Sea level is 1000mbYou are posting water vapour at 500mb, which...

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    Sea level is 1000mb
    You are posting water vapour at 500mb, which is 5-6 km up.

    Try having a slightly wider look at water vapour in the whole atmosphere.  As the science has:
    https://www.nasa.gov/topics/earth/features/vapor_warming.html
    “This new data set shows that as surface temperature increases, so does atmospheric humidity,” Dessler said. “Dumping greenhouse gases into the atmosphere makes the atmosphere more humid. And since water vapor is itself a greenhouse gas, the increase in humidity amplifies the warming from carbon dioxide."

    and it's definitely us
    https://phys.org/news/2014-07-vapor-global-amplifier.html
    A new study from scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science and colleagues confirms rising levels of water vapor in the upper troposphere – a key amplifier of global warming – will intensify climate change impacts over the next decades. The new study is the first to show that increased water vapor concentrations in the atmosphere are a direct result of human activities.Read more at: https://phys.org/news/2014-07-vapor-global-amplifier.html#jCp
    "The study is the first to confirm that human activities have increased water vapor in the upper troposphere," said Brian Soden, professor of atmospheric sciences at the UM Rosenstiel School and co-author of the study.To investigate the potential causes of a 30-year moistening trend in the upper troposphere, a region 3-7 miles above Earth's surface, Soden, UM Rosenstiel School researcher Eui-Seok Chung and colleagues measured water vapor in the upper troposphere collected by NOAA satellites and compared them to climate model predictions of water circulation between the ocean and atmosphere to determine whether observed changes in atmospheric water vapor could be explained by natural or man-made causes. Using the set of climate model experiments, the researchers showed that rising water vapor in the upper troposphere cannot be explained by natural forces, such as volcanoes and changes in solar activity, but can be explained by increased greenhouse gases, such as CO2.

 
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