08 May 2014:
Natural Variations May Account
For Up to Half of Greenland's Warming
Up to half of the recent climate change in Greenland and surrounding regions — which have warmed at roughly twice the pace of the rest of the planet since 1979 — may be due to natural climate variations that originate in the tropical Pacific and are not connected
Meltwater from Russell Glacier
with the overall warming of the Earth, a new study
says. Still, at least half the warming remains attributable to rising global carbon dioxide emissions, according to research published in the journal Nature
. Climate data and advanced computer models show that changes in the western tropical Pacific Ocean, which has been about 0.3 degrees warmer than normal, have caused shifts in atmospheric pressure over the North Atlantic. Those changes set off a stationary wave in the atmosphere that arcs in a great circle from the tropical Pacific toward Greenland, pulling warmer air over that massive island. "Along this wave train there are warm spots where the air has been pushed down, and cold spots where the air has been pulled up," one author explained. "And Greenland is in one of the warm spots."
05 May 2014:
New European Satellites
To Give More Detailed Views of Earth
The European Space Agency has begun launching
a series of satellites designed to collect detailed environmental data around the globe — from radar-based, high-definition imagery to information about the
atmosphere's chemical composition. The first satellite in the ESA's Copernicus program, the Sentinel 1A, was launched last month and has already returned many striking images based on radar data, such as this view of Brussels, Belgium, in which the dense urban area contrasts with the city's heavily vegetated surroundings. Once Sentinel satellite 1B is launched next year, the two will be able to map the entire globe in six days, giving researchers and conservationists a powerful way to monitor both short- and long-term changes in the environment. Four additional groups of satellites are set to launch this year. Those arrays will focus on high-resolution photo imagery, topography, surface temperatures, and atmospheric chemistry.
01 May 2014:
Extent of Marine Litter
Documented in Major Seafloor Survey
A major survey of the ocean floor has found trash piling up throughout the Atlantic and Arctic oceans and Mediterranean Sea, reaching depths of nearly 3 miles below the surface, according to scientists
Marine litter from study
European research organizations. Litter was located at each of the 600 sites surveyed, with plastic accounting for 41 percent and derelict fishing gear 34 percent. Glass, metal, wood, cardboard, clothing, pottery, and unidentified materials were also found. Garbage accumulated at sites as far as 2,000 kilometers (1,243 miles) from land and at depths up to 4.5 kilometers (2.8 miles), according to the report. Seafloor litter is a major problem since it can accumulate in and kill marine animals that mistake it for food. The trash can also entangle fish, seabirds, and coral. "This survey has shown that human litter is present in all marine habitats, from beaches to the most remote and deepest parts of the oceans," one author said. "These were [humans'] first visits to many of these sites, but we were shocked to find that our rubbish has got there before us."
11 Apr 2014:
Parasitic Flatworm Could Be
Major Threat to Coral Reefs, Scientists Say
A coral-eating flatworm with a unique camouflaging strategy could be a major threat to the world's coral reefs, according to
researchers in the U.K. The parasite, called Amakusaplana acroporae
, infects a type of staghorn coral known as acropora, a major component
Amakusaplana acroporae, a parasitic coral flatworm
of reefs, and can destroy its coral host very quickly. The parasite has been detected at the Great Barrier Reef, and because it has no known natural predators, researchers are concerned it could spread quickly and decimate reefs worldwide. A novel camouflaging strategy makes the flatworm difficult to detect and monitor, the researchers say. When eating the coral tissue, the worm also ingests the coral's symbiotic algae. Instead of digesting the algae completely, the worm keeps a fraction of them alive and distributes them, along with the fluorescent pigments that give coral its characteristic hue, throughout its gut so that it perfectly mimics the appearance of the coral. The parasite has been identified in numerous aquarium-based corals, and biologists worry that it could spread rapidly if aquarium-raised coral, fish, or seaweed are introduced to natural reef environments.
E360 Announces Contest
Yale Environment 360
For Best Environmental Videos
is holding a contest to honor the best environmental videos. Entries must be videos that focus on an environmental issue or theme, have not been widely viewed online, and are a maximum of 15 minutes in length. The first-place winner will receive $2,000, and two runners-up will each receive $500. The winning entries will be posted on Yale Environment 360
. The deadline for entries is June 6, 2014. Read further contest information.
28 Mar 2014:
West Antarctic Glacial Loss
Is Rapidly Intensifying, New Study Shows
Six massive glaciers in West Antarctica are dumping far more ice into the Southern Ocean than they were 40
An 18-mile crack in the Pine Island Glacier
years ago and now account for 10 percent of the world’s sea level rise
, according to a new study. Reporting in Geophysical Research Letters
, an international team of scientists said that the amount of ice draining from the six glaciers has increased by 77 percent since 1973. The scientists said that the ice loss from the six glaciers is so substantial that it equals the amount of ice draining annually from the entire Greenland Ice Sheet. The scientists used satellite data from 1973 and 2013 to gauge the ice loss from the six glaciers. The Pine Island Glacier
is moving more rapidly to the sea than any of the other six, with its speed increasing from 1.5 miles per year in 1973 to 2.5 miles per year in 2013. The glaciers are dumping more ice into the sea primarily because warmer ocean waters are loosening the ice sheets’ hold on the sea floor, which speeds up glacial flow.
17 Mar 2014:
Northeast Greenland Glaciers
Are Now Melting Rapidly, Study Finds
The glaciers of northeast Greenland, long thought to be the most stable part of the massive Greenland ice sheet, are melting at an accelerating pace, losing roughly 10
billion tons of ice annually for the past decade, say researchers
from the U.S. and Denmark. The finding will likely boost estimates of global sea level rise, which had previously not accounted for massive ice loss from that region, scientists say. The Zachariae ice stream in northeast Greenland, which drains 16 percent of the ice sheet, has retreated roughly 12.4 miles in the past decade, outpacing the fast-moving Jakobshavn glacier, which has retreated 21.7 miles over the last 150 years. Ice loss from the region is likely accelerating, the researchers say, because ice dams in nearby bays that had been blocking the glaciers' paths are now also melting, freeing the way for the glaciers to flow into the ocean.
06 Mar 2014:
Warm River Water Plays Major
Role in Arctic Sea Ice Melt, Study Finds
Relatively warm water flowing into the Arctic Ocean from rivers contributes significantly to Arctic sea ice melt each summer, a phenomenon that will intensify as the region warms, according to NASA researchers
. The river discharge not only melts coastal sea ice, it also has
a wider climate impact as it creates more open water, which is darker than ice and absorbs more heat from sunlight. As these NASA images show, when water from Canada's Mackenzie River flowed into the Beaufort Sea in the summer of 2012, average surface temperature of the open water rose by 6.5 degrees C (11.7 degrees F) after the pulse of river water. Flow from the Mackenzie raised sea surface temperatures as far as 350 kilometers (217 miles) from the coast. The researchers note that river discharge is becoming an increasingly important contributor to melting Arctic sea ice because the volume and temperature of fresh water discharge is increasing as inland Arctic areas warm more each summer.
05 Mar 2014:
Routes of Young Sea Turtles
Shed Light on Mystery of Turtles' Lost Years
By placing satellite tags on newborn sea turtles along the coast of Florida and tracking them in the western Atlantic Ocean, researchers have gained new insights
into the early migrations of threatened and endangered
turtles during their so-called "lost years" between hatching and returning to coastal waters as large juveniles. Rather than swimming in the currents of the North Atlantic gyre, as scientists had assumed, the young turtles actually leave the gyre and travel to the Sargasso Sea, which lies in the middle of the North Atlantic Ocean. While there, sensors on the turtles' shells registered more heat than the scientists expected, leading them to believe
that the young turtles swim near the surface of the Sargasso, basking in sunlight and feeding on a type of seaweed that grows in deep ocean waters. "From the time they leave our shores, we don't hear anything about them until they surface near the Canary Islands, which is like their primary school years," said an author of the study.
28 Feb 2014:
Seafaring Drones Could Reveal
Mysterious Lives of Sharks, Researchers Say
New automated watercraft
are helping scientists understand the secret lives of great white sharks, which gather in large numbers each winter in an area nicknamed the "White Shark Cafe." Although this stretch of ocean between Baja California and Hawaii
contains relatively few food sources, the sharks congregate and display strange behaviors, perhaps related to mating or feeding, one researcher explained to the San Francisco Chronicle
. Scientists haven't had a way to efficiently track and observe sharks in this environment, but new seafaring drone technologies might change that. For example, drones could follow migrations by homing in on acoustic tags on the sharks themselves. Marine biologists at Stanford
were recently able to track two great whites on their journeys from California to Hawaii and the White Shark Cafe, as the map shows, but current technology only allows scientists to recreate the sharks' journeys after monitoring tags pop off and are recovered. The new drones may prove useful not only for tracking sharks and other pelagic fish in real time, but also for collecting important ocean data such as temperature, acidity, and salinity, researchers said.
19 Feb 2014:
Loss of Arctic Sea Ice
Has Greater Warming Impact Than Expected
The steady disappearance of Arctic sea ice, which is causing the exposed and darker surface of the Arctic Ocean to absorb more sunlight, is having a more profound impact on global warming
estimated, according to a new study. The decline of albedo, or reflectivity, from the Arctic Ocean equals roughly 25 percent of the warming caused by rising carbon dioxide levels, according to scientists at the University of California, San Diego. The impact of this "albedo feedback," in which the highly reflective white surface of sea ice is replaced by heat-absorbing open ocean, is considerably stronger than climate models had predicted, according to the UCSD research
, published in the Proceedings of the National Academy of Sciences.
Researchers had thought increasing Arctic cloud cover might slow the albedo feedback, but this study indicates that is not happening.
03 Feb 2014:
Greenland's Jakobshavn Glacier
Is Moving at Record Speeds, Study Finds
Greenland's Jakobshavn Glacier is flowing into the ocean at a record pace of more than 17 kilometers per year, according to research
by U.S. and German scientists. The glacier, which drains 6 percent of the
massive Greenland ice sheet, moved at a rate of 46 meters per day in the summer of 2012 — four times the glacier's 1990s summer pace. The unprecedented speed appears to be the fastest ever recorded for any glacier or ice stream in Greenland or Antarctica, the researchers report in the journal The Cryosphere
. Scientists estimate the glacier added about 1 millimeter to global sea levels from 2000 to 2010; its faster flow into the ocean means Jakobshavn will add even more water over the current decade. Widely thought to be the source of the iceberg that sunk the Titanic
in 1912, the researchers say Jakobshavn is flowing at record speeds because its front edge, called the calving front, now overlies a particularly deep spot on the ocean floor. "As the glacier’s calving front retreats into deeper regions, it loses ... the ice in front that is holding back the flow, causing it to speed up," the lead researcher explained.
Interview: Activist Kumi Naidoo
On Russia and the Climate Struggle
Kumi Naidoo, the international executive director of Greenpeace, is intimately familiar with the Prirazlomnaya drilling platform in the Russian Arctic. In 2012, he and five other Greenpeace activists were hosed down with frigid water and pelted with pieces of metal as they attempted to climb aboard the platform.
Greenpeace and Prirazlomnaya were back in the news recently when 28 Greenpeace members were arrested and held for several months for storming the rig before being released in December. In an interview with Yale Environment 360
, Naidoo talks about what’s needed to get global climate talks off the ground and launch a green energy revolution, and the reason his activist organization has decided to take such a strong stand against oil drilling in the rapidly melting Arctic Ocean. "We went back [to Prirazlomnaya]," says Naidoo, "because we’re trying to draw a line in the ice, because once this starts it will have breached another threshold of meeting our rapacious appetite for oil and gas in the most fragile of environments." Read the interview.
13 Jan 2014:
Pine Island Glacier Has
Melted Beyond Tipping Point, Study Says
A major Antarctic ice mass, the Pine Island Glacier, is melting irreversibly and could add as much as a centimeter to global sea level rise over the next 20 years alone, according to new research published in Nature Climate Change
. Calculations show that the Pine Island Glacier's "grounding line" — where land-based ice meets a floating ice shelf that is an extension of the
glacier — has retreated roughly 10 kilometers in the past decade. Scientists say that the grounding line is in the process of a 40-kilometer retreat that could push it beyond an important tipping point. Pine Island Glacier is a major contributor to global sea level rise
and has been losing massive amounts of ice for decades, accounting for 20 percent of the West Antarctic Ice Sheet's total ice loss
. An international research team says that the Pine Island Glacier has been losing 20 billion tons of ice annually for the past two decades and could lose 100 billion tons annually over the next 20 years. The glacier "has started a phase of self-sustained retreat and will irreversibly continue its decline," says Gael Durand, a glaciologist with France's Grenoble Alps University.
09 Jan 2014:
Faced With Sea Ice Loss,
Emperor Penguins Alter Breeding Tactics
Confronted with the loss of sea ice in some parts of Antarctica, four colonies of emperor penguins have come up with an innovative breeding strategy
to adapt to their changing environment. Using satellite images,
an international team of scientists tracked the four colonies from 2008 to 2012. In the first three years, the emperor penguins hatched and incubated eggs in their customary fashion — atop the sea ice that freezes during the Antarctic winter and spring. But in 2011 and 2012, sea ice did not form until a month after the breeding season began. As a result, the emperor penguins, which are the largest penguin species on earth, did something never before witnessed by scientists: They climbed the nearly sheer walls of large, floating ice shelves — huge structures, often hundreds of square miles in extent, that flow from land-based glaciers into the sea. In the region of the four colonies, the ice shelf walls reach as high as 100 feet. The scientists say the altered breeding behavior could demonstrate how ice-dependent emperor penguins may adapt to a warming world.
31 Dec 2013:
Atlantic Ocean Zooplankton
Are Now Reproducing in Arctic Waters
For the first time, scientists have discovered species of Atlantic Ocean zooplankton reproducing in Arctic waters
. German researchers say the discovery indicates a possible shift in the Arctic zooplankton community as
The amphipod Themisto compressa
the region warms, one that could be detrimental to Arctic birds, fish, and marine mammals. Studying traps that have been suspended for 13 years in the Fram Strait, scientists from the Alfred Wegener Institute found that small species of crustaceans common to the Atlantic are increasingly moving into Arctic waters. The researchers found fertile females as well as individuals at all stages of development, showing that the Atlantic species is reproducing in the frigid waters. The one-centimeter amphipods are smaller than respective Arctic species, meaning that the spread of the Atlantic crustaceans northward could reduce the volume of food available to Arctic predators. The research was published in the journal Marine Ecology Progress Series
Photo Essay: Documenting the Swift
Change Wrought by Global Warming
For 25 years, photographer Peter Essick has traveled the world for National Geographic
magazine, with many of his recent assignments focusing on the causes and consequences of climate change. In a Yale Environment 360
photo essay, we present a gallery of images he took while on assignment in Antarctica, Greenland, and other far-flung locales affected by climate change. View the photo gallery.
09 Dec 2013:
Intensifying Storms Are
Contributing To Ongoing U.S. Wetlands Loss
The U.S. is losing wetlands at a rate of 80,000 acres per year, in part because of intensifying coastal storms and sea level rise, according to a new government study
. From 2004 to 2009, the country lost more than 360,000 acres of freshwater and saltwater wetlands, a decline driven both by traditional factors, such as coastal development, as well as worsening storms and slowly rising seas, the study says. The rate of loss is a signal that government efforts to protect and restore wetlands are failing to keep pace with major environmental changes, experts told The Washington Post
. The most pronounced wetlands losses were along the Gulf of Mexico, where major hurricanes have wreaked havoc on coastal lands. Along the Atlantic coast, a rapid increase in coastal development is funneling stormwater runoff into wetlands that cannot handle it, the study said. The loss rate of 80,000 acres annually represents a 25 percent increase over the rate of wetlands loss during 1998-2004, the last time government agencies examined the problem.
03 Dec 2013:
Microplastic Pollution Harms
Worms at Bottom of Food Chain, Study Finds
As plastic trash accumulates in ocean ecosystems, it may be damaging worms and other sensitive marine life at the bottom of the food chain, scientists report. Two British studies found
that microplastics — tiny remnants, less than 5 mm in diameter, from the breakdown of plastic trash — made seafloor worms eat
Beach sediments churned by a lugworm
less and transferred pollutants from the plastics to the worms. Because they ate less, the worms had less energy to invest in important functions
such as growth, reproduction, and churning sediments, one of their most important roles in the ocean ecosystem. The worms also absorbed harmful chemicals from the debris
, including hydrocarbons, antimicrobials, and flame retardants, researchers said. Lugworms, often called the "earthworms of the sea," are considered an indicator species because they feed on ocean floor sediments. Microplastics have been accumulating in those sediments since the 1960s, and, although each particle is nearly invisible, taken together microplastics are the most abundant form of solid-waste pollution on the planet.
29 Nov 2013:
Wide Mangrove Destruction
Is Documented Along Coast of Myanmar
Rapid agricultural expansion destroyed nearly two-thirds of the mangrove forests
in Myanmar’s Ayeyarwady Delta between 1978 and 2011, increasing the region’s vulnerability to cyclones and typhoons, according to a new study. Using remote sensing imagery
and field data, researchers from Myanmar and Singapore said that the dense mangrove cover in the Ayeyarwady Delta declined from 2,623 square kilometers to 1,000 square kilometers in that 33-year period. The main cause was agriculture expansion and the researchers said that if rates of destruction continue at their current pace the delta’s mangroves could be completely deforested by 2026. Reporting in the journal Global Environmental Change
, the scientists said the loss of mangroves in the Ayeyarwady Delta could put the region at greater risk of major storms such as Cyclone Nargis, which killed 138,000 people in Myanmar in 2008. But the researchers said the destruction could be slowed if Myanmar creates coastal protected areas.
26 Nov 2013:
Updated Conservation List
Finds Forest Giraffes on Brink of Extinction
In an updated list released today, the International Union for the Conservation of Nature (IUCN) noted some significant successes and failures in global wildlife
Okapi, or forest giraffe
conservation efforts. A major success story is the leatherback sea turtle
, whose Atlantic population has recovered enough for the species to be considered only vulnerable, rather than critically endangered. The IUCN attributed the leatherback rebound to better protection of nesting beaches and reduced fisheries bycatch. The updated Red List contains more somber news, though, for the blue-tongued forest giraffe
, the national symbol of the Democratic Republic of the Congo. The striped-legged forest giraffe, a species of okapi, is on the brink of extinction due mainly to the long, ongoing civil war in that country, which has led to increased poaching and loss of habitat. The Red List's ranks of threatened species have grown by 352 species since this summer
, Mongabay reports, with roughly 21,000 species now listed as threatened.
Fish 2.0: A Contest Seeks to Foster
A More Sustainable Seafood Industry
Twenty pioneers in the sustainable seafood business climbed a stage at Stanford University in November in an effort to woo the judges at the Fish 2.0 contest
Click to Enlarge
HM Terry Co.
The winning project connects fishermen directly to customers.
with proposals on how to change the way the U.S. catches, distributes, and markets fish. A business competition at heart, Fish 2.0 brought together entrepreneurs and investors to spur innovation in the tradition-bound seafood industry. Competitors's proposals ranged from converting waste at fish processing plants to expanding a Hawaiian network of aquaponic growers, who raise fish and vegetables together in tanks, into the developing world. One proposal aimed to create a data system to track catches in real time, enabling fisheries managers to hold the line on harvests. Contestants headed home with more than $75,000 in prize money. Read more.
19 Nov 2013:
Pollution From Plastic Trash
May Make Tiny Island a Superfund Site
The U.S. Environmental Protection Agency plans to study whether plastic pollution on a small island in the Pacific Ocean is severe enough to warrant listing it as a Superfund clean-up site
. Tern Island, a 25-acre strip of land about 500 miles northwest of the Hawaiian island
Oahu, is home to millions of seabirds, sea turtles, and the endangered Hawaiian monk seal. The U.S.-based Center for Biological Diversity asked the EPA to add the entire Northwestern Hawaiian Islands and parts of the so-called Great Pacific Garbage Patch
to the list of federal Superfund sites due to extreme marine debris pollution, but the agency has only agreed to undertake an environmental study on Tern Island. The island is awash with debris ranging from plastic water bottles and bits of plastic to discarded fishing gear and home appliances. Studies have shown the trash can take a heavy toll on wildlife — seabirds, for example, often ingest bits of plastic after mistaking them for food and eventually die of starvation. The EPA study is the first step of a potentially years-long process to determine if the island qualifies for listing under the 1980 Superfund law.
13 Nov 2013:
Plastic Debris in Ocean
Has Spawned a 'Plastisphere' of Organisms
The plastic debris that litters the world's oceans has developed its own unique and diverse microbial ecosystem, researchers report. The microscopic community, which scientists dubbed the "plastisphere,"
includes more than 1,000 species of algae, bacteria, microscopic plants, symbiotic microbes, and possibly even pathogens, the researchers say in Environmental Science & Technology
. Some of the plastisphere microbes, many of which had never before been documented, contain genes that could help break down hydrocarbons, indicating the microbes may play a role in degrading the debris, the research shows. Plastic trash is the most abundant type of debris in the ocean, inflicting harm on fish, birds, and marine mammals that are entangled by it or ingest it. Until now, researchers hadn't looked at microbes living on the debris, which make up a sort of artificial "microbial reef," one of the scientists said
Interview: Using Robots to Unlock
Mysteries of CO2 and the Oceans
As climate change accelerates, scientists are focusing on the key role the world’s oceans play in absorbing half the planet’s carbon dioxide. But the precise mechanisms
Robotic Wave Glider
by which the oceans remove carbon from the atmosphere and the consequences for marine life remain poorly understood. That has led Tracy Villareal, a professor of marine science at the University of Texas at Austin, to devote his research to diatom phytoplankton. To better understand how these tiny organisms mitigate climate change, Villareal has become a pioneer in the use of a wave- and solar-powered ocean-going robot, known as the Wave Glider. In an interview with Yale Environment 360
, Villareal discusses why unlocking the secrets of diatoms is critical to understanding climate change and how deploying robots will revolutionize marine science. “There are all sorts of wild robotic systems under development,” he says. Read the interview.
08 Nov 2013:
Antarctic Researchers Discover
Strips of Rock That Slow Flow of Glaciers
Narrow ribs of dirt and rock beneath Antarctic glaciers help slow the glaciers' flow into the sea, according to new research
from scientists at Princeton University and the British Antarctic Survey. Using satellite measurements of the Pine Island Glacier and Thwaites
Glacier, both in West Antarctica, researchers discovered bands they call "tiger stripes" underlying the glaciers. The stripes serve as zones of friction and prevent sliding, much like non-slip flooring, the researchers report in Science
. Understanding the factors that control the glaciers' flow to the sea is important because their melting contributes significantly to sea level rise. The Pine Island and Thwaites glaciers are particularly important, as together they've contributed about 10 percent of the observed global sea level rise over the past 20 years.
14 Oct 2013:
World Ocean Conditions Worse
Than Previously Thought, Analysis Finds
The world's oceans are deteriorating more rapidly than scientists had thought due to rising carbon dioxide levels and associated warming, according to a new analysis
by European scientists. By many indicators, ocean conditions are even worse than outlined last
Sea butterfly without shell
month by the U.N. Intergovernmental Panel on Climate Change's assessment report on the physical effects of global warming, the researchers say. Sinking oxygen levels, which could decline by 1 to 7 percent by 2100, increasing ocean acidification, and overfishing of more than 70 percent of marine populations are among the biggest threats to ocean ecosystems, the scientists report in Marine Pollution Bulletin
. Mollusks and other sensitive organisms are increasingly being found with corroded shells, a result of rising dissolved CO2 concentrations; within 20 to 40 years ocean acidity levels may reach the point where coral reefs are eroded faster than they can regenerate, the review said.
07 Oct 2013:
Nutrient Recycling by Sponges
Is Vital in Sustaining Reefs, Study Says
Sponges are the unsung heroes of coral reefs, helping the vibrant ecosystems thrive in the marine equivalent of a desert, a Dutch team working in the Caribbean has found
. Scientists had long questioned how reefs, some
of the most productive communities on earth, were able to survive in low-nutrient tropical seas. Bacteria help recycle some nutrients, but the so-called "microbial loop" can't account for the high rates of carbon, nitrogen, and phosphorous recycling needed to maintain a coral reef, researchers say. Sponges fill that void by drawing in plankton and organic matter expelled by the corals and shedding cells that other reef organisms ingest as food, the researchers report in Science
. The "sponge loop," as the Dutch team calls the process, recycles 10 times more organic material than bacteria do and produces as many nutrients as all other primary producers in a coral reef combined, they say.
24 Sep 2013:
Major Wind and Rain Belts
Could Shift North as Earth Warms
A study of warming at the end of the last Ice Age indicates that future warming caused by the burning of fossil fuels will likely shift the planet's rain and wind belts northward, say researchers
at Columbia University's Lamont-Doherty Earth Observatory. Regions that are already dry — including the western U.S., western China, and the Middle East — could grow drier, while equatorial Africa and monsoonal Asia may become wetter. An examination of data such as polar ice cores and ocean sediments shows that as the last Ice Age ended 15,000 years ago, northward shifts in the tropical rain belt and mid-latitude jet stream occurred as the temperature gradient between the northern and southern hemispheres increased. That sharper gradient came about because the land mass-dominated northern hemisphere warmed faster than the ocean-dominated southern hemisphere, according to the study, published in the Proceedings of the National Academy of Sciences
. Researchers say a similar pattern could develop in years to come as the northern hemisphere continues to warm faster than the southern hemisphere.
13 Sep 2013:
Warmer Ocean Water Is Key
Factor in Melting Ice Shelves, Study Says
Recent research into one of West Antarctica's most rapidly melting glaciers and ice shelves has shown that rising ocean temperatures and a series of channels lacing the underside of
Edge of Pine Island ice sheet
the shelf are the key factors in the rapid thinning of the shelf
and the swift advance of the glacier behind it. Reporting in Science
, U.S. scientists said that instruments deployed on and under the Pine Island Glacier and ice shelf over the past two years have shown that warmer ocean water has been flowing through a series of channels under the shelf, causing the 31-mile-long floating slab of ice to thin at the alarming rate of 2.4 inches per day and loosening the shelf's hold on the bedrock below. The melting ice shelf itself doesn't contribute to sea level rise, but as it thins it allows more of the land-based Pine Island Glacier to flow into the sea,
which is contributing to sea level rise.