Do airplane contrails add to climate change? Yes, and the problem is about to get worse

Discussion in 'Environment & Conservation' started by Josephwalker, Jul 28, 2019.

  1. skepticalmike

    skepticalmike Well-Known Member

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    This graph of the Holocene in blue is a temperature reconstruction based on proxy data with the shaded area representing +/-1 standard deviation of certainty. The error bars are huge so
    how can we find a 1000 year cycle or a 1500 year cycle from that graph? What peer-reviewed research backs up your claim of a global 1000 to 1500 year natural cycle during the Holocene? Today's warmth is global in scale (98%) of the earth where previous periods of warmth were often regional or a result of orbital forcing (Holocene Climatic Optimum).

    CO2 levels have been very high during the past but what relevance is that to what is happening today?

    Ditlevsen P.D., Anderson K.K., Svenson A. (2007 2/28)
    "The DO-climate events are probably noise induced: statistical investigation of the claimed 1470 years cycle". Clim. Past. 3 (1): 129–134. doi:10.5194/cp-3-129-2007. ISSN 1814-9332

    The blue curve is derived from a temperature reconstruction of the Holocene with the shaded area representing +/- 1 standard deviation of uncertainty. Notice the huge uncertainty in the graph.
    How can we detect a global-mean temperature change from such uncertain data? This graph is from Relclimate.org.


    [​IMG]

    Figure 1 Blue curve: Global temperature reconstruction from proxy data of Marcott et al, Science 2013. Shown here is the RegEM version – significant differences between the variants with different averaging methods arise only towards the end, where the number of proxy series decreases. This does not matter since the recent temperature evolution is well known from instrumental measurements, shown in red (global temperature from the instrumental HadCRU data). Graph: Klaus Bitterman (From Realclimate.org, The end of the Holocene)
     
    Last edited: Aug 25, 2019
  2. skepticalmike

    skepticalmike Well-Known Member

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    How is global warming beneficial to the millions of people living within a few feet from sea level or in hot climates like the Mideast? How is it beneficial
    to California or to farmers living in the Great Plains?
    It is generally accepted as a fact by all climate scientists that carbon dioxide is a greenhouse gas with a long residence time and a known radiative forcing value.
    The global radiative forcing of carbon dioxide in 2017 relative to 1750 was 2.0 watts/square meter in 2017. It was 1.3 watts/square meter in 1990, 1.5 watts/sq m
    in 2000 , and 1.8 watts/sq. meter in 2010. This is settled science.
     
    Last edited: Aug 25, 2019
  3. Distraff

    Distraff Well-Known Member

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    Yes, CO2 was 8000 PPM and the great plains were under water. You have to be careful comparing today and the dinosaur era because other climate factors were different. But in general, raising CO2 back to dinosaur era levels will lead to dinosaur era temperature.
     
  4. skepticalmike

    skepticalmike Well-Known Member

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    I think that the most likely scenario is something between the RCP2.6 and the RCP4.5. I agree that much of the press concentrates too much on the most unlikely worst case scenario.
    RCP2.6 assumes emissions peak between 2010 and 2020 and then decline substantially.The radiatitve frocing under 2.6 peaks at 3.1 watts/meter in mid-century and declines to
    2.6 watts/meter by 2100. The global mean temperature would be kept to 1.5 degrees C. above pre-industrial levels under RCP2.6. We will use up all of our carbon budget within 12
    years under RCP2.6 assuming a constant rate of CO2 emissions. All fossil fuel burning would have to end after that with a 50% probability of success (1.5 degree C max).. How likely is that?


    I[​IMG]
    From Wikipedia



    [​IMG]
    green is RCP2.6, red is RCP4.5,
    From skeptical science.com
     
    Last edited: Aug 25, 2019
  5. AFM

    AFM Well-Known Member Past Donor

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    Where is the Medieval, Roman, and Minoan warm periods followed by subsequent cooling ??? Don't you check what you post against natural history ???
     
  6. AFM

    AFM Well-Known Member Past Donor

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    The growing season is longer, there is more precipitation, and more CO2 increases plant growth rate.

    Who is living a few feet from the ocean ??? It will take ~ 100 years for the oceans to rise one foot.

    So what ??? Your forcing estimates are irrelevant if the contributions of clouds is not understood. And the models don’t understand it.
     
  7. AFM

    AFM Well-Known Member Past Donor

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    That’s absurd. CO2 trails warming. It is a consequence of it.
     
  8. AFM

    AFM Well-Known Member Past Donor

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    Why aren’t you interested in understanding the previous 9 Holocene warming instead of believing that CO2 is completely responsible for our current warm period ??? Instead you push for totalitarian control of global society in order to eliminate fossil fuels resulting in regressive results which do infinitely more harm to poor people. That’s ridiculous and impossible. The totalitarian states like China which is by far the highest emitter of CO2 will never tank their economies for the myth of harmful global warming.

    Where are all the climate refugees ???
     
  9. skepticalmike

    skepticalmike Well-Known Member

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    What previous 9 Holocene warming periods? I have asked you before to produce evidence to support these global Holocene warming periods. I want peer reviewed citations.

    I favor democracy. I don't know what China will do in the future, that is a big unknown. They are the worlds leader in solar energy and they have a strong
    scientific base. Maybe they will develop efficient fuel cells and develop solar energy.
     
  10. skepticalmike

    skepticalmike Well-Known Member

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    CO2 trails warming when we look at the ice core data from the past. What does that prove? It takes time for CO2 to be released from the oceans after warming has been
    initiated by some perturbation to the climate like the tilt of the earth becoming greater with increased solar energy incident on the poles. CO2 is then a feedback and will
    trail the warming. You can't have dramatic temperature change in the past without CO2 and methane contributing greatly to the warming. Every climate scientist knows
    this but self-taught individuals who read anti-climate nonsense are easily manipulated.
     
  11. skepticalmike

    skepticalmike Well-Known Member

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    The cloud models are compared with observations so they are close. We could have either a hotter or a cooler climate than predicted by the models.

    There is no evidence of clouds (an unforced variation) causing rapid climate change during the past 2000 years.

    Most experts are predicting around 2 feet of sea level rise by the end of the century and the sea level will continue to rise at a much faster rate beyond

    2100 if we don't curtail CO2.
     
  12. Distraff

    Distraff Well-Known Member

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    Historically we didn't have humans around pumping around CO2 so something else would cause an initial warming, which would cause a death spiral with greenhouse gasses to be released causing warming which causes more greenhouse gas release. Ice ages happen when the reverse happens, cooling causes greenhouse gas reduction which causes more cooling.

    As a result, we see the warming start, greenhouse gas levels start going up a little later, more warming, and more greenhouse gas release.
     
  13. AFM

    AFM Well-Known Member Past Donor

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    I’ve provided all that before. You and all other alarmists ignore it.

    The Chinese are the world leader in exporting solar. They have eliminated their internal subsidies on solar and are refusing to pay existing ones.
     
  14. AFM

    AFM Well-Known Member Past Donor

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    It proves that CO2 does not drive global warming. We are not experiencing dramatic temperature changes.
     
  15. AFM

    AFM Well-Known Member Past Donor

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    No climate model understands clouds.

    Model output is not data.
     
  16. AFM

    AFM Well-Known Member Past Donor

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    Death spiral ??? That’s ridiculous. Where were the death spirals in the past natural history ???
     
  17. Distraff

    Distraff Well-Known Member

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    Ice ages. Its a bit like the death spiral of a stock market crash where people selling causes more people to sell. This is the same for ice ages when lower temperatures results in less water vapor and CO2 the atmosphere, which results in less greenhouse heat trapping, which result in more cooling. The opposite happens for getting out of ice ages.
    https://www.pri.org/stories/2015-08-21/greenhouse-gases-killed-last-ice-age-new-study-finds
     
    Last edited: Aug 26, 2019
  18. AFM

    AFM Well-Known Member Past Donor

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    There you go. CO2 trails temperature.
     
  19. AFM

    AFM Well-Known Member Past Donor

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    What causes the temperature changes ??? It’s the sun with the oceans acting as thermal batteries and circulation transportation. Also cold kills - humans prosper in the warming part of the cycles.
     
  20. Distraff

    Distraff Well-Known Member

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    The sun is a big one with short-term climate cycles and long-term cycles. Oceans are thermal batteries and are responsible for short-term climate cycles with El Ninos and La Ninas. There are greenhouse gasses, the biggest one is water vapor, but we also have CO2 and methane along with some smaller ones. Orbital shifts cause temperature changes. The color of the earth can take in a different amount of heat causing temperature changes. Cloud cover can cause temperature changes. Volcanoes and meteor impacts can cause them too.

    Yes, but that was because we didn't have humans digging up CO2 and pumping it into the sky. And CO2 along with other greenhouse gasses acted like positive feedbacks warming up the earth to get us out of ice ages.

    At the beginning of the 1800s we were in a mini-ice age and are simulating this process by pumping out a massive amount of CO2 and Methane and are seeing a radical temperature increase as a result.

    We are going to start seeing positive feedbacks kick in and further warming over the next several thousand years as a result.
     
  21. AFM

    AFM Well-Known Member Past Donor

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    Significant CO2 emissions did not start until the 50’s. The warming in the 30’s and 40’s was at the same rate as the 80’s and 90’s.

    There is no such thing as trigger points or overall positive feedback.

    Our current warming is completely in the mid range of the other 9 Holocene warming periods. Where are all the climate refugees.
     
    Last edited: Aug 26, 2019
  22. Distraff

    Distraff Well-Known Member

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    The 30s and 40s saw warming because the sun was warming and because of the more modest CO2 emissions. In the 80s and 90s, the sun wasn't warming but CO2 emissions were much higher. CO2 doesn't completely control all warming and won't stop all cooling. There are other climate factors to consider but CO2 is the biggest thing changing right now over the long term.

    We know positive feedbacks exist. For example, when the earth warms, ice melts which makes the earth more blue instead of white. Blue is darker than white. Darker colors soak in more heat and warms the planet further.
     
    Last edited: Aug 26, 2019
  23. AFM

    AFM Well-Known Member Past Donor

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    How much does CO2 contribute ??

    There is no overall feedback or tipping point.
     
  24. AFM

    AFM Well-Known Member Past Donor

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    So significant solar in the 30’s but not today ??? Why is that ?? Are there solar cycles or other factors than TSI ???
     
  25. mamooth

    mamooth Well-Known Member Past Donor

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    Fake News. Thus, WUWT put it on the front page.

    Basically, the defendant ran out the clock. No rulings were made on the merits of the case. Mann was not ordered to pay costs.

    I understand that the poster didn't understand that. After all, deniers get all their information from the cult, and that's what the cult told him.
     

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