Tumblelog by Soup.io
Newer posts are loading.
You are at the newest post.
Click here to check if anything new just came in.

July 27 2012

22:26

January 31 2012

18:35

The Oceanic Conveyor Belt: Climate Change Tipping Points Being Reached in the Arctic, Western Boundary Ocean Currents


Accelerated changes in the Arctic are moving ocean currents poleward and threaten the oceanic conveyor belt

Two new research papers by authoritative climate research teams were announced this week — one on climate change tipping points being reached in the Arctic and a second on warming of long-distance, poleward-moving ocean currents. The results of the studies show that warming of both the Arctic and western boundary currents is happening faster than has been anticipated, prompting the researchers to publicly urge that efforts to adapt to abrupt climate change be intensified globally.

Climate Change Tipping Points in the Arctic

In “Abrupt climate change in the Arctic,” University of Western Australia (UWA) Ocean Institute researchers lead by director and Winthrop Professor Carlos Duarte found that the Arctic is warming at a rate three times faster than the global average, which has caused Arctic summer sea ice to melt and recede at a pace faster than researchers have forecast.

Arctic summer sea ice may be limited to the the waters off northern Greenland and Ellesmere Island in as short a period as the next decade, and is likely to disappear entirely by the middle of the century, according to a WA News report. The warming’s occurring so fast that it’s not only threatening Arctic ecosystems and traditional ways of life, the Arctic may change from being a net carbon sink to a net source of greenhouse gas emissions.

The fast warming Arctic is opening up new sea lanes and a bonanza of resource exploration and exploitation, as well as political controversy over resource rights. However, faster than anticipated warming and melting will also have “abrupt knock-on effects” across major world cities in northern mid-latitudes, a list that includes Beijing, Berlin, London, Moscow, New York and Tokyo. Tentatively linked is the occurrence of much colder winters in Europe.

Warming of Western Ocean Boundary Currents

Also published in Nature Climate Change, “Enhanced warming over the global subtropical western boundary currents,” is a global study of fast-moving, long-distance ocean currents, such as the Gulfstream, that distribute heat and moisture from warming tropical ocean waters globally.

Moving along the western boundaries of the world’s ocean basins, changes in water temperature of these currents also have significant, large-scale effects on climate globally. Releasing heat and moisture on their way from the equator to the poles, they affect atmospheric jet streams and mid-latitude storms and patterns, as well as ocean absorption of carbon dioxide.

Reconstructing and re-examining data sets using new methods, the research team found that “the post-1900 surface ocean warming rate over the path of these currents is two to three times faster than the global mean surface ocean warming rate. The accelerated warming is associated with a synchronous poleward shift and/or intensification of global subtropical boundary currents in conjunction with a systematic change in winds over both hemispheres.”

The faster than expected warming of these long-distance, poleward moving ocean currents “may reduce the ability of the oceans to absorb anthropogenic carbon dioxide over these regions,” according to the report’s authors. “Uncertainties in detection and attribution of these warming trends remain,” they note, “pointing to a need for a long-term monitoring network of the global western boundary currents and their extensions.”

The Oceanic Conveyor Belt and Climate Change

Though not stated by the authors, the increasing incidence of unusual extreme storms, such as 2011′s Hurricane Irene, which carried as far north as the US’ mid-Atlantic and New England regions, and Typhoon Washi, which struck the southern Philippine island of Mindanao, may be evidence of the faster than expected melting of Arctic ice and faster than expected warming of western ocean boundary currents.

Moreover, the changes in both Arctic sea ice and western boundary currents are both aspects of what’s now known as the “oceanic conveyor belt” – scientific knowledge that’s come to us thanks to groundbreaking hypothesizing, testing and research performed by Wallace Broecker.

The abruptness and scale of the climate changes that increasingly appear to be headed our way warrant much greater attention by world leaders and policy makers. While exaggerated for dramatic effect, they bring to mind the popular disaster film, “The Day after Tomorrow,” the science of which is based on a shutting down of the oceanic conveyor belt Broecker first theorized, and the occurrence of world-changing super-storms that bring on a new Ice Age in a matter of months.

As UWA’s Prof. Duarte was quoted as saying, “We need to stop debating the existence of tipping points in the Arctic and start managing the reality of dangerous climate change.”

 

Image credit: NASA Ocean Motion

Sponsored post

October 11 2011

18:52

Effects of Global Warming Posing Threats from the Arctic to Australia


Arctic sea ice - 2011It seems climate change deniers will try every trick in the book and go to almost any lengths to spread their message and gain supporters. You can’t deny what people and all forms of life around the world are experiencing, however, or the growing mountain of evidence supporting climate change theory being amassed by good, honest climate science.

The following are excerpts from noteworthy climate science and climate-related developments around the world in the past week.

* Rising average temperatures are threatening Australia’s water supply. A report commissioned by Australia’s Federal Dept. of Climate Change predicts that average temperatures will rise 0.6 and 2.9 degrees Celsius by 2050, and that overall precipitation will drop by as much as 24% by 2050.

Runoff from snow melt and precipitation in the “Australian Alps,” which stretch from Victoria to New South Wales, produces an estimated average 9600 gigatons of water a year. Reduced to dollars and cents terms, that’s as much as US$9.8 billion annually. The mountain runoff also supplies nearly 30% of the Murray-Darling River system, which in turn is the source of water for Australia’s primary agricultural lands and farms. Alps’ water helps support some 2.1 million of Australia’s total 21.9 million population.

* Younger, thinner sea ice once again dominated the Arctic in September, according to the National Snow and Ice Data Center. Young, thin ice is much more prone to melt than older, thicker ice. The decreasing ice cover is also a positive global warming feedback cycle as it reduces the amount of sunlight reflected back into the atmosphere, termed the albedo effect.

The amount of sea ice four years old or older has been declining steadily, while sea ice one to two-years old has been increasing in the Arctic basin. Four year-old or older ice made up 45% of total Arctic sea ice in 1984. That compares to around 9% as of this September.

* Danger zones are emerging across the Himalayas as rising temperatures cause glaciers to melt. The melting Imja glacier in the Nepalese Himalayas “is a high-altitude disaster in the making – one of dozens of danger zones emerging across the Himalayas,” according to a report from The Guardian. Mountain regions from the Andes to the Himalayas are warming and melting faster than average. The melting Himalayan glaciers undoubtedly pose numerous and varied short- and long-term threats across one the world’s most heavily populated regions, which includes the entire Indian subcontinent.

* Samoa’s electric power company has asked all residents to cut their water consumption as drought has brought the island nation’s water reservoirs to lows and has caused rivers and creeks to completely dry up.

“At the moment we are mainly encouraging communities to minimize all the adverse impacts into the water shed areas because that’s not helping the situation at the moment, especially for surface water,” Suluimalo Penaia, assistance chief executive of the Water Resource Division, was quoted as saying in a news report. “There’s not much we can do. All we are doing at the moment is just monitoring the impacts, which one is actually flowing at the moment for the surface water and which are the main streams that are totally dried up at the moment.”

* More often heard than seen, American pikas living in the US Rocky Mountains are moving up to higher elevations as a result of the changing, warming climate. The American pika is second species that conservationists have petitioned for protection under the U.S. Endangered Species Act (ESA) because of climate change-associated threats. The polar bear was the first.

Low-elevation pika populations around the region are at high risk from climate change. In Yosemite National Park, they have migrated more than 500 feet up-slope over the last 100 years. That’s coincided with a temperature increase of 5.4 °F in Yosemite, according to a Talking Science report.

Between 1999 and 2008, pikas in the Great Basin on the eastern edge of the Sierra Nevada have undergone an almost five-fold increase in extinction rate and an 11-fold increase in the rate of up-slope retreat.

Enhanced by Zemanta

June 30 2011

22:28

New Climate “Normals” Begin on July 1st – Warmer is the New Norm : NOAA Releases 2010 State of the Climate Report


New weather normal baseline data is adopted on July 1st

Tomorrow the National Oceanic and Atmospheric Administration (NOAA) will incorporate new baseline data reflecting new climate “normals” for 1981-2010. For the past decade baseline normals spanned the period from 1971-2000.

These normals “serve as a 30 year baseline average of important climate variables that are used to understand average climate conditions at any location and serve as a consistent point of reference,” said the NOAA in a press release this week. Based on updated data encompassing the past decade (and leaving the 70′s behind), temperatures in the US are, on average, 0.5 degrees Fahrenheit warmer in the new baseline normal than the previous.

That’s to be expected given the warming of the past decade, says National Climatic Data Center director Thomas Karl: “The climate of the 2000s is about 1.5 degree F warmer than the 1970s, so we would expect the updated 30-year normals to be warmer.”

In every state the annual average maximum and minimum temperature has increased within the contiguous US, according to NOAA data. Warming has increased in all seasons, but winter months have seen much more rapid increase in temperatures than summer months (see image below).

Temperatures have warmed in the US for all seasons, but much more rapidly in winter monthsState of the Climate 2010
Earlier this week NOAA released it’s annual State of the Climate Report for 2010. The report is compiled by nearly 370 scientists from 45 nations and shows 2010 as one of the two warmest years on record. Not all of the extreme weather events of 2010 are indicators of the larger climactic trend, but as a summary report from NOAA explains:

“In the background of many unique events, long-term trends are visible in the data; despite snow and cold in some locations, tens of thousands of observations around the world combine to reveal a 2010 average global surface temperature among the two warmest years on record.”

Among the climate indicators noted in the report:

  • Arctic Oscillation – the Arctic Oscillation is an atmospheric climate pattern the typically confines colder air to northern latitudes. When the pattern flips, frigid air flows out of the Arctic, contributing to more severe winters farther south and warmer conditions in Arctic regions.
  • Snow and ice - decrease in snow cover of the Northern Hemisphere between December 2009 and May 2010 was the largest in more than 40 years. Globally, mountain glaciers lost mass for then 20th consecutive year. Greenland lost more ice than in any previous year on record. Arctic sea ice shrank to its third smallest area on record. In September, ice extent was so small that for the first time in modern history, the Northwest Passage and Northern Sea Route were both open to navigation. Conversely, due to by air circulation patterns, Antarctic sea ice grew to record levels during the Southern winter.
  • Sea level – Sea levels across the globe continue to rise, on average, due to thermal expansion and melting glaciers and ice sheets.
  • Air temperature – Air temperature above land was the second warmest on record. The Arctic warmed at about twice the rate of lower latitudes.
  • Oceans
    • Sea surface temperature: despite a cooling in the eastern tropics of the Pacific Ocean of 2 degrees F due to transitioning from El Niño to La Niña, global average sea surface temperatures were the third highest on record.
    • Ocean heat content: 2010 was on par with 2009 and was among the “highest values on record,” according to the report. Oceans store much of the heat trapped by increasing greenhouse gases.
  • Greenhouse gases - Carbon dioxide levels in the atmosphere increased at a rate greater than the average over the past 30 years.

 

Additional sources and further reading:
Washington Post

NOAA State of the Climate 2010 Highlights
(pdf)

Image credits: NOAA

Enhanced by Zemanta
Older posts are this way If this message doesn't go away, click anywhere on the page to continue loading posts.
Could not load more posts
Maybe Soup is currently being updated? I'll try again automatically in a few seconds...
Just a second, loading more posts...
You've reached the end.
(PRO)
No Soup for you

Don't be the product, buy the product!

close
YES, I want to SOUP ●UP for ...