Category Archives: Ocean sediment

The Ocean2K “Hockey Stick”

The long-awaited (and long overdue) PAGES2K synthesis of 57 high-resolution ocean sediment series (OCEAN2K) was published a couple of weeks ago (see here here). Co-author Michael Evans’ announcement made the results sound like the latest and perhaps most dramatic Hockey Stick yet: Today, the Earth is warming about 20 times faster than it cooled during the past 1,800 […]

Important New North American East Coast Proxy Data

One of my long-standing interests is the location of ocean sediment series that enable apples-to-apples comparison of the 20th century to the mid-Holocene.   These are not nearly as common as one would think.   Ocean sediment series covering the Holocene typically stop prior to the 20th century due to core recovery problems and, on […]

Ground-truthing Marcott

The MD99-2275 core offshore Iceland is a very high-resolution ocean sediment core, results of which over the past millennium have been discussed here from time to time. Alkenone and diatom results for the last millennium have been available for about 10 years. MD99-2275 results were used in PAGES2K Arctic and Hanhijarvi 2013, also Trouet et […]

New Data and Upside-Down Moberg

I’ve been re-examining SH proxies for some time now, both in connection with PAGES2K and out of intrinsic relevance.  In today’s post, I’ll report on a new (relatively) high-resolution series from  the Arabian Sea offshore Pakistan (Boll et al 2014, Late Holocene primary productivity and sea surface temperature variations in the northeastern Arabian Sea: implications […]

Rosenthal et al 2013

There has been considerable recent attention to Rosenthal et al 2013: WUWT here, Judy Curry here, Andy Revkin here. The article itself presents a Holocene temperature reconstruction that is very much at odds both with Marcott et al 2013 and Mann et al 2008. And, only a few weeks after IPCC expressed great confidence in […]

The Impact of TN05-17

TN05-17 is by far the most influential Southern Hemisphere core in Marcott et al 2013- it’s Marcott’s YAD061, so to speak. Its influence is much enhanced by the interaction of short-segment centering in the mid-Holocene and non-robustness in the modern period. Marcott’s SHX reconstruction becomes worthless well before the 20th century, a point that they […]

Alkenone Divergence offshore Iceland

The longest very high-resolution alkenone core that I’m aware of is Sicre et al’s MD99-2275 (plus splices) from offshore Iceland (67N 18W). It is 4550 years long, its most recent value is 2001AD and its resolution is 4 years. Marcott used nearby core JR51GC-35 (also at 67N 18W), also an alkenone record, which had a […]

Alkenone Divergence in Peru

Gutierrez et al (GRL 2011) pdf here; data here is another very high resolution alkenone series that is well-dated in the 20th century. It was taken in an upwelling zone offshore Peru at a similar latitude to Quelccaya. Like the high-resolution series offshore Morocco and Namibia, it shows a sharp decline in alkenone-estimated SST in […]

Alkenone Divergence

While there are disappointingly few high-resolution alkenone ocean cores with 20th century resolution, there are a few. Given the importance of this class of proxy in Marcott et al, one would have thought the performance of high-resolution alkenones in the 20th century would have been of interest to Marcott et al, but they were silent […]

Bent Their Core Tops In

In today’s post, I’m going to show Marcott-Shakun redating in several relevant cases. The problem, as I’ve said on numerous occasions, has nothing to do with the very slight recalibration of radiocarbon dates from CALIB 6.0.1 (essentially negligible in the modern period in discussion here), but with Marcott-Shakun core top redating.


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