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Unforced Variations: Mar 2016

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This month’s open thread. Pros and cons of celebrity awareness-raising on climate? The end of the cherry-picking of ‘pauses’ in the satellite data? Continuing impacts of El Niño? Your choice (except for the usual subjects to be avoided…).

Unforced Variations: Feb 2016

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This month’s open thread.

Just so you know, a lot of people have complained that these threads have devolved – particularly when the discussion has turned to differing visions of solutions – and have therefore become much less interesting. Some suggestions last month were for a side thread for that kind of stuff that wouldn’t clog interesting issues of climate science. Other suggestions were for tighter moderation. The third suggestion is that people really just stay within the parameters of what this site has to offer: knowledgeable people on climate science issues and context for the science that’s being discussed elsewhere. For the time being, let’s try the last one, combined with some moderation. The goal is not to censor, but rather to maintain somewhere where the science issues don’t get drowned out by the noise.

Unforced variations: Jan 2016

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Happy New Year, and happy new open thread.

As per usual, nuclear energy is off-topic – it’s not that it’s uninteresting, but it ends up dominating conversation to the total exclusion of everything else and just becomes repetitive and dull. Recent excursions on this topic shows what happens when we relax the moderation, so back to being strict about this. If you want to discuss this, please go somewhere else.

Hiatus or Bye-atus?

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Guest commentary by Stephan Lewandowsky, James Risbey and Naomi Oreskes

The idea that global warming has “stopped” has long been a contrarian talking point. This framing has found entry into the scientific literature and there are now numerous articles that address a presumed recent “pause” or “hiatus” in global warming. Moreover, the “hiatus” also featured as an accepted fact in the latest IPCC report (AR5). Notwithstanding its widespread use in public and apparent acceptance in the scientific community, there are reasons to be skeptical of the existence of a “hiatus” or “pause” in global warming [Ed: see also this previous post]. We have examined this issue in a series of three recent papers, which have converged on the conclusion that there is not now, and there never has been, a hiatus or pause in global warming.

[Read more…] about Hiatus or Bye-atus?

And the winner is…

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Remember the forecast of a temporary global cooling which made headlines around the world in 2008? We didn’t think it was reliable and offered a bet. The forecast period is now over: we were right, the forecast was not skillful.

Back around 2007/8, two high-profile papers claimed to produce, for the first time, skilful predictions of decadal climate change, based on new techniques of ocean state initialization in climate models. Both papers made forecasts of the future evolution of global mean and regional temperatures. The first paper, Smith et al. (2007), predicted “that internal variability will partially offset the anthropogenic global warming signal for the next few years. However, climate will continue to warm, with at least half of the years after 2009 predicted to exceed the warmest year currently on record.” The second, Keenlyside et al., (2008), forecast in contrast that “global surface temperature may not increase over the next decade, as natural climate variations in the North Atlantic and tropical Pacific temporarily offset the projected anthropogenic warming.”

This month marks the end of the forecast period for Keenlyside et al and so their forecasts can now be cleanly compared to what actually happened. This is particularly interesting to RealClimate, since we offered a bet to the authors on whether the results would be accurate based on our assessment of their methodology. They ignored our offer but now the time period of the bet has passed, it’s worth checking how it would have gone.

[Read more…] about And the winner is…

References

  1. D.M. Smith, S. Cusack, A.W. Colman, C.K. Folland, G.R. Harris, and J.M. Murphy, "Improved Surface Temperature Prediction for the Coming Decade from a Global Climate Model", Science, vol. 317, pp. 796-799, 2007. http://dx.doi.org/10.1126/science.1139540
  2. N.S. Keenlyside, M. Latif, J. Jungclaus, L. Kornblueh, and E. Roeckner, "Advancing decadal-scale climate prediction in the North Atlantic sector", Nature, vol. 453, pp. 84-88, 2008. http://dx.doi.org/10.1038/nature06921