Science and Technology links (July 25th 2020)

  1. I was taught that human beings only arrived to America recently (15,000 years ago). It turns out that it is wrong. There were human beings in America 30,000 years ago. (Source: Nature)
  2. Quantum tuneling is not instantaneous contrary to what you were told.
  3. The U.S. Air Force is planning to introduced a new automated combat aircraft. They call it Skyborg.
  4. The inexpensive supplement glucosamine seems to be associated with lower risks of death.
  5. The Roman empire thrived under warm conditions:

    This record comparison consistently shows the Roman as the warmest period of the last 2000 years, about 2 °C warmer than average values for the late centuries for the Sicily and Western Mediterranean regions. After the Roman Period a general cooling trend developed in the region with several minor oscillations. We hypothesis the potential link between this Roman Climatic Optimum and the expansion and subsequent decline of the Roman Empire.

    (Source: Nature)

    It is estimated that current global warming trends could lead to a global rise in temperature by more than 2 °C though less than 3 °C.

Published by

Daniel Lemire

A computer science professor at the University of Quebec (TELUQ).

5 thoughts on “Science and Technology links (July 25th 2020)”

  1. As a climate economist I must protest re current global warming trends: Only with drastic GHG emissions reduction measures, globally, do typical climate forecasts flatten out at some potentially palatable increases of maybe 2-3 degrees. Estimates under business-as-usual lead to continued warming by 4, 5, 6, and more degrees, essentially straight up as time continues, along with carbon concentration and cumulative emissions. This seems near absolute consensus among climate scientists (and economists), even if there is large uncertainty not least due to climate sensitivity (degree warming per carbon increase). It is not even clear when even just emission rates could fall without drastic measures in the near future.

    Sidenote admittedly without reading the quoted paper in full: Theories linking rise and fall of empires abound, that a 1-2 deg temperature change in its own right would have had a decisive (and maybe generalizable to today, that’s why its interesting at all, right?) influence for the fate of the Roman empire, does sound simply very unlikely to me – well and else it actually should probably mean any type of climate temperature change should generally worry us more than it does, independent of the exact level details.

    1. Estimates under business-as-usual lead to continued warming by 4, 5, 6, and more degrees, essentially straight up as time continues, along with carbon concentration and cumulative emissions. This seems near absolute consensus among climate scientists

      Here is a recent international assessment on this issue: a doubling of CO2 would (with high probability) lead to a 1.5‐4.5°C rise in temperature.

      If you think that more than a doubling of CO2 is likely in our lifetime, please provide a credible reference.

  2. Not sure our own lifetime should be center stage. As I wrote, in business-as-usual, I just have never heard any evidence for the warming increase (and carbon concentration indeed) to magically stop without further ado, and to do so (with some reasonable certainty) below 3 degrees, as your original statement seems to suggest. I’d be keen to understand whether you can provide evidence for this – if true very relieving – view? Carbon concentration is now near 420 ppm, up from the pre-industrial 280 ppm, i.e. half-way through towards doubling. Annual carbon emission rates have multiplied from 6 bn ton CO2/y in 1950 to some 37 bn ton in 2019 and seem to be continuing to rise, maybe there’s some hope they stop rising (thanks to considerable efforts), and maybe there’s hope concentrations stop doing what they did so far, rise convexely over the past 50 years.

    1. Not sure our own lifetime should be center stage.

      It is increasingly difficult to make predictions further in the future… 50 years, 100 years… 150 years…

      But it is a bit irrelevant. Three degrees is a lot. If you want to discuss what happens with 7 degrees…. well, that’s another discussion.

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