To no-one’s great surprise, 2015 was clearly a record year in all the surface temperature analyses (GISTEMP, NOAA, HadCRUT4, Cowtan&Way, JMA + Berkeley Earth). There is a lot of discussion of this in the press, and on the relevant websites, so not much to add here. A few figures didn’t make it into the official announcement (audio) though…
Climate Science
Marvel et al (2015) Part 2: Media responses
This is a second post related to the new Marvel et al (2015) paper. The first post dealing with the substantive content is here.
What with #AGU15 going on, and a little bit of overlap in content with Shindell (2014), NASA wasn’t particularly keen to put out a press release for the paper, but we did get a ‘web special‘ put out on Friday Dec 18th, the last day of AGU and a few days after the paper appeared online. I’ve been involved with many similar releases for papers and it is always a struggle to concisely say why a paper is interesting while not overselling it or being too technical (which is why only a small fraction of papers get press releases at all).
As we’ve previously remarked about other people’s press releases (eg. Stainforth et al or Willerslev et al), properly calibrating the aspect of a release that will get picked up by the media can be tricky, and so it proved in this case.
[Read more…] about Marvel et al (2015) Part 2: Media responses
References
- K. Marvel, G.A. Schmidt, R.L. Miller, and L.S. Nazarenko, "Implications for climate sensitivity from the response to individual forcings", Nature Climate Change, vol. 6, pp. 386-389, 2015. http://dx.doi.org/10.1038/nclimate2888
Marvel et al (2015) Part 1: Reconciling estimates of climate sensitivity
This post is related to the substantive results of the new Marvel et al (2015) study. There is a separate post on the media/blog response.
The recent paper by Kate Marvel and others (including me) in Nature Climate Change looks at the different forcings and their climate responses over the historical period in more detail than any previous modeling study. The point of the paper was to apply those results to improve calculations of climate sensitivity from the historical record and see if they can be reconciled with other estimates. But there are some broader issues as well – how scientific anomalies are dealt with and how simulation can be used to improve inferences about the real world. It also shines a spotlight on a particular feature of the IPCC process…
[Read more…] about Marvel et al (2015) Part 1: Reconciling estimates of climate sensitivity
References
- K. Marvel, G.A. Schmidt, R.L. Miller, and L.S. Nazarenko, "Implications for climate sensitivity from the response to individual forcings", Nature Climate Change, vol. 6, pp. 386-389, 2015. http://dx.doi.org/10.1038/nclimate2888
Unforced variations: Jan 2016
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.
Unforced Variations: Dec 2015
#AGU15
So this week it’s the biggest Earth Science meeting on the planet…
There is a lot of great science that will be freely streamed via AGU On-Demand (registration required), and there’ll be a lot of commentary using the hashtag #AGU15. Many posters will be available online too. A few highlights have already been discussed by Victor Venema related to the surface temperature station datasets, but there’ll be much more on offer if you dig deeper.
As the week goes on, we’ll link to anything good we see, and we’ll be happy to host any commentaries that anyone has on specific climate sessions or talks.
Happy conferencing!
#COP21
Apparently there is a climate conference of some sort going on. Happy to answer any science questions as they arise…
Hiatus or Bye-atus?
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.
Reports of our demise…
… have of course been greatly exaggerated. But we are having some issues with our domain name. The back story is perhaps interesting to others, so here is quick summary of the situation.
Update: The account details have been restored and the domains renewed. We should be back to normal in a couple of days.
And the winner is…
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
- 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
- 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