Posted on 11/25/2005 10:41:45 PM PST by neverdem
Climate record highlights extent of man-made change.
Current levels of greenhouse gases in the atmosphere are higher than at any time in the past 650,000 years, say researchers who have finished cataloguing air bubbles trapped for millennia inside Antarctic ice. The record, which extends back over the past eight ice ages, shows that today's concentrations of carbon dioxide and methane far outstrip those in the past.
Atmospheric carbon dioxide levels have risen 200 times faster over the past 50 years than at any other time during this period, says Thomas Stocker of the University of Bern, Switzerland, who led the analysis.
The researchers studied air bubbles preserved in ice drilled from the Antarctic ice sheet as part of the European Project for Ice Coring in Antarctica (EPICA). The ice core represents a logbook of the state of the world's climate (see 'Frozen time') and goes back 210,000 years further than previous records.
After searching ice spanning the period of 390,000-650,000 years before present, Stocker's team has discovered that carbon dioxide levels in the atmosphere did not exceed 290 parts per million during that time. Today, that figure is around 375 parts per million.
The situation is similar for methane: during this period, levels hovered around 600 parts per billion. Today's atmospheric methane concentration is well over 1,700. Stocker and his colleagues report the results in Science1,2.
Unprecedented push
The burning of fossil fuels in the industrial era has pushed greenhouse-gas levels far beyond their natural fluctuations, says Stocker. "This is really something unprecedented," he says. Humans, by releasing fossil fuels from their imprisonment underground, are now adding greenhouse gases to the atmosphere on top of those released as part of natural climate cycles.
The news comes as world leaders plan to attend a United Nations climate change conference in Montreal, Canada, which begins on 28 November. Delegates will discuss current efforts to reduce greenhouse emissions, and what plans should follow on from the initial phase of the Kyoto Protocol, which ends in 2012.
The past four ice ages and their intervening warm periods are thought not to have been typical. Glacial cycles before this had longer, cooler intervening periods than more recent ones. Researchers are unsure why this is, although they hope the ice cores may hold some clues.
Unnatural changes
The newly analysed ice does show that although the climate is in constant flux, it is capable of producing extended warm phases even when carbon dioxide levels are stable, says Stocker. Two places in the record, for example, are marked by periods of almost 30,000 years when temperature hardly changed at all. And the beginning of these 'interglacial' phases was not linked to rises in carbon dioxide.
That's not to say that current rises in temperature are due to natural shifts, as some climate-change sceptics have claimed. "The CO2 emitted now is not part of the natural cycle," Stocker points out.
"In the palaeorecord there's no human activity driving the change," says Chris Jones, of the Hadley Centre for Climate Prediction and Research in Exeter, UK. The current challenge facing climate modellers is to work out the one-way effect of the huge spike in greenhouse gases now being pumped into our skies by human activities.
References doi:10.1038/news051121-14 SiegenthalerU., et al. Science, 310. 1313 - 1317 (2005). SpahniR., et al. Science, 310. 1317 - 1321 (2005).
Well if you believe in creationism like I do then the Earth is only about 6000 years old, so all this data is just a bunch of hogwash.
If you know the answer, you can find the "evidence"
Yep ... Its down the drain ...
(ducks low to avoid being hit by flying barbs)
Thanks for the post and the reminder. Too often, we get caught up in our mundane day to day tasks and forget we need to take care of the planet as well. ==> We lose sight of the big picture and can't see the forest for the trees.
This is the main point of divergence when you think this true. An environmentalist whacko, when told this fact, and how human intervention might up this to 4.25% (my figure, only to serve to argue the point), will tell you that the additional 0.25% will thrust the entire climate out of whack. But then you need simply point out that volcanoes pump out equivalent, even greater amounts of CO2 (and pollutants) and the earth swallows it up, readjusting and stabilizing in only a few months.
Human involvement in the climate is anecdotal, at best.
The fractions being referenced in the article are really very small. To me, a non scientist, they would seem to fall within the margin of error.
I think he did?Wasn't that book he wrote called"The Earth In A Lurch"??
Exactly!Why should cattle have all the fun!!We enjoy FLATULENCE too!!!
After reading this,I got up and put on my cd of "In A Yugo"by Paul Shanklin!
I'm reminded of the weather reports stating that"This Is The Hottest Summer In One Hundred Years"!!What were WE doing to make it(the weather)so hot one hundred years ago???
After all, we are the problem, right?
ping. What's your take? Just curious.
Good point. Care to extrapolate on it?
May I suggest bathing?
Your wife must have found something worthy in you, if your dating life were so bad, and still she married you.
According to tree rings, there was a 500 year drought with
associated warming millions of years ago in the West. Long
before humans inhabited earth.
Are you saying man because of his presence is responsible for these changes?
Early man (cavemen) caused greenhouse gasses by his flatulence.
You had stinky dates.
Therefore you're a caveman. :)
don't you mean OUTPUT?
That orrifice was not made for input.
You embarrass yourself.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.