Sunday, January 26, 2014

Settled Science: New paper finds effect of man on climate is "highly uncertain"

A new paper published in Science finds "the radiative forcing (that is, the perturbation to Earth's energy budget) caused by human activities is highly uncertain, making it difficult to predict the extent of global warming."

One of several reasons for this high uncertainty is the complexity of determining the cooling effects of aerosols, which reflect sunlight back to space, and can also seed cloud formation. According to the authors, "Aerosols counteract part of the warming effects of greenhouse gases, mostly by increasing the amount of sunlight reflected back to space. However, the ways in which aerosols affect climate through their interaction with clouds are complex and incompletely captured by climate models." "Recent advances have led to a more detailed understanding of aerosol-cloud interactions and their effects on climate, but further progress is hampered by limited observational capabilities and coarse-resolution climate models."

The huge uncertainties with respect to clouds, aerosols, solar amplification mechanisms, ocean oscillations, and natural variability all make a mockery of the IPCC claim of increased confidence as its climate models increasingly diverge from temperature observations. 



Science
Vol. 343 no. 6169 pp. 379-380 
DOI: 10.1126/science.1247490
  • PERSPECTIVE
ATMOSPHERIC SCIENCE

Climate Effects of Aerosol-Cloud Interactions

  1. Leo Donner4
+Author Affiliations
  1. 1The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
  2. 2University of New South Wales, Sydney 2052, Australia.
  3. 3University of Washington, Seattle, WA 98195-1640, USA.
  4. 4National Oceanic and Atmospheric Administration, Geophysical Fluid Dynamics Laboratory, Princeton, NJ 08540, USA.
  1. ↵*Corresponding author. E-mail: daniel.rosenfeld@huji.ac.il
Aerosols counteract part of the warming effects of greenhouse gases, mostly by increasing the amount of sunlight reflected back to space. However, the ways in which aerosols affect climate through their interaction with clouds are complex and incompletely captured by climate models. As a result, the radiative forcing (that is, the perturbation to Earth's energy budget) caused by human activities is highly uncertain, making it difficult to predict the extent of global warming (1, 2). Recent advances have led to a more detailed understanding of aerosol-cloud interactions and their effects on climate, but further progress is hampered by limited observational capabilities and coarse-resolution climate models.
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10 comments:

  1. AnonymousJanuary 27, 2014 at 7:40 AM

    The consensus of the climate models is that Reality is in denial.

    ReplyDelete
  2. UnknownJanuary 27, 2014 at 4:05 PM

    As a validity test, rerun all the global circulation models with CO2 estimated contribution set at zero and see if their predictive value is better, worse, or the same. There must be a way to falsify a model if the model is going to be scientifically useful.

    ReplyDelete
    Replies
    1. MSJanuary 27, 2014 at 5:40 PM

      A 'no change' model outperforms IPCC models by a factor of 7

      http://hockeyschtick.blogspot.com/2013/10/a-scientific-no-change-in-temperature.html

      The models are basically simply a curve fit to CO2 concentrations, as shown by Salby

      You don't even need a climate model to show what climate models predict - projections are based upon a single independent variable - CO2

      http://hockeyschtick.blogspot.com/2013/06/climate-scientist-dr-murry-salby.html

      Delete
  3. AnonymousJanuary 27, 2014 at 11:39 PM

    The confidence level given by the IPCC is not about the accuracy of their model: it is about the fact man-made emissions are the cause of more than half of the observed warming since 1950. The discrepancy between the IPCC models and observations is, by definition, natural variability. So: the less warming, the more confident the IPCC is about the fact we are responsible for half of it.

    Therefore, it is BECAUSE climate models increasingly diverge from temperature observations that the IPCC claims increased confidence!

    See the details for this argument in my post on WUWT: http://wattsupwiththat.com/2013/11/21/from-90-to-95-confidence-level-how-ipcc-claims-can-be-at-the-same-time-consistent-and-absurd/

    ReplyDelete
    Replies
    1. AnonymousJanuary 28, 2014 at 5:27 AM

      Perverse!!! So if we're responsible for 1% of warming during warm years, we end up responsible for 100% of warming during cold years. A perfect psychotic schema---- logical, but loony.

      Delete
  4. UnknownJanuary 28, 2014 at 10:34 AM

    Take the graphic presentation of Hadley-CRUT measurements of the last 100 years and break it in half. The two halves are indistinguishable either in amount of total warming or pattern of increase, which suggests that any increase in human contribution makes no difference whatsoever. This seems to me to effectively falsify the CO2 theory. Skeptics should push this fact.
    I suspect that the shift in language from "global warming" to the meaningless but apparently equally scary term "climate change" was brought about by the realization by many environmental zealots that the global warming scare might soon lack credibility.

    ReplyDelete
  5. AnonymousJanuary 29, 2014 at 2:24 PM

    http://www.accuweather.com/en/weather-blogs/climatechange/prediction-of-future-influence/22690208

    ReplyDelete
  6. AnonymousJanuary 30, 2014 at 9:27 AM

    http://www.bishop-hill.net/blog/2014/1/30/where-next-for-climate-policy.html

    ReplyDelete
  7. MSFebruary 11, 2014 at 12:39 PM

    http://wattsupwiththat.com/2014/01/27/picture-of-how-our-climate-is-affected-by-greenhouse-gases-is-a-cloudy-one/#comment-1551838

    ReplyDelete

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