Sunday, August 23, 2015

Open Thread - Science Division

Some things which caught Eli's Eye, but, it being summer, only a few comments from the meadow are likely.

- A really interesting paper in Climate of the Past Discussions, a collaboration between the PAGES2K (turbo proxy reconstructions) and PIMP3  PMIP3 (modeling of the past) groups "Continental-scale temperature variability in PMIP3 simulations and PAGES 2k regional temperature reconstructions over the past millennium" which will not bring smiles in certain quarters.  Warning, it is another Hansen, et al seventy pager.  To quote from the abstract:

Here, the recent set of temperature reconstructions at the continental scale generated by the PAGES 2k project and the collection of state-of-the-art model simulations driven by realistic external forcings following the PMIP3 protocol are jointly analysed. The first aim is to estimate the consistency between model results and reconstructions for each continental-scale region over time and frequency domains. Secondly, the links between regions are investigated to determine whether reconstructed global-scale covariability patterns are similar to those identified in model simulations. The third aim is to assess the role of external forcings in the observed temperature variations. From a large set of analyses, we conclude that models are in relatively good agreement with temperature reconstructions for Northern Hemisphere regions, particularly in the Arctic. This is likely due to the relatively large amplitude of the externally forced response across northern and high latitudes regions, which results in a clearly detectable signature in both reconstructions and simulations. Conversely, models disagree strongly with the reconstructions in the Southern Hemisphere.
It is not clear whether one should trust the models or the reconstructions, if for no other reason than there are fewer proxy's from the South.  Get busy.

- And indeed some have.  In a related development Sigi and about twenty others, settle the issue of when volcanic  eruptions took place in the past by aligning ice core proxy records.   "Timing and climate forcings of volcanic eruptions for the past 2,500 years"(no open source at the moment) provides a huge lever for the paleoclimate types to move their work forward on both the physical and historical levels.
Volcanic eruptions contribute to climate variability, but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice cores and subsequent cooling from climate proxies such as tree rings. Here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual-to-decadal temperature variability in the Northern Hemisphere during the past 2,500 years. Our results are based on new records of atmospheric aerosol loading developed from high-resolution, multi-parameter measurements from an array of Greenland and Antarctic ice cores as well as distinctive age markers to constrain chronologies. Overall, cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes. Our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth-century pandemics, famines, and socioeconomic disruptions in Eurasia and Mesoamerica while allowing multi-millennium quantification of climate response to volcanic forcing.
Variation in timing smears out and diminishes the effects of large eruptions and disappears that of smaller ones.  This new work, and aligning it with PAGES2K certainly requires a re-evaluation of Maas and Portman who in 1989 concluded that only the effects of the larges eruptions could be seen in the climate record records.

IEHO comparison of PAGES2K regional reconstructions using the Sigi et al chronology will allow major progress in identifying the sites of the smaller (and some of the larger) eruptions as well as refining estimates of global and regional volcanic forcings.  This, in turn will drive progress in paleoclimate modeling as well as estimation of immediate and equilibrium climate sensitivity.

Consider this an open thread.


Victor Venema said...

Warning, it is another Hansen, et al seventy pager.

I guess he is too busy to write a concise manuscript.

Victor Venema said...

Misinterpreted that sentence. See that Hansen was not involved.

EliRabett said...

Sometimes Eli is obscure by accident

BBD said...

Er, Eli, in your second sentence, that would be PMIP not the other thing ;-)

EliRabett said...

Yes, rabetts suffer from dyslexia

Barton Paul Levenson said...

I would really like to have a good time series for volcanic activity. The DVI only goes up through 1995 even with the extension, and aerosol time series tend to go no further back than 1900 and to end around 2000. If anyone can put me onto a comprehensive volcanic time series, I'd say thankee-sai.

afeman said...

Neither science nor meta, but policy, sort of. Maybe something for an "individual action" thread.

Rich Pulchasky, commenting at Crooked Timber, makes a vigorous argument (unbeloved by many) that a person's time, effort, and money are better spent putting the lever on institutions than installing PV on your house or whatever. As an example he notes that getting a single powerplant to reduce emissions by 1% achieves the same as 4600 people doing the full Amish.

This could be off by orders of magnitude and still be way ahead.


Blogger profile said...

Solar power on your own home, if not overengineered, is a good way of combating the problem. You use less power from fossil fuels, less money FOR fossil fuel exploiting industries, and the price of renewables drop even further from economies of scale and wide competition.

Indeed it is the two-hit punch of "not paying them for their electricity" and "make solar cheaper" that IS a lever on those industries.

Because remember this: you are not a customer, you are a CONSUMER. You have no choice but to buy, and the only choice you have is "from whom?". The industry can therefore discard customer service and just be equally bad for all their customers. Sure you'll lose some, but you'll gain people leaving their previous bad supplier, hoping you'll be better. And poor customer service is both easier to maintain AND cheaper and therefore profitable, so a natural and unforced collusion will form: any member trying to do better will either lose money (and how will customers know they're better? Every other company claim they are customer focussed and a winner in "What the heck, they provide power" some years ago, so no flood of users) in the expense of providing that service or have to charge more (and who picks an unknown that is more expensive? Not a large number of people).

The only leverage you have is to become a customer who CAN choose not to play NOT a consumer forced to pick who to play with.