Category Archives: climate

Holocene forcing, trends and conundrums

Before  Marcott et al (2013) published their synthesis of over 70 Holocene palaeoclimate reconstructions, I didn’t have a strong expectation of how global annual mean temperature should vary over the Holocene, except that changes would be small relative to glacial-interglacial changes. Marcott et … Continue reading

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Seasonally biased proxies and the Holocene temperature conundrum

Last year, Marcott et al (2013) published a synthesis of Holocene proxy temperature records showing a warm early Holocene followed by a slight cooling in the mid and late Holocene. Liu et al, in a paper to be published in PNAS, … Continue reading

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Early warning signals before the Bølling transition

Towards the end of the last glaciation, as solar insolation at high latitudes slowly increased as the Earth’s orbit changed, the climate over Greenland suddenly tipped from a glacial climate to an interglacial climate — a warming of over 10°C — in a … Continue reading

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The tropical thermostat is broken

I mainly work on Holocene and late glacial palaeoclimate, occasionally delving back as far as the last glacial maximum, but the tools I use are of value for reconstructing climate over a longer period, albeit with greater uncertainty. The Pliocene, … Continue reading

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Scroll bar defeats Lord Monckton

I’ve been watching some of the videos from the Heartland’s fake climate conference in Las Vegas. It is the real cargo cult: all the trappings of a real conference, none of the substance. Lord Monckton has a lunchtime keynote: light … Continue reading

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Thoughts on tipping points relevant to Praetorius & Mix (2014)

Tipping points are scary. The response of climate and other environmental systems to external forcing might not be a gradual, reversible change but a flip from one stable state to another. It may be very difficult to reverse this transition. … Continue reading

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A minimal model for estimating climate sensitivity

One of the classic tells that a fake climate skeptic is trying to squeeze a weak paper into the literature is that they submit it to a journal where it falls outside the usual scope of papers published there. The problem … Continue reading

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This is a “good” solar-proxy correlation

It has been a while since I have posted a review of a paper purporting to find a correlation between a proxy and solar activity. This is not for lack of interest — plans are developing for a meta-analysis, but some … Continue reading

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A biased and incomplete summary of Sea Ice Proxy workshop

Sea-ice is an important component of the Earth’s climate system, for example, it greatly increases the proportion of sunlight reflected at high latitudes – the albedo of ice is ~0.6 whereas it is only 0.1 for open water. Because of … Continue reading

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Small tornado in Bremerhaven

The last couple of days I’ve been discussing sea-ice reconstructions at the Pages Sea-Ice Proxy workshop in Bremerhaven. A huge range of proxies have been presented, ranging from traces of halogens in ice cores to transfer function based reconstructions. One … Continue reading

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