline definitions …

See also here

Discovery Of Massive Volcanic CO2 Emissions Puts Damper On Global Warming Theory

by J.E. Kamis, November 6, 2018 in ClimateChangeDispatch


Recent research shows that the volume of volcanic CO2 currently being emitted into Earth’s atmosphere is far greater than previously calculated, challenging the validity of the man-made global warming theory.

he cornerstone principle of the global warming theory, anthropogenic global warming (AGW), is built on the premise that significant increases of modern era human-induced CO2 emissions have acted to unnaturally warm Earth’s atmosphere.

A warmed atmosphere that directly, or in some cases indirectly fuels anomalous environmental disasters such as ocean warming, alteration of ocean chemistry, polar ice sheet melting, global sea level rise, coral bleaching and most importantly dramatic changes in climate.

There are numerous major problems with the AGW principle.

Identification of Volcanic vs. Man-made CO2