Russia’s Northern Fleet has been conducting naval training near Dover. Two battleships and two supply vessels worked on operations and communications in conditions of adverse weather and heavy marine traffic.

“Today a squadron of warships and support vessels of the Northern Fleet headed by a large anti-submarine ship, the Severomorsk, crossed the narrowest part of the English Channel and passed into the Bay of the Seine,” said Russia’s defense ministry.

The crews held a series of survival exercises in case of flooding or fire, as well as anti-submarine training.

After the training, in one of the world’s most crowded waterways, where the squadron was constantly shadowed by the British Navy’s HMS Tyne offshore patrol vessel, the task force went further and anchored in the international waters of the Seine Bay to wait out a storm.

British Navy’s HMS Tyne (Image from wikimedia.org)

Both Britain’s and France’s navies confirmed the location of the Russian ships, but denied that the Russians were doing any training.

“They are not holding exercises. They're just waiting in a zone where they are allowed to be several times a year," the French Navy's information service said as cited by Reuters.

Sky News ✔ @SkyNews Follow Russia says four of its ships have carried out a drill in the English Channel.http:// news.sky.com/story/1382025/ russian-navy-holds-exercises-in-the-channel 6:24 AM - 28 Nov 2014 167 RETWEETS 47 FAVORITES

"Our information indicates that the ships are transiting and have been delayed by weather conditions. They are not exercising in the Channel, as some Russian headlines would have us believe,” said NATO's military spokesman Lieutenant-Colonel Jay Janzen.

Russia’s Navy reported that the crews are not going to sit out the storm in an idle manner. Instead, the crews will train in repelling underwater warfare attacks and practice radio-electronic warfare.

Large landing craft Aleksandr Otrakovsky (Photo by Dmitriy Kachur/picasaweb.google.com)

The captains of the task force use every opportunity to test their crews should a situation arise.

While sailing in high latitudes, Russian sailors trained by providing assistance to a vessel in distress. They also did electronic communication training and cargo transfers from ship to ship.

When NATO patrol aircrafts approached the task force in North Sea waters, air raid alerts were sounded and crews trained air defense maneuvers.

Combat duty assignments of the large anti-submarine ship, the Severomorsk, specifically practiced the detection and elimination of waterborne targets.

The task group left its homeport of Severomorsk above the Arctic Circle on November 20 and has already covered 1,700 nautical miles, crossing successively the Barents Sea, the Norwegian Sea and the North Sea before entering the Strait of Dover.

Northern Fleet warships will steam for the Gulf of Aden to protect vessels there from Somalia pirate attacks.

When we think about the concept of mass extinctions, we tend to think of something pretty dramatic. For instance, we now know that the dinosaurs were wiped out by a six-mile-wide asteroid that hit the Earth at thousands of miles per hour. Its impact, according to the new Smithsonian Channel documentary Mass Extinction: Life at the Brink (airing Sunday night), had the force of “a hundred million nuclear bombs,” unleashing tsunamis hundreds of feet in height that hurtled across the ocean "at the speed of a jet."

So yeah, that's pretty dramatic. And yet many scientists think that today we may be on the verge of another creeping mass extinction -- the sixth the planet has seen -- even as most people barely notice it happening.

Consider just one species highlighted by Mass Extinction: the African lion, or Panthera leo. There are some 32,000 to 35,000 lions left, according to arecent scientific estimate. But as of 1950, their numbers were vastly higher; one group of experts puts them at 500,000, and Mass Extinction uses the number 400,000. Either way, that's a 90 percent or more decline.

The lion numbers, stark as they are, are pretty solid, says Anthony Barnosky, a biologist at the University of California-Berkeley who is featured in the film, and who authored the book Dodging Extinction: Power, Food, Money and the Future of Life on Earth.

"We know that from historic records of where lions used to be, and where they clearly are not any more. So it’s a combination of using the historical data about what we know distributions were over the past couple of centuries, combined with some very detailed studies, censuses of how many lions are out there in known populations over the past half century."

The chief cause of lion declines? "Indiscriminate killing in defense of life and livestock, coupled with prey base depletion," says the International Union for Conservation of Nature, which has the African lion on its "red list" of threatened species.

African lions aren't unique. A similar story, according to Barnosky, could be told about tigers, rhinos, and any number of other species. "We have killed about 50 percent of the world’s vertebrate wildlife in just the past 40 years," he says. "We've killed half the numbers of individuals. We've fished 90 percent of the fish out of the seas. So these are big things we’re doing to the world."

Mass Extinction examines both at the asteroid strike that killed off the dinosaurs 66 million years ago, and also the "Great Dying" at the end of the Permian period 252 million years ago, when some 90 percent of Earth's species vanished in the wake of massive volcanic eruptions in Siberia.

In each of these cases, the global extinction was caused not only by an immediate dramatic event, but by its subsequent effect on the planet's oceans and atmospheres. The asteroid impact led to so much smoke in the atmosphere that the sun's radiation was cut down dramatically, leading to great climatic changes. And the dramatic vulcanism that ended the Permian triggered global warming and ocean acidification by putting lots of carbon dioxide in the atmosphere.

In other words, these past extinctions have been tied to dramatic changes in the global climate. That is not the principal cause of the current extinction -- yet. So far, we've been threatening species by taking their habitat away for farming and for our growing populations. But global warming may now act on top of that.

"It's like adding a match to gasoline," says Barnosky.

You can watch a preview of Mass Extinction below: