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In 1956, a documentary by Jacques Cousteau

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won both the Palme d'Or[br]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[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 upon where you are[br]and the time of year,

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

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Invertebrates, like snapping shrimp,[br]fish, and marine mammals all use sound.

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They use sound to study their habitat,

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to keep in communication[br]with each other, 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 describes as a desert,

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because it is so cold, and so remote,[br]and ice-covered for much of the year.

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Despite this, 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[br]really 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 and then delight you.

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

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your ears are telling you that out there

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are bowhead and beluga whales,[br]walruses, and bearded seals.

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The ice too make sounds.

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It screeches, and cracks, and pops,[br]and groans as it collides and rubs

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when temperature,[br]or currents, or winds change.

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

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bowhead whales are singing.

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You would never expect that,

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because we humans,[br]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[br]how 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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Sound transmits very well underwater,[br]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 is[br]especially important

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because not only do Arctic marine mammals[br]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,[br]so they have to surface to breathe.

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They might listen 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, it can be[br]a cacophony of sound.

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(Buzzing, whizzing, squeaking,[br]whistling, wailing sounds)

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But when the ice is frozen solid,

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

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the underwater Arctic has[br]some 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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Climate change and decreases[br]in sea ice are also altering

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the underwater soundscape of the Arctic,

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

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We are, in effect, with climate change,

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conducting a completely[br]uncontrolled 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[br]from six weeks to four months.

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

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as an increase in the open water season,

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

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Not only is the extent of ice changing

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but the age and the width of ice is too.

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You may well have heard[br]that a decrease in seasonal sea ice

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is causing loss of habitat[br]for animals that rely on sea ice

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such as ice seals,[br]or walruses, 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[br]in sea ice are also altering

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the underwater 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,[br]which are underwater microphones.

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We record ambient noise,[br]the noise all around us.

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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, from the water,[br]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,[br]the bubbles break.

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When they do, 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 that the Arctic[br]can have 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

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in the Arctic have 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,[br]sub-Arctic species are moving north

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

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Arctic whales, like this bowhead,[br]have no dorsal fin.

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

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Having something sticking off of your back

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is not very conducive[br]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,[br]we're hearing the sounds

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of fin whales, humpback whales,[br]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, an invasion[br]of the Arctic by sub-Arctic 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 sub-Arctic animals?

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

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What are the new sounds[br]that they are producing

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doing to the soundscape underwater?

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Third: land.

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By land, 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 humans[br]to occupy the Arctic more often.

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It has allowed increases[br]in oil 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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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

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loud, low-frequency 'whoomps'[br]every 10 - 20 seconds,

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

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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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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[br]from other animals or from sea ice.

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

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

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These new sounds are loud,[br]and they are 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 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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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 sub-Arctic animals[br]from migrating north,

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but we can work on local solutions[br]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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The good news is there are people[br]working on this right now.

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But ultimately, we humans[br]have to do the hard work

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of reversing, or at the very least,

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decelerating human-caused[br]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 Inuit say[br]can live 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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In retrospect, 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)