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If you look to the paper the article is about - 'A limited role for unforced internal variability in 20th century warming.' - it does seem to demonstrate that n

If you look to the paper the article is about - 'A limited role for unforced internal variability in 20th century warming.' - it does seem to demonstrate that natural cycles play small role and the way it is set up it doesn't have to look at all natural cycles to do that. >Using a two-box impulse response model, we demonstrate that multidecadal ocean variability was unlikely to be the driver of observed changes in global mean surface temperature (GMST) after 1850 A.D. Instead, virtually all (97-98%) of the global low-frequency variability (> 30 years) can be explained by external forcing. We find similarly high percentages of explained variance for inter-hemispheric and land-ocean temperature evolution. edit - link to paper - https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0555.1?af=R& https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0555....

taneq 7y ago
It still seems ass-about to me. The study doesn't show that natural cycles don't do much, it shows that in our models the external forcing they added is sufficient to cause the observed results. We already know there's more going on than our models account for (consider the post-9/11 discovery of global dimming from airliner exhausts, as one example). There are probably a heap of effects pushing the measured temperatures in each direction that we don't yet know about. (Note that I'm not saying natural cycles ARE responsible for the bulk of observed warming - just that this research doesn't seem to prove they're NOT.)
- inflatableDodo 7y ago
  >(Note that I'm not saying natural cycles ARE responsible for the bulk of observed warming - just that this research doesn't seem to prove they're NOT.) Well it can't, can it? All it can do is provide evidence one way or another. Now if you think that there is a problem in the model they are using, could you point to it and explain the specific issue? I assume that it is somewhat updated since 9/11 and I also suspect that aerosol effects of airliner exhausts will have been known about to the subject of atmospheric physics, 9/11 will have just given some solid numbers. Which are now presumably in the models.
  - taneq 7y ago
    OK, OK, I was using laymans' terms. If you want to get picky about can't-prove-a-negatives then read it as "this research doesn't seem to provide much evidence that they're NOT."
    - inflatableDodo 7y ago
      If you think that there is a problem in the model they are using, could you point to it and explain the specific issue?
- snowwrestler 7y ago
  It's worth noting that the 9/11 U.S. insolation study showed a human-created mitigating factor, not a causal factor. That is, it showed that high-altitude contrails create clouds high enough to raise the average albedo and reflect solar energy that otherwise would reach the surface. This is, to some extent, "hiding" a portion of the true warming one would expect from the current mix of the atmosphere and solar activity. That doesn't offer evidence either way for a hypothesis that there are natural processes yet undescribed that could surprise us with their contribution to warming. Discovering one new thing about a complex phenomenon doesn't make it more likely that another new thing is out there to be discovered. If anything, it makes it less likely, on the theory that there are a finite number of factors contributing to a result of given significance in a deterministic system--in this case, global average temperature trend. And anyway, what we're really worried about is long-term warming, and this paper is not about that. It's about factors that contribute to temperature variance on shorter time scales during the known long-term warming. From the article: > However, the relative influences of natural drivers of climate change – such as volcanic eruptions, ocean cycles, and the sun – on warmer and cooler phases superimposed on the long-term warming trend is still an area of active research. There are two levels to the question of global warming. One is the overall, global question--are we making the surface of the Earth warmer by burning fossil fuels? This is a relatively simple question to answer, so simple that it was first proposed over a century ago, basically when thermodynamics was being invented. Very little contemporary research goes toward answering this question; it has basically been answered. The other level is: can we predict the consequences of this warming at time scales and resolutions relevant to human society? This is an incredibly complex endeavor and where the bulk of contemporary time and resources are spent (including this paper).
  - taneq 7y ago
    I wasn't trying to show that there are specifically natural factors as yet undescribed, just that there was a significant factor that we didn't know about until recently. This indicates that we could easily have missed others (natural or otherwise), and so any argument which assumes that our climate models are complete is flawed from the start. > what we're really worried about is long-term warming, and this paper is not about that Well, it sort of is, because it's saying that the argument against long term warming is that our short term observations are being caused by some cyclic behaviour rather than human CO2 emissions. We can't just carve off "long term warming" as a separate already-agreed thing (at least, not using the results in this paper).

taneq 7y ago

It still seems ass-about to me. The study doesn't show that natural cycles don't do much, it shows that in our models the external forcing they added is sufficient to cause the observed results. We already know there's more going on than our models account for (consider the post-9/11 discovery of global dimming from airliner exhausts, as one example). There are probably a heap of effects pushing the measured temperatures in each direction that we don't yet know about. (Note that I'm not saying natural cycles ARE responsible for the bulk of observed warming - just that this research doesn't seem to prove they're NOT.)

inflatableDodo 7y ago
>(Note that I'm not saying natural cycles ARE responsible for the bulk of observed warming - just that this research doesn't seem to prove they're NOT.) Well it can't, can it? All it can do is provide evidence one way or another. Now if you think that there is a problem in the model they are using, could you point to it and explain the specific issue? I assume that it is somewhat updated since 9/11 and I also suspect that aerosol effects of airliner exhausts will have been known about to the subject of atmospheric physics, 9/11 will have just given some solid numbers. Which are now presumably in the models.
- taneq 7y ago
  OK, OK, I was using laymans' terms. If you want to get picky about can't-prove-a-negatives then read it as "this research doesn't seem to provide much evidence that they're NOT."
  - inflatableDodo 7y ago
    If you think that there is a problem in the model they are using, could you point to it and explain the specific issue?
snowwrestler 7y ago
It's worth noting that the 9/11 U.S. insolation study showed a human-created mitigating factor, not a causal factor. That is, it showed that high-altitude contrails create clouds high enough to raise the average albedo and reflect solar energy that otherwise would reach the surface. This is, to some extent, "hiding" a portion of the true warming one would expect from the current mix of the atmosphere and solar activity. That doesn't offer evidence either way for a hypothesis that there are natural processes yet undescribed that could surprise us with their contribution to warming. Discovering one new thing about a complex phenomenon doesn't make it more likely that another new thing is out there to be discovered. If anything, it makes it less likely, on the theory that there are a finite number of factors contributing to a result of given significance in a deterministic system--in this case, global average temperature trend. And anyway, what we're really worried about is long-term warming, and this paper is not about that. It's about factors that contribute to temperature variance on shorter time scales during the known long-term warming. From the article: > However, the relative influences of natural drivers of climate change – such as volcanic eruptions, ocean cycles, and the sun – on warmer and cooler phases superimposed on the long-term warming trend is still an area of active research. There are two levels to the question of global warming. One is the overall, global question--are we making the surface of the Earth warmer by burning fossil fuels? This is a relatively simple question to answer, so simple that it was first proposed over a century ago, basically when thermodynamics was being invented. Very little contemporary research goes toward answering this question; it has basically been answered. The other level is: can we predict the consequences of this warming at time scales and resolutions relevant to human society? This is an incredibly complex endeavor and where the bulk of contemporary time and resources are spent (including this paper).
- taneq 7y ago
  I wasn't trying to show that there are specifically natural factors as yet undescribed, just that there was a significant factor that we didn't know about until recently. This indicates that we could easily have missed others (natural or otherwise), and so any argument which assumes that our climate models are complete is flawed from the start. > what we're really worried about is long-term warming, and this paper is not about that Well, it sort of is, because it's saying that the argument against long term warming is that our short term observations are being caused by some cyclic behaviour rather than human CO2 emissions. We can't just carve off "long term warming" as a separate already-agreed thing (at least, not using the results in this paper).