Scientists scour past for future climate clues

Ice core sample [image credit: Discovering Antarctica]

Of course they are pushing the usual doom and gloom messages based on dubious greenhouse gas theories, but a glimmer of light perhaps is that they accept the Earth has warmed and cooled in the past due to unknown factors. They in effect admit the obvious, namely that attribution of climate change to humans in some, or any, degree cannot be quantified at present.

As the pace of global warming outstrips our ability to adapt to it [Talkshop comment – allegedly], scientists are delving deep into the distant past, hoping that eons-old Antarctic ice, sediments and trees chart a path to navigate our climate future, says Phys.org.

“What interests us is to understand how the climate works,” says Didier Roche of France’s National Centre for Scientific Research (CNRS).

At the Laboratory for Climate and Environment Sciences (LSCE), just outside Paris, the aim is to establish a comprehensive record of climate change dating back hundreds of thousands of years, to chart the repeated warming and cooling cycles the Earth has gone through and to try to understand what drives them.

Get that far and it becomes possible to determine what part humans play in the current global warming phase through the massive greenhouse gas emissions, principally CO2 and methane, that have come with industrialisation and population growth.

A key research tool are the cores of ice, some dating back 800,000 years, which contain tiny bubbles of trapped air and are drilled out at depths of up to 3.2 kilometres (two miles) by the European Project for Ice Coring in Antarctica (EPICA).

While the air bubbles reveal CO2 and other greenhouse gas levels, similar cores of sediment or tree ring records help build up the picture of Earth’s climate.

From the gas bubbles “we can reconstitute the composition of the atmosphere,” said Anais Orsi, researcher at France’s Atomic Energy Commission (CEA).

Particles of dust meanwhile “can tell us if there were lots of forest fires in Patagonia or if Australia was going through a very dry spell,” she said.

As for trees, with their very clear record of growth rings, “they can tell us about temperature, sunlight, humidity levels,” said Valerie Daux, professor at the University Versailles-Saint Quentin, just outside Paris.

Levels of the carbon 14 isotope, which allow for a close dating of material, provide another line of investigation to establish “at what speed an ecosystem can adapt to climate change,” said the CEA’s Christine Hatte.

Climate models essential

All the data is collected and processed to be put into climate models and then extrapolated into what appears set to be a much warmer future.

Full article here.