Last year when I was here, I was speaking to you about a swim
which I did across the North Pole.
And while that swim took place three years ago,
I can remember it as if it was yesterday.
I remember standing on the edge of the ice,
about to dive into the water,
and thinking to myself, I have never ever
seen any place on this earth
which is just so frightening.
The water is completely black.
The water is minus 1.7 degrees centigrade,
or 29 degrees Fahrenheit.
It's flipping freezing in that water.
And then a thought came across my mind:
if things go pear-shaped on this swim,
how long will it take for my frozen body
to sink the four and a half kilometers
to the bottom of the ocean?
And then I said to myself, I've just got to get this thought
out of my mind as quickly as possible.
And the only way I can dive
into that freezing cold water
and swim a kilometer
is by listening to my iPod and really revving myself up,
listening to everything from beautiful opera
all the way across to Puff Daddy,
and then committing myself a hundred percent --
there is nothing more powerful than the made-up mind --
and then walking up to the edge of the ice
and just diving into the water.
And that swim took me
18 minutes and 50 seconds,
and it felt like 18 days.
And I remember getting out of the water
and my hands feeling so painful
and looking down at my fingers,
and my fingers were literally the size of sausages
because -- you know, we're made partially of water --
when water freezes it expands,
and so the cells in my fingers
had frozen and expanded
and burst.
And the most immediate thought when I came out of that water
was the following:
I'm never, ever
going to do another cold water swim
in my life again.
Anyway, last year, I heard about the Himalayas
and the melting of the -- (Laughter)
and the melting of the glaciers
because of climate change.
I heard about this lake, Lake Imja.
This lake has been formed in the last couple of years
because of the melting of the glacier.
The glacier's gone all the way up the mountain
and left in its place this big lake.
And I firmly believe
that what we're seeing in the Himalayas
is the next great, big battleground
on this earth.
Nearly two billion people --
so one in three people on this earth --
rely on the water from the Himalayas.
And with a population increasing as quickly as it is,
and with the water supply from these glaciers --
because of climate change --
decreasing so much,
I think we have a real risk of instability.
North, you've got China; south, you've India, Pakistan, Bangladesh,
all these countries.
And so I decided
to walk up to Mt. Everest,
the highest mountain on this earth,
and go and do a symbolic swim
underneath the summit
of Mt. Everest.
Now, I don't know if any of you have had the opportunity to go to Mt. Everest,
but it's quite an ordeal getting up there.
28 great, big, powerful yaks
carrying all the equipment up onto this mountain --
I don't just have my Speedo,
but there's a big film crew who then
send all the images around the world.
The other thing which was so challenging about this swim
is not just the altitude.
I wanted to do the swim at 5,300 meters above sea level.
So it's right up in the heavens.
It's very, very difficult to breath. You get altitude sickness.
I feels like you've got a man standing behind you with a hammer
just hitting your head all the time.
That's not the worst part of it.
The worst part was this year was the year where they decided
to do a big cleanup operation on Mt. Everest.
Many, many people have died on Mt. Everest,
and this was the year they decided to go
and recover all the bodies of the mountaineers
and then bring them down the mountain.
And when you're walking up the mountain
to attempt to do something
which no human has ever done before, and, in fact, no fish --
there are no fish up there swimming at 5,300 meters --
When you're trying to do that,
and then the bodies are coming past you,
it humbles you,
and you also realize very, very clearly
that nature is so much more powerful
than we are.
And we walked up this pathway,
all the way up.
And to the right hand side of us
was this great Khumbu Glacier.
And all the way along the glacier we saw
these big pools of melting ice.
And then we got up to this small lake
underneath the summit of Mt. Everest,
and I prepared myself
the same way as I've always prepared myself,
for this swim which was going to be so very difficult.
I put on my iPod, I listened to some music,
I got myself as aggressive as possible --
but controlled aggression --
and then I hurled myself
into that water.
I swam as quickly as I could
for the first hundred meters,
and then I realized very, very quickly,
I had a huge problem on my hands.
I could barely breathe.
I was gasping for air.
I then began to choke,
and then it quickly led to me vomiting in the water.
And it all happened so quickly:
I then -- I don't know how it happened -- but I went underwater.
And luckily, the water was quite shallow,
and I was able to push myself off the bottom of the lake
and get up and then take another gasp of air.
And then I said, carry on. Carry on. Carry on.
I carried on for another five or six strokes,
and then I had nothing in my body,
and I went down to the bottom of the lake.
And I don't where I got it from,
but I was able to somehow
pull myself up and as quickly as possible
get to the side of the lake.
I've heard it said that drowning
is the most peaceful death that you can have.
I have never, ever heard
such utter bollocks.
(Laughter)
It is the most frightening and panicky feeling
that you can have.
I got myself to the side of the lake.
My crew grabbed me,
and then we walked as quickly as we could
down -- over the rubble --
down to our camp.
And there, we sat down,
and we did a debrief about what had gone wrong
there on Mt. Everest.
And my team just gave it to me straight.
They said, Lewis, you need to have
a radical tactical shift
if you want to do this swim.
Every single thing which you have learned
in the past 23 years of swimming,
you must forget.
Every single thing which you learned
when you were serving in the British army,
about speed and aggression,
you put that to one side.
We want you to walk up the hill in another two days' time.
Take some time to rest and think about things.
We want you to walk up the mountain in two days' time,
and instead of swimming fast,
swim as slowly as possible.
Instead of swimming crawl, swim breaststroke.
And remember, never ever swim with aggression.
This is the time to swim
with real humility.
And so we walked back up
to the mountain two days later.
And I stood there
on the edge of the lake,
and I looked up at Mt. Everest --
and she is one of the most beautiful mountains on the earth --
and I said to myself, just do this slowly.
And I swam across the lake.
And I can't begin to tell you
how good I felt
when I came to the other side.
But I learned two very, very
important lessons there on Mt. Everest,
and I thank my team of Sherpas who taught me this.
The first one is
that just because something has worked in the past so well,
doesn't mean it's going to work in the future.
And similarly,
now, before I do anything,
I ask myself what type of mindset
do I require
to successfully complete a task.
And taking that into the world of climate change --
which is, frankly,
the Mt. Everest of all problems --
just because we've lived the way we have lived for so long,
just because we have consumed the way we have for so long
and populated the earth the way we have for so long,
doesn't mean that we can carry on
the way we are carrying on.
The warning signs are all there.
When I was born, the world's population
was 3.5 billion people.
We're now 6.8 billion people,
and we're expected to be 9 billion people
by 2050.
And then the second lesson,
the radical, tactical shift.
And I've come here to ask you today:
what radical tactical shift
can you take in your relationship to the environment,
which will ensure
that our children and our grandchildren
live in a safe world
and a secure world,
and most importantly, in a sustainable world?
And I ask you, please, to go away from here
and think about that one
radical tactical shift
which you could make,
which will make that big difference,
and then commit a hundred percent to doing it.
Blog about it, tweet about it, talk about it,
and commit a hundred percent,
because very, very few things
are impossible to achieve
if we really put our whole minds to it.
So thank you very, very much.
(Applause)