Severe Flooding Hits Jakarta, Indonesia

Severe flooding is going on in Jakarta, Indonesia in the past few weeks, with some of the most severe flooding since going on since last Sunday. Members of the Environment Ministry have placed some of the blame on climate change. The following are selections from Indonesian bloggers. Brandon from The Java Jive has posted a gallery of photos taken during the flooding here.

“…we thought it’d be a good idea to go out and take some pics and video of the scene. We weren’t considering the fact that some people had died from electrocution, that we were walking around dead rats, sewage, snakes, and random potholes that would swallow us whole. But what we saw was worth every moment of discomfort.

I haven’t seen such an odd scenario since September 11. Remember on that sunny morning when everyone was just walking around in a daze, as if our society was on autopilot? It was like that all over again but without the tragedy and sadness to cope with. The day before, there was a mad dash to get supplies, groceries, and fresh water. This day, those stores were all closed; employees couldn’t get to work, suppliers couldn’t get fresh food, and the electricity was off regardless.

…Surely the flooding is due to a number of factors ranging from the deforestation of the volcanic highlands which surround Jakarta, the filth and garbage blocking the main rivers and canals, the lack of a large-scale canal to draw the water away, and of course the concrete conundrum. Is there much else that could have been done? I’d like to think so.” – The Java Jive

“Parts of Jakarta were flooded last week. It rained hard for two days but the ground was not yet saturated as the monsoon had been mild so far this year. So the rain alone should not have been enough to cause the massive flooding that certain areas experienced. All sorts of explanations have been whirling around but most point at corrupt and/or ineffective government. Much of Jakarta is at or below sea level so it is very important to control the amount of water coming into the city from the surrounding hills and within the city itself. This is done by a canal sytem through which water can be moved from one part of the city to another and eventually out to sea. Well, this did not work last week. Several of our friends houses and cars were damaged and we were inconvenienced somewhat but 1000’s of people lost everything – and as is typical in the developing world – it is the poor who are most effected. Those with money have second stories on their houses and the means to evacuate.” – Indobaja

“The floods continue here in Jakarta with the TV showing how four houses collapsed today into the River Ciliwung as the rushing waters have undercut the river bank. And that’s a five minute stroll from Jakartass Towers. For the past three or four weeks otherwise empty houses in our area have been dry havens for dispossessed families. It is these families who have now lost everything.” – Jakartass
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Physics Today
August 2003, page 30
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Physics Today
August 2003, page 30

The Discovery of Rapid Climate Change

Spencer Weart
Only within the past decade have researchers warmed to the possibility of abrupt
shifts in Earth's climate. Sometimes, it takes a while to see what one is not
prepared to look for.

--

—————————————-
“This suggests that current model projections may in fact provide a conservative estimate of future Arctic change, and that the summer Arctic sea ice may disappear considerably earlier than IPCC projections,” says Stroeve.
———————————————-

NCAR/UCAR/UOP
News Release

Arctic Ice Retreating More Quickly Than Computer Models Project

April 30, 2007

BOULDER-Arctic sea ice is melting at a significantly faster rate than projected by even the most advanced computer models, a new study concludes. The research, by scientists at the National Center for Atmospheric Research (NCAR) and the University of Colorado’s National Snow and Ice Data Center (NSIDC), shows that the Arctic’s ice cover is retreating more rapidly than estimated by any of the 18 computer models used by the Intergovernmental Panel on Climate Change (IPCC) in preparing its 2007 assessments.

The study, “Arctic Sea Ice Decline: Faster Than Forecast?” will appear tomorrow in the online edition of Geophysical Research Letters. It was led by Julienne Stroeve of the NSIDC and funded by the National Science Foundation, which is NCAR’s principal sponsor, and by NASA.

“While the ice is disappearing faster than the computer models indicate, both observations and the models point in the same direction: the Arctic is losing ice at an increasingly rapid pace and the impact of greenhouse gases is growing,” says NCAR scientist Marika Holland, one of the study’s co-authors.

The authors compared model simulations of past climate with observations by satellites and other instruments. They found that, on average, the models simulated a loss in September ice cover of 2.5 percent per decade from 1953 to 2006. The fastest rate of September retreat in any individual model was 5.4 percent per decade. (September marks the yearly minimum of sea ice in the Arctic.) But newly available data sets, blending early aircraft and ship reports with more recent satellite measurements that are considered more reliable than the earlier records, show that the September ice actually declined at a rate of about 7.8 percent per decade during the 1953-2006 period.

“This suggests that current model projections may in fact provide a conservative estimate of future Arctic change, and that the summer Arctic sea ice may disappear considerably earlier than IPCC projections,” says Stroeve.

Thirty years ahead of schedule

The study indicates that, because of the disparity between the computer models and actual observations, the shrinking of summertime ice is about 30 years ahead of the climate model projections. As a result, the Arctic could be seasonally free of sea ice earlier than the IPCC- projected timeframe of any time from 2050 to well beyond 2100.

The authors speculate that the computer models may fail to capture the full impact of increased carbon dioxide and other greenhouse gases in the atmosphere. Whereas the models indicate that about half of the ice loss from 1979 to 2006 was due to increased greenhouse gases, and the other half due to natural variations in the climate system, the new study indicates that greenhouse gases may be playing a significantly greater role.

There are a number of factors that may lead to the low rates of simulated sea ice loss. Several models overestimate the thickness of the present-day sea ice and the models may also fail to fully capture changes in atmospheric and oceanic circulation that transport heat to polar regions.

March ice

Although the loss of ice for March is far less dramatic than the September loss, the models underestimate it by a wide margin as well. The study concludes that the actual rate of sea ice loss in March, which averaged about 1.8 percent per decade in the 1953 -2006 period, was three times larger than the mean from the computer models. March is typically the month when Arctic sea ice is at its most extensive.

The Arctic is especially sensitive to climate change partly because regions of sea ice, which reflect sunlight back into space and provide a cooling impact, are disappearing. In contrast, darker areas of open water, which are expanding, absorb sunlight and increase temperatures. This feedback loop has played a role in the increasingly rapid loss of ice in recent years, which accelerated to 9.1 percent per decade from 1979 to 2006 according to satellite observations.

Walt Meier, Ted Scambos, and Mark Serreze, all at NSIDC, also co-authored the study.

The National Center for Atmospheric Research and UCAR Office of Programs are operated by UCAR under the sponsorship of the National Science Foundation and other agencies. Opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any of UCAR’s sponsors.

Ã‚Â© 2006, UCAR
” … modelling studies typically try to distinguish between cloudy and cloud-free regions of the atmosphere. But the new results show that this distinction is less clear-cut than has been thought … ”
——————————

news@nature.com – the best science journalism on the web
Published online: 24 April 2007; | doi:10.1038/news070423-6

Every cloud has an invisible haloUnseen particles may confuse climate models.

Philip Ball

Clouds have unseen portions that stretch for many kilometres.
AddStyle

Clouds are bigger than they look, according to new measurements by atmospheric scientists in Israel and the United States. They say that clouds are surrounded by a ‘twilight zone’ of diffuse particles, invisible to the naked eye, extending for tens of kilometres around the cloud’s visible portion.

These vast, sparse haloes of droplets may have been overlooked in atmospheric studies, the researchers say. And they think that this could have skewed attempts to understand how clouds influence climate.

Clouds are one of the biggest sources of uncertainty in efforts to measure and predict global warming. They have two opposite effects: increasing warming by absorbing heat radiated from the planet’s surface (which is why cloudy nights are warmer), while offsetting this by reflecting sunlight back into space from cloud tops.

Most atmospheric scientists now think that clouds have an overall global cooling effect. Measurements of warming trends therefore have to take into account whether the skies are cloudy or not, and model forecasts of future warming may hinge on whether they predict more or less cloudiness.

Cloudy distinction

Such modelling studies typically try to distinguish between cloudy and cloud-free regions of the atmosphere. But the new results show that this distinction is less clear-cut than has been thought, say Ilan Koren of the Weizmann Institute of Science in Rehovot, Israel, and his colleagues, who publish their discovery in Geophysical Research Letters (1) .

Clouds are formed when floating solid particles called aerosols – dust, for example – act as ‘seeds’ on which water droplets grow. Aerosols reflect light, and do so more strongly as they grow by accumulating water. The large droplets in clouds reflect most visible light, which is what makes clouds look white and opaque.

Koren and his colleagues first demonstrated that it is relatively easy to see from digital photographs that clouds are surrounded by an invisible haze, made up of these water-coated, or humidified, aerosols. If the parts of the photo containing visible white stuff are masked out, the surrounding haze comes into view.

This haze extends far further than anyone has ever imagined. “People may have seen these extended haloes anecdotally,” says Koren’s colleague Lorraine Remer of the NASA Goddard Space Flight Center in Greenbelt, Maryland. “But thanks to a new generation of instruments, the satellite observations have got much better, and we can look on larger scales, with more sensitivity and at finer resolution.”

Satellite images of clouds over the Atlantic Ocean show that the sky’s reflectance – a measure of how much humidified aerosol it contains – falls very gradually with increasing distance from the edge of a cloud, and is still declining at least 20-30 kilometres away, Koren’s team says.

Into the twilight zone

To study these twilight zones further, the researchers studied several years’ worth of images collected by a global network of ground-based lightmeters called AERONET, usually used to monitor the brightness of the Sun.

Sudden dips in the light detected by these instruments are automatically logged as indicating the passage of a cloud. Koren and colleagues discovered that it can take well over an hour for light levels to recover fully after a cloud has passed, indicating that their haloes are very broad.

Not all clouds will have a big twilight zone, the researchers say. For example, the halo might be tightly reined in around the sharp-edged white cumulus clouds that form when moist, warm air rises and cools. But they estimate that for typical global cloud coverage, the halo could encompass as much as two-thirds of the sky usually classed as cloud-free.

Remer says that some climate models might already include these extended cloud haloes – they should ‘grow’ them automatically if they do a good job of capturing the humidity variations of the air. But other, simpler, models might neglect the effect.

As a result, Remer suspects that the overall cooling effect of aerosols may have been underestimated. But she admits that it is too early to say whether that is really the case, or how significant an impact it might have on climate predictions.

“Right now there is a discrepancy between what global models predict for aerosol effects and what satellites measure,” she says. “This might be part of the reason for that.”

References
1. Koren I., et al. Geophys. Res. Lett., 34. L08805 (2007).

Story from news@nature.com:
http://news.nature.com//news/2007/070423/070423-6.html

————————————————
” … modelling studies typically try to distinguish between cloudy and cloud-free regions of the atmosphere. But the new results show that this distinction is less clear-cut than has been thought … ”
——————————

news@nature.com – the best science journalism on the web
Published online: 24 April 2007; | doi:10.1038/news070423-6

Every cloud has an invisible haloUnseen particles may confuse climate models.

Philip Ball

Clouds have unseen portions that stretch for many kilometres.
AddStyle

Cloudy distinction

Into the twilight zone

“Right now there is a discrepancy between what global models predict for aerosol effects and what satellites measure,” she says. “This might be part of the reason for that.”

References
1. Koren I., et al. Geophys. Res. Lett., 34. L08805 (2007).

Story from news@nature.com:
http://news.nature.com//news/2007/070423/070423-6.html

Nature Publishing Group, publisher of Nature, and other science journals and reference works

Ã‚Â© 2006 Nature Publishing Group
Permanent drought predicted for Southwest

Study says global warming threatens to create a Dust Bowl-like period. Water politics could also get heated.

By Alan Zarembo and Bettina Boxall
Times Staff Writers
April 6 2007

The driest periods of the last century – the Dust Bowl of the 1930s and the droughts of the 1950s – may become the norm in the Southwest United States within decades because of global warming, according to a study released Thursday.

The complete article can be viewed at:

HYPERLINK
“http://www.latimes.com/news/science/la-sci-swdrought6apr06,0,122112.sto
ry?coll=la-home-headlines”
\nhttp://www.latimes.com/news/science/la-sci-swdrought6apr06,0,122112.

CHICAGO TRIBUNE
January 29, 2007

http://www.chicagotribune.com/news/nationworld/sns-ap-climate-report,1,766245.story?coll=chi-news-hed

New Climate Report Too Rosy, Experts Say
By SETH BORENSTEIN
AP Science Writer

WASHINGTON — Later this week in Paris, climate scientists will issue a
dire forecast for the planet that warns of slowly rising sea levels and
higher temperatures. But that may be the sugarcoated version.

Early and changeable drafts of their upcoming authoritative report on
climate change foresee smaller sea level rises than were projected in 2001 in the last report. Many top U.S. scientists reject these rosier numbers. Those calculations don’t include the recent, and dramatic, melt-off of big ice sheets in two crucial locations:

They “don’t take into account the gorillas — Greenland and Antarctica,” said Ohio State University earth sciences professor Lonnie Thompson, a polar ice specialist. “I think there are unpleasant surprises as we move into the 21st century.”

Michael MacCracken, who until 2001 coordinated the official U.S. government reviews of the international climate report on global warming, has fired off a letter of protest over the omission.

The melting ice sheets in Greenland and Antarctica are a fairly recent
development that has taken scientists by surprise. They don’t know how to predict its effects in their computer models. But many fear it will mean the world’s coastlines are swamped much earlier than most predict.

Others believe the ice melt is temporary and won’t play such a dramatic role.

That debate may be the central one as scientists and bureaucrats from
around the world gather in Paris to finish the first of four major global warming reports by the Intergovernmental Panel on Climate Change. The panel was created by the United Nations in 1988.

After four days of secret word-by-word editing, the final report will be issued Friday.

The early versions of the report predict that by 2100 the sea level will rise anywhere between 5 and 23 inches. That’s far lower than the 20 to 55 inches forecast by 2100 in a study published in the peer-review journal
Science this month. Other climate experts, including NASA’s James Hansen, predict sea level rise that can be measured by feet more than inches.

The report is also expected to include some kind of proviso that says
things could be much worse if ice sheets continue to melt.

The prediction being considered this week by the IPCC is “obviously not the full story because ice sheet decay is something we cannot model right now, but we know it’s happening,” said Stefan Rahmstorf, a climate panel lead mauthor from Germany who made the larger prediction of up to 55 inches of sea level rise. “A document like that tends to underestimate the risk,” he said.

“This will dominate their discussion because there’s so much
contentiousness about it,” said Bob Corell, chairman of the Arctic Climate Impact Assessment, a multinational research effort. “If the IPCC comes out with significantly less than one meter (about 39 inches of sea level rise), there will be people in the science community saying we don’t think that’s a fair reflection of what we know.”

In the past, the climate change panel didn’t figure there would be large melt of ice in west Antarctica and Greenland this century and didn’t factor it into the predictions. Those forecasts were based only on the sea level rise from melting glaciers (which are different from ice sheets) and the physical expansion of water as it warms.

But in 2002, Antarctica’s 1,255-square-mile Larsen B ice shelf broke off and disappeared in just 35 days. And recent NASA data shows that Greenland is losing 53 cubic miles of ice each year — twice the rate it was losing in 1996.

Even so, there are questions about how permanent the melting in Greenland and especially Antarctica are, said panel lead author Kevin Trenberth, chief of climate analysis at the National Center for Atmospheric Research in Colorado.

While he said the melting ice sheets “raise a warning flag,” Trenberth said he wonders if “some of this might just be temporary.”

University of Alabama at Huntsville professor John Christy said Greenland didn’t melt much within the past thousand years when it was warmer than now. Christy, a reviewer of the panel work, is a prominent so-called skeptic. He acknowledges that global warming is real and man-made, but he believes it is not as worrisome as advertised.

Those scientists who say sea level will rise even more are battling a
consensus-building structure that routinely issues scientifically cautious global warming reports, scientists say. The IPCC reports have to be unanimous, approved by 154 governments — including the United States and oil-rich countries such as Saudi Arabia — and already published peer-reviewed research done before mid-2006.

Rahmstorf, a physics and oceanography professor at Potsdam University in Germany, says, “In a way, it is one of the strengths of the IPCC to be very conservative and cautious and not overstate any climate change risk.”

* __

On the Net:

Intergovernmental Panel on Climate Change: http://www.ipcc.ch/

The Observer UK
Sunday 21 January 2007

Global Warming: The Final Verdict
By Robin McKie

A study by the world’s leading experts says global warming
will happen faster and be more devastating than
previously thought.

Global warming is destined to have a far more destructive and
earlier impact than previously estimated, the most authoritative
report yet produced on climate change will warn next week.

A draft copy of the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change, obtained by The Observer,
shows the frequency of devastating storms – like the ones that
battered Britain last week – will increase dramatically. Sea levels
will rise over the century by around half a metre; snow will
disappear from all but the highest mountains; deserts will spread;
oceans become acidic, leading to the destruction of coral reefs and
atolls; and deadly heatwaves will become more prevalent.

The impact will be catastrophic, forcing hundreds of millions of
people to flee their devastated homelands, particularly in tropical,
low-lying areas, while creating waves of immigrants whose movements
will strain the economies of even the most affluent countries.

The really chilling thing about the IPCC report is that it is the
work of several thousand climate experts who have widely differing
views about how greenhouse gases will have their effect. Some think
they will have a major impact, others a lesser role. Each paragraph
of this report was therefore argued over and scrutinised intensely.
Only points that were considered indisputable survived this process.
This is a very conservative document – that’s what makes it so
scary,’ said one senior UK climate expert.

Climate concerns are likely to dominate international politics
next month. President Bush is to make the issue a part of his state
of the union address on Wednesday while the IPCC report’s final
version is set for release on 2 February in a set of global news
conferences.

Although the final wording of the report is still being worked
on, the draft indicates that scientists now have their clearest idea
so far about future climate changes, as well as about recent events.
It points out that:

12 of the past 13 years were the warmest since records began;

ocean temperatures have risen at least three kilometres
beneath the surface;

glaciers, snow cover and permafrost have decreased in both hemispheres;

sea levels are rising at the rate of almost 2mm a year;

cold days, nights and frost have become rarer while hot days,
hot nights and heatwaves have become more frequent.

And the cause is clear, say the authors: ‘It is very likely that
[man-made] greenhouse gas increases caused most of the average
temperature increases since the mid-20th century,’ says the report.

To date, these changes have caused global temperatures to rise by
0.6C. The most likely outcome of continuing rises in greenhouses
gases will be to make the planet a further 3C hotter by 2100,
although the report acknowledges that rises of 4.5C to 5C could be
experienced. Ice-cap melting, rises in sea levels, flooding, cyclones
and storms will be an inevitable consequence.

Past assessments by the IPCC have suggested such scenarios are
‘likely’ to occur this century. Its latest report, based on
sophisticated computer models and more detailed observations of snow
cover loss, sea level rises and the spread of deserts, is far more
robust and confident. Now the panel writes of changes as ‘extremely
likely’ and ‘almost certain’.

And in a specific rebuff to sceptics who still argue natural
variation in the Sun’s output is the real cause of climate change,
the panel says mankind’s industrial emissions have had five times
more effect on the climate than any fluctuations in solar radiation.
We are the masters of our own destruction, in short.

There is some comfort, however. The panel believes the Gulf
Stream will go on bathing Britain with its warm waters for the next
100 years. Some researchers have said it could be disrupted by cold
waters pouring off Greenland’s melting ice sheets, plunging western
Europe into a mini Ice Age, as depicted in the disaster film The Day
After Tomorrow.

The report reflects climate scientists’ growing fears that Earth
is nearing the stage when carbon dioxide rises will bring
irreversible change to the planet. ‘We are seeing vast sections of
Antarctic ice disappearing at an alarming rate,’ said climate expert
Chris Rapley, in a phone call to The Observer from the Antarctic
Peninsula last week. ‘That means we can expect to see sea levels rise
at about a metre a century from now on – and that will have
devastating consequences.’

However, there is still hope, said Peter Cox of Exeter
University. ‘We are like alcoholics who have got as far as admitting
there is a problem. It is a start. Now we have got to start drying
out – which means reducing our carbon output.’

NASA/Goddard Space Flight Center
Public release date: 12-Jan-2007

Contact: Rob Gutro@nasa.gov
Robert.J.Gutro@nasa.gov
301-286-4044

NASA presentations at the 87th AMS Annual Meeting

NASA researchers will present findings on a variety of Earth science
topics at the 87th American Meteorological Society Annual Meeting,
which runs Jan. 14 through Jan. 18, at the H.B. Gonzalez Convention
Center, 200 E. Market Street, San Antonio, Texas.

Following are noteworthy NASA presentations, in chronological order:

Is Rainfall Increasing in the Tropics?

TIME: Tue., Jan. 16, 2:30 p.m. EST (1:30 p.m. CST), Room 214B

SESSION: 4A.1

Tropical rainfall variations and possible long-term changes are
examined using multi-year data and satellites, including NASA’s
Tropical Rainfall Measuring Mission. This presentation will focus on
techniques used to determine the influence of volcanic events,
climate events like El Nino, and other variables on rainfall patterns
over land and ocean.

Diurnal, Synoptic, Subseasonal and Interannual Acceleration of the
Global Hydrological Cycle in IPCC AR4 Model Simulations TIME: Tue.,
Jan. 16, 2:30 p.m. EST (1:30 p.m. CST), Room 214B SESSION: 4A.6

This talk will present results from ongoing research to assess how
much the global water cycle is projected to speed up under future
climate change conditions. The authors analyze computer simulations
to evaluate changes projected in precipitation, evaporation and
precipitable water on various time scales.

The Impact of Large-Scale Climate Variability on Weather

TIME: Wed., Jan. 17, 9:30 a.m. EST (8:30 a.m. CST), Room 214D

SESSION: 2.3

Scientists present findings from recent experiments using computer
climate models to examine the link between extreme weather and modes
of large-scale climate variability. The talk will focus on extreme
winter storms over the United States and how they are influenced by
the El Nino-Southern Oscillation and other climate variables.

Predictability and Forecast Skill of the Madden-Julian Oscillation

TIME: Wed., Jan. 17, 9:30 a.m. EST (8:30 a.m. CST), Room 214D

SESSION: 2.6

Researchers have begun intensive efforts to improve modeling
capabilities of large-scale, sub-seasonal recurrent patterns in the
tropics and mid-latitudes. The presentation will examine the
predictability and forecast skill analysis of the Madden-Julian
Oscillation, a mode of climate variability in the Pacific that plays
a major role in global weather patterns.

Assessment of Climate Variability and Change in the New York
Metropolitan Region

TIME: Wed., Jan. 17, 5:00 p.m. EST (4:00 p.m. CST), Room 214D

SESSION: 5.2

Climate change presents significant risk-management challenges to the
New York metropolitan region. Researchers will present findings about
future climate scenarios that illustrate how higher temperatures,
rising sea levels and precipitation changes will influence the
region’s coastal infrastructure and water supply.

University of Minnesota
Public release date: 10-Jan-2007

Contact: David Ruth
druth@umn.edu
612-624-1690

University of Minnesota conference to look at global warming and
government responses

MINNEAPOLIS / ST. PAUL (1/10/2007) –With the scientific data on global climate change so widely available, why do some nations’ governments take action while others deny that the problem even exists? In the middle of the United States’ warmest winter on record, a conference at the University of Minnesota will bring together social scientists from around the world to investigate that very question. “Risk and Response to Global Environmental Change: Lessons from Cross-National Social Science Research” will take place Thursday, Jan. 25 and Friday, Jan. 26 at Cowles Auditorium, Humphrey Center, 301 19th Ave. S., Minneapolis.

Global climate change is usually examined from a science perspective
— the only way society knows about the problem. But in practice,
governments and societies often disregard scientific knowledge. The
conference brings together social scientists who, by comparing different national responses and global agreements, are examining the
social, political and cultural factors that make for the best public policy. These factors help governments take science seriously as the basis for assessing risk and making responses to global climate change (GCC) and related environmental problems. Factors under investigation include those that strengthen “advocacy networks,” such as opportunities for interest groups like business and non-governmental organizations (NGOs) to talk together and create
joint recommendations.

On the day after the conference, visiting researchers will gather to review the discussions of the previous two days and design a research project to take what is known about human and governmental reaction to GCC to the next level. These sociologists, political scientists and other social scientists will then conduct research in about 15 nations where they will develop case studies that offer comparisons and contrasts between government reactions, with the goal of knowing what tactics countries can borrow from each other to help address the
problem. Nations to be involved in the research project include Canada, China, England, Germany, Greece, Japan, Korea, the Netherlands, the United States and others. Ultimately, the research team hopes to use their research to halt global warming. A follow up conference is scheduled for spring 2007 in Greece.

Conference speakers will include former Vice President Walter Mondale; Leslie King, dean of the Clayton H. Riddell Faculty of Environment, Earth, and Resources at the University of Manitoba; and researchers from the United States, Canada, Germany and the Netherlands.

###
—

Warming, Snowcover, Monsoons, & Marine Life

http://earthobservatory.nasa.gov/Study/Monsoon/printall.php>http://earthobservatory.nasa.gov/Study/Monsoon/printall.php

The New York Times The Week In Review
http://www.nytimes.com/2007/01/14/weekinreview/14basics.html

January 14, 2007

The Basics Connecting the Global Warming Dots

By ANDREW C. REVKIN

If thought of as a painting, the scientific picture of a growing and
potentially calamitous human influence on the climate has moved from being abstract a century ago to impressionistic 30 years ago to pointillist today.

The impact of a buildup of carbon dioxide and other greenhouse gases is now largely undisputed. Almost everyone in the field says the consequences can essentially be reduced to a formula: More CO2 = warmer world = less ice = higher seas. (Throw in a lot of climate shifts and acidifying oceans for good measure.)

But the prognosis – and the proof that people are driving much of the
warming – still lacks the sharpness and detail of a modern-day photograph, which makes it hard to get people to change their behavior.

Indeed, the closer one gets to a particular pixel, be it hurricane
strength, or the rate at which seas could rise, the harder it is to be
precise. So what is the basis for the ever-stronger scientific agreement on the planet’s warming even in the face of blurry details?

As in a pointillist painting, the meaning emerges from the broadest view, from the “balance of evidence,” as the scientific case is described in the periodic reports issued by an enormous international network of experts: the Intergovernmental Panel on Climate Change, www.ipcc.ch. The main findings of the panel’s fourth assessment since 1990 will be released in Paris on Feb. 2.

In the panel’s last report, issued in 2001, and in more recent studies
reviewed for the coming report, various trends provide clues that human
activity, rather than natural phenomena, probably caused most of the recent warming. A number of trends have been identified:

Ã‚Â¶The global average minimum nighttime temperature has risen. (This is
unlikely to be caused by some variability in the sun, for example, and
appears linked to the greenhouse gases that hold in heat radiating from the earth’s surface, even after the sun has gone down.)

Ã‚Â¶The stratosphere, high above the earth’s surface, has cooled, which is an expected outcome of having more heat trapped by the gases closer to the surface, in the troposphere. (Scientists say that variations in the sun’s output, for example, would instead cause similar trends in the two atmospheric layers instead of opposite ones.)

Ã‚Â¶There has been a parallel warming trend over land and oceans. (In other words, the increase in the amount of heat-trapping asphalt cannot be the only culprit.)

“There’s no urbanization going on on the ocean,” said Jay Lawrimore, chief of the climate monitoring branch of the National Climatic Data Center in Asheville, N.C.

Another important finding comes from computer simulations of the climate system. While the several dozen top models remain rough approximations, they have become progressively better at replicating climate patterns, past and present.

In the models, the only way to replicate the remarkable warming, and
extraordinary Arctic warming, of recent decades is to add greenhouse gases as people have been doing, Dr. Lawrimore said.

“Without the greenhouse gases,” he said, “you just don’t get what we’ve
observed.”

Dartmouth News > News Releases > 2007 > January > The winds of change

Dartmouth College Office of Public Affairs * Press Release
Posted 01/23/07 * Susan Knapp * (603) 646-3661

Dartmouth researchers learn that North America’s wind patterns have
shifted significantly in the past 30,000 years

Dartmouth researchers have learned that the prevailing winds in the
mid latitudes of North America, which now blow from the west, once
blew from the east. They reached this conclusion by analyzing 14,000-
to 30,000-year-old wood samples from areas in the mid-latitudes of
North America (40-50Ã‚Â°N), which represents the region north of Denver
and Philadelphia and south of Winnipeg and Vancouver.

The researchers report their findings online on Jan. 23 in the
journal Geology, published by the Geological Society of America.

“Today in the mid-latitude zone of North America, marine moisture is
transported either from the west coast by westerly winds, or from
both the west and east coasts by storms,” says Xiahong Feng, the
paper’s lead author and a professor of earth sciences. “In this
study, we found evidence that during the last glacial period, about
14-36 thousand years ago, the prevailing wind in this zone was
easterly, and marine moisture came predominantly from the East Coast.”

Feng explains that global climate change is often manifested by
changes in general atmospheric circulation, i.e. winds, and this
results in changing temperature and precipitation patterns. Clues of
past climates usually hint at temperature and precipitation changes,
but this is the first time that changing continental wind patterns
have been reconstructed.

The researchers gathered their evidence using oxygen and hydrogen
isotopic compositions of cellulose extracted from ancient wood. Feng
and her team interpret the historic prevailing easterlies to be a
result of a growing and intensifying northern circumpolar vortex,
which was influenced by the powerful Laurentide Ice Sheet, an
enormous mass of ice that covered a great deal of northern North
America. Under this circulation regime, the jet stream shifted
southward, and as a result, the Pacific Northwest received much less
marine moisture from the Pacific. This is consistent with earlier
studies of vegetation in the Pacific Northwest, indicating that the
region was significantly drier during the last glaciation.

“This study is likely to open up new avenues of research based on
oxygen and hydrogen isotopes in old wood,” says Feng. “Climate change
involves interactions among temperature, precipitation, and wind, but
until now research has rarely been able to observe or confirm
prehistoric winds and their continental-scale patterns. In the
future, studies using this methodology will be able to look into
ancient climates through a new window, and test hypotheses about
climate change mechanisms. Such studies can potentially lead to more
realistic formulations of future climate scenarios and better
evaluations of their plausibility.”

In addition to Xiahong Feng, who also holds the Frederick Hall
Professorship in Mineralogy and Geology at Dartmouth, other authors
on the paper include: Allison L. Reddington, a member of the
Dartmouth Class of 2004; Anthony M. Faiia, Dartmouth research
associate; Eric S. Posmentier, adjunct professor of earth sciences at
Dartmouth; Yong Shu, Dartmouth PhD candidate; and Xiaomei Xu, from
the Earth System Science Department at the University of California,
Irvine.

“This study began as Allison Reddington’s undergraduate honors
thesis,” says Feng. “This exemplifies the extraordinary opportunities
that undergraduates at Dartmouth have to become integral parts of
research groups.”

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