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“Less than 2 °C warming by 2100 unlikely”

from  Nature Climate Change 

Less than 2 °C warming by 2100 unlikely

Adrian E. Raftery, Alec Zimmer, Dargan M. W. Frierson, Richard Startz & Peiran Liu

The recently published Intergovernmental Panel on Climate Change (IPCC) projections to 2100 give likely ranges of global temperature increase in four scenarios for population, economic growth and carbon use1. However, these projections are not based on a fully statistical approach. Here we use a country-specific version of Kaya’s identity to develop a statistically based probabilistic forecast of CO2 emissions and temperature change to 2100. Using data for 1960–2010, including the UN’s probabilistic population projections for all countries2, 3, 4, we develop a joint Bayesian hierarchical model for Gross Domestic Product (GDP) per capita and carbon intensity. We find that the 90% interval for cumulative CO2 emissions includes the IPCC’s two middle scenarios but not the extreme ones. The likely range of global temperature increase is 2.0–4.9 °C, with median 3.2 °C and a 5% (1%) chance that it will be less than 2 °C (1.5 °C). Population growth is not a major contributing factor. Our model is not a ‘business as usual’ scenario, but rather is based on data which already show the effect of emission mitigation policies. Achieving the goal of less than 1.5 °C warming will require carbon intensity to decline much faster than in the recent past.

  1. August 2, 2017 at 1:15 pm

    That’s all on the assumption that there is a «global warming» caused by CO2 emissions… Some heterodox climatologists (not Al Gore…) dispute that claim and go as far as claiming that it is the other way round… It is the warming (due to other factors, namely the Sun and the cosmic radiation from other stars…) that causes the increase in CO2.
    On the other hand those same climatologists («deniers», «skeptics»…) accept that there is a minute influence of man-made climate variation but that climate has always been in a state of change, anyway… They refer to the «Roman Warm Period» (vineyards in England…) and the Middle Age «little age ice»… And then there are those that forecast a coming «ice age»…
    Go figure… (just saying, I am no expert!…)

    • patrick newman
      August 2, 2017 at 2:16 pm

      Sorry, that’s jus a load of garbage. These days deniers are much more sophisticated and subtle but still in denial!

    • José M. Sousa
    • August 2, 2017 at 5:33 pm

      Aside from the vigorous politics of global climate catastrophe, and aside from questions about the psychopathology of denial, and aside from my overriding question — what planet do you live on? — I’m curious: what on earth in your worldview could have possibly led you to this website?

  2. Jerry Lobdill
    August 2, 2017 at 1:44 pm

    I wonder how long these climate change deniers will persist. And it is obvious this one is not a scientist.

  3. José M. Sousa
    August 2, 2017 at 1:57 pm

    There is no such thing as heterodox climatologists. This not economics!

  4. August 2, 2017 at 3:04 pm

    Earth’s fever indicates illness brought on by chemical pollution caused by excessive economic activity and supported by governments more concerned with finance than people.

    The cancer epidemic among humans also indicates increased chemical pollution.

  5. August 2, 2017 at 3:16 pm

    Good to see that you at least accept you have no expertise in the field of climate science. You should also, in all honesty, accept that 98% of climate scientists think that the overwhelming cause of climate change today is anthropogenic. Thus the anthropogenic explanation is a consensus view.

  6. August 2, 2017 at 5:22 pm

    Just for the record.
    1. The posting of this message in a blog dedicated to «Real World Economics» was to me a bit surprising,
    2. I have been following this blog for a couple of years and always got the impression that it could be classified as «heterodox» (meaning «as opposed to the neoclassical orthodoxy»). In that context I refer to the 98% of climatologists that work with the IPCC (97% it was, the last time I checked…) as «orthodox» and the remaining 2% or 3% (plus all those who claim to be independent but are accused of being funded by «big oil and big coal») those I would classify as «heterodox» (see Prof Judith Curry, for an example).
    3. The limited extent of my knowledge of «climate», «weather» and «global warming» (a.k.a. «climate change») comes from «half dozen» lectures (the first ones, some 50 years ago in the Air Force), from accredited scientists. The last one was less than a year ago by the Chief Meteorologist of India (a couple of hours explaining weather and climate and the models used by climatologists and weather forecasters); plus the reading of several books on Ecology. The very first one was «The Silent Spring» by Rachel Carson. Another one was «The Doomsday Book» by Gordon Rattray. In this particular book three was a forecast that by the year 2.000 there would be no blue skies to be seen from the surface of our planet… And, of course, the books by the Club of Rome.
    4. The only branch of Science in which I do claim some measure of expertise (a couple of PhD’s) is in the field of Social Sciences (including the Sociology of Science) and, more specifically, in the field of «The Political Economy of Development».
    5. In this context, these are my comments/responses to some of the comments already posted.
    5.1 – Science is not a matter of consensus and – unfortunately – it is extremely easy for the «powers that be», to control the «lines of research that are to be pursued or not». (that’s «101» of «Sociology of Science»…)
    5.2 – Just like there seems to be a «consensus among 97% of climatologists» that «the Science is settled» and that this or that phenomenon is bound to happen, there is a consensus among 97% of economists» (probably, just guessing…), that «the “Science (of Economics” is settled».
    5.3 – I make no comment on the eventual consequences of «alarmism» and the phenomenon of «crying wolf».
    5.4 – I am all against pollution, I am a militant of recycling and one of my hobbies has been that of gardening and specially planting trees (a couple of hundreds in three different countries).
    5.5 – Looking at the debate – which I follow, also out of curiosity – I am sometimes led to consider the possibility that this could be a «red herring», while the real problems of mankind (a few billions in the Global South) go unnoticed.
    5.6 – In the many dozens of videos and many dozens of articles that I have read on this subjects, I have only once (I repeat, only once) seen a reference – and in passing – to «Molten Salt Reactors» (Thorium Cycle), as an alternative solution (for energy production) to reduce CO2 emissios (assuming that that reduction is a good thing). And without plenty of clean energy, there is no way that the «peoples of the Global South» are ever going to reach a decent level of living. On this point of «clean energy», my fellow citizens who proclaim that Portugal now produces most of its energy from «renewables», hardly ever mention the pollution that was left in China (but not only), in the actual production of solar panels and windmills…
    P.S. – Due to academic exposure to the field of «Complexity Sciences» and professional experience in Information Processing, I do claim some measure of expertise in the field of development of models to simulate complex systems.

    • August 2, 2017 at 6:00 pm

      What a nice surprise to read your response. I looked up heterodox earlier to make sure I knew it was an adjective that could be used beyond economics.

      There is one idea where you couple increased energy to an increased standard of living in semi deprived social economies which I believe might need some tempering by how much energy is wasted by what we refer to as advanced economies.

      I have recently learned to live without meat, for example. Meat is environmentally negative to such a degree that I decided to experiment with vegetables, fruits and grains only. There is no excuse for harming the world with the willful ignorance of eating something unhealthy for the individual and Earth.

      My point is the less developed parts of the world can exceed the comforts of capitalist corporatism and use far less energy doing so by avoiding the stupidity of advertised consumption habits.

      A second area of huge energy loss is regained by recognizing the human body is only15% efficient and the excrement therefore contains 85% of the original food value.

      Imagining a future where humans are surviving as happy and health beings is easier for me starting from the poor and undeveloped majority than from the advanced economies which are designed to grow faster and faster to infinity.

    • August 3, 2017 at 7:52 am

      Heterodox usually refers to holding views or beliefs contrary to or different from an acknowledged standard, a traditional form, or an established religion. Unorthodox and unconventional are frequently used as synonyms. In his time Galileo was a heterodox physical scientist. Today, “string” theory in physics is heterodox. Relativity in 1905 was heterodox. Heterodox has a long history in science, in religion, and even politics. In 1700 democracy was heterodox.

      Unlike religion and politics scientists developed a methodology to deal with heterodox science. It’s called “peer review.” The goal of peer review is to develop a consensus among scientists in an area of study. The process assumes that scientific work completed and written up can be reviewed by other scientists who assess the validity and value of its hypotheses, methods, observations, and findings. Thus, ranking scientific work and conclusions from least to most valid and valuable. Over years, sometimes decades the reviews have the potential to create consensus on specific scientific questions. The current consensus on climate change has been developed over 200+ years. You can track this process on the website of the American Association for the Advancement of Science (https://www.aaas.org, especially https://www.aaas.org/climate50). Be careful in searching for other sources on the process. Dozens of fake and semi-fake sites have been created over the last 10 years that are just covers for denying climate change science.

    • José M. Sousa
      August 3, 2017 at 9:57 am

      «the 98% of climatologists that work with the IPCC » They don´t work with the IPCC. The IPCC – some of those 98% – just reviews their work.

    • José M. Sousa
      August 3, 2017 at 10:00 am

      «Science is not a matter of consensus and – unfortunately – it is extremely easy for the «powers that be», to control the «lines of research that are to be pursued or not». (that’s «101» of «Sociology of Science»…)» In the specific field of climate change this is ridiculous!

      • José M. Sousa
        August 3, 2017 at 11:12 am

        For the simple reason that the «powers that be» are those of fossil fuels, that overwhelmingly power our modern economies. Those are the ones that don´t want to hear about climate change.

    • José M. Sousa
      August 3, 2017 at 10:09 am

      You should try to read the actual reports of the IPCC. There you could find something about thorium and development issues in general associated to climate change:

      «Alternative nuclear fuel cycles, beyond the once-through uranium
      cycle, and related reactor technologies are under investigation. Partial
      recycling of used fuels, such as the use of mixed-oxide (MOX)
      fuels where U-235 in enriched uranium fuel is replaced with recycled
      or excess plutonium, is utilized in some nations to improve uranium
      resource utilization and waste-minimization efforts (OECD and NEA,
      2007; World Nuclear Association, 2013). The thorium fuel cycle is an
      alternative to the uranium fuel cycle, and the abundance of thorium
      resources motivates its potential use (see Section 7.4.3). Unlike natural
      uranium, however, thorium does not contain any fissile isotopes. An
      external source of fissile material is necessary to initiate the thorium
      fuel cycle, and breeding of fissile U-233 from fertile Th-232 is necessary
      to sustain the fuel cycle (IAEA, 2005b).» http://www.ipcc.ch/pdf/assessment-report/ar5/wg3/ipcc_wg3_ar5_chapter7.pdf

  7. August 2, 2017 at 8:56 pm

    One more data point for the model.

    “”All of the foods that we or any animal eat are incorporated after digestion into body tissues. Most Americans, for example, chemically look like walking corn cobs because the foods we eat contain so much corn syrup.”


  8. August 3, 2017 at 3:20 pm

    Wow… Where, in my posting did I deny «climate change»?!… It is changing all the time… It has been changing for millions of years… Where in my posting did I deny that coal-fired plants increase the emission of CO2?… And where in my posting did I even mention (or deny…) the immense possibilities of new technologies (coming up all the time) not only to save energy but also to produce clean energy without the use of fossil fuels?…
    But the bashing and «recommendations to go and read this and that all “peer-reviewed”» (then again, here comes «the Sociology of Science…»…), is but a sad reflection of the type of debate that is offered to whoever just dares to «sing out of tone»…
    In the meantime, I am quite happy to upload to this blog – in due time and after translation time – the script of a «power point» of a lecture that I have prepared and delivered a couple of times under the theme «Energy, Environment and Civilization»… The aim of that «lecture» is quite simply to enable citizens in general to have a better understanding of what is at stake. So that there is more support for the ecological movement in general… But then it seems, for some strange/awkward reason, that is not easy to any a polite discussion on this subject. Also, as a side remark, with «allies» such as Trump and Lord Monckton, who needs «adversaries» in any discussion of climate change?… Have a nice day ;)

    • José M. Sousa
      August 3, 2017 at 4:44 pm

      It is you that used expressions such as “red herring”, insinuating all the 98% scientists are manipulated, insinuating this is all about Al Gore´s manipulation, denying anthropogenic climate change by saying climate always changed, repeating ad nauseam arguments that have been longtime deconstructed, citing discredited climatologists and proposing solutions that are manifestly inadequate for the nature and magnitude of the problem.

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