Earth Warming

[kaima]

The choice of titles was to avoid "Global Warming" and its prejudices. Alaska is warming, of that there is no doubt. The latest on Earth Warming now goes back 650,000 years and shows (ad did the tracs to 400,000 years) that we are beyond any past records...

From the NY Times, the latest I have read:
November 25, 2005
Rise in Gases Unmatched by a History in Ancient Ice
By ANDREW C. REVKIN
Shafts of ancient ice pulled from Antarctica's frozen depths show that for at least 650,000 years three important heat-trapping greenhouse gases never reached recent atmospheric levels caused by human activities, scientists are reporting today.

The measured gases were carbon dioxide, methane and nitrous oxide. Concentrations have risen over the last several centuries at a pace far beyond that seen before humans began intensively clearing forests and burning coal, oil and other fossil fuels.

The sampling and analysis were done by the European Program for Ice Coring in Antarctica, and the results are being published today in the journal Science.

The evidence was found in air bubbles trapped in successively older ice samples extracted from a nearly two-mile-deep hole drilled in a remote spot in East Antarctica called Dome C.

Experts familiar with the findings who were not involved with the research said the samples provided a vital long-term view of variations in the atmosphere and Antarctic climate. They say the data will help test and improve computer models used to forecast how accumulating greenhouse emissions will affect the climate.

Some climate experts not involved in the research said the findings also confirmed that the buildup of carbon dioxide and other heat-trapping smokestack and tailpipe emissions was taking the atmosphere into uncharted territory.

The longest previous record of carbon dioxide fluctuations, compiled from ice cores collected at the Russian research station at Vostok, in East Antarctica, goes back slightly more than 400,000 years.

"They've now pushed back two-thirds of a million years and found that nature did not get as far as humans have," said Richard B. Alley, a geosciences professor at Pennsylvania State University who is an expert on ice cores. "We're changing the world really hugely - way past where it's been for a long time."

James White, a geology professor at the University of Colorado, Boulder, not involved with the study, said that although the ice-age evidence showed that levels of carbon dioxide and the other greenhouse gases rose and fell in response to warming and cooling, the gases could clearly take the lead as well.

"CO2 and climate are like two people handcuffed to each other," he said. "Where one goes, the other must follow. Leadership may change, or they may march in step, but they are never far from each other. Our current CO2 levels appear to be far out of balance with climate when viewed through these results, reinforcing the idea that we have significant modern warming to go."

The new data from the ice cores also provides the first detailed portrait of conditions during ice-age cycles that occurred more than 400,000 years ago - a point in Earth's two-million-year history of cold periods and warm intervals after which some unknown influence lengthened ice ages and shortened and amplified the warm periods.

Both before and after that transition, the ice record shows, there was always a tight relationship between amounts of the greenhouse gases and air temperature.

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.

Last year, the same cores provided new evidence that the current warm period, the Holocene, which began about 12,000 years ago, is similar to the longer warm periods that were typical before 400,000 years ago, and could last at least another 16,000 years.

The European team is analyzing deeper, older sections of the Dome C ice cores, and the researchers said they might be able to take the climate record back 800,000 years, possibly providing information about yet another early warm interval similar to the Holocene.

The new long-term record is essentially creating a subset of climate science, letting scientists compare different warm periods. They can then sort out influences, including greenhouse gases, said Gavin A. Schmidt, a climate modeler at the Goddard Institute for Space Studies in Manhattan.

www.nytimes.com/2005/11/25/science/earth/25core.html

[Thanks]

Kai, thanks for the interesting revalation. Carl

[Alaska]

Kai, what evidence of warming have you seen in Alaska? Carl

[nancy]

Tonight we watched a program on the History Channel about the "Little Ice Age." At the end, they talked about the potential results of the current global warming trend, which could actually result in a new ice age in some areas.

Research at WHOI: www.whoi.edu/institutes/occi/currenttopics/abruptclimate_joyce_keigwin.html

and even some Russians promote global warming: web.themoscowtimes.com/stories/1995/05/30/034.html

[sciwriter]

Nancy, thanks for the info.. I can't access the second site, though. Carl

[nancy]

Carl,

I can't get that second link again... it was a story in the Moscow Times about a splinter group in Russia in 1995 called "Subtropical Russia"

Here's a quote from another article:

It's probably hard to scare Russians with the specter of life getting a bit warmer. After all, when the Beer Lovers' Party mounted its tongue-in-cheek drive for the Duma in 1995, its platform included cheap beer, low taxes, a man for every woman and a woman for every man. But of all the Beer Lovers' daydreams, only its pledge to raise the temperature across Russia was able to sustain an entire splinter group, the Subtropical Russia Movement. (Ambitiously, they also promised to lower the boiling temperature of water.)

[sciwriter]

Nancy, thanks for the quote. I'd add And Vodka won't be needed to keep warm (LOL). Carl

[justjohn]

Alarm over dramatic weakening of Gulf Stream

Slowing of current by a third in 12 years could bring more extreme weather

Temperatures in Britain likely to drop by one degree in next decade

Ian Sample, science correspondent
Thursday December 1, 2005
The Guardian

The powerful ocean current that bathes Britain and northern Europe in warm waters from the tropics has weakened dramatically in recent years, a consequence of global warming that could trigger more severe winters and cooler summers across the region, scientists warn today.

Researchers on a scientific expedition in the Atlantic Ocean measured the strength of the current between Africa and the east coast of America and found that the circulation has slowed by 30% since a previous expedition 12 years ago.

The current, which drives the Gulf Stream, delivers the equivalent of 1m power stations-worth of energy to northern Europe, propping up temperatures by 10C in some regions. The researchers found that the circulation has weakened by 6m tonnes of water a second. Previous expeditions to check the current flow in 1957, 1981 and 1992 found only minor changes in its strength, although a slowing was picked up in a further expedition in 1998. The decline prompted the scientists to set up a £4.8m network of moored instruments in the Atlantic to monitor changes in the current continuously.

The network should also answer the pressing question of whether the significant weakening of the current is a short-term variation, or part of a more devastating long-term slowing of the flow.

If the current remains as weak as it is, temperatures in Britain are likely to drop by an average of 1C in the next decade, according to Harry Bryden at the National Oceanography Centre in Southampton who led the study. "Models show that if it shuts down completely, 20 years later, the temperature is 4C to 6C degrees cooler over the UK and north-western Europe," Dr Bryden said.

Although climate records suggest that the current has ground to a halt in the distant past, the prospect of it shutting down entirely within the century are extremely low, according to climate modellers.

The current is essentially a huge oceanic conveyor belt that transports heat from equatorial regions towards the Arctic circle. Warm surface water coming up from the tropics gives off heat as it moves north until eventually, it cools so much in northern waters that it sinks and circulates back to the south. There it warms again, rises and heads back north. The constant sinking in the north and rising in the south drives the conveyor.

Global warming weakens the circulation because increased meltwater from Greenland and the Arctic icesheets along with greater river run-off from Russia pour into the northern Atlantic and make it less saline which in turn makes it harder for the cooler water to sink, in effect slowing down the engine that drives the current.

The researchers measured the strength of the current at a latitude of 25 degrees N and found that the volume of cold, deep water returning south had dropped by 30%. At the same time, they measured a 30% increase in the amount of surface water peeling off early from the main northward current, suggesting far less was continuing up to Britain and the rest of Europe. The report appears in the journal Nature today.

Disruption of the conveyor-belt current was the basis of the film The Day After Tomorrow, which depicted a world thrown into chaos by a sudden and dramatic drop in temperatures. That scenario was dismissed by researchers as fantasy, because climate models suggest that the current is unlikely to slow so suddenly.

Marec Srokosz of the National Oceanographic Centre said: "The most realistic part of the film is where the climatologists are talking to the politicians and the politicians are saying 'we can't do anything about it'."

Chris West, director of the UK climate impacts programme at Oxford University's centre for the environment, said: "The only way computer models have managed to simulate an entire shutdown of the current is to magic into existence millions of tonnes of fresh water and dump it in the Atlantic. It's not clear where that water could ever come from, even taking into account increased Greenland melting."

Uncertainties in climate change models mean that the overall impact on Britain of a slowing down in the current are hard to pin down. "We know that if the current slows down, it will lead to a drop in temperatures in Britain and northern Europe of a few degrees, but the effect isn't even over the seasons. Most of the cooling would be in the winter, so the biggest impact would be much colder winters," said Tim Osborn, of the University of East Anglia climatic research unit.

The final impact of any cooling effect will depend on whether it outweighs the global warming that, paradoxically, is driving it. According to climate modellers, the drop in temperature caused by a slowing of the Atlantic current will, in the long term, be swamped by a more general warming of the atmosphere.

"If this was happening in the absence of generally increasing temperatures, I would be concerned," said Dr Smith. Any cooling driven by a weakening of the Atlantic current would probably only slow warming rather than cancel it out all together. Even if a slowdown in the current put the brakes on warming over Britain and parts of Europe, the impact would be felt more extremely elsewhere, he said.

[sciwriter]

www.cnn.com/2005/TECH/science/05/10/gulfstream/

Changes in Gulf Stream could chill Europe
New data on global warming; thinning polar ice cap
By Marsha Walton
CNN

Tuesday, May 10, 2005


FACT BOX
THE GULF STREAM

The Gulf Stream is a pattern of warm water extending
from the Gulf of Mexico to the British Isles. It is
responsible for the mild climate of Western Europe,
which is at a much higher latitude than most of New
England, but experiences much milder weather. Wind
patterns over the ocean pull the warm water from the
Gulf into the Northeast Atlantic.

Source: NASA

(CNN) -- One outcome of global warming could be a dramatic cooling
of Britain and northern Europe.
Scientists now have evidence that changes are occurring in the Gulf
Stream, the warm and powerful ocean current that tempers the western
European climate.
Without the influence of the Gulf Stream and its two northern
branches, the North Atlantic Drift and the Canary Current, the
weather in Britain could be more like that of Siberia, which shares
the same latitude.
Cambridge University ocean physics professor Peter Wadhams points to
changes in the waters of the Greenland Sea. Historically, large
columns of very cold, dense water in the Greenland Sea, known as
"chimneys," sink from the surface of the ocean to about 9,000 feet
below to the seabed. As that water sinks, it interacts with the warm
Gulf Stream current flowing from the south.
But Wadhams says the number of these "chimneys" has dropped from
about a dozen to just two. That is causing a weakening of the Gulf
Stream, which could mean less heat reaching northern Europe. The
activity in the Greenland Sea is part of a global pattern of ocean
movement, known as thermohaline circulation, or more commonly the
"global conveyor belt."
Wadhams presented his findings at a meeting of the European
Geosciences Union in Vienna, Austria, last month.
When Wadhams began his studies of Arctic Sea ice more than 30 years
ago, there was not a focus on a warming of the region or the ice
becoming thinner. His research aboard British Royal Navy submarines
began as a way to use new tools, such as sonar, to study this harsh
region of the planet.
"Initially the idea was just to map what the ice thickness
distribution was," Wadhams said. "You cannot measure it with
satellites, and to drill through it is difficult," he said.
But year after year, a dramatic pattern emerged.
"We discovered the ice was getting rapidly thinner. It has thinned
by 40 percent in the past 20 years," said Wadhams.
Wadhams and other scientists say the slowing of the Gulf Stream
could contribute to other severe effects on the planet, such as the
complete melting of the Arctic ice cap in the summer months. That
could eliminate the habitat and lead to the extinction of Arctic
wildlife, including the polar bear. Current predictions indicate
that could happen as early as 2020 or as late as 2080.
Scientists are getting other information about the disappearing ice
cap from Alaskan Inuits. They report changes in where and when
certain species of fish have been found, and in populations of seals
and polar bears.
Other oceanographers stress that Wadhams' findings are one piece of
a very complex earthly puzzle.
Terrence Joyce, senior scientist in the department of physical
oceanography at Woods Hole Oceanographic Institution in
Massachusetts, says it's important not to get alarmist, but instead
to keep up a wide array of research.
For a dramatic climate change to take place, "A whole bunch of
pieces have to fit together. Certainly this is one of them. We need
to keep paying attention, and people are doing that," he said.
Woods Hole is conducting research that measures the path and
temperature of some parts of the Gulf Stream.
Such a dramatic climate change would not take place in five days,
but rather several years, said Joyce.