Archives par mot-clé : CO2

Study: plants are globally getting more efficient thanks to rising carbon dioxide

by University of California, September 12, 2017 in WUWT


A trend toward greater discrimination under higher CO2 levels is broadly consistent with tree ring studies over the past century, with field and chamber experiments, and with geological records of C3 plants at times of altered atmospheric CO2, but increasing discrimination has not previously been included in studies of long-term atmospheric 13C/12C measurements. We further show that the inferred discrimination increase of 0.014 ± 0.007‰ ppm−1 is largely explained by photorespiratory and mesophyll effects.

The Correlation of Seismic Activity and Recent Global Warming

by Arthur Viterio, 2016, in  J Earth Science Climate Change


Earth’s climate is a remarkably “noisy” system, driven by scores of oscillators, feedback mechanisms, and radiative forcings. Amidst all this noise, identifying a solitary input to the system (i.e., HGFA MAG4/6 seismic activity as a proxy for geothermal heat flux) that explains 62% of the variation in the earth’s surface temperature is a significant finding.

See also here

Carbon dioxide emission-intensity in climate projections: Comparing the observational record to socio-economic scenarios

by F. Pretis and M. Roser, June 2017, Energy, Elsevier


 

The wide range of socio-economic scenarios in climate projections results in high uncertainty about climate change.

We compare socio-economic scenario projections to observations over 1990–2010.

Global CO2 emission intensity increased despite all major scenarios projecting a decline.

Under-projection of emission intensity raises concerns about achieving emission targets.

 

Volcanic eruptions drove ancient global warming event

by Marcus Gutjah et al., August 30,  2017 in PhysOrg


A natural global warming event that took place 56 million years ago was triggered almost entirely by volcanic eruptions that occurred as Greenland separated from Europe during the opening of the North Atlantic Ocean,

The amount of carbon released during this time was vast—more than 30 times larger than all the fossil fuels burned to date and equivalent to all the current conventional and unconventional fossil fuel reserves we could feasibly ever extract.” Ridgwell said.

An unexpected finding was that enhanced organic matter burial was important in ultimately sequestering the released carbon and accelerating the recovery of the Earth’s ecosystem without massive extinctions.

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Quantifying the causes of the recent decrease in US CO2 emissions

by Roger Andrews, August 23, 2017 in Energy Matters (blog)


Between 2007 and 2015 total annual US CO2 emissions decreased by 740 million tons (12%). An updated analysis shows that 35% of this decrease was caused by natural gas replacing coal in electricity generation, 30% by lower fuel consumption in the transportation sector, 28% by renewables replacing

Réchauffement climatique : le CO2 atmosphérique n’a pas toujours été le coupable

by Alex Barral et al., 2017 (U. Lyon-CNRS)


La comparaison des fluctuations du CO2 atmosphérique retracées à partir de ces estimations avec des courbes des changements de température a révélé de fortes baisses du CO2 atmosphérique (200-300 ppm), couplées à de fortes hausses de la température moyenne à la surface du globe (5-8°C) à l’échelle de quelques millions d’années.

Record-shattering 2.7-million-year-old ice core reveals start of the ice ages

by Paul Voosen, August 15, 2017


Scientists announced today that a core drilled in Antarctica has yielded 2.7-million-year-old ice, an astonishing find 1.7 million years older than the previous record-holder

(…)

If the new result holds up, says Yige Zhang, a paleoclimatologist at Texas A&M University in College Station, the proxies will need to be recalibrated. “We have some work to do.”

On Carbon Dioxide Toxicity

by Blair King, April 10, 2016


Specifically the Bureau of Land Management Health Risk Evaluation for Cabon Dioxyde  points out:

A value of 40,000 ppm is considered immediately dangerous to life and health based on the fact that a 30-minute exposure to 50,000 ppm produces intoxication, and concentrations greater than that (7-10%) produce unconsciousness (NIOSH 1996; Tox. Review 2005). Additionally, acute toxicity data show the lethal concentration low (LCLo) for CO2 is 90,000 ppm (9%) over 5 minutes (NIOSH 1996).

See also The Lake Nyos Disaster

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Underground magma triggered Earth’s worst mass extinction with greenhouse gases

by Howard Lee, geologist, August 9, 2017 in WUWT


Earth’s most severe mass extinction, the “Great Dying,” began 251.94 million years ago at the end of the Permian period, with the loss of more than 90% of marine species. Precise rock dates published in 2014 and 2015 proved that the extinction coincided with the Siberian Traps LIP, an epic outpouring of lava and intrusions of underground magma covering an area of northern Asia the size of Europe.

But those rock dates presented science with a new puzzle: why was the mass extinction event much shorter than the eruptions? And why did the extinction happen some 300,000 years after the lava began to flow?

No Direct Human Health Risk Under a CO2 Exposure of 3000 ppm

by W. Liu et al., August 1st 2017


And what did these analyses reveal?

Not surprisingly, when all was said and done, the authors report that “increasing [the] CO2 concentration to 3000 ppm at 35°C did not cause changes in any of the measured responses.” They did note, however, that the heart rates of the subjects were slightly reduced under elevated CO2 conditions (Figure 1, top left panel), although these reductions were not statistically significant.

100 companies to blame for 71% of carbon “pollution”, but world’s worst corporates are Big Government

by JoNova, August 2017


Since 1988, a mere 100 companies have been responsible for 71 percent of the entire world’s industrial greenhouse gas emissions.

This data comes from an inaugural report published by the Carbon Disclosure Project (CDP), an environmental non-profit. Charting the rapid expansion of the fossil fuel industry in the last 28 years, they have now released some truly staggering numbers on the world’s major carbon polluters.