This topic contains 3 replies, has 1 voice, and was last updated by  Editor 4 months, 3 weeks ago.

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  • #15556

    Editor
    Keymaster

    Implication of strongly increased atmospheric methane concentrations for chemistry–climate connections

    We emphasize that the applied doubling of present-day CH4 surface mixing ratios is not unrealistic as it is even part of the RCP 8.5 scenario. [..] we find that the CH4 lifetime increases quasilinearly with enhanced surface mixing ratios. This is ascribed to a strong reduction in OH, which is the main sink of CH4 in the troposphere. We conclude that the strong reduction in OH will also influence other radiatively active, air-quality-relevant and ozone-depleting substances in the troposphere. The radical OH is the most important atmospheric detergent and its reduction will enhance the residence time of these substances, as well as of CH4, and thereby increase the global radiative burden.

  • #15557

    Editor
    Keymaster

    Potential Instability of Gas Hydrates along the Chilean Margin Due to Ocean Warming

    An increase in temperature might cause the dissociation of gas hydrate that could strongly affect gas hydrate stability. Moreover, we found that the high seismicity of this area could have a strong effect on gas hydrate stability.

  • #15558

    Editor
    Keymaster

    Scientists discovered an entirely new reason for methane venting from the Arctic Shelf

    “We conducted experiments focusing on the interaction between frozen rocks containing relict methane hydrates and salt solutions at different negative temperatures. We found that salt migration to the frozen hydrate-containing rocks intensifies the pore gas hydrates dissociation and accelerates their thawing

    Salt
    Warmer, saltier polar water could change global ocean currents

    If more warm salty water is reaching the bottom of the ice shelves than in previous years, this could fuel an increase in ice-shelf melt.

    Atmospheric warming altering ocean salinity

    Records showed that the saltier parts of the ocean increased salinity — or their salt content — by 4 percent in the 50 years between 1950 and 2000. If the climate warms by an additional 2 or 3 degrees, the researchers project that the water cycle will turn over more quickly, intensifying by almost 25 percent.

    [..] the ocean waters around Antarctica are getting less salty because the waters are being refreshed by the melting ice cap.

    “The most important part of the research is the basic observation that the 50-year trend in salinization is indeed that the fresh water is getting fresher and the saltwater saltier,” said Dean Roemmich, a professor of oceanography at the Scripps Institution of Oceanography. “It is a fundamental change.”

    Salinity, Ocean Circulation & Climate

    Surface winds drive currents in the upper ocean. Deep below the surface, however, ocean circulation is primarily driven by changes in seawater density, which is determined by salinity and temperature. In some regions such as the North Atlantic near Greenland, cooled high-salinity surface waters can become dense enough to sink to great depths.

    Studies suggest that seawater is becoming fresher in high latitudes and tropical areas dominated by rain, while in sub-tropical high evaporation regions, waters are getting saltier. Such changes in the water cycle could significantly impact not only ocean circulation but also the climate in which we live.

    • This reply was modified 4 months, 3 weeks ago by  Editor.
    • This reply was modified 4 months, 3 weeks ago by  Editor.
    • This reply was modified 4 months, 3 weeks ago by  Editor.
  • #15589

    Editor
    Keymaster

    Summary
    New Mechanism for Methane Hydrate Dissociation Discovered http://climatestate.com/2019/06/19/new-mechanism-for-methane-hydrate-dissociation/

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