The principle of parsimony says that simpler explanations are to be preferred. Even I as a poor dimwitted social scientist know that to be a basic axiom in science. So why is it an amazing discovery that “The timing and the amplitude of temperature changes [in the Northern Hemisphere] are reproduced in the tropical temperatures. The patterns are incredibly similar.”?

Surely normal, well-known principles of gaseous and heat diffusion would lead us to expect that without invoking carbon dioxide?

And the “discovery” that warming tends to be global will surely come as no surprise to Al Gore and all the other preachers of global warming! They too appear to assume that normal, well-known principles of gaseous and heat diffusion would lead us to expect warming to be global.

To help others get on top of this momentous discovery, I follow the BBC summary of the article below with the original journal abstract

A “global pattern” of change in the Earth’s climate began 2.7 million years ago, say scientists. Researchers found that, at this point, temperature patterns in the tropics slipped into step with patterns of Ice Ages in the Northern Hemisphere.

They report in the journal Science that atmospheric CO2 could be the “missing link” to explain this global pattern.

The findings, they say, reveal a “feedback process” that could have been magnified by greenhouse gases. This loop of feedback could have intensified both the Ice Ages in the Northern Hemisphere, and temperature fluctuations in the tropics.

Professor Timothy Herbert from Brown University in Rhode Island, US, led the research. He and his colleagues, in the US and China, analysed mud cores from the seabed in the four tropical ocean basins – the Arabian Sea, the South China Sea, the eastern Pacific and the equatorial Atlantic Ocean.

These mud cores are laid down over millions of years – as sediments of dead plant and animal material sink to the ocean floor. So by analysing the chemical composition of this material – specifically the chemical remains of one ancient and tiny marine organism – the scientists were able to produce a timeline of temperature changes.

The team “found a fingerprint in the sequence of temperature changes” – a pattern that began 2.7 million years ago, Professor Herbert explained. He told BBC News: “The timing and the amplitude of temperature changes [in the Northern Hemisphere] are reproduced in the tropical temperatures. The patterns are incredibly similar.”

He added that the study provided the first direct evidence of a global pattern in climate change that dated back almost three million years. Professor Herbert added that the “best global mechanism” to explain this link was the level of atmospheric greenhouse gases.

Dr Carrie Lear, a palaeoclimate scientist from Cardiff University in the UK, agreed that carbon dioxide was the likely “culprit”. She told BBC News: “This study reveals a feedback process that has magnified climate change since the inception of Northern Hemisphere glaciation 2.7 million years ago. “It seems the tropical warming caused by high CO2 levels set off a chain of events resulting in additional greenhouse gases, including water vapour, being released to the atmosphere, thus causing further warming.”

Dr Lear said that such studies of past climate change were “invaluable in understanding the current climate system, and hence predicting future change”.

SOURCE

Tropical Ocean Temperatures Over the Past 3.5 Million Years

By Timothy D. Herbert et al.

Determining the timing and amplitude of tropical sea surface temperature (SST) change is an important part of solving the puzzle of the Plio-Pleistocene ice ages. Alkenone-based tropical SST records from the major ocean basins show coherent glacial-interglacial temperature changes of 1° to 3°C that align with (but slightly lead) global changes in ice volume and deep ocean temperature over the past 3.5 million years. Tropical temperatures became tightly coupled with benthic {delta}18O and orbital forcing after 2.7 million years. We interpret the similarity of tropical SST changes, in dynamically dissimilar regions, to reflect “top-down” forcing through the atmosphere. The inception of a strong carbon dioxide–greenhouse gas feedback and amplification of orbital forcing at ~2.7 million years ago connected the fate of Northern Hemisphere ice sheets with global ocean temperatures since that time.

Science 18 June 2010: Vol. 328. no. 5985, pp. 1530 – 1534

Posted by John J. Ray (M.A.; Ph.D.). For a daily critique of Leftist activities, see DISSECTING LEFTISM. To keep up with attacks on free speech see TONGUE-TIED. Also, don’t forget your daily roundup of pro-environment but anti-Greenie news and commentary at GREENIE WATCH . Email me here

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