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Tag Archive: co2

  1. Future carbon dioxide, climate warming potentially unprecedented in 420 million years

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    Posted: 04 Apr 2017 09:44 AM PDT  full ScienceDaily article here

    Over the next 100 to 200 years, carbon dioxide concentrations in the Earth’s atmosphere will head towards values not seen since the Triassic period, 200 million years ago. Furthermore, by the 23rd century, the climate could reach a warmth not seen in 420 million years, say researchers….

    …It is well recognised that the climate today is changing at rates well above the geological norm. If humanity fails to tackle rising CO2 and burns all the readily available fossil fuel, by AD 2250 CO2 will be at around 2000 ppm — levels not seen since 200 million years ago.

    Professor Foster adds: “However, because the Sun was dimmer back then, the net climate forcing 200 million years ago was lower than we would experience in such a high CO2 future. So not only will the resultant climate change be faster than anything Earth has seen for millions of years, the climate that will exist is likely to have no natural counterpart, as far as we can tell, in at least the last 420 million years.“…

    Gavin Foster et al. Future climate forcing potentially without precedent in the last 420 million years. Nature Communications, April 2017 DOI: 10.1038/NCOMMS14845

  2. Global CO2 emissions are flat for 3rd year, but need decline

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    • CO2 emissions globally have been level 3 years in a row
    • CO2 emissions decoupling from economy as new energy sources emerge
    • CO2 emissions need to decline; only 50 years left to get to zero

    Scott Waldman, E&E News reporter Monday, March 20, 2017  Full story here

    For the third year in a row, the carbon dioxide emissions that drive climate change worldwide have been level. The emissions pause is particularly noteworthy because it comes despite a growing global economy, the International Energy Agency announced. That’s a sign that carbon emissions are “decoupling” from the economy as other sources of energy come online.

    Researchers measured 32.1 metric gigatons of CO2 emissions in 2016, the same as in the previous two years. That’s even as the global economy grew 3.1 percent. The stagnation, according to IEA, is due to the growth of renewable energy, more switching from coal to natural gas, improved energy efficiency programs, and additional nuclear facilities coming online.

    … Emissions declined in both the United States and China, and stayed level in Europe. That’s because of increased natural gas usage and a reduction in coal usage in the United States and China. Dangerous smog levels in major cities have also forced the Chinese government to crack down on air pollution. In the United States, emissions dropped 3 percent, to the lowest level since 1992, as the economy grew 1.6 percent. In China, emissions declined 1 percent, while the economy grew 6.7 percent. The country also expanded the reliance of its electrical grid on hydro and wind sources as well as nuclear.

    Three years without emissions growth is notable, but it needs to be turned into a decline, said Glen Peters, a senior researcher at the Center for International Climate and Environmental Research-Oslo in Norway. He said the ultimate goal is to get to zero, and there’s only about 50 years left to hit that target.

    “It’s a meaningful first start, some baby steps; we’re starting to turn around and look at walking in the right direction,” he said. “If emissions are going to go down, they’ve got to go flat first, so this is the first step, so the important thing is to make sure they don’t start rising again. The next thing is to concentrate on making sure they go downwards.”…

  3. Oceans warming 13% faster than thought, warming doubled in last 2 decades

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    New study improves estimates of the rate of ocean warming – a critical component of climate change

    • rate of CO2 into atmosphere 40% higher since 1980
    • ocean is warming about 13% faster than we previously thought.
    • ocean warming has accelerated– from 1992 its is almost 2x warming rate from 1960.
    • it is only since about 1990 that the warming has penetrated to depths below about 700 meters.

    New research has convincingly quantified how much the Earth has warmed over the past 56 years. Human activities utilize fossil fuels for many beneficial purposes but have an undesirable side effect of adding carbon dioxide to the atmosphere at ever-increasing rates. That increase – of over 40%, with most since 1980 – traps heat in the Earth’s system, warming the entire planet….

    …Since about 2005 a new type of sensing device has been deployed (the Argo float system). These floats (approximately 3500 in total at any time) are spread out across oceans where they autonomously rise and fall in the ocean waters, collecting temperature data to depths of 2000 meters.  When they rise to the ocean surface, they send their data wirelessly to satellites for later analysis. Hence we can now map the ocean heat content quite well…

    …a paper just published today in Science Advances uses a new strategy to improve upon our understanding of ocean heating to estimate the total global warming from 1960 to 2015….shows we are warming about 13% faster than we previously thought. Not only that but the warming has accelerated. The warming rate from 1992 is almost twice as great as the warming rate from 1960. Moreover, it is only since about 1990 that the warming has penetrated to depths below about 700 meters….

  4. Scientists uncover huge 1.8 million square kilometers reservoir of melting carbon under Western United States

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    Posted: 13 Feb 2017 06:07 AM PST  full story here

    New research describes how scientists have used the world’s largest array of seismic sensors to map a deep-Earth area of melting carbon covering 1.8 million square kilometers. Situated under the Western US, 350km beneath Earth’s surface, the discovered melting region challenges accepted understanding of how much carbon Earth contains — much more than previously understood. 

    ….He continued, “Under the western US is a huge underground partially-molten reservoir of liquid carbonate. It is a result of one of the tectonic plates of the Pacific Ocean forced underneath the western USA, undergoing partial melting thanks to gasses like CO2 and H2O contained in the minerals dissolved in it.”

    ….As a result of this study, scientists now understand the amount of CO2 in Earth’s upper mantle may be up to 100 trillion metric tons. In comparison, the US Environmental Protection Agency estimates the global carbon emission in 2011 was nearly 10 billion metric tons — a tiny amount in comparison. The deep carbon reservoir discovered by Dr. Hier-Majumder will eventually make its way to the surface through volcanic eruptions, and contribute to climate change albeit very slowly.

    “We might not think of the deep structure of Earth as linked to climate change above us, but this discovery not only has implications for subterranean mapping but also for our future atmosphere,” concluded Dr Hier-Majumder, “For example, releasing only 1% of this CO2 into the atmosphere will be the equivalent of burning 2.3 trillion barrels of oil. The existence of such deep reservoirs show how important is the role of deep Earth in the global carbon cycle

    Saswata Hier-Majumder, Benoit Tauzin. Pervasive upper mantle melting beneath the western US. Earth and Planetary Science Letters, 2017; 463: 25 DOI: 10.1016/j.epsl.2016.12.041

  5. Why the ocean has absorbed more carbon over the past decade

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    Posted: 08 Feb 2017 01:46 PM PST  full article here

    With the ocean absorbing more carbon dioxide over the past decade, less of the greenhouse gas is reaching the Earth’s atmosphere. That’s decidedly good news, but it comes with a catch: Rising levels of carbon dioxide in the ocean promote acidification, which breaks down the calcium carbonate shells of some marine organisms….

    new research….demonstrates that a slowdown of the ocean’s overturning circulation is the likely catalyst. Their findings appear in the journal Nature. “Such a slowdown is consistent with the projected effects of anthropogenic climate change, where warming and freshening of the surface ocean from melting ice caps leads to weaker overturning circulation,” DeVries explained….

    ….According to DeVries, this finding may seem counterintuitive. Prevailing scientific wisdom asserts that the deceleration of circulation diminishes the ocean’s ability to absorb anthropogenic CO2 from the atmosphere as surface waters warm and become saturated with CO2.  “While that is true, there is another effect that appears to be more important in the short term,” DeVries said. “The weaker overturning circulation brings less naturally CO2-rich deep waters to the surface, which limits how much of that gas in the deep ocean escapes to the atmosphere. That causes the ocean to absorb more CO2 from the atmosphere.

    Tim DeVries, Mark Holzer, Francois Primeau. Recent increase in oceanic carbon uptake driven by weaker upper-ocean overturning. Nature, 2017; 542 (7640): 215 DOI: 10.1038/nature21068

  6. Young People’s Burden: Requirement of Negative CO2 Emissions

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    James Hansen, et al. Young People’s Burden: Requirement of Negative CO2 Emissions. Earth System Dynamic doi:10.5194/esd-2016-42

    Abstract. The rapid rise of global temperature that began about 1975 continues at a mean rate of about 0.18 °C/decade, with the current annual temperature exceeding +1.25 °C relative to 1880–1920. Global temperature has just reached a level similar to the mean level in the prior interglacial (Eemian) period, when sea level was several meters higher than today, and, if it long remains at this level, slow amplifying feedbacks will lead to greater climate change and consequences.

    The growth rate of climate forcing due to human-caused greenhouse gases (GHGs) increased over 20 % in the past decade mainly due to resurging growth of atmospheric CH4, thus making it increasingly difficult to achieve targets such as limiting global warming to 1.5 °C or reducing atmospheric CO2 below 350 ppm.

    Such targets now require “negative emissions”, i.e., extraction of CO2 from the atmosphere. If rapid phasedown of fossil fuel emissions begins soon, most of the necessary CO2 extraction can take place via improved agricultural and forestry practices, including reforestation and steps to improve soil fertility and increase its carbon content. In this case, the magnitude and duration of global temperature excursion above the natural range of the current interglacial (Holocene) could be limited and irreversible climate impacts could be minimized.

    In contrast, continued high fossil fuel emissions by the current generation would place a burden on young people to undertake massive technological CO2 extraction, if they are to limit climate change. Proposed methods of extraction such as bioenergy with carbon capture and storage (BECCS) or air capture of CO2 imply minimal estimated costs of 104–570 trillion dollars this century, with large risks and uncertain feasibility.

    Continued high fossil fuel emissions unarguably sentences young people to either a massive, possibly implausible cleanup or growing deleterious climate impacts or both, scenarios that should provide both incentive and obligation for governments to alter energy policies without further delay.

  7. Some good news about climate change- enhanced terrestrial uptake of CO2 from 2002-2014

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    November 10 at 1:44 PM

    On election day, the U.S. was busy voting for a president…But on the same day, a paper published in Nature Communications Tuesday actually contained some of the better news about climate change that we’ve heard in a while. Granted, even that doesn’t make it very sunny — just a modest bit of evidence suggesting a slight, temporary reprieve in the rate at which we’re altering the planet.

    Trevor Keenan of Lawrence Berkeley National Laboratory and his colleagues examined what is called the “terrestrial carbon sink”: How much trees, plants, and other aspects of global land surfaces are managing to pull carbon dioxide out of the air. Every year, you see, humans pump many billion tons of the stuff into the atmosphere, but not all of it stays there to warm the planet. A very significant fraction ends up getting absorbed by the ocean. Another large fraction gets pulled in by land-based plants which use it for photosynthesis. And so on.

    What the new study shows is that from 2002 to 2014, plants appear to have gone into overdrive, and started pulling more carbon dioxide out of the air than they had before. The result was that the rate at which carbon dioxide accumulates in the atmosphere did not increase during this time period, although previously, it had grown considerably in concert with growing greenhouse gas emissions….

    Kennan et al. Recent pause in the growth rate of atmospheric CO2 due to enhanced terrestrial carbon uptake. Nature Communications 7, Article number: 13428 (2016)  doi:10.1038/ncomms13428

    http://www.nature.com/articles/ncomms13428