WEEK 1: Still Stuck in a Climate Argument
By HENRY FOUNTAIN
When a ship carrying scientists and adventure tourists became stuck in ice in the Antarctic late last month, climate change skeptics had a field day. On Twitter and other social media sites, they pointed out that a group whose journey was meant to highlight the effects of global warming was trapped by a substance that was supposed to be melting.
“Global warming idiots out of danger,” one noted when the ship’s 52 passengers were finally helicoptered to safety Thursday after more than a week on the ice.
The episode had little connection to climate change — shifting winds had caused loose pack ice to jam against the ship — and this was far from the first time that a ship had been trapped, even in the Antarctic summer. But sea ice cover in the Antarctic is changing, and scientists see the influence of climate change, although they say natural climate variability may be at work, too.
“The truth is, we don’t fully understand what’s going on,” said Ted Maksym, a researcher at the Woods Hole Oceanographic Institution.
Unlike the Arctic, where sharp declines in recent decades in the ice that floats on sea surfaces have been linked to warming, sea ice in the Antarctic has actually increased, scientists who study the region say. Averaged over the entire Antarctic coast, the increase is slight — about 1 percent a decade. At the same time, larger increases and decreases are being seen on certain parts of the continent.
“We’re constantly struggling against that statement, that Antarctic ice is increasing,” said Sharon E. Stammerjohn, a scientist at the Institute of Arctic and Alpine Research at the University of Colorado. “It misses key changes that are happening. And there are really strong climate signals in those changes.”
Most of the sea ice changes are occurring in an area covering about a third of the Antarctic coast, from the Ross Sea to the Bellingshausen Sea and the Antarctic Peninsula, said Paul Holland, a researcher with the British Antarctic Survey. Areas around the Ross Sea, for example, have seen large increases in ice, while in the Bellingshausen and along the peninsula, ice cover has declined sharply. (The area where the research ship became stuck, west of the Ross Sea, has had a slight increase in ice cover over the past 35 years.)
Researchers agree that the changes in those seas are related to north-south winds that circulate clockwise around a stationary zone of increasingly lower-pressure air. That brings warmer air from the north into the Bellingshausen Sea and peninsula, pushing ice against the coast and melting some of it, and colder air from the south into the Ross Sea, which spreads the ice away from the coast and creates more of it.
But why that low-pressure air is getting lower is still a subject of debate. Scientists say that increases in greenhouse gas concentration in the atmosphere, as well as depletion of atmospheric ozone, have changed temperature gradients from the tropics to the poles, which affects atmospheric circulation.
“There are clear signals of winds increasing due to climate change” in the Southern Ocean around the Antarctic, Dr. Stammerjohn said. Those intensifying winds might be affecting the low-pressure zone, she said, but there are also other factors that do not rule out natural variability.
“The jury is definitely still out on that,” Dr. Stammerjohn said.
Whatever the explanation, much of the Bellingshausen is now ice free for long periods each summer. That allows the relatively warmer waters of the Southern Ocean to flow more freely to the more permanent ice that extends from the land in glaciers and sheets.
“The combination of the warm ocean and the effects of waves on these glaciers may increase the rate of loss of glacial ice,” Dr. Maksym said.
The consensus now is that there is a net loss of ice from Antarctica’s ice sheets and glaciers, Dr. Maksym added, and it is the melting of this ice, rather than any loss of sea ice, that concerns scientists who study sea-level increases.
He cautioned that there was still a lot unknown about Antarctic sea ice, which has been studied far less than Arctic ice. In many ways the regions are opposites — the Arctic is an ocean largely hemmed in by land, while Antarctica is a land mass surrounded by a vast open ocean — so lessons learned from studying one do not necessarily apply to the other.
“The skeptics do have a good point,” Dr. Maksym said. “Why are we not paying as much attention to what’s going on in the Antarctic? There are good reasons to figure out why these changes are happening.”
Questions: Answer in complete sentences (or write the question and then answer). Please do not copy directly from the article!
1. What happened to the ship? What did some people remark about it on twitter?
2. What actually caused the ship’s problem?
3. What kind of fluctuations has the Arctic seen?
4. How does this compare with the Antarctic?
5. What do researchers suspect is causing the change?
6. How does the author compare the Arctic and Antarctic?
7. In at least 4 sentences, discuss your thoughts about global warming, the research being conducted, and what theories you think are the most convincing.
WEEK 2: $18 Billion Price Put on Effort to Block Carp
By MICHAEL WINES
The most effective methods of keeping Asian carp from invading the Great Lakes via Chicago’s web of waterways could cost up to $18.4 billion and take 25 years to put in place, the federal Army Corps of Engineers concluded in a study released Monday.
But a corps official cautioned in a telephone briefing for journalists that there was no guarantee that the carp or other unwanted species would not get into the lakes by then.
The agency’s 210-page study, first ordered by Congress in 2007, laid out eight options to prevent the carp and other unwanted species from entering Lake Michigan, ranging from continuing existing efforts to building barriers that would seal the lake from the five Chicago-area streams that are linked to it.
Either blocking the lakefront waterways or blocking their two sources further inland would offer the greatest protection from invading species, the report said. But both options would prevent barges and other boats from using those routes, and would increase pollution in the lake and the waterways.
Most of the other options would be cheaper and would preserve some access to the lake, but would be somewhat less effective.
The report arrived amid growing concern that some so-called nuisance species, led by two strains of the carp, may already have bypassed existing barriers and entered Lake Michigan. The carp, which multiply quickly and eat huge amounts of plankton, are seen as a threat to commercial and sport fish that feed on plankton during at least some stages of their lives.
A water sample collected last May near Green Bay, Wis., contained DNA fragments of silver carp. After that discovery, senators from Great Lakes states called for immediate action to block a carp invasion. In 2012, Congress ordered the secretary of the Army to start designing and preparing to build an effective barrier should it be deemed justified.
Corps officials said Monday that no barrier would be built without holding public hearings, consulting the many government agencies with a stake in the matter and getting Congress’s blessing.
Conservation groups generally want carp and other invasive species to be blocked as quickly as possible, but commercial shippers and recreational boat organizations have expressed concerns about options that would seal off the lake.
Officials have taken a number of steps to keep the carp out of the lake, including physically removing scores of thousands of them from the Illinois River, the source of all five waterways, and installing an underwater electric barrier on the Chicago Sanitary and Ship Canal inland from the five streams.
The electric barrier was once believed to be effective, but a recent report by the Army Corps and the federal Fish and Wildlife Service said entire schools of fish frequently slip through it, swept along by barge wakes or in water beneath metal boat hulls where the electric current is weakened.
Federal officials say there is no evidence that carp have entered Lake Michigan, noting that the closest sighting of the fish in the Illinois River was still 55 miles from the lake.
Questions: Answer in complete sentences (or write the question and then answer). Please do not copy directly from the article!
1. What is the problem with the carp?
2. What are 2 of the solutions the team came up with?
3. What are the upsides and downsides of these plans? (In at least 2 sentences)
4. Why are the carp a threat?
5. What evidence do they have that the carp may have already reached Lake Michigan?
6. What do conservationists want? What do shippers want?
7. What system is currently in place? Is it effective, why? (In at least 2 sentences)
WEEK 3: With Extra Anchovies, Deluxe Whale Watching
By ERICA GOODE
MONTEREY, Calif. — It began with the anchovies, miles and miles of them, their silvery blue bodies thick in the waters of Monterey Bay.
Then the sea lions came, by the thousands, from up and down the California coast, and the pelicans, arriving in one long V-formation after another. Fleets of bottlenose dolphins joined them.
But it was the whales that astounded even longtime residents — more than 200 humpbacks lunging, breaching, blowing and tail flapping — and, on a recent weekend, a pod of 19 rowdy orcas that briefly crashed the party, picking off sea lions along the way.
“I can’t tell you where to look,” Nancy Black, a marine biologist leading a boat full of whale watchers last week, said as the water in every direction roiled with mammals. “It’s all around.”
For almost three months, Monterey and nearby coastal areas have played host to a mammoth convocation of sea life that scientists here say is unprecedented in their memories, inviting comparisons to African scenes like the wildebeest migration or herds of antelope on the Serengeti. Humpback whales, pelicans and sea lions are all common summer sights off the Monterey coast, with its nutrient-rich waters. But never that anyone remembers have there been this many or have they stayed so long, feeding well into November.
“It’s a very strange year,” said Baldo Marinovic, a research biologist with the Institute for Marine Sciences at the University of California, Santa Cruz.
What has drawn the animals is a late bloom of anchovies so enormous that continuous, dense blankets of the diminutive fish are visible on depth sounders. The sea lions, sea birds and humpbacks (which eat an average of two tons of fish a day) appear to have hardly made a dent in the population. Last month, so many anchovies crowded into Santa Cruz harbor that the oxygen ran out, leading to a major die-off.
Marine researchers are baffled about the reason for the anchovy explosion.
“The $64,000 question is why this year?” said Dr. Marinovic, who noted that anchovies had been unusually scarce for the last five or six years and that when they do thrive, they usually appear in the spring and early summer.
He and other scientists speculated that a convergence of factors — a milder than usual fall, a strong upwelling of colder water, the cycling of water temperatures in the bay — have created what Dr. Marinovic called “the perfect storm.”
“Now they’re all kind of concentrating on the coast,” he said of the anchovies. “They seem to seek out Monterey Bay because the water tends to be a little warmer and the eggs will develop quickly.” The fish, he said, “are providing a feast for all these things that feed on them.”
The frenzy has been a boon for whale-watching companies like Monterey Bay Whale Watch, of which Ms. Black is the owner, and for their customers.
In a normal season, passengers are lucky to see one or two humpbacks and a single whale breaching. On the trip last week, more than 60 whales were spotted feeding in the deep water of the canyon offshore, and the breaches were almost too numerous to count — in one case, two whales arced their bodies out of the water in unison, like competitors in an Olympic synchronized swimming event. Foul-smelling whale breath occasionally permeated the air.
Ms. Black said that for the first time this year — she has studied whales here since 1986, specializing in orcas — she has seen evidence that the humpbacks are feeding cooperatively with groups of thousands of sea lions. The sea lions dive simultaneously, surfacing a few minutes later. They herd the anchovies into tight balls, called bait balls, and the whales scoop them up, several hundred in a mouthful. Food is plentiful enough that the giant cetaceans — an adult male humpback measures 45 to 50 feet in length, Ms. Black said, and weighs a ton per foot — can afford to take breaks to play.