Ecology, Climate Change and Related News

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Tag Archive: co2

  1. 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….

  2. 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

  3. 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

  4. 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.

  5. 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