RECENT WARMING OF ARCTIC MAY AFFECT WORLDWIDE CLIMATE

Maybe these guys are on to it.... will a new Ice Age be the result of 
Global Warming?
http://www.gsfc.nasa.gov/topstory/20011116meltwater.html#top

The global warming (climate change) feedback loop is already so strong we
won't stop it by curtailing green house gas emissions even if we could.
We may not need to do anything to stop excessive fossil fuel 
consumption from exacerbating climate change but watch the peak of 
world oil production result in forced conservation strategies

We are experiencing the convergence of many interesting historical trends.
It may be the economic consequences of conflicts over remaining 
resources that most effect us near term.

Tim Jones

October 23, 2003

http://www.gsfc.nasa.gov/topstory/2003/1023esuice.html

RECENT WARMING OF ARCTIC MAY AFFECT WORLDWIDE CLIMATE

Click here to go directly to images, animations and additional information
http://www.gsfc.nasa.gov/topstory/2003/1023esuice.html#addlinfo


 Recently observed change in Arctic temperatures and sea ice cover 
may be a harbinger of global climate changes to come, according to a 
recent NASA study. Satellite data -- the unique view from space -- 
are allowing researchers to more clearly see Arctic changes and 
develop an improved understanding of the possible effect on climate 
worldwide.

The Arctic warming study, appearing in the November 1 issue of the 
American Meteorological Society's Journal of Climate, shows that 
compared to the 1980s, most of the Arctic warmed significantly over 
the last decade, with the biggest temperature increases occurring 
over North America.

"The new study is unique in that, previously, similar studies made 
use of data from very few points scattered in various parts of the 
Arctic region," said the study's author, Dr. Josefino C. Comiso, 
senior research scientist at NASA's Goddard Space Flight Center, 
Greenbelt, Md. "These results show the large spatial variability in 
the trends that only satellite data can provide." Comiso used surface 
temperatures taken from satellites between 1981 and 2001 in his study.

The result has direct connections to NASA-funded studies conducted 
last year that found perennial, or year-round, sea ice in the Arctic 
is declining at a rate of nine percent per decade and that in 2002 
summer sea ice was at record low levels. Early results indicate this 
persisted in 2003.

Researchers have suspected loss of Arctic sea ice may be caused by 
changing atmospheric pressure patterns over the Arctic that move sea 
ice around, and by warming Arctic temperatures that result from 
greenhouse gas buildup in the atmosphere.

Warming trends like those found in these studies could greatly affect 
ocean processes, which, in turn, impact Arctic and global climate, 
said Michael Steele, senior oceanographer at the University of 
Washington, Seattle. Liquid water absorbs the Sun's energy rather 
than reflecting it into the atmosphere the way ice does. As the 
oceans warm and ice thins, more solar energy is absorbed by the 
water, creating positive feedbacks that lead to further melting. Such 
dynamics can change the temperature of ocean layers, impact ocean 
circulation and salinity, change marine habitats, and widen shipping 
lanes, Steele said.

In related NASA-funded research that observes perennial sea-ice 
trends, Mark C. Serreze, a scientist at the University of Colorado, 
Boulder, found that in 2002 the extent of Arctic summer sea ice 
reached the lowest level in the satellite record, suggesting this is 
part of a trend. "It appears that the summer 2003 -- if it does not 
set a new record -- will be very close to the levels of last year," 
Serreze said. "In other words, we have not seen a recovery; we really 
see we are reinforcing that general downward trend." A paper on this 
topic is forthcoming.

According to Comiso's study, when compared to longer term 
ground-based surface temperature data, the rate of warming in the 
Arctic over the last 20 years is eight times the rate of warming over 
the last 100 years.

Comiso's study also finds temperature trends vary by region and 
season. While warming is prevalent over most of the Arctic, some 
areas, such as Greenland, appear to be cooling. Springtimes arrived 
earlier and were warmer, and warmer autumns lasted longer, the study 
found. Most importantly, temperatures increased on average by 1.22 
degrees Celsius per decade over sea ice during Arctic summer. The 
summer warming and lengthened melt season appears to be affecting the 
volume and extent of permanent sea ice. Annual trends, which were not 
quite as strong, ranged from a warming of 1.06 degrees Celsius over 
North America to a cooling of .09 degrees Celsius in Greenland.

If the high latitudes warm, and sea ice extent declines, thawing 
Arctic soils may release significant amounts of carbon dioxide and 
methane now trapped in permafrost, and slightly warmer ocean water 
could release frozen natural gases in the sea floor, all of which act 
as greenhouse gases in the atmosphere, said David Rind, a senior 
researcher at NASA's Goddard Institute of Space Studies, New York. 
"These feedbacks are complex and we are working to understand them," 
he added.

The surface temperature records covering from 1981 to 2001 were 
obtained through thermal infrared data from National Oceanic and 
Atmospheric Administration satellites. The studies were funded by 
NASA's Earth Science Enterprise, which is dedicated to understanding 
the Earth as an integrated system and applying Earth System Science 
to improve prediction of climate, weather and natural hazards using 
the unique vantage point of space.


 Seasons of Change: Evidence of Arctic Warming Grows

SYNOPSIS:

Experts have long regarded Earth's polar regions as early indicators 
for global climate change. But until the last few years, wide 
ranging, comprehensive research about overall polar conditions has 
been challenging to conduct. Now a more than twenty-year record of 
space based measurements has been analyzed by researchers at NASA's 
Goddard Space Flight Center. Based on their findings, evidence of a 
warming planet continues to grow.


CHANGING SEASONS, CHANGING ICE

Research and data collection of Arctic Ocean ice isn't easy. But in 
this sequence using data collected by a number of satellites from 
1979 to 2003, we see how scientists have been able to stitch together 
a careful record of sea ice in that part of the world. In 2002 
scientists recorded the lowest concentration of sea ice ever in The 
Arctic. While temperature changes vary across the vast expanse of The 
Arctic, overall trends suggest that decreasing ice concentrations are 
due to a significant increase in ocean warming, from rising surface 
temperatures to the total number of annual "melt days".

Less ice means more open water. More open water means greater 
absorption of solar energy. More absorption of solar energy means 
increased rates of warming in the ocean, which naturally tends to 
yield faster rates of ice loss.

The data used to create these images come from a variety of different 
instruments flying on a group of satellites; they include the 
scanning multi-channel microwave radiometer attached to the Nimbus 7 
satellite, and the special sensor microwave imagers attached to the 
Defense Meteorological Satellite Program's F8, F11, and F13 
satellites.

Part of the challenge for researchers was in the elimination of "bad 
data", from atmospheric interference to instrument calibration issues 
and more. One reason that data acquired by microwave detecting 
instruments such as those flying on the DMSP satellites is that 
microwaves can penetrate the cloud cover that frequently blankets the 
Arctic. One of the most apparent characteristics of Arctic ice is 
just how dynamic and complex an environment it is. Through continued 
research and gathering of data, scientists hope to achieve a better 
level of understanding about the processes at work in the cryosphere.

Arctic perennial sea ice has been decreasing at a rate of 9% per 
decade. The first image shows the minimum sea ice concentration for 
the year 1979, and the second image shows the minimum sea ice 
concentration in 2003. The data used to create these images and the 
following animation were collected by the Defense Meteorological 
Satellite Program (DMSP) Special Sensor Microwave Imager (SSMI). 
Credit: NASA


WARMER AND COOLER

Space based observation facilitate a kind of thoroughness that ground 
based observations cannot realistically approach. Based on 20 years 
of data collected by infrared measurements, surface warming trends in 
The Arctic are eight times greater than trends over the past 100 
years, suggesting a rapid acceleration in warming. According to this 
study, the sea ice melt season has increased by 10 to 17 days per 
decade.

The readings are not uniform, however. While average temperatures are 
increasing throughout The Arctic, there are several places where 
there appear to be cooling trends. Greenland is a good example; the 
data there suggest a mild decrease in average temperatures through 
the time period being analyzed.

The data used to create these images were collected by the AVHRR 
instruments onboard the NOAA POES satellites.


Click on image to view animation

This animation shows surface temperature anomalies in the Arctic for 
each year from 1981 through 2002. The orange and red colors represent 
an increase of 0 to 7 degrees C, while the blue colors represent a 
decrease of 0 to 7 degrees. Each color step indicates a change of 
0.25 degrees Celsius. The data used to create images 5, 6, and 7 were 
collected by the AVHRR instruments onboard the NOAA POES satellites. 
Credit: NASA

High resolution image

Sea ice extent reached a record minimum in September, 2002, and 
retreated to almost the same position in September, 2003, as observed 
using satellite passive microwave data. The absence of ice off 
Greenland is particularly unusual. Sea ice concentration in the 
western sector of the Arctic Ocean was anomalously low as well. 
Credit: NSIDC

PRESSURE TO CHANGE

Taken in isolation, one year's worth of data does not tell us much. 
Just as we all know that some days of the year might be unusually hot 
or cold, we intuitively understand that dramatic events in isolation 
are simply anomalies.

But many samples of data can imply change. Taken as collections of 
information, trends begin to emerge based on a pattern. In this 
sequence we see how 21 years of accumulated data indicate temperature 
trends in the Arctic. While the overall direction of the trend 
suggests warming for the region, there are many places where the 
average temperature is falling year after year.

Click on image to view animation

This animation shows overall warming and cooling trends in the Arctic 
over a 22-year period from August 1981 to July 2002. The orange and 
red colors represent an increase of 0 to 0.4 degrees C, while the 
blue colors represent a decrease of 0 to 0.4 degrees. Each color step 
indicates a change of 0.02 degrees Celsius. Note that while much of 
the Arctic has experienced warming, some regions exhibit an overall 
cooling pattern. Credit: NASA

Still image of 20 year trends: low res,high res



Color-coded trends in the sea ice cover are shown for autumn, winter, 
spring and summer using AVHRR surface temperature data from 1981 to 
2001. The trends are very positive in summer and mainly positive in 
autumn and spring suggesting a change towards longer melt periods. In 
winter, large areas are shown to have negative trends but these areas 
are also where the sea ice cover has been increasing in winter during 
the same period. Credit: NASA



The length of the melt season inferred from surface temperature 
weekly data has been increasing by 9, 12, 12, and 17 days per decade 
in sea ice covered areas, Greenland, Eurasia (>60o lat), and North 
America (>60o lat), respectively. Longer melt periods would mean 
reduced growth season, thinner sea ice and less extensive sea ice 
cover in the summer. Credit: NASA

BRIGHT WHITE REFLECTS LIGHT-
THE GLOBAL ROLE OF THE POLAR CAPS

The polar caps not only hold much of the planet's total fresh water, 
but also play an important role in regulating the Earth's 
temperature. The relevant characteristic is called albedo. It's a 
measure of how much radiation, or light, is reflected from a body. 
Similar to how a white shirt helps keep a person cooler in the summer 
than a black shirt, the vast stretches of polar ice covering much of 
the planet's top and bottom reflect large amounts of solar radiation 
falling on the planet's surface. Were the ice caps to appreciably 
recede, sunlight that otherwise would have been reflected back into 
space would get absorbed by the darker, denser mass of ocean and land 
beneath. As light is absorbed, the environment is heated, thus 
intensifying a feedback loop: a warmer planet yields more ice melting 
thus an even warmer planet.

Click on image to view animation

This is a conceptual animation showing how polar ice reflects light 
from the sun. As this ice begins to melt, less sunlight gets 
reflected into space. It is instead absorbed into the oceans and 
land, raising the overall temperature, and fueling further melting. 
Credit: NASA

IS THE OCEAN RISING?

This animation provides a closer perspective of the relationship 
between ice and solar reflectivity. As glaciers, the polar caps, and 
in this case, icebergs melt, less sunlight gets reflected into space. 
It is instead absorbed into the oceans and land, thus raising the 
overall temperature, and adding energy to a vicious circle.

Of the many concerns voiced by scientists who study global warming 
trends, rising ocean levels is one of the most dramatic. An average 
rise in global ocean levels of just a few inches could have 
devastating effects on coastal towns, cities, and ecosystems. Why 
then is even the slightest risk of a shrinking polar cap not sounding 
alarms all across the world's lowland regions?

It comes down to a simple principle proved thousands of years ago by 
the Greek philosopher and scientist Archimedes. He showed that a 
body, in this case the floating ice of the North Pole, immersed in a 
fluid, is buoyed up by a force equal to the weight of the displaced 
fluid. In other words, since the northern pack ice is already 
floating its melting would not independently cause ocean levels to 
rise. However, the attending planetary conditions necessary to 
facilitate polar melting would likely have other enormous effects on 
the environment. These include the likely melting of the ice sheets 
covering Greenland and the vast reaches blanketing southern polar 
cap. As the ice over Greenland and Antarctica is NOT floating, a 
corresponding rise in the world's sea level would almost certainly 
result if it melted.

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