The warming we see now truly is extraordinary in the context of thousands of years.
We understand and have done for quite some time, the climate is changing
and that is because of anthropogenic, human, activities, mainly our emissions of greenhouse gases.
So this has been unequivocal for some period of time now.
So I'm a climate scientist with particular interest in extreme weather and in glacier-climate interactions.
Within Asia we have this set of mountains
that we can regard as really the roof of the world, high mountain Asia.
And once we get above 5,000 metres in those ranges, even though there's a lot of area above that altitude,
we find almost no weather stations because they're just very hard spots to get to.
So clearly we're very concerned about how quickly the glaciers there may retreat,
how small they may get as the climate warms. So what we're looking at in Everest
or around the vicinity of Everest, this retreat of glaciers, is of worldwide importance
we would say because of the amount of water that is stored in what we call the water towers
the water towers being a way of referring to the enormous reservoirs of snow and ice
that are stored in the world's high mountains.
Now globally around 1.9 billion people live downstream of water towers.
so long term we're concerned about declines in fresh water coming from these water towers,
short term, we're concerned about there being too much water and the increased risk of floods.
So I was involved in a National Geographic and Rolex Perpetual Planet expedition to Everest
and that was a huge multi-disciplinary project and my part in that project,
along with Baker Perry from Appalachian State University in the US,
was to coordinate the installation of five weather stations
up from about 3,800 metres, all the way to as high as we could get on Everest
to better understand the climate on Everest.
And it took someone like National Geographic to take the plunge
on what is a very risky endeavour scientifically and, sort of, from an exploration point of view.
Everest is at the the frontier, it's the highest point on Earth. It really is life at the extreme.
So the plan was to install five weather stations in the vicinity of Everest, getting progressively higher
and taking a vertical profile of the atmosphere by installing at different elevations.
And we were aware that trying to do this, there'll be some serious obstacles in the way
that are related to the extreme physical environment that we'd be operating in.
So we needed to design weather stations that were very very light, easy to deploy and
could be carried through the very very challenging terrain one would encounter going up the slopes of Everest.
The first weather station is also the lowest station that we installed.
It's in a village called Phortse which happens to be the home to most of the Sherpa
who took us and guided us higher up on the mountain.
And the weather station we installed there is the most comprehensive of all of our weather stations
because it's a really easy environment to work in compared to being higher on the mountain.
And that weather station measures everything required to work out what's happening to water in the region,
how much water is falling in the form of precipitation, so we're measuring that with
a very sophisticated precipitation sensor that allows us to weigh the amount of snow and rain that falls
and we're also measuring all the weather elements required to work out things like
how much moisture can be evaporated from the land surface
to really understand the cycling of energy and water.
And it's a cycling of those parameters allow us to understand things like how much smaller
or predict things like how much smaller the glaciers may get given certain scenarios of warming.
So in order to do that we're measuring the air temperature, the relative humidity, the wind speed,
how much sunshine is coming in from the Sun, how much is being reflected from the surface below
and how much thermal radiation or long wave radiation is coming from the atmosphere
and how much is being emitted from the surface below.
It's a significant physical undertaking trying to ascend Everest.
It lasts in the order of two months from start to finish
and it's a bit of a war of attrition against your body, the whole the whole experience.
You know any particular day when you're high up doing some of the high altitude work
there's not much oxygen, that affects your ability to concentrate
and that really makes you get very very tired very quickly so you physically can't walk very quickly.
It's cold, that affects your ability to perform fine motor skills
with your fingers that's needed to install the weather stations.
I've always suffered a bit with cold hands in cold weather and this trip was no different.
So I got some minor frost nip, the first stage of frostbite, on most of my fingers.
I think that was actually associated with one morning at Camp Three,
which is around 7,000 metres, being a bit slow to put my gloves on when preparing for the day.
So I wasn't aware of anything particularly severe at the time,
it was only the days following, when we were still at high altitude,
I noticed that the ends of my fingers appeared to be a little dead
and then over the course of several weeks the blisters appeared and then ultimately disappeared
and there was some healthy new pink flesh waiting for me underneath.
So avalanches are a very real risk on the mountain they're also very frequent.
We would hear avalanches most days or nights
and they're very intimidating to listen to when you're laying in your tent at night
because we know that avalanches do kill people on Everest. There's very little you can do,
if you're in the wrong place wrong time then, unfortunately that can be that.
One of the most dramatic parts of the climb is passing through the Khumbu Icefall.
And the icefall is where the Khumbu Glacier, the thing that you're camped on
and that most of the ascent up Everest takes place over,
it's where that part of the Glacier is moving really fast.
And where it moves really fast, the ice breaks up into these big blocks
and that means it's quite difficult to physically move across that surface.
The blocks are broken leaving these big crevasses, these big holes if you like to fall down.
So you have to find your way, pick your way through these ice blocks,
climbing up vertical sections where the ice blocks have shattered and climbing over crevasses.
And the route through there is fixed by the Icefall Doctors,
these remarkable, a remarkable group of people that set the route,
lay out ladders and fix lines for other climbers to follow.
And they set it up in a way that's quite safe for you to traverse.
So you can clip into these ropes and make sure you're safe if you fall off one of these ladders.
The risk that can't be eliminated is that that comes from collapse of the ice blocks
or from avalanches either side of the mountain coming down onto the Icefall.
And that's a real risk, it's killed lots of people in the past
and that was something we were certainly very cautious of
and certainly it was something we were a bit nervous of too going through that region.
One of our aims was to set a weather station up as high as we could.
And we ultimately settled on a site called the Balcony
which is at 8,430 metres, so about 400 meters short of the summit.
We chose that site as the home of the highest weather station in the world
and the first ever above 8,000 metres,
a nice sort of flat area, a bit of exposed bedrock,
it's a good home for a very special weather station.
The data from the weather stations are not just being logged or stored
on the computers that sit inside the weather stations because if they were,
it would be pretty inconvenient to go and collect data from them.
So the data are also being transmitted during daylight hours via a satellite
to a server in North America, a National Geographic server.
And we're able to access those data whenever we like, so we can see in almost real time
what the conditions are like on the mountain.
And those variables, the weather in near real time,
you can view that on the National Geographic website
and they're also being tweeted out by a Twitter robot during most hours.
So you can see in almost real time what's going on up there.
We're seeing that the temperatures up there during the monsoon are quite a bit warmer than we expected.
And also the really intense sunshine that climbers have long spoken about
in terms of how warm it makes them feel whilst moving through the Western Cwm,
we now find out that those levels are really really high,
sometimes as much solar radiation, as much sunshine as you can expect on the edge of space.
And that's so intense that on occasion it's warming the snow surface up to the melting point
even though the air temperature can perhaps be below minus 10 degrees.
So the big picture is, it may mean that the glaciers in this region at really high altitude where
we haven't monitored before are perhaps more sensitive to climate warming than we previously thought.
Most abiding memory of the expedition was actually just after we'd come back to base camp
from installing the Balcony weather station
and we were left with the Sherpa celebrating the end of the expedition,
realising that their backyard is Everest.
They regularly guide people up and down Everest
and now Everest was front and centre for global science.
It was putting the region on the map for another reason entirely and these guys
had also played a role in helping to address a global challenge that they're nothing to do with.
You know climate's changing rapidly in the region, the emissions per person of
greenhouse gases in Nepal are next to nothing compared to people in the West.
So they are facing the challenges of climate change and helping to address them,
helping to perform this frontier science.
So we have gone to an awful lot of effort to try and understand what the
current climate is like up there. And the reason we've done that is because
without knowing the current climate we're very poorly equipped to answer questions
like how much snow and ice may be left in the Himalayas as the climate warms.
And until we know that, we know very little about the future fresh water security
for perhaps around 2 billion people on Earth.
So the stakes are really very high and it's because those stakes are high that it's worth
going into these environments, pursuing this frontier science to try and answer those questions.