Storms and Floods

Tropical Storms

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A Stormier-Hotter World Linked to Climate Change

Britain’s national weather service says there is no longer any doubt that recent larger and more damaging storms are connected to a warming global climate.

Much of the U.K. is suffering from the worst in a series of inundations that have submerged vast tracts of the nation during the past three years.

A barrage of winter storms in recent months has seen some flood-weary communities swamped more than once.

While the Met Office’s chief scientist, Dame Julia Slingo, says it is not possible to blame any specific storm on global warming, she said a trend toward more volatile weather patterns due to climate change is clear.

“We have records going back to 1766 and we have nothing like this,” she said at a press conference in London.

Slingo’s comments came just before Australian researchers announced that human greenhouse gas emissions were the likely cause of last year’s record-breaking heat in the country.

The previous Australian summer was the hottest on record and the year 2013 brought the highest average annual temperature in over 100 years of observations.

Climate experts Sophie Lewis and David Karoly told the Australian Meteorological and Oceanographic Society’s annual conference that human activities, particularly emissions of carbon dioxide, are clearly to blame for the record heat.

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NewsBytes:

UK – Floods in southwest England and elsewhere have submerged crops and destroyed cattle bedding and feed, with the consequences likely to be felt for months, or even years, in terms of lower production of both crops and meat. Britain’s Environment Agency had issued 416 flood warnings and alerts, as of early Thursday, including 16 under its most serious category, indicating danger to life. Thousands of acres of farmland in Britain are under water, with some submerged for weeks.

Wildlife

Giant Unnamed Jellyfish Found on Australian Beach

A huge specimen of an unnamed species of jellyfish washed up on a beach south of Hobart, Australia, last month.

A photo taken of the nearly 5-foot-wide creature by Josie Lim after her family came across it caught the attention of experts at the Commonwealth Scientific and Industrial Research Organization (CSIRO), who are in the process of naming the new type of lion’s mane jelly.

These jellyfish “look like a dinner plate with a mop hanging underneath … they have a really raggedy look to them,” said CSIRO expert Lisa-ann Gershwin. She called the find a “truly magnificent animal.”

Recent years have seen huge blooms of jellyfish in Tasmanian waters, and Gershwin says scientists are not sure why.

She told reporters that such a population explosion is likely to be having a significant impact on the marine ecosystem off southeastern Australia.

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Global Warming

Arctic Sea Ice Melt Season Getting Longer

The summer melt season for Arctic sea ice has lengthened by a month or more since 1979, a new study finds.

The primary culprit is a delayed fall freeze-up — the autumn chill when sea water freezes into ice — but the fallout remains the same: the Arctic ice cap is stuck in a vicious feedback loop betwixt its warming environment and melting ice, researchers reported Feb. 4 in the journal Geophysical Research Letters.

The Arctic is one of the fastest warming places on Earth. Temperatures here are rising twice as fast as the global average. As the atmosphere warms, the Arctic ice cap has shrunk by 12 percent per decade since 1978, when scientists started tracking ice with satellites, according to NASA. The seven lowest September ice extents (a measure of the total ice cover) have been in past 10 years, including 2013.

As the ice cover gets smaller, the amount of heat absorbed by the Arctic Ocean rises. Bright, white ice reflects most of the sun’s energy, but the darker ocean water soaks it up.

“The ocean has gained so much heat it takes a while to release it,” said lead study author Julienne Stroeve, a senior scientist at the National Snow and Ice Data Centre in Boulder, Colo. “That’s delaying the autumn freeze-up.”

In the past decade, the additional heat stored in the upper ocean has increased Arctic sea surface temperatures by 0.9 degrees to 2.7 degrees Fahrenheit (0.5 to 1.5 degrees Celsius), Stroeve and her colleagues report. These warmer ocean temperatures prolong the summer melt season because the ocean must fall below about 29 F (minus 1.9 C) before new sea ice forms.

 

In the Kara, Laptev, East Siberian, Chukchi and Beaufort seas, the fall freeze now comes between six and 11 days later each decade since 1979. The researchers found a similar trend in the East Greenland and Barents seas, where the fall freeze may now be delayed by as much as 40 days per decade.

Oil and gas companies are already exploiting this delay by pushing for drilling leases that allow extraction and exploration well into autumn, Stroeve said. But year-to-year ice conditions can still vary dramatically.

Stroeve notes that while the overall trend is for less sea ice and a longer summer melt season, within the Arctic, ocean and weather conditions can influence how much ice is present. For instance, ice cover in the Bering Sea has increased by 20 percent in recent years, the study finds. Winds pushing sea ice south into the Bering Sea may be the cause, though scientists are still debating the reasons for the added ice cover here.

Stroeve plans further work to investigate whether the spring warming is caused by an increase in atmospheric moisture, which means more clouds and solar radiation absorption, or whether warm air coming from the south plays a role. She also hopes to track ice thickness. In the 1980s, 70 percent of the Arctic ice cap was thick, multiyear ice, which survives the summer melting. By the end of 2012, less than 20 percent of the ice cap was multiyear ice — most of the ice cover was seasonal ice, only a year old. The thinner seasonal ice melts faster.