If you want my immediate reaction, I think Mann has gone too far this time to erase natural variability. Mann has been one of those who have previously identified a clear ~60 year semiperiodic signal in the North Atlantic, and now he argues that it's doesn't really exist? Now, such multidecadal variations have been poorly understood. Curry et al. have attempted to shed some light on this through the stadium-wave hypothesis, the propagation of various oscillations creating a low-frequency signal, and perhaps Mann is trying to shoot every bit of this idea down. But even if something is poorly understood, it doesn't mean that it can't exist.
Anyway, it's a bold conclusion. The oscillations should lead to more sea ice around Svalbard in the coming decades (but since the period and amplitudes may not be very regular, it's hard to tell by how much). Given the current global warming trend, a such increase in sea ice would be very difficult to explain if these oscillations don't exist. So it will be interesting to see how this ends.
Speaking of Svalbard, Longyear airport just had its 108th consecutive month with above normal temperatures in December, which ended at -10.8C. The 1961-1990 normal is -13.4C. The previous 1931-1960 normal, however, is -9.9C, and the new 1991-2020 normal seems to become about -9.3C. I wonder if Mann is suggesting that this -9.9C, -13.4C, -9.3C apparent climatic variation is incorrect. There is no official 1901-1930 normal, but I'm pretty sure using the limited data available data will indicate a temperature well below -9.9C. The winters of the 1910's were extremely cold.
I found his conclusions a little extreme also. There are clear multidecadal oscillations of varying lengths. The interesting thing is when you superimpose a anthropogenic signal on top of that, does the result change from a historical perspective? That would have major implications for the value of using analogs in long range weather forecasting (beyond a couple of weeks.) For example, around here, the major discussion has been that the weather is not behaving like its current ENSO state. We are going into a historically warm pattern for January that is supposed to last for multiple weeks, it's like a more extreme ENSO pattern than what it actually is.
On a different topic, look up the series Blue Planet 2 on BBC America. It's EXCELLENT. It shows the vast variety of life in the depths of the oceans and what warming is doing to them. The answer to deep sea drilling should be a perpetual NO! 90% of all life lives down there and life may have started down there and the life there is so magnificently alien-like that I cant help but think that actual alien life would be like that. They showed fish with transparent heads where you can see their brains through their skulls (so they can look up without having to move their heads, they can actually look through their skulls!), fish that communicate by flashing different patterns of lights (we still dont know what they are saying to each other) and fish discovered 6km down that have actual feet and walk on the ocean floor and one particularly weird fish with two different sized eyes, one that always looks down and the other (much larger) that always looks up! They showed a part about coral reefs and what bleaching is doing to them and all the species dependent on them including clown fish that actually build homes inside the reefs and keep them clean.
The winters during both world wars were extremely cold here also, the two cold "champions" being 1917-18 and 1942-43. It was around -13F in December in 1917 and I haven't found any other temp in any other December in any other year even close to that. 1942-43 was the last time we had multiple lows of below zero F and the last time we had a low that was colder than -2F 1933-34 was our coldest winter with a -15F in February, but outside of that winter, the 30s were mild. The abrupt change to consistently mild weather began in the 1950s around here, with a bit of a reprieve during the 60s and 70s, but resumption during the 80s and accelerating afterwards. Our increase in precip from around 42 in per year to over 50 in per year began around 2000 along with a big increase in large precip events (both rain and snow).
Also, I know this has been talked about before, but I recently read this:https://www.sciencemag.org/news/2017/07 ... -you-about
The best way to reduce your carbon footprint is one the government isn’t telling you about
By Sid PerkinsJul. 11, 2017 , 4:30 PM
Recycling and using public transit are all fine and good if you want to reduce your carbon footprint, but to truly make a difference you should have fewer children. That’s the conclusion of a new study in which researchers looked at 39 peer-reviewed papers, government reports, and web-based programs that assess how an individual’s lifestyle choices might shrink their personal share of emissions.
Many commonly promoted options, such as washing clothes in cold water or swapping incandescent bulbs for light-emitting diodes, have only a moderate impact (see chart, below), the team reports today in Environmental Research Letters. But four lifestyle choices had a major impact: Become a vegetarian, forego air travel, ditch your car, and—most significantly—have fewer children.