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  • #14019

    Mari
    Participant

    The Mystery of Earth’s Oxygen

    To Donald E. Canfield, there’s something astonishing in every breath we take. “People take oxygen for granted because it’s just there and we breathe it all the time,” said Dr. Canfield, a geochemist at the University of Southern Denmark. “But we have the only planet we know of anywhere that has oxygen on it.”

    http://www.nytimes.com/2013/10/03/science/earths-oxygen-a-mystery-easy-to-take-for-granted.html?_r=0

    #14072

    ulvfugl
    Keymaster

    The cause of the hole’s sudden appearance in Yamal – which translates as ‘the end of the world’ – in the far north of Siberia is not yet known.

    There has been web speculation about the crater indicating ‘the arrival of a UFO craft’.

    But one Russian expert says the cause is more likely to be global warming releasing gases under the surface, which then explode like a champagne cork.

    Experts say that the darkening around the inner rim of the crater indicates ‘severe burning’ which scorched its edges.

    http://www.dailymail.co.uk/travel/travel_news/article-2693105/Giant-hole-appears-Siberia-Huge-crater-emerges-end-world.html

    #14152

    ulvfugl
    Keymaster

    WEDNESDAY, JULY 23, 2014

    #14201

    ulvfugl
    Keymaster
    #14210

    ulvfugl
    Keymaster

    The key objectives of PAGE21 are:

    • to improve our understanding of the processes affecting the size of the arctic permafrost carbon and nitrogen pools through detailed field studies and monitoring, in order to quantify their size and their vulnerability to climate change,
    • to produce, assemble and assess high-quality datasets in order to develop and evaluate representations of permafrost and related processes in global models,
    • to improve these models accordingly,
    • to use these models to reduce the uncertainties in feedbacks from arctic permafrost to global change, thereby providing the means to assess the feasibility of stabilization scenarios, and
    • to ensure widespread dissemination of our results in order to provide direct input into the ongoing debate on climate-change mitigation.

    http://www.page21.eu/

    #14220

    ulvfugl
    Keymaster
    #14271

    ulvfugl
    Keymaster

    #14277

    ulvfugl
    Keymaster
    #14301

    ulvfugl
    Keymaster

    Earth’s atmospheric CO2 concentration (ca) for thePhanerozoic Eon is estimated from proxies andgeochemical carbon cycle models. Most estimates come with large, sometimes unbounded uncertainty.

    Here, we calculate tightly constrained estimates of ca using a universal equation for leaf gas exchange, with key variables obtained directly from the carbon isotope composition and stomatal anatomy of fossil leaves. Our new estimates, validated against ice cores and direct measurements of ca, are less than 1000 ppm for most of the Phanerozoic, from the Devonian to the present, coincident with the appearance and global proliferation of forests.

    Uncertainties, obtained from Monte Carlo simulations, are typically less than for ca estimates from other approaches. These results provide critical new empirical support for the emerging view that large (~2000–3000 ppm), long-term swings in ca do not characterize the post-Devonian and that Earth’s long-term climate sensitivity to ca is greater than originally thought.

    http://climatestate.com/2014/07/30/co2-in-earth-history-the-past-400-million-years/

    #14324

    ulvfugl
    Keymaster
    #14420

    ulvfugl
    Keymaster
    #14459

    ulvfugl
    Keymaster
    #14515

    Mari
    Participant
    #14529

    ulvfugl
    Keymaster
    #14594

    ulvfugl
    Keymaster

    For the first time, scientists are now able to measure how much surface and groundwater is lost during droughts by measuring how much the land rises as it dries. Those are the conclusions of the new study published Aug. 21 in the journal Science by researchers at the Scripps Institution of Oceanography at the the University of California-San Diego.

    The drought that is devastating California and much of the West has dried the region so much that 240 gigatons worth of surface and groundwater have been lost, roughly the equivalent to a 3.9-inch layer of water over the entire West, or the annual loss of mass from the Greenland Ice Sheet, according to the study.

    http://www.scientificamerican.com/article/epic-drought-in-west-is-literally-moving-mountains/?&WT.mc_id=SA_DD_20140822

    #14639

    ulvfugl
    Keymaster

    First let me write one thing, and that is that we are not in Kansas anymore. And with that I mean that we are in totally uncharted country. Icelandic Met Office has the best volcanologists on the planet, and they pretty much never make a mistake. They are quite simply the best and their reputation at this site is set in solidified lava.

    So, when people like that in an hour first states that a small eruption has started and an hour later recant on the statement it does not hamper our confidence in their abilities, it is instead a sign of how “out there” what we are seeing right now really is.What is happening now is really like if you walked down a familiar street and turn a corner and find yourself in the fabled Land of Oz

    So it is time to sit down and calmly go through what is happening, and what has happened previously. Of course this will just skim the surface, but hopefully it will be enlightening.

    First let me write one thing, and that is that we are not in Kansas anymore. And with that I mean that we are in totally uncharted country. Icelandic Met Office has the best volcanologists on the planet, and they pretty much never make a mistake. They are quite simply the best and their reputation at this site is set in solidified lava.

    So, when people like that in an hour first states that a small eruption has started and an hour later recant on the statement it does not hamper our confidence in their abilities, it is instead a sign of how “out there” what we are seeing right now really is.

    What is happening now is really like if you walked down a familiar street and turn a corner and find yourself in the fabled Land of OzSo it is time to sit down and calmly go through what is happening, and what has happened previously. Of course this will just skim the surface, but hopefully it will be enlightening.

    There is of course not any beginning to our story, instead this story has been ongoing for 14 million years, and what we are seeing now is just a single word in the entire story of Iceland’s birth and growth.

    So, let us just say that Bárðarbunga is the largest volcano of its type on the planet, and that it has had the largest lava flood eruptions in the last 10 000 years, and that it is prone to have what is called rifting fissure eruptions.

    http://volcanocafe.wordpress.com/2014/08/24/bardarbunga-nature-of-the-beast/

    #14933

    ulvfugl
    Keymaster
    #14935

    ulvfugl
    Keymaster

    The movement of tectonic plates that created the Mediterranean Sea and the Alps also sparked the drying of the Sahara some 7 million years ago, according to the latest computer simulations of Earth’s ancient climate.

    Though North Africa is currently covered by the world’s largest non-polar desert, climate conditions in the region have not been constant there for the last several million years. Subtle changes in Earth’s tilt toward the sun periodically increase the amount of solar energy received by the Northern Hemisphere in summer, altering atmospheric currents and driving monsoon rains. North Africa also sees more precipitation when less of the planet’s water is locked up in ice. Such increases in moisture limit how far the Sahara can spread and can even spark times of a “green Sahara”, when the sparse desert is replaced by abundant lakes, plants and animals.

    Before the great desert was born, North Africa had a moister, semiarid climate. A few lines of evidence, including ancient dune deposits found in Chad, had hinted that the arid Sahara may have existed at least 7 million years ago. But without a mechanism to explain how it emerged, few scientists thought that the desert we see today could really be that old. Instead, most scientists argue that the Sahara took shape just 2 to 3 million years ago. Terrestrial and marine evidence suggest that North Africa underwent a period of drying at that time, when the Northern Hemisphere started its most recent cycle of glaciation.

    http://www.smithsonian.com/science/sahara-millions-years-older-thought-180952735/

    #14976

    ulvfugl
    Keymaster

    Dr Peter Ward 2013 Lectures on Global Warming & Mass Extinctions

    #14977

    ulvfugl
    Keymaster

    OK, pie chart #1-
    Methane is being released at a constant or increasing rate. Methane lost to oxidation will be more than made up for by new methane, released over that 30 year period. The pie chart is misleading, because it tells us only what we already knew – that methane lifetime is less than CO2 lifetime. The pie chart says nothing about the relative contributions of methane caused warming to CO2 caused warming 30 years from now, because it neglects methane released during that interval.

    Pie chart #2-

    This chart also tells us something we already knew. Current contributions from Arctic methane hydrates are small. It’s the huge size of the enormous hydrate reservoir combined with its potential for spontaneous dissociation under continued global heating that concerns many of us. So, it’s future emissions from the hydrates that concern many of us, not the current emissions.

    Pie chart #3-

    This pie chart is misleading because it draws a false equivalence between CO2 and methane – methane has a much greater short term greenhouse potency, added to its long term greenhouse impact after it is oxidized into CO2. Draw the same chart with reasonable assumptions for methane GWP, in terms of total cumulative radiative forcing, and the methane hydrate and Arctic permafrost methane slices could take up 95 percent of the pie.

    This chart also neglects the different volatility of the carbon in the different reservoirs. It’s not likely that a worldwide coal fire will release all of the carbon in coal without human intervention, for example. But the Arctic methane hydrates could spontaneously dissociate under the impact of global heating without direct human intervention. The Arctic is warming the fastest of all regions on the earth, so the impact of the Arctic hydrates could be the greatest. Also, the size of the methane hydrate reservoir is not well known, and it could in fact be several times as large as is shown.

    Draw the chart in terms of total cumulative radiative forcing, and take into account worst case scenarios about the global methane hydrate inventory, and the methane hydrate total cumulative radiative forcing could take up as much as 99% of the area of the pie.

    – See more at: http://www.realclimate.org/index.php/archives/2014/09/the-story-of-methane-in-our-climate-in-five-pie-charts/comment-page-1/#comment-601755

    #14990

    ulvfugl
    Keymaster

    “If all the models agree with the observations, uncertainty is probably pretty low. If they wildly disagree, uncertainty is pretty high,” Fisher said. “The models were all over the board.”
    Fisher stressed that all of these models “are perfectly valid representations of what’s going on in the Arctic.” Without more real-world measurements, it’s not possible to be sure which comes closest to reality.
    Scientists urgently want to understand the state of Arctic carbon because there are huge stores of carbon from dead vegetation locked in permafrost — and permafrost is turning out not to be as permanently frozen as its name implies. With the Arctic warming much faster than the rest of the planet, permafrost is thawing. Those carbon stores could be released into the atmosphere either slowly or in a giant burst, further accelerating the pace of climate change.
    “We’re opening Pandora’s box by warming the permafrost,” Fisher said. “In the Amazon, if you cut down a tree and release carbon to the atmosphere, you can plant another tree that will reabsorb that lost carbon. In the Arctic, the carbon stored in permafrost represents millennia of accumulated dead vegetation. If you lose that carbon to the atmosphere, you can’t get it back that easily.”

    http://www.sciencedaily.com/releases/2014/09/140926101859.htm

    #14992

    ulvfugl
    Keymaster

    When it Comes to The Arctic Methane Monster, What We Don’t Know Really Could Kill Us — NASA Model Study Shows Very High Carbon Release Uncertainty

    http://robertscribbler.wordpress.com/2014/09/29/when-it-comes-to-the-arctic-methane-monster-what-we-dont-know-really-could-kill-us-nasa-model-study-shows-very-high-carbon-release-uncertainty/

    #15024

    ulvfugl
    Keymaster

    Sean says:
    29 Sep 2014 at 10:22 PM
    @31 Sean

    email reply from Prof Peter Ward, working in the field at a fossil dig site.

    Quote: “Staring at the five methane pies not getting it.”

    – See more at: http://www.realclimate.org/index.php/archives/2014/09/the-story-of-methane-in-our-climate-in-five-pie-charts/comment-page-1/#comments

    #15105

    ulvfugl
    Keymaster

    #15203

    ulvfugl
    Keymaster
    #15219

    ulvfugl
    Keymaster
    #15254

    ulvfugl
    Keymaster

    It is known that carbon dioxide emissions cause the Earth to warm, but no previous study has focused on examining how long it takes to reach maximum warming following a particular CO2 emission. Using conjoined results of carbon-cycle and physical-climate model intercomparison projects (Taylor et al 2012, Joos et al 2013), we find the median time between an emission and maximum warming is 10.1 years, with a 90% probability range of 6.6–30.7 years. We evaluate uncertainties in timing and amount of warming, partitioning them into three contributing factors: carbon cycle, climate sensitivity and ocean thermal inertia. If uncertainty in any one factor is reduced to zero without reducing uncertainty in the other factors, the majority of overall uncertainty remains. Thus, narrowing uncertainty in century-scale warming depends on narrowing uncertainty in all contributing factors. Our results indicate that benefit from avoided climate damage from avoided CO2 emissions will be manifested within the lifetimes of people who acted to avoid that emission. While such avoidance could be expected to benefit future generations, there is potential for emissions avoidance to provide substantial benefit to current generations.

    http://iopscience.iop.org/1748-9326/9/12/124002/article

    #15302

    ulvfugl
    Keymaster

    #15346

    ulvfugl
    Keymaster

    Methane is leaking from permafrost offshore Siberia

    http://phys.org/news/2014-12-methane-leaking-permafrost-offshore-siberia.html

    #15368

    Mari
    Participant

    http://unews.utah.edu/news_releases/past-global-warming-similar-to-todays/

    http://www.nature.com/ngeo/journal/v8/n1/full/ngeo2316.html

    The rate at which carbon emissions warmed Earth’s climate almost 56 million years ago resembles modern, human-caused global warming much more than previously believed, but involved two pulses of carbon to the atmosphere, University of Utah researchers and their colleagues found.

    The findings mean the so-called Paleocene-Eocene thermal maximum, or PETM, can provide clues to the future of modern climate change. The good news: Earth and most species survived. The bad news: It took millennia to recover from the episode, when temperatures rose by 5 to 8 degrees Celsius (9 to 15 degrees Fahrenheit).

    “There is a positive note in that the world persisted, it did not go down in flames, it has a way of self-correcting and righting itself,” says University of Utah geochemist Gabe Bowen, lead author of the study published today in the journal Nature Geoscience. “However, in this event it took almost 200,000 years before things got back to normal.”

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