Archive for the 'Science' Category

Eight Disappearing Islands?

Saturday, April 18th, 2009

Maldives from spaceThe website Treehugger recently suggested eight places — low-lying islands, more specifically — that will “soon” be uninhabitable due to climate change.

They are:

  • the Maldives, in the Indian Ocean
  • Tuvalu, Kiribati, the Carteret Islands (off PNG), and Majuro Atoll (Marshall Islands) in the Pacific
  • Lamu and Pate, Kenyan coastal islands
  • Bhola, in southern Bangladesh
  • Key West, off southern Florida

“Soon” is a relative term here–many of these places would still be inhabitable for decades, under current sea-level rise forecasts.

The Pacific islands involve relatively small numbers of people; they could actually be moved, though this would involve irreparable cultural destruction. Bangladesh illustrates another level of impact: millions of people live on these low-lying islands, and tens of millions in vulnerable coastal areas.

This is of course a tiny part of the problem; hundreds of thousands of islands are in danger of disappearing or greatly shrinking in the face of sea-level rise.

(Thanks to Stu Gagnon for the tip.)

Image: Maldives from space, courtesy NASA

A New Island in Tonga?

Saturday, March 21st, 2009

Tonga's flagThis week an undersea volcano began erupting in Tonga, six miles off the main island of Tongatapu, near the small volcanic islands of Hunga Tonga and Hunga Ha’apai.

It has formed new land, but its status is unclear:

  • Some sources report a new island. That would mean that it was the world’s newest volcanic island.
  • Pictures and this account suggest that it may have started as two vents, one in the sea and the other on Hunga Ha’apai, and that any new land created was soon joined to this pre-existing island. This account says Hunga Ha’apai has grown by thousands of square feet.

National Geographic has video, as does Scientific American.

The largest extraterrestrial island?

Monday, March 5th, 2007

NASA has reported the possible discovery of a large lake on Saturn’s moon Titan.

The lake may have an island of considerable size — 150 by 90 km — making it about 10,000 square km, about the size of the largest island of Hawaii.  However, NASA warns that “The island may actually be a peninsula connected by a bridge to a larger stretch of land.”  At the least, there are some clear smaller islands visible above the large one.
Island in Titan lake

A new island off Greenland — and more to come?

Sunday, January 21st, 2007

The NYT reports that previously unknown islands are appearing off the coast of Greenland as glaciers and iceshelves retreat.
Explorer Dennis Schmitt discovered in September that what had been thought to be a small peninsula — visible here on Google Maps — is now surrounded by open water.

A few details about the new island:

  • Name: informally, Uunartoq Qeqertoq (“warming island”)
  • Location: central coast of eastern Greenland, at 71 degrees 29′ north, 21 degrees 52′ west
  • Area: roughly 9 sq miles / 23 sq km
  • Height: roughly 2000 feet, judging by surrounding terrain
  • Discovery: September 2005

Islands emerging from the ice are becomeing more common, according to John Collins Rudolf, the NYT reporter.

  • A Danish cartographer “spotted several new islands in an area where a massive ice shelf had broken up.”
  • A glacier scientist found that a former nunatak — an isolated mountain surrounded by glacier — now was 10 km out to sea from the ice.
  • Another explorer found an emergent island off Svalbard in August 2006.

Rudolf also notes that this accelerated melting is unexpected, and could result in faster sea level rise.  A geoscientist suggests that it might add a foot or two to sea level, threatening low-lying islands.

It could get worse.  Rudolf writes, “Over the long term, much larger sea-level rises would render the world’s coastlines unrecognizable, creating a whole new series of islands.”

The world’s newest island

Wednesday, November 15th, 2006

A submarine eruption in Tongan waters has created the world’s newest volcanic island, southwest of the island of Late, at the lower left in this satellite view:

NASA image of Tongan eruption

The island, at Home Reef, appears substantial: as of August, when it was discovered by a Swedish yacht whose crew took these pictures, it had at least three small hills.

The odds are that the island will not last long. The Home Reef volcano produces islands regularly, and did so in 2004, 1984, and twice in the 1850s, according to NASA and the Smithsonian’s Volcanoes of the World.

Image courtesy of NASA.

The islands of Titan?

Wednesday, August 2nd, 2006

NASA has released new images suggesting there are indeed islands on Saturn’s moon Titan.

Artist's conception of Titan's surface

A continent-size area appears to have many lakes, not of water but of some kind of liquid hydrocarbon. There may even be some islands visible — see the “lake” on the left side of this image.

Islands could figure in the confirmation of the lakes’ existence. Said a scientist, “We could hope to see sea-surface textures due to waves diffracting around islands, or vortices in the wake of islands.”

(Image: NASA)

Ghost island off San Francisco

Wednesday, July 12th, 2006

I have always been intrigued by ancient islands now drowned under the waves by rising seas.

I was looking at the lovely new Geology of the San Francisco Bay Region, a guidebook by Doris Sloan, and noticed such an island about 20 miles off Point Reyes, northwest of the city.

Between 18,000 and 14,000 years ago, the rising ocean cut off a hill on the coastal plain, forming an island. Animals would have become stranded there, and over the next few thousand years some might have begun to evolve in their isolation. But the island continued to shrink, and by 11,500 years ago had been reduced to a few small islets. They submerged by 10,500 years ago, and the life of the place came to an end.

The remains of the island can still be seen, as Cordell Bank, where divers swim amidst the pinnacles that were the last remains of the island before it was gone.

[geology]

Taiwan to rejoin China

Tuesday, April 25th, 2006

Due to plate tectonics, Taiwan is creeping toward the mainland, and the island will unite with the continent in “a few million years.”

Meanwhile, the same article reports that the island is getting rapidly taller: the same tectonic processes are pushing up its mountains at 2 or 3 cm a year.

The first islanders

Saturday, April 8th, 2006

The first vertebrate islanders — or at least their relatives — have been identified by paleontologists working on Ellesmere Island in the Canadian Arctic.

The creatures, dubbed Tiktaalik roseae, appear to be a transitional form between fish and land animals, and lived 375 million years ago.

They may have been among the first vertebrates to venture onto islands, where they would have joined insects and spiders.

Extraterrestrial islands: Titan

Tuesday, April 4th, 2006

PBS’s “NOVA” this evening suggests that Saturn’s huge moon Titan likely has islands.

It was once thought that the moon might have methane seas or lakes.  That may not be the case, but it may have two kinds of islands:

  • Methane is a liquid on supercold Titan, and methane flows in river channels that resemble those of Earth.  There are probably both sedimentary islands and a few flowing around ice bedrock.
  • There are water islands as well: cryovolcanoes erupt water mixed with ammonia, forming a frigid water lava that sometimes surrounds islands.