Greenhouse-gas levels highest for 650,000 years

news@nature.com ^ | 24 November 2005 | Michael Hopkin

[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).

[neverdem]

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.

Hmmm

Tiny bubbles in ice hundreds of thousands of years old hold the key to understanding greenhouse gases, past and future.
© W. Berner/University of Bern

Ancient air bubbles shed light on greenhouse gases (Global Warming) AP version

Rise in Gases Unmatched by a History in Ancient Ice NY Times

While the overall climate pattern has been set by rhythmic variations in Earth's orientation to the Sun, the records show that carbon dioxide and methane consistently made the interglacial climate warmer than it would otherwise have been, said Thomas Stocker, one of the researchers and a physicist at the University of Bern in Switzerland.

[MJY1288]

LOL, What were the green house gas levels 650,000 years ago?
Did Al Gore record them when he was inventing the internet?

[CALawyer]

Current levels of greenhouse gases in the atmosphere are higher than at any time in the past 650,000 years.

What great news! Since it was considerably warmer as recently as 1,000 years ago (when Greenland was actually "green"), I guess we can disregard all of these dire predictions about greenhouse gas emissions and start gassing up our SUVs again. The idea that man-made activity can influence the earth's weather patterns is a joke.

[The Red Zone]

Global warming has saved us from what would otherwise have been another ice age.

[aliquando]

Well, the world has been around for anywhere from 4 to 6 billion years. Modern humans (Homo Sapiens), have been around for (very debatable) anywhere from 350,000 to 1.5 years. These numbers are off the top of my head, but its seems to me that the world has been through some drastic changes. Most of it has happened while life has been present. I know that most of it supposedly has only been during the existence of bacteria, but da_n, give us a shot here, we are one very adaptable critter. If you want to go with the Earth only being a few thousand years old, then you can ignore this post. Please add more relevant info, as I said, these numbers are off top of my head. I am pretty good at remembering the sequences and processes, but stink at dates.(ask my wife!)

[melt]

Being alive is a threat to being alive.

[Jeff Chandler]

In a related story, Mexican food has become the most popular type of food worldwide.

[marron]

There is no time to lose. We have to send more factories to China.

[truemiester]

"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."
This of course comes from cows.
Apparently, cows drive big cars. This is why the CO2 is up.
I knew it. (Conspiracy undertone sacracm off{or is it?})

[aliquando]

The greatest cause of cancer is getting old.

[woofie]

Im uncertain but death seems inevitable

[basalt]

let me get this straight, man cannot make it rain, or sprinkle for that matter, or snow or have any effect whatsoever on the weather, yet if we all drive little hybred cars we can cool an entire planet...oooooooooooooooooook

[MCH]

This just in...

Archeologists have just discovered an ancient tablet buried in the mud in the Carribean...

After deencryption, it chronicles the passage of major legislation in ancient Atlantis about 650,000 years ago by then Atlantian emporer, Alus Gorexia, to outlaw Space-Alien Universal Vehicles (SUVs) for environmental reasons.

Corroborating evidence? You decide.

[UncleJeff]

Agriculture has been around for 10,000 years, all of it climatically stable. All civilizations are dependent on agriculture.

[Candor7]

These ECO Farts augment the increasing rise of methane gas also!

650,000 years ago the gases were higher but then, THE WORLD DID NOT END!

[Candor7]

"The CO2 emitted now is not part of the natural cycle," Stocker points out.



THEY ARE PART OF THE NATURAL CYCLE. What a moron!

[MNJohnnie]

BS. Pure take data and make it say what I want to believe for Political reasons junk science. Sorry but this is just more "Green" propaganda. 1 volcano eruption does more damage then all "man made" pollution. Since this time frame would cover periods of extended vulcanism, it is pure nonsense to claim "man man" damage. Just stupid propaganda

[BadAndy]

"Current levels of greenhouse gases in the atmosphere are higher than at any time in the past 650,000 years..."

With a little effort we can beat that record.

[bobdsmith]

1 volcano eruption does more damage then all "man made" pollution

I don't think that is anywhere near true

[MNJohnnie]

I don't think that is anywhere near true

That is the whole problem, most Greens obviously do not think. It is a basic fact. Think about it. One volcano pumps out thousands of tons of material directly into the upper atmosphere.

Kracatoa blew up and the year 1776-1777 was known as "the year with out a summer" because it effected globally the world's weather patterns. Not a "gradual centuries long change" of the Hysteric Leftists but a direct world wide change within months of the eruption. The facts are NOT on the side of the Environmental Wackos with their Socialism in drag "green" dogma.