tagged w/ Ocean Warming
Researchers at the Lawrence Livermore National Laboratory found that greenhouse gases were responsible for warming oceans, further strengthening the claim that climate change is human-made.
"The bottom line is that this study substantially strengthens the conclusion that most of the observed global ocean warming over the past 50 years is attributable to human activities," said study author and climate scientist Peter Gleckler, according to Live Science.
It is estimated that the oceans account for 90 percent of the heat accumulated on Earth over the past 50 years, the study said.
Read more on GlobalPost: Climate change will produce more wildfires in the US
The research used computer models to test a variety of situations that could have caused ocean warming – a phenomenon that has not been contested.
When greenhouse gas emissions were added to the model, the temperature fluctuations began to make sense.
Indeed, the team of researchers from the US, Australia and Japan found that natural fluctuations by themselves do not explain warming in the ocean’s upper layers, said Discovery.
The study was published in the journal Nature Climate Change.
More at the linkResearchers at the Lawrence Livermore National Laboratory found that greenhouse gases... more
Despite what you may read or see in the mainstream media, out in the real world, massive and rapid changes are taking place in many ecological systems as a result of global warming. The Earth seems to be already convinced of global warming and is responding quickly.
Perhaps the most significant, and likely most enduring, are the shifts taking place in the Earth's oceans. Whilst many readers may have read or heard about Ocean Acidification, there are numerous other changes taking place in the oceans which should be equally as concerning. One such phenomena to appear in the last few decades is mass coral bleaching, a consequence of the continued warming of the oceans. Once vast stretches of colourful reefs teeming with marine life are being reduced to lifeless rubble covered in seaweed or slime. Many areas are not recovering, and the scale and frequency of bleaching worldwide is getting worse. In fact, early reports suggest 2010 may have witnessed the largest single bleaching event ever recorded.
The lowdown on coral bleaching
Reef-coral are actually a symbiosis (a mutually beneficial relationship) between the coral polyp, an anemone-like creature, and tiny algae called zooxanthellae. The coral provide shelter and nutrients for the algae , and in exchange the algae provide carbohydrates (food) to the polyp, using energy from the sun (photosynthesis) and the nutrients provided by the coral. These algae live in the skin tissue of the polyp and produce the coloured pigments which make coral reefs so visually spectacular. When this partnership breaks down the polyps expel the algae, which leads to the "bleached" effect. Although the polyp does feed using its tentacles to snare food, the bulk of its nutrition (90%+) comes from the algae, and they are a critical component of coral skeleton formation and therefore reef maintenance and growth. Without symbiotic algae, the coral can die from starvation, or become so weakened by a lack of food, that it succumbs to harmful bacteria (Mao-Jones 2010), and/or seaweeds which can poison and kill coral on contact.
Because reef-coral have adapted tolerance to a narrow band of environmental conditions, bleaching can occur for a number of reasons, such as ocean acidification, pollution, excess nutrients from run-off, high UV radiation levels, exposure at extremely low tides and cooling or warming of the waters in which the coral reside. Typically these events are very localized in scale and if bleaching is mild, the coral can survive long enough to re-acquire new algal partners. So bleaching in itself is not something new, but mass coral bleaching on the huge scale being observed certainly appears to be, and represents a whole new level of coral reef decline.
Ocean warming is driving mass coral bleaching
As coral reefs operate very near to their upper limit of heat tolerance (Glynn & D'Croz 1990), bleaching en masse happens when the surface waters get too warm above their normal summer temperature, and are sustained at this warmer level for too long. The intensity of bleaching corresponds with how high, and how long temperatures are elevated and, as one might expect, the intensity of bleaching affects the rate of survival. Small rises of 1 -2 degree C, for weeks at a time, usually induce bleaching.
This episodic ocean warming has been most pronounced worldwide during El-Nino events, when the Pacific Ocean exchanges heat to the atmosphere and surface waters. In recent years though, severe mass bleaching is happening outside of El-Nino because of the "background" ocean warming. The huge mass bleaching in the Caribbean in 2005, a non El-Nino year, and again this year is a prime example of this (Eakin 2010) . Evidence connecting warm surface waters and mass coral bleaching has strengthened to the extent that the National Oceanic and Atmospheric Administration (NOAA) has a coral bleaching alert system in place. This alert system accurately forecasts mass coral bleaching based on satellite data of sea surface temperatures.
Hot water + Coral = Dead coral
So how does hot water kill coral?. It requires both high water temperatures and sunlight. Oxygen is released as waste during photosynthesis and like all chemical processes this is affected by temperature, speeding up as more energy (warmth) is applied. When water temperatures rise too high the protective mechanisms to prevent heat damage, employed by the coral and the algae, are overwhelmed. The zooxanthellae algae produce high levels of oxygen waste which begin to poison the coral polyp. In acts of self-preservation the coral kick out the algae, and in doing so become susceptible to starvation, opportunistic diseases, competitive seaweeds and macroalgae (slime to you and me) . Coral can succumb to the effects of bleaching years later, and for those coral that survive, growth effectively ceases and full recovery can take anything up to a decade.
Coral resilience is futile
On a world scale coral reefs are in decline, and it makes for rather depressing reading for an avid diver like myself. Over the last 30-40 years 80% of coral in the Caribbean have been destroyed (Gardner 2003) and 50% in Indonesia and the Pacific (Bruno & Selig 2007). Bleaching associated with the 1982 -1983 El-Nino killed over 95% of coral in the Galapagos Islands (Glynn 1990), and the 1997-1998 El-Nino alone wiped out 16% of all coral on the planet. Globally about 1% of coral is dying out each year. Not all of this continual decline is solely down to bleaching of course, pollution and other human activities are also contributing, but bleaching is speeding up the loss of coral.
cont.Despite what you may read or see in the mainstream media, out in the real world,... more
C02 is expected to reach 770 ppm (up from 390 today, which is already higher than the goal of 350 ppm earlier in the century), and remain above 550 ppm for the next NINE CENTURIES. Big changes ahead...
It may be too late to stop the seas from eventually rising and flooding Earth's coastlines. Even if humans manage to eliminate carbon dioxide emissions completely by the year 2100, ocean warming set in motion by the end of this millennium could trigger the collapse of the West Antarctic Ice Sheet and flood New York City, Hong Kong, and other coastal cities, a new study suggests.
Sea level rises when meltwater from land-based masses of ice, such as glaciers, flows into the ocean. But sea level also increases when heat from the atmosphere gets mixed into the upper layers of the ocean, causing that water to expand. In recent decades, this thermal expansion has provided, on average, only about one-quarter of the 1.8 millimeters of sea level rise seen each year, but its contribution is increasing, studies suggest.
Now researchers point to an even bigger threat from warm ocean waters. The floating ice shelves that ring Antarctica could melt. So could the seaward end of land-based ice streams. That would lead to a long-term, catastrophic rise in sea level.
The new analysis, conducted by Nathan Gillett, a climate scientist at the University of Victoria in Canada and his colleagues, considers a rosy scenario. The team assumes that carbon dioxide emissions will rise at moderate rates from now until 2100, when people will switch to renewable energy sources and stop producing carbon dioxide. In this scenario, atmospheric concentrations of the greenhouse gas peak at about 770 parts per million (approximately twice today's level of approximately 390 ppm), Gillett says. Even though no new humanmade carbon dioxide emissions are produced after 2100 and terrestrial and marine ecosystems continue soaking it up, carbon dioxide levels remain above 550 ppm for the next 9 centuries. Oceans will be slow to soak up the atmospheric carbon dioxide, and terrestrial ecosystems—many of which have been storing carbon gradually for centuries—will begin to release some of that carbon after the year 2200, the model suggests. As a result, ocean warming persists throughout the millennium, the researchers reported online yesterday in Nature Geoscience.
Much of that warmth is mixed directly into surface seas by wave action. But some is injected into deeper ocean layers by the thermohaline circulation, a pattern of ocean currents that carries warm, salty water from the North Atlantic southward to the Antarctic. Overall, the team's model suggests that the temperature of waters surrounding the icy continent at depths between 500 and 1500 meters will rise approximately 3˚C between the years 2105 and 2995. Add that to an Antarctic surface warming of as much as 9˚C since the mid-1800s, and that's a recipe for melting ice. At particular risk is the West Antarctic Ice Sheet, a 2.2-million-cubic-kilometer, potentially unstable ice mass that sits on the sea floor at depths where Antarctic waters are warming the most.
Ocean warming alone will result in 25 centimeters of sea-level rise by 2100 and 1 meter by 3000, the researchers estimate. But if warming waters melt the major ice shelves of western Antarctica, which act like dams to hold immense quantities of ice on shore, the entire western portion of the Antarctic ice sheet could melt away. Previous studies hint that such a collapse could boost sea level as much as 4 meters, swamping coasts worldwide.
The team's analysis "looks like a solid study, and the most interesting new result is the tie to the West Antarctic Ice Sheet," says Richard Alley, a climate scientist at Pennsylvania State University, University Park. Human-caused warming, he says, could influence Antarctica's land ice many centuries after we stop burning fossil fuelsC02 is expected to reach 770 ppm (up from 390 today, which is already higher than the... more
NASA scientists say the current El Niño, ocean warming in the tropical Pacific may finally be weakening according to satellite data.NASA scientists say the current El Niño, ocean warming in the tropical Pacific... more
It is an "increasingly remote possibility" that human activity is not the main cause of climate change, according to a major Met Office review of more than 100 scientific studies that track the observed changes in the Earth's climate system.
The research will strengthen the case for human-induced climate change against sceptics who argue that the observed changes in the Earth's climate can largely be explained by natural variability.
Climate scientists and the UN's climate body, the Intergovernmental Panel on Climate Change (IPCC), have come under intense pressure in recent months after the IPCC was forced to admit it had made two errors in its fourth assessment report published in 2007. Emails hacked from climate scientists at the University of East Anglia in November have also sparked a series of inquiries into allegations of a lack of transparency by researchers and manipulation of the peer review process.
Asked whether his study was specifically scheduled as a fightback, Peter Stott, who led the review, said that the paper was originally drafted a year ago. But he added: "I hope people will look at that evidence and make up their minds informed by the scientific evidence."
Scientists matched computer models of different possible causes of climate change - both human and natural - to measured changes in factors such as air and sea temperature, Arctic sea ice cover and global rainfall patterns. This technique, called "optimal detection", showed clear fingerprints of human-induced global warming, according to Stott. "This wealth of evidence shows that there is an increasingly remote possibility that climate change is being dominated by natural factors rather than human factors." The paper reviewed numerous studies that were published since the last IPCC report.
Optimal detection considers to what extent an observation can be explained by natural variability, such as changing output from the sun, volcanic eruptions or El Niño, and how much can be explained by the well-established increases in carbon dioxide and other greenhouse gases in the atmosphere.
According to Nasa, the last decade was the warmest on record and 2009 the second warmest year. Temperatures have risen by 0.2C per decade, over the past 30 years and average global temperatures have increased by 0.8C since 1880.
The evidence that the climate system is changing goes beyond measured air temperatures, with much of the newest evidence coming from the oceans. "Over 80% of the heat that's trapped in the climate system as a result of the greenhouse gases is exported into the ocean and we can see that happening," said Stott. "Another feature is that salinity is changing - as the atmosphere is warming up, there is more evaporation from the surface of the ocean [so making it more salty], which is most noticeable in the sub-tropical Atlantic."
more at link....It is an "increasingly remote possibility" that human activity is not the... more
According to the Charles Darwin Foundation's Stuart Banks, one in five of the 43 threatened Galapagos marine species may already be extinct.
In a landmark article published today by respected science journal, Global Change Biology, Stuart Banks, Senior Marine Scientist with the Charles Darwin Foundation (CDF), headquartered in Galapagos, teams with the world´s leading marine researchers in calling for increased focus on the forces of climate change.
Banks asserts that:
"Galapagos is well-known for being unique, but what is less apparent is how tenuous the archipelago's unique status really is." He reveals that of the 43 threatened Galapagos marine species, one in five may already be extinct.
The article provides an in-depth analysis of major studies charting changes in Galapagos biodiversity and marine ecosystems over the past 30 years. Former CDF Marine Sciences Director and ongoing CDF collaborator Graham Edgar of the University of Tasmania led the development of the paper bringing together such luminaries as Sylvia Earle; National Geographic Society, and Peter Glynn, University of Miami, Les Kaufmann, Boston University, and CDF´s Stuart Banks.
In a sobering snapshot, Banks explains that:
"The unpredictable mix of El Niño, increased human presence, and global climate change is a recipe for the breakdown of natural ecological functions with serious impact on the recovery potential of species and habitats."
The article cites the Galapagos Marine Reserve as being "a near ideal environment for quantifying effects of oceanographic anomalies and fisheries on marine biodiversity, and for modeling future impacts of climate change," areas of study currently being addressed by CDF's Galapagos Climate Change Initiative.
This major new body of investigation takes a much-needed step in understanding the ties between climate, biodiversity, and the human impact, and will combine new and historical data to increase understanding of these relationships.
REPORT: Wildlife of Galapagos Islands 'devastated by ocean warming'
Ocean warming and human activity have devastated the coastal wildlife of the Galapagos Islands, say scientists.
Several species of marine plants and animals are believed to have become extinct and many others are seriously threatened, a new report reveals. Researchers blame the impact of rising ocean temperatures coupled with fishing and tourism.
Once abundant coral reefs and kelp beds had been wiped out in just a few decades, said the scientists from US-based Conservation International. Species that were previously plentiful such as the Galapagos black-spotted damselfish, the 24-rayed sunstar and the Galapagos stringweed were now thought to have vanished. Dozens of others, including the Galapagos penguin, were within ''a hairsbreadth of annihilation''.
Based on criteria laid down by the International Union for the Conservation of Nature's Red List, two species were ''probably'' extinct, another seven ''possibly'' extinct, and a further 36 ''vulnerable, endangered or critically endangered''. Over-fishing had led to an expansion of sea urchin populations, which in turn had upset the delicate web of marine life in the islands, said the scientists.
The researchers warned the Galapagos was a ''canary in a coalmine'' indicating what the world could expect from global warming.
http://www.savegalapagos.org/news/charles-darwin-foundation/According to the Charles Darwin Foundation's Stuart Banks, one in five of the 43... more