Month: January 2016

reblogged from Climate Etc.
Undersea volcanoes may be impacting long-term climate change

by Alan Longhurst

I think this paper on on ocean tides, sea-floor volcanoes and Milankevitch cycles is a game changer.

Mid-ocean ridge eruptions as a climate valve

Maya Tolstoy

Abstract. Seafloor eruption rates and mantle melting fueling eruptions may be influenced by sea level and crustal loading cycles at scales from fortnightly to 100 kyr. Recent mid-ocean ridge eruptions occur primarily during neap tides and the first 6 months of the year, suggesting sensitivity to minor changes in tidal forcing and orbital eccentricity. An ~100 kyr periodicity in fast-spreading seafloor bathymetry and relatively low present-day eruption rates at a time of high sea level and decreasing orbital eccentricity suggest a longer-term sensitivity to sea level and orbital variations associated with Milankovitch cycles. Seafloor spreading is considered a small but steady contributor of CO2 to climate cycles on the 100 kyr time scale; however, this assumes a consistent short-term eruption rate. Pulsing of seafloor volcanic activity may feed back into climate cycles, possibly contributing to glacial/interglacial cycles, the abrupt end of ice ages, and dominance of the 100 kyr cycle.

M. Tolstoy, Mid-ocean ridge eruptions as a climate valve, doi:10.1002/2014GL063015, Geophys. Res. Lett. 2015 [abstract] [manuscript]

A post at WUWT includes the press release from Columbia University

The AGU also issued a press release [link]

Source: On the likelihood of recent record warmth

Judith Curry’s conclusions regarding the much publicized paper by Mann et al. in Nature:

As I see it, this paper is a giant exercise in circular reasoning:

1. Assume that the global surface temperature estimates are accurate; ignore the differences with the satellite atmospheric temperatures
2. Assume that the CMIP5 multi-model ensemble can be used to accurately portray probabilities
3. Assume that the CMIP5 models adequately simulate internal variability
4. Assume that external forcing data is sufficiently certain
5. Assume that the climate models are correct in explaining essentially 100% of the recent warming from CO2

In order for Mann et al.’s analysis to work, you have to buy each of these 5 assumptions; each of these is questionable to varying degrees.

In a study presented at the American Geophysical Union on December 17, 2015, Watts et al showed that the land-based meteorological sites used for measuring temperature in the continental United States (CONUS) yield more than 50% bias in the 30-year trend for temperature change.  READ MORE…

The latest version of HadCRUT4 (a collaborative product of the Met Office Hadley Centre and the Climatic Research Unit at the University of East Anglia), one of the major ground-based global temperature sets, is significantly and obviously diverging from the projections made by the CMIP5 computer models, which are featured prominently in the IPCC AR5 published in 2013-14.  READ MORE…

The latest data indicate it is likely that the current El Niño has peaked and that while similar to the 1997-98 El Niño, it is not quite as strong either 1997-98 or 1982-83. READ MORE…

You may have seen this graph or similar ones promulgated by the Environmental Protection Agency purporting to show a dramatic increase in US Wildfire damage since 1983. READ MORE…

As expected, 2015 came in a distant third place to 2010 and 1998 for warmest year on record, according to the latest lower troposphere temperature data from both Remote Sensing Systems and the University of Alabama at Huntsville, the two independent organizations that maintain and report on satellite temperature data. READ MORE…