Tag Archives: climate change

Soaring Arctic temperatures – a warning from history

Soaring Arctic temperatures – a warning from history – environment – 09 July 2010 – New Scientist.

With carbon dioxide levels close to our own, the Arctic of the Pliocene epoch may have warmed much more than previously thought – and the modern Arctic could go the same way.

Ashley Ballantyne at the University of Colorado, Boulder, and colleagues analysed 4-million-year-old Pliocene peat samples from Ellesmere Island in the Arctic archipelago to find out what the climate was like when the peat formed.

At that time, CO2 levels are thought to have been close to current levels – around 390 parts per million – but global temperatures were around 2 to 3 °C warmer than today. It was the last warm period before the onset of the Pleistocene glaciation, and is used by climate researchers as a model for our future climate.

Previous studies using computer models have suggested that the Pliocene Arctic was also warmer than it is today – up to 10 °C warmer. A little warming can trigger a lot more in the Arctic because the loss of light-reflecting sea ice and the spread of plants across the land increase the amount of solar energy that is absorbed.

Peat heat

Ballantyne’s team estimated the temperature of the period at which the peat formed by measuring three things that are affected by temperature: the concentration of various chemical compounds, levels of a certain isotope in tree rings and the amount and types of fossilised vegetation.

The group’s analysis suggests the samples formed when average local temperatures were about -0.5 °C. That is 19 °C warmer than temperatures today – more than the previous computer models had estimated.

“These results should be alarming,” says Ballantyne. Although it could take centuries for current global temperatures to respond to rising CO2 levels, we can expect the Arctic to warm much more than the rest of the planet, he says.

Marci Robinson of the US Geological Survey in Reston, Virginia, agrees that Arctic warming is of concern, but doesn’t think it will match that of the Pliocene.

In a model study now in review, Robinson mathematically removed a seabed ridge that now stretches from Greenland to Scotland because it was much lower in the Pliocene. Without the ridge obstruction, warm water would have been able to travel more freely from lower latitudes to Arctic regions, allowing more warming, says Robinson. This would suggest that modern Arctic warming might fall about 5 °C short of that of the Pliocene. Even so, Robinson’s estimate means Arctic temperatures would rise by 14 °C.

BASE OF OCEAN FOOD CHAIN DYING!!! (avail on g-news for only a few hours..)

Beneath The Waves, Ctd

The Atlantic (blog) – ?18 hours ago?
The scientists I spoke with cite four basic reasons the initial eco-fears seem overblown. First, the Deepwater Horizon oil, unlike the black glop from the

‘Marine phytoplankton steadily declining over 20th century’

Oneindia – ?Jul 29, 2010?
London, July 29 (ANI): Scientists have, for the first time, found evidence that microscopic marine algae known as “phytoplankton” have been declining

Plankton declining across oceans

BBC News – ?Jul 29, 2010?
The amount of phytoplankton – tiny marine plants – in the top layers of the oceans has declined markedly over the last century, research suggests.

Vital Marine Plants in Steep Decline

Wall Street Journal – Gautam Naik – ?Jul 28, 2010?
Rising sea temperatures can harm the tiny plant life that forms the base of the oceans’ food chain as well as affect the diversity of marine

Plants at base of ocean food chain in decline, study finds

Globe and Mail – ?Jul 28, 2010?
Phytoplankton in the Baltic Sea. Phytoplankton are the foundation of the ocean food web, make half the world’s oxygen and suck up harmful carbon dioxide.

Warmer seas put marine food chain at risk

ABC Online – Alison Caldwell – ?Jul 28, 2010?
Phytoplankton are important because they generate roughly half of all organic matter on the planet and produce half the world’s oxygen.

Scientists Report Steep Decline in Algae Critical to Marine Food Chain

Voice of America – Jessica Berman – ?Jul 28, 2010?
The global population of a marine algae called phytoplankton has declined by 50 percent since the middle of the last century, threatening marine creatures

Blogs

Bad news for the food chain: Phytoplankton declining by 1% per year

Greenfudge.org (blog) – Daniel Boyce – ?3 hours ago?
Phytoplankton – the microscopic algae that form the basis for marine food chains – have declined by 40% since 1950, at a rate of 1% per year.

Phytoplankton in decline: bye bye food chain?

New Scientist (blog) – Michael Marshall – ?Jul 29, 2010?
Ocean life is being wiped out from the bottom up. The global population of microscopic plants that float in ocean water and support most marine life has

A warmer ocean is a less green one

Discover Magazine (blog) – ?Jul 28, 2010?
The Earth’s oceans are mysterious and largely unexplored. Many of their inhabitants are familiar to us but their whereabouts and numbers are far less clear.
Timeline of articles

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Plankton declining across oceans

?Jul 29, 2010? – BBC News