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In 1956, a documentary[br]by Jacques Cousteau won

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both the Palme d'Or and an Oscar award.

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This film was called,[br]"Le Monde Du Silence,"

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or, "The Silent World."

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The premise of the title was that[br]the underwater world was a quiet world.

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We now know, 60 years later,

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that the underwater world[br]is anything but silent.

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Although the sounds[br]are inaudible above water

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depending on where you are[br]and the time of year,

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the underwater soundscape can be as noisy[br]as any jungle or rainforest.

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Invertebrates like snapping shrimp,[br]fish and marine mammals

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all use sound.

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They use sound to study their habitat,

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to keep in communication with each other,

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to navigate,

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to detect predators and prey.

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They also use sound by listening[br]to know something about their environment.

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Take, for an example, the Arctic.

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It's considered a vast,[br]inhospitable place,

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sometimes described as a desert,

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because it is so cold and so remote

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and ice-covered for much of the year.

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And despite this,

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there is no place on Earth[br]that I would rather be than the Arctic,

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especially as days lengthen[br]and spring comes.

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To me, the Arctic really[br]embodies this disconnect

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between what we see on the surface[br]and what's going on underwater.

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You can look out across the ice --[br]all white and blue and cold --

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and see nothing.

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But if you could hear underwater,

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the sounds you would hear[br]would at first amaze

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and then delight you.

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And while your eyes are seeing[br]nothing for kilometers but ice,

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your ears are telling you that out there[br]are bowhead and beluga whales,

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walrus and bearded seals.

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The ice, too, makes sounds.

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It screeches and cracks[br]and pops and groans,

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as it collides and rubs when temperature[br]or currents or winds change.

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And under 100 percent sea ice[br]in the dead of winter,

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bowhead whales are singing.

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And you would never expect that,

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because we humans,

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we tend to be very visual animals.

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For most of us, but not all,

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our sense of sight is how[br]we navigate our world.

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For marine mammals that live underwater,

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where chemical cues[br]and light transmit poorly,

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sound is the sense by which they see.

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And sound transmits very well underwater,

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much better than it does in air,

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so signals can be heard[br]over great distances.

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In the Arctic, this[br]is especially important,

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because not only do Arctic marine[br]mammals have to hear each other,

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but they also have to listen[br]for cues in the environment

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that might indicate[br]heavy ice ahead or open water.

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Remember, although they spend[br]most of their lives underwater,

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they are mammals,

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and so they have to surface to breathe.

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So they might listen[br]for thin ice or no ice,

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or listen for echoes off nearby ice.

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Arctic marine mammals live in a rich[br]and varied underwater soundscape.

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In the spring,

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it can be a cacophony of sound.

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(Marine mammal sounds)

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But when the ice is frozen solid,

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and there are no big temperature[br]shifts or current changes,

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the underwater Arctic has some[br]of the lowest ambient noise levels

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of the world's oceans.

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But this is changing.

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This is primarily due to a decrease[br]in seasonal sea ice,

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which is a direct result of human[br]greenhouse gas emissions.

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We are, in effect, with climate change,

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conducting a completely uncontrolled[br]experiment with our planet.

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Over the past 30 years,

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areas of the Arctic have seen[br]decreases in seasonal sea ice

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from anywhere from[br]six weeks to four months.

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This decrease in sea ice is sometimes[br]referred to as an increase

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in the open water season.

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That is the time of year when[br]the Arctic is navigable to vessels.

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And not only is the extent[br]of ice changing,

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but the age and the width of ice is, too.

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Now, you may well have heard

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that a decrease in seasonal sea ice[br]is causing a loss of habitat

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for animals that rely on sea ice,

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such as ice seals,[br]or walrus, or polar bears.

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Decreasing sea ice is also causing[br]increased erosion along coastal villages,

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and changing prey availability[br]for marine birds and mammals.

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Climate change and decreases in sea ice

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are also altering the underwater[br]soundscape of the Arctic.

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What do I mean by soundscape?

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Those of us who eavesdrop[br]on the oceans for a living

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use instruments called hydrophones,

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which are underwater microphones,

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and we record ambient noise --

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the noise all around us.

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And the soundscape describes[br]the different contributors

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to this noise field.

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What we are hearing on our hydrophones

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are the very real sounds[br]of climate change.

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We are hearing these changes[br]from three fronts:

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from the air,

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from the water

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and from land.

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First: air.

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Wind on water creates waves.

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These waves make bubbles;

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the bubbles break,

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and when they do,

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they make noise.

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And this noise is like a hiss[br]or a static in the background.

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In the Arctic, when it's ice-covered,

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most of the noise from wind[br]doesn't make it into the water column,

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because the ice acts as a buffer[br]between the atmosphere and the water.

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This is one of the reasons

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that the Arctic can have[br]very low ambient noise levels.

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But with decreases in seasonal sea ice,

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not only is the Arctic now open[br]to this wave noise,

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but the number of storms[br]and the intensity of storms in the Arctic

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has been increasing.

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All of this is raising noise levels[br]in a previously quiet ocean.

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Second: water.

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With less seasonal sea ice,

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subarctic species are moving north,

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and taking advantage of the new habitat[br]that is created by more open water.

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Now, Arctic whales, like this bowhead,

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they have no dorsal fin,

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because they have evolved to live[br]and swim in ice-covered waters,

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and having something sticking[br]off of your back is not very conducive

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to migrating through ice,

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and may, in fact, be excluding[br]animals from the ice.

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But now, everywhere we've listened,

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we're hearing the sounds[br]of fin whales and humpback whales

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and killer whales,

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further and further north,

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and later and later in the season.

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We are hearing, in essence,

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an invasion of the Arctic[br]by subarctic species.

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And we don't know what this means.

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Will there be competition for food[br]between Arctic and subarctic animals?

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Might these subarctic species introduce[br]diseases or parasites into the Arctic?

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And what are the new sounds[br]that they are producing

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doing to the soundscape underwater?

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And third: land.

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And by land ...

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I mean people.

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More open water means[br]increased human use of the Arctic.

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Just this past summer,

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a massive cruise ship made its way[br]through the Northwest Passage --

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the once-mythical route[br]between Europe and the Pacific.

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Decreases in sea ice have allowed[br]humans to occupy the Arctic more often.

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It has allowed increases in oil[br]and gas exploration and extraction,

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the potential for commercial shipping,

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as well as increased tourism.

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And we now know that ship noise increases[br]levels of stress hormones in whales

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and can disrupt feeding behavior.

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Air guns, which produce loud,[br]low-frequency "whoomps"

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every 10 to 20 seconds,

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changed the swimming and vocal[br]behavior of whales.

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And all of these sound sources[br]are decreasing the acoustic space

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over which Arctic marine mammals[br]can communicate.

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Now, Arctic marine mammals[br]are used to very high levels of noise

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at certain times of the year.

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But this is primarily from other[br]animals or from sea ice,

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and these are the sounds[br]with which they've evolved,

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and these are sounds that are vital[br]to their very survival.

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These new sounds[br]are loud and they're alien.

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They might impact the environment[br]in ways that we think we understand,

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but also in ways that we don't.

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Remember, sound is the most[br]important sense for these animals.

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And not only is the physical habitat[br]of the Arctic changing rapidly,

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but the acoustic habitat is, too.

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It's as if we've plucked these animals up[br]from the quiet countryside

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and dropped them into a big city[br]in the middle of rush hour.

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And they can't escape it.

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So what can we do now?

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We can't decrease wind speeds

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or keep subarctic animals[br]from migrating north,

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but we can work on local solutions

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to reducing human-caused underwater noise.

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One of these solutions[br]is to slow down ships

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that traverse the Arctic,

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because a slower ship is a quieter ship.

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We can restrict access[br]in seasons and regions

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that are important for mating[br]or feeding or migrating.

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We can get smarter about quieting ships

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and find better ways[br]to explore the ocean bottom.

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And the good news is,

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there are people[br]working on this right now.

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But ultimately,

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we humans have to do the hard work

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of reversing or at the very[br]least decelerating

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human-caused atmospheric changes.

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So, let's return to this idea[br]of a silent world underwater.

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It's entirely possible

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that many of the whales[br]swimming in the Arctic today,

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especially long-lived species[br]like the bowhead whale

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that the Inuits say can live[br]two human lives --

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it's possible that these whales[br]were alive in 1956,

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when Jacques Cousteau made his film.

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And in retrospect,

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considering all the noise[br]we are creating in the oceans today,

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perhaps it really was "The Silent World."

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Thank you.

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(Applause)