Hawaiian Islands weather details & Aloha paragraphs / December 17-18, 2009

Interesting: Evacuations have moved thousands of people to shelters as the Mt. Mayon continues to spew ash and lava. The Philippine volcano has had several minor eruptions over the past several days, and a full-scale eruption is considered imminent. So far at least 30,000 people have been displaced in anticipation of an eruption, according to BBC News.

A major eruption would not only be another mark on an already lengthy list of natural disasters for the island nation this year, but it would also have impact well beyond the Philippines. Such an eruption would loft a massive cloud of ash high overhead.

Due to the seasonal southward displacement of the jet stream’s high-level westerly winds, any such major ash cloud could be drawn into the busy cross-Pacific flight paths, which would disrupt international air travel.

The Philippines has already suffered a range of natural disasters this year. Tropical cyclones caused widespread flooding and destructive winds. At least 10 tropical cyclones affected, directly or indirectly, the Philippines during 2009. Two of these, Typhoon Ketsana (Ondoy) and Typhoon Parma (Pepeng), had severe and destructive weather impacts.

Interesting2: The US Geologoic Survey released a technical paper detailing new research into oceanic circulation that could help improve projections of future climate conditions. The deep ocean is affected more by surface warming than previously thought, and this understanding allows for more accurate predictions of factors such as sea level rise and ice volume changes.

High ocean surface temperatures have also been found to result in a more vigorous deep ocean circulation system. This increase results in a faster transport of large quantities of warm water, with possible impacts including reduction of sea ice extent and overall warming of the Arctic. "The deep ocean is relatively unexplored, and we need a true understanding of its many complex processes," said U.S. Geological Survey Director Marcia McNutt.

"An understanding of climate change and its impacts based on sound, objective data is a keystone to the type of long-term strategies and solutions that are being discussed now at the United Nations conference in Copenhagen." USGS scientists created the first ever 3-D reconstruction of an ocean during a past warm period, focusing on the mid-Pliocene warm period 3.3 to 3 million years ago.

"Our findings are significant because they improve our previous understanding that the deep ocean stayed at relatively constant, cold temperatures and that the deep ocean circulation system would slow down as surface temperatures increased," said USGS scientist Harry Dowsett. "By looking at conditions in the past, we acquire real data that allow us to see the global climate system as it actually functioned."

"The average temperature of the entire ocean during the mid-Pliocene was approximately one degree warmer than current conditions, showing that warming wasn’t just at the surface but occurred at all depths" said USGS scientist Marci Robinson. "Temperatures were determined by analyzing marine plankton fossils, which are organisms that inhabited the water’s surface, as well as fossils of bottom-dwelling organisms, known as ostracodes."

The USGS led this research through the Pliocene Research, Interpretation and Synoptic Mapping group. The primary collaborators in PRISM are Columbia University, Brown University, University of Leeds, University of Bristol, the British Geological Survey and the British Antarctic Survey.

Interesting3: The climate change that took place in Mesopotamia around 2000 BC did not lead to war, but in fact led to the development of a new shared identity. Although increasing drought often leads to competition and conflict, there seems to be no evidence of this in northern Mesopotamia according to Dutch researcher Arne Wossink.

Wossink studied how the farmers and nomads in northern Mesopotamia — currently the border area between Turkey, Syria and Iraq — responded to the changes in climate that took place between 3000 and 1600 BC. He expected to find considerable evidence of competition: as food and water became scarcer the natural result could well be conflict.

He discovered, however, that the farmers developed much closer bonds with the semi-nomadic cattle farmers. The archaeologist analyzed previous finds from the area as well as ancient texts. His research shows the importance of not seeing climate as the only cause: human responses in particular play a major role.

Wossink studied three regions and only one of these demonstrated traces of competition between settlements. However, the completion in this area was probably due to the strong population growth that was taking place there. The farmers in northern Mesopotamia chose not to compete with one another, but to adapt to the circumstances.

Wossink shows that the arrival of the Amorites, who had until that time been regarded as (semi-)nomadic, was not simply a process of infiltration. The rise in the Amorites should be seen as the spread of an identity that brought crop farmers and cattle farmers together. By adopting the Amoritic identity, the farmers gained access to a large trading network that was necessary to survive the period of drought.

Interesting4: A new analysis of the geological record of the Earth’s sea level, carried out by scientists at Princeton and Harvard universities and published in the Dec. 16 issue of Nature, employs a novel statistical approach that reveals the planet’s polar ice sheets are vulnerable to large-scale melting even under moderate global warming scenarios. Such melting would lead to a large and relatively rapid rise in global sea level. According to the analysis, an additional 2 degrees of global warming could commit the planet to 20 to 30 feet of long-term sea level rise.

This rise would inundate low-lying coastal areas where hundreds of millions of people now reside. It would permanently submerge New Orleans and other parts of southern Louisiana, much of southern Florida and other parts of the U.S. East Coast, much of Bangladesh, and most of the Netherlands, unless unprecedented and expensive coastal protection were undertaken.

And while the researchers’ findings indicate that such a rise would likely take centuries to complete, if emissions of greenhouse gases are not abated, the planet could be committed during this century to a level of warming sufficient to trigger this outcome.

The study was written by Robert Kopp, who conducted the work as a postdoctoral researcher in Princeton’s Department of Geosciences and Woodrow Wilson School of Public and International Affairs; Frederik Simons, an assistant professor of geosciences at Princeton; Jerry Mitrovica, a professor of geophysics at Harvard; Adam Maloof, an assistant professor of geosciences at Princeton; and Michael Oppenheimer, a professor of geosciences and international affairs in Princeton’s Woodrow Wilson School.

As part of the study, the researchers compiled an extensive database of geological sea level indicators for a period known as the last interglacial stage about 125,000 years ago. Polar temperatures during this stage were likely 5 to 9 degrees Fahrenheit warmer than today, as is expected to occur in the future if temperatures reach about about 4 to 6 degrees Fahrenheit above pre-industrial levels.

"The last interglacial stage provides a historical analog for futures with a fairly moderate amount of warming; the high sea levels during the stage suggest that significant chunks of major ice sheets could disappear over a period of centuries in such futures," Kopp said. "Yet if the global economy continues to depend heavily on fossil fuels, we’re on track to have significantly more warming by the end of century than occurred during the last interglacial.

I find this somewhat worrisome." Oppenheimer added, "Despite the uncertainties inherent in such a study, these findings should send a strong message to the governments negotiating in Copenhagen that the time to avoid disastrous outcomes may run out sooner than expected."

Interesting5: A real possibility does exist for developing a new generation of foods that make people feel full by releasing anti-hunger aromas during chewing, scientists in the Netherlands are reporting after a review of research on that topic. Such foods would fight the global epidemic of obesity with aromas that quench hunger and prevent people from overeating.

Their article appears in ACS’ Journal of Agricultural and Food Chemistry. Rianne Ruijschop and colleagues note that scientists long have tried to develop tasty foods that trigger or boost the feeling of fullness. Until recently, that research focused on food’s effects in stomach after people swallow it.

Efforts now have expanded to include foods that release hunger-quenching aromas during chewing. Molecules that make up a food’s aroma apparently do so by activating areas of the brain that signals fullness. Their analysis found that aroma release during chewing does contribute to the feeling of fullness and possibly to consumers’ decisions to stop eating.

The report cites several possible applications, including developing foods that release more aroma during chewing or developing aromas that have a more powerful effect in triggering feelings of fullness.

Interesting6: Like an angry dog, a volcano growls before it bites, shaking the ground and getting "noisy" before erupting. This activity gives scientists an opportunity to study the tumult beneath a volcano and may help them improve the accuracy of eruption forecasts, according to Emily Brodsky, an associate professor of Earth and planetary sciences at the University of California, Santa Cruz.

Brodsky presents recent findings on pre-eruption earthquakes on Wednesday, December 16, at the fall meeting of the American Geophysical Union in San Francisco. Each volcano has its own personality. Some rumble consistently, while others stop and start. Some rumble and erupt the same day, while others take months, and some never do erupt.

Brodsky is trying to find the rules behind these personalities. "Volcanoes almost always make some noise before they erupt, but they don’t erupt every time they make noise," she said. "One of the big challenges of a volcano observatory is how to handle all the false alarms."

Brodsky and Luigi Passarelli, a visiting graduate student from the University of Bologna, compiled data on the length of pre-eruption earthquakes, time between eruptions, and the silica content of lava from 54 volcanic eruptions over a 60-year span. They found that the length of a volcano’s "run-up"–the time between the onset of earthquakes and an eruption–increases the longer a volcano has been dormant or "in repose."

Furthermore, the underlying magma is more viscous or gummy in volcanoes with long run-up and repose times. Scientists can use these relationships to estimate how soon a rumbling volcano might erupt. A volcano with frequent eruptions over time, for instance, provides little warning before it blows.

The findings can also help scientists decide how long they should stay on alert after a volcano starts rumbling. "You can say, ‘My volcano is acting up today, so I’d better issue an alert and keep that alert open for 100 days or 10 days, based on what I think the chemistry of the system is,’ " Brodsky said.