|
TOKYO
-- Japanese scientists have gone back in time to study
the earth's climate by drilling more than 3 kilometres
into Antarctica's ice sheet, a researcher said on Tuesday.
Yoshiyuki Fujii said the cores are among the oldest samples
yet extracted by scientists and hoped bubbles of gas,
such as carbon dioxide, trapped in the core samples will
offer clues to past patterns of global climate change.
They might also further highlight the threat from global
warming by giving a million-year-old record of carbon
dioxide and methane levels in the atmosphere. Both are
powerful greenhouse gases.
"By analyzing the ice we would like to decipher
climate and temperature conditions that stretch back to
ages that have not been clarified before," said Fujii,
director-general of the National Institute of Polar Research.
In particular, he hoped the samples would explain changes
to the earth's climate from an inversion of the earth's
magnetic field that occurred around 790,000 years ago. During
such an event, the earth's magnetic poles switch entirely.
Fujii told Reuters the team in Antarctica drilled near
their base located at an altitude of 3,810 meters (12,600
feet). The samples would be brought to Japan for analysis.
This is believed to be the oldest sample allowing such
analysis, although isolated ice samples believed to be
about six million years old have previously been found,
Fujii said.
Last year, several European studies of Antarctic ice
core samples released findings that showed current levels
of methane and carbon dioxide in the atmosphere are higher
than at any time in the past 650,000 years.
Scientists in those studies also drilled down to about
three kilometers (two miles)
Many scientists believe rising levels of carbon dioxide
released from burning fossil fuels and methane from agriculture
are warming the atmosphere, threatening to cause greater
extremes of weather, melting ice caps and rising sea levels.
Scientists said last year was the second warmest year
on record since 1860 and that eight of the 10 warmest
years since records began have occurred in the past decade.
-
Red Orbit -
|
