Importance of Natural Resources

Climate Science and its Fundamental Role in 21st Century Challenges


OK. Well, thanks all for coming. It’s a great pleasure to introduce our very
special speaker today. But, before I do, I just want to mention that
this is being recorded. So, any questions after the presentation,
just wait for the mic. This is being, as I said, video recorded – just
of the presentation and the voiceover, and also aspects of this lecture have been published. And, we’re going to put it on the Center for
Climate Science’s website. So, you have some sort of written document,
to a large extent a lecture. There’s probably some things in here that’s
not quite covered. But, nevertheless, it’s a very great pleasure
to introduce Dame Julia Slingo, who’s not only a colleague of mine and been a colleague
of mine for quite a long time, but she’s also become a dear friend. And, so, I’ve got a CV here. I just don’t quite know what to say. It’s kind of hard to introduce her. She, as you probably – many of you know – she
was until about two years ago the Chief Scientist for the Met Office. She has all sorts of accolades. And, while she was the Chief Scientist at
the Met Office, she really was – really was – sort of shaped the weather and climate sciences
of the U.K. was one of the most influential – most influential scientists in the U.K.
at that time. She has many sort of accolades. She is a former member of the U.S. National
Academy of Engineering. She’s a fellow of the Role Society. She has been awarded the OBE. Also, of the readers because I just called
the Dame, but the Dame of the Order of the British Empire. She has more flipping letters of the alphabet
attached to her name than there are letters of the alphabet. So, I can’t go through all of these. There’s a British thing to do: to have these
letters attached to your name. She also has an honorary degree in 8 different
universities. She’s not going to quite catch Sir David Attenburough
, who has 35 honorary degrees. But, you know, it’s a kind of a really impressive
resume. She’s also designate in this is not just a
term of endearment she’s also designated as a National Treasure. So, she’s a national treasure but actually,
literally, a National Treasure. And, so, you know, it’s a great pleasure to
introduce her. But, before I bring her up, I also want to
note there’s a couple of special members in the audience too: the Consul General of the
U.K., Michael Howells, is in the front here. And, the Deputy Consul General, Collette Weston,
is also in the audience here. When a National Treasure comes to these foreign
shores, they have to be in attendance, I guess. OK. So, it’s really a great pleasure to introduce
Julia. It’s going to be a fascinating talk. I think we will all enjoy it. And, welcome. [Applause]
Thank you very much Graeme. I’m not sure about the National Treasure bit,
but anyway…� it’s really good to be here. Although I’m retired, I’m not completely inactive. I do spend more time in the garden and sitting
on the sofa than I used to and singing in choirs and for some reason…� . But, I
thought it would be really interesting to give you a sort of a sense of where climate
science is. Where it’s come from, actually, because sometimes
we don’t do that and to talk about two cutting-edge pieces of research that I initiated in my
final year or so when I was Chief Scientist. So, I want to talk about climate science and
actually give you a sense of its fundamental role still in addressing 21st century challenges. It’s very easy for us to say, if we’re thinking
of climate change, that we’ve got the answer, and all we need to do now is to fund all the
technologists and engineers to find all the solutions. Well, that’s not – that’s not true. There is a lot of fundamental climate science
still to do, and we need to remember that. But, let’s start with sort of just saying
what is climate. Well, this is a quote – not by Mark Twain,
as it is often assumed, but, by a geography professor: “The climate is what you expect,
weather is what you get.” And, so, when we think about climate, we have
to actually think about the weather. And, this has been really my theme – all my
time at the Met Office, where we did everything from early weather forecasting to long term
climate change, was that the fundamental science is the same. And, actually, for going to talk about the
climate, we have to talk about the weather because the way we’ll feel climate change
is actually through extremes of weather. It won’t be the 2 degree Celsius rise in global
mean temperature for sure. So this – you will see – this theme running
throughout the lecture. And, climate science is about understanding
the earth’s climate, of course, through a combination of theory, observations and computational
models. I’m going to tell you quite a bit about the
theory and the long legacy of that theory. I’m going to talk not very much about observations
at all, just touch on them, and then – suppose – spend most of my time talking about climate
models and weather models, and how we can use them to address 21st century challenges. So, we’re going to have a bit of history,
British history, to some extent but also American history because – I think – there’s quite
a lot of us who work in climate or in related fields who probably don’t know some of this
stuff. And, we’re going to start with Halley of Halley’s
comet. And, you know this is the age of polymaths. People dabbled in all sorts of things. And, he dabbled in trying to understand the
trade winds. And, of course, the U.K., being a maritime
nation, they knew all of – they had sailed the world seas, and they knew about the winds. And, this is a very iconic picture that was
published in 1686, showing the winds – the Trade Winds – the winds of the world. And, where he’s actually put these little
dashes here is where the wind reverses with season. So, this is the monsoon. They knew about the southwest monsoon and
the northeast monsoon. And, how they pondered about or why do we
have these Trade Winds that converge pretty much on the equator? And, he argued that it had to be – to do with
the passage of the sun during the day, as it went around the equator. It warmed the air up as it passed, and it
threw the air in behind it as the sun went past. And, so, you have easterly winds. And, that was in 1686 in the Philosophical
Transactions of the Royal Society. The Royal Society was founded in 1660. So, this is one of its very early publications. And, that’s basically what they thought at
that time. That it was just to do with the passage of
the sun. You have to go forward then about another
50 years to 1735 and George Hadley, who actually postulated that it was more to do with the
conservation of velocity. “How the air ‘as it moved from the tropics
towards the equator, having a less velocity’ of diurnal rotation ‘than the parts of the
earth it arrives at, will have a relative motion contrary to that of the earth in those
parts.” So, he’d already worked out that it was to
do with the fact that we live on a sphere and that velocity was conserved. And, he also postulated that the air converges. In the hot regions, the air rises and descends
somewhere else, and hence the Hadley circulation. He actually wasn’t a particularly eminent
scientist, and I couldn’t find a picture of him anywhere. You can find pictures of other Hadley’s, but
George was obviously – maybe this was his big work. Anyway, very, very interesting. But, there we are in 1735. We’ve got at least the essence of the Hadley
circulation. And, then you have to go really quite a long
way forward – another 100 years – to Coriolis, who talked about the movement of objects within
a rotating frame of reference. And, Coriolis didn’t actually think about
a rotating sphere, the planet, but – of course – his ideas are pretty quickly taken up by
an American, in this case Ferrel, who worked out that because of the Coriolis force that
if a body is moving -if it’s moving to the – into the northern hemisphere it’s deflected
to the right, in the southern hemisphere to the left. And, that, actually – really – then, did explain
the Trade Winds, and indeed the mid-latitude westerlies, which were known then as the passage
winds. So, you had the Trade Winds for the easterlies
and the passage winds for the westerlies. And, he – of course – worked out that it was
the absolute angular momentum and not the absolute velocity that explains the winds
of the world. So, Ferrel was pretty important in actually
establishing that because we live on a rotating sphere we’re going to have easterlies and
westerlies. Interesting, it was published in the Nashville
Journal of Medicine and Surgery, which probably says there wasn’t much in meteorology going
on in the U.S. at that time – who knows – it’s extraordinary isn’t it? And, then, we have to go forward to Rossby. So, here, we’ve got this. We’ve explained the trades, and we’ve explained
the jets. But, actually, it was Rossby, again working
in the U.S., Swedish scientist working in the U.S., who I think – of course – set the
foundations of Dynamical Meteorology and Oceanography, and he establishes the theory of planetary
waves, that’s what we call Rossby waves, as a result of the Earth’s rotation and of the
stratification of the atmosphere or the ocean. And, these Rossby waves – basically – set
the scale of the general circulation that we know today. So, this is Rossby’s original drawing of Rossby
waves. And, within those, you get waves breaking. You get the formation of lows and highs, sets
the scale of our synoptic systems. This is actually a picture of the flow in
the middle troposphere. In the very cold spell in 2014, and basically
what you’re seeing here are these characteristics, in this case, quite well amplified Rossby
waves, here. So, here we are. We’re in the mid-20th century before we really
have an understanding that it’s the rotation rate of the planet and the stratification
of the atmosphere that sets the scale of all our weather and hence the scale of the climate. And, those Rossby waves are modified, of course,
by the presence of mountains and the presence of the oceans versus the land. But, fundamentally it’s about earth’s rotation. So, there are some big constraints on the
nature of our weather and climate and very fundamental properties of the planet. So, that’s where we are with Dynamical Meteorology. We go back into the 19th century, and, there
was another group of physicists in this case who were looking at other aspects of the planet:
it’s energy balance. And, here we’ve got John Tyndall, who was
working on trying to understand – they were very puzzled as to why the Earth was so warm. Because if you do a straight energy balance
for a black body, the Earth should be quite a lot colder than it is. And, it was Tyndall – really, who was able
to explain that the atmosphere, particularly water vapor, is a very strong greenhouse gas
and that that’s trapping radiation. But, he also showed that these gases were
emitters as well as absorbers of radiation. And, that’s really important for understanding
the energy balance of the planet. And, here we are 1861, round about the same
time – I guess – as Ferrel, who was working on the Trade Winds in the mid-latitude westerlies. We have this paper on the absorption and radiation
– we would say emission – of heat by gases and vapors and on the physical connection
of radiation, emission, absorption and conduction. And, we would call that transmission of radiation. Again, in the Royal Society and this is Tyndall’s
experiments, a very well-known picture, where he actually measured the infrared effects
of various gases. So, here we are in 1860, understanding that
we have the sun’s energy coming in but actually it’s gases and vapors that actually track
the infrared radiation and keep the planet warm. This idea was taken up actually by Arrhenius,
who was a Nobel Prize winning physicist – Norway. In actually, in 1896 he made the 1st prediction
of global warming. And, then, he published in his book on “Worlds
in the Making” in 1908, this statement about understanding that the enormous combustion
of coal was going to lead to an increase in the amount of carbon dioxide in the atmosphere. So, the theory of anthropogenic global warming
is not new. It’s been known for a very long time. And, he postulated that if you double the
CO2 concentration you’re going to get a temperature rise of 4 degrees Celsius, which is actually
still within the IPCC range. It’s at the upper end, but actually we might
think that probably he may be actually not far of being right. But, interestingly, Arrhenius then went on
to say “By the influence of the increasing percentage of carbonic acid, CO2, in the atmosphere,
we may hope to enjoy ages of more equable and better climates, especially as regards
the colder regions of the earth, ages when the earth will bring forth much more abundant
crops than at present, for the benefit of rapidly propagating mankind.” So, he had a very positive view of the effects
of global warming from very much just the sort of – I think a non-dynamical view of
what the climate – how the climate system works. You know that pretty well – and of course
– at that stage in the early part of the 20th century people were much more concerned that
we were going into another ice age than anything else. So, this is probably seen as quite a good
thing. So, here we are. We’ve got the dynamical basis of the climate. We’ve got the energy basis of the climate. But, of course, there’s an interesting other
little story that was going on in the British Empire, which we often don’t hear about. And, this is the story of the British in India. And, this is Henry Blanford, who went to India
as its first Director of the Indian Met Department. And, when he got to India, he thought, Gosh! This is great! Here we have order and regularity of the climate
as prominent in India as, “Atmospheric phenomena, as are caprice and uncertainty those of their
European counterparts.” What he was talking about was that when he
looked at his anemometer, he could see the diagonal and semi diagonal pressure waves,
pretty well all the pressure variation he got in India… where is… where we live
in the U.K, the pressure is going all over the place. And, the weather is constantly changing. And, he thought that he’d found in India a
special place where he could understand meteorology. I won’t read it all. But it’s sort of savoring to think that when
I was working in monsoons, on the Indian monsoon in the 1990’s, we thought that actually the
complexity of India’s position with its relationship with the Indian Ocean, with the Himalayas,
with all the other aspects of the circulation that India was probably the most difficult
place to understand the meteorology, rather than the easiest. Anyway, Blanford thought he got a great place
where he could do something. But, of course, he got… he came very rapidly
unstuck because we have the global famine the Great Famine of 1876 to 1878, where there
was a massive failure of the monsoon rains. And, here we see actually again the conjunction
of politics and science – reminiscent of where we are today. All science is very much in the political
frame. And, it was at the end of the 19th century
because Britain relied very heavily on India for its cotton and grain harvests, and Indian
taxes, and to pay the dividends to investors was dependent entirely on the monsoon rains,
which actually are mostly incredibly stable. So, everything had been geared to the regular
return of the monsoon rains. And, India was a vitally important asset to
the British Empire. So, Blanford was told you’ve got to sort this
out. We can’t have this anymore. We need to control famine through climate
prediction. We need to know what the what the monsoon
is going to do, so that we can govern India more effectively. So, they spent a lot – Blanford then spent
a lot of time thinking about is it to do with Himalayan snow cover. They thought it was the 11 years solar cycle
that had something to do with it. In fact, later on we know this was one of
the biggest El Ninos ever observed. What happened in these years… an El Nino
leads very often to failure of the monsoon rains. But, he didn’t know any of that. Although he did know that drought in India
was also concurrent with drought in Australia. He had a friend, taught in Australia, who
told him that. And, then, we come to one of my great heroes,
Sir Gilbert Walker, who turned up in India at the beginning of the 20th century. And, he really got to grips with this and
pioneered statistical climate forecasting, which was basically how we did climate predictions,
seasonal forecasting all the way through the early first half of the 20th century. Indeed, in India it’s still done in this way. He called it seasonal fore-shadowing. He didn’t call it forecasting. I think actually fore-shadowing is rather
a good word, because we never know quite what the seasonal forecast is going to really tell
us. But, he performed masses of statistical correlations. He had a huge number of staff doing all these
analyzing all these data. And, he said, “I think that the relationships
of world weather are so complex that our only chance of explaining them is to accumulate
the facts empirically.” And, that’s true, until we come to the age
of supercomputing, when we now have a different way of understanding things. So, he discovered these various oscillations,
but he also set the idea that the climate of one region can be heavily influenced by
the climate of another. So, in other words, when you look in a region
– the variability of the climate in a region – you have to understand it within the global
context of these oscillations, what we now call “tele connections”. So, this is the beginning of understanding
climate variability. And, of course, it all came together with
Bjerknes in the 1960s, who had been working on El Nino and the ocean and realizing that
El Nino was a couple phenomenon, and that you had to have a and, that it was linked
to this thing called the Southern Oscillation, which Gilbert Walker had discovered, which
was why India had drought. When there’s an El Nino and the two things
came together and we got to the phenomena… the mode of climate variability climate that
we call the El Nino, the Southern Oscillation. And, actually it was Bjerknes, who realized
that actually when you perturb the ocean temperatures and atmospheric circulation in these ways,
you turn you perturb the overturning cells across the tropics, which he named the Walker
Circulation. So, the Hardley circulation is the north-south. The Walker circulation, we think of as the
east west. And..we really have this concept of the ocean
atmosphere system as being critical for understanding the climate. And, then – of course – we come to CO2. And, here is the latest curve, going up to
December this year. And, this – of course – is Keeling’s, known
as the Keeling Curve. I joined the Met Office somewhere around about
here. And, writing the 1st radiation codes and cloud
codes to go in our latest climate model. And, I wrote a paper somewhere around about
here, which was on cloud feedbacks and water vapor feedbacks on a double CO2 world, in
a very simple model published in a book called: Carbon Dioxide Climate and Society. I thought this is a bit of fun, an intellectual
exercise. I little knew that actually… what we were
observing… I think we used to use 320, the number in
our mobile, then, that actually we would be way up here at 410 in my lifetime. And, that this curve effectively represents
the big one, one of the great challenges for society. Now, so, this has been a massive – this has
been a huge story for climate science through the past 40 years. And, critical to all of that – of course – has
been the way in which we’ve observed the planet. When I started in the Met Office, we were
just getting the 1st satellite images. I did all my early work plotting radius on
the sense and thinking we had very little understanding of the global planet. The global system, now of course, we know
a vast amount about it. And, we continually – as I say – actually
given the planet a health check. Here and of course J.P.L. and NASA been heavily
involved in quite a lot of this. So, Earth observation has given us enormous
insight. But, actually, I would argue that all observations
do is tell you what is happening. They don’t necessarily tell you why it’s happening. So, the other big change – of course – is
the development of climate models, which is where I started my career, building the first
climate models in the U.K. And, just because I think it’s a the general
audience – I just want to say a little bit about what these things are, because not everybody
understands them. They basically simulate the climate system
and actually the weather, based on some very fundamental laws of physics. And, they help us to explain how the climate
system works, why it’s changing, and what’s our future climate maybe like. So, I often call this my laboratory. So, like any scientist I want the best laboratory
that I can get my fingers on. So, I want the best model, and I want the
biggest supercomputer because actually the scale and the usefulness of climate models
is heavily tied up with the increase in super computing power. And, I was well known in the U.K. for going
to meetings with funders and ministers and saying I need more money for supercomputing. And, I did manage to get 100 million out of
the U.K. government while I was Chief Scientist arguably what is still the biggest machine
dedicated to weather and climate prediction. And, so, you know that’s what you do. I want the best laboratory because this is
where we test ideas. So, these things – basically – what we do
is we cut the world up. We cut the atmosphere and the oceans up into
volumes. And, typically, in the horizontal, the grid
squares have up to now been around 100 to say 50 kilometers, so quite coarse. And, we have about 85 slices through the atmosphere. So, you’re producing hundreds of thousands
of volume, which you then describe with their physical properties and integrate those properties
forward in time using some fundamental physics. They’re big codes, and the latest unified
model code at Met Office was about 2,000,000 lines of code. And, they need machines that are several petaflops
to run. And, they produce a vast amount of data, so… But, actually, what’s behind them all – well
you know – it’s actually classical physics. So, when you actually look at what we’re doing
within these models, we’re actually back to Newtonian – Newton’s 2nd law of motion. We have to add in the Coriolis force, which
makes it slightly more complicated because we’re on a rotating sphere. But it’s fundamentally force equals mass times
acceleration. We have used, and not so much now, this concept
of balance, hydrostatic balance. But, fundamentally at the gross scale that
describes why the pressure decreases with height. It’s a balance between the vertical pressure
gradient force and the pull of gravity. In very high resolution models now we don’t
use that balance because in systems like hurricanes and some thunderstorms there isn’t a balance
instantaneously. They’re very non-hydrostatic. Mass Continuity – quite simply – what comes
in at the bottom has to go up and come out at the top. Ideal Gas Equation, everybody knows that from
basic physics. First Law of Thermodynamics – the linking
heating to changes in the winds. Now, this is where Earth’s climate, particularly
in the troposphere, gets really interesting, because the Earth’s temperature is such that
you can have water in solid, liquid or vapor form. And, when you change from one form to another,
you release or take up latent heat. And, so, you can actually move heat around
the system, through moving water around the system and then changing its state. And, this is – in fact – the latent heat released
when clouds and rain form actually dominates the Earth’s ‘heat engine’. So, that’s why�and, we’ll see that in a
minute. This is why understanding how the atmosphere
and the Earth’s climate works is so complicated, because we can carry water in three forms. And, here’s the Clausis-Clapeyron Equation,
which relates the amount of water that the air can hold depending on its temperature. We often quote this equation to argue that
as the world warms there’s more water vapor in the atmosphere. And, therefore, we can have more severe storms. And, then some very fundamental things to
do with radiation, Planck and Stefan-Boltzmann Laws that link thermal radiation emitted by
black body to temperature. And, Kirchoff’s Law – that link absorption
and emission of radiation by atmospheric gases. That’s basically what we’re doing when we
build a climate model. We’re taking some very classical immutable
laws of physics and coding them up to describe the evolution of the atmosphere and the oceans. And, what you get out is something that looks
like this. So, this is a simulation done actually rather
a long time ago now. And, there are probably some better ones around
– at 12 kilometer grid – so, this was done on a very big machine, and it’s representation
of the infrared temperature, the black body temperature of clouds and the surface. So, the white clouds are high clouds. The black surface is looking down almost to
the ocean. If you’re very… you can see the sun come
past. There it goes. And, when the sun comes past, the clouds build
up and then fade away. This is entirely simulated by the model from
those equations. The only fundamental constraints on this are
the rotation rate of the planet and the solar constant – how much solar energy enters the
system. This model is generating the water vapor in
the atmosphere through physics. And, in this case, we would have given it
the other greenhouse gases, but not water vapor. So, it’s actually working out its own energy
balance. It can see the mountains and so forth. Now, if you are an aficionado of tropical
convection, like I am, you know this is actually not very good. These clouds are not quite right. The frontal systems in these latitudes – very
beautifully described – they’re part of the Rossby waves that I talked about earlier. But, the tropics is really quite difficult,
and the reason is that when you build these models – and because of the computer power
available to you – you have to make your grid boxes quite large, otherwise you just can’t
get the problem through the machine. And, so, over the years we’ve spent most of
our time trying to understand how to represent physics that goes on a scale smaller than
the model grid. How to represent their bulk effects? And, there are things like the boundary layer
and turbulence and mountains, atmospheric composition, smog, radiation – probably one
of the more tractable problems. But, the bit that’s really still a major challenge
for us is all of this: What’s happening to the water cycle? How does cumulus convection work? How do we represent it? How does precipitation form? How do clouds form in polluted and unpolluted
atmospheres? And, so, we’re still absolutely – we have
so much to do. But, we have actually – I think – some really
interesting new breakthroughs. In the last decade, we’ve seen – I think – a
new age coming for climate and weather science. From first of all advanced Earth observation
– this is the A-Train, but particularly what we call the Active Sensors in Space. Graeme’s been very much involved with… have
allowed us to look down into these clouds and see where the precipitation is formed
and to understand in combination with other observations what the processes are. It actually transformed a lot of our thinking
about how rain is produced, particularly in convective clouds. And, then – of course – we’ve had this ability
now to perform very high resolution simulations. This is one we did a few years ago at the
Met Office of Super-typhoon Megi, at 1.5 kilometer simulation. And, what you can see here is it starts from
a very smooth field. And, the physics of the model generates all
these interesting clouds structures, just from the physics. This is actually a remarkable simulation of
this particular event with the cloud bunce and so forth. And, if you put that along with this sort
of information, you learn an awful lot of new things about how convection latent heat
release interacts with the dynamics of the system to grow things like hurricanes and
typhoons and so on. So, this is been a huge breakthrough in the
last decade. And, I think the ability now to do what I
call computational field experiments to study in great detail this system – for example
– which you could never do in real life. You couldn’t go and look at the four dimensional
structure of a system like that in every bit of detail to understand what it’s doing. You can with the simulation. So, this is really, really exciting for our
understanding of some of the fundamental physics that’s going on. Of course, it’s been for us in the Met Office. This became part of our operational system
while I was Chief Scientist. It was a major revolution in weather forecasting. This is an example of a forecast way back
in 2012. This is the radar image here, and this is
the model forecast. And, this was actually a red alert in the
U.K. for heavy rain through just where I live, which is about here. I was actually due to go to a garden party
at the Vice Chancellor’s house at Exeter University. And, needless to say, I stayed at home. I couldn’t have got out at the time, if I
had wanted to. This was very typical of the quality of forecast
all these colors are the early rain rates. So, it gives now a very, very good sense of
the flood risk and surface water flooding. And, it’s just been an amazing advance. And, we’ve used the same models now to look
at local climate change scenarios and shown that actually we have the potential for much
more intense rainfall in summer in the U.K. It’s much greater than we thought from low
resolution, course grained models. So, it’s completely changing our perception
of how we must adapt to changing rainfall patterns in the future with global warming. So, that’s where we’ve come. We’ve come all the way through that history
of climate science, the fundamental physics, to be able to talk about local flooding. And, that’s important because I want to now
sort of say – well – how does that relate to the 21st century changing landscape. And, I’m going to weather and climate risk
because that was weather that we just saw there. And, this is a diagram I often use to talk
about where our science fits. It’s very important. When we think about weather climate variability
and change, which is what I was working on at the Met Office that we don’t forget that
these things are happening within the world that is also under major pressures from urbanization,
population growth, and limited natural resources of particularly water. Water will arguably become the most precious
resource on the planet – I think – in the next few decades. So, we have to look at it in that context. And, therefore, it’s no good to say, well,
OK we’ve had climate change in the past or we’ve had these things in the past, and it
was all fine. The point is the world is not the same as
it was in the past. The now an awful lot of us on the planet,
and we live in big cities. And, we depend on the globally interconnected
economies and supply chains. So, we have to look at our science in that
context. And, these things in this middle circle essentially
influence the securities on which we rely for our health and wellbeing. And, again, what’s really important here is
that we don’t look at each of these in isolation. You can’t look at food security without looking
at water security and so on. They’re all interrelated. So, we have to think now of our science and
place it within this broader context of the things that we rely on for our health and
wellbeing and for the sustainability of the planet. And, therefore, you know I was my feeling
was 2015 was really quite a landmark year in lots of ways. We had Paris. First time governments had accepted the evidence
of climate change and agreed to do something about it. We have the Sendai Agreement on Disaster Risk
Reduction. And, we have the Sustainable Development GOALS. And, all of those depend on a strong basis
in weather and climate science. And, so, you know this is sort of some grand
words, but actually this is very real. And, we see this happening now, not in the
future with climate change. And interestingly, if we wanted to argue the
case for our science, this is from the World Economic Forum last year, looking at the likelihood
and impact of the global risks. And, what’s at the top? Everything to do with extreme weather events,
natural disasters, failure of climate change mitigation and adaptation are regarded as
the most critical, the top risks. Some down here as well, too. But, actually, I think that’s very striking. So, we have to advance our science. And, it’s fortunate that I think we do have
some new tools in the toolbox: these are from my time as Chief Scientist. But, these are important – this concept now
that we forecast across time scales seamlessly from near term weather to what we call the
extended range to the monthly to decadal. Actually, this time scale, the next year,
or the next 10 – 20 years is actually where a lot of people are going to make their decisions. And, then we’ve got long term climate change. But, the idea here is the same science, the
same modeling techniques go through all these timescales. You add different things out here to do with
the Earth system that you don’t need back here. But, the fundamental atmosphere – ocean science
is the same. And, likewise with seamless – just now – this
concept of seamless prediction across space scales from the global models that we run
in climate and the weather forecasting to get what we call the synoptic drivers of local
weather through to what I was just showing you – the regional predictions of 1 kilometer
to give you the local meteorology, and then feeding that into all sorts of impact systems
to get both the probability of local hazards to give you impact scenarios and narrative
This is flood risk, in this particular case. But, this is the way the science is developed. So, we’re actually in a place where I think
we can do some useful things. So, just very quickly, I wanted to just give
you a couple of examples. This is the U.K. in the early part of 2014
and in December 2015, terrible flooding. And, I was very much at the sharp end of some
of this, being the Chief Scientist. And, of course what you get from the Minister
is – well – first of all “Is this climate change?” Well, actually, when you look at the rainfall
of river records for the U.K. for the last 100 years you can’t say. We have a hugely variable climate. It was very hard to say it’s climate change. And, then the Minister went on to ask me to
– clear after this event – he said “How much rain are we – could we get? Could we get three times the amount? What is the plausible worst case for U.K.
flooding in the next ten years?” And, you go How do I answer that? And, he wants the answer in six weeks. So, when you work in policy related science,
you have to move fast. So, these are really, really difficult questions. They look simple. He thought they were simple. They’re very difficult to answer. So, what do we do? Well, actually, I could take you back to another
bit of fundamental science. And, this is Ed Lorenz and his famous quote,
“One flap of a seagull’s wings may forever change the course of the weather.” And, this has been the fundamental part of
why we do ensemble prediction. We never make one forecast anymore. We make 50 or whatever because we know that
chaos theory tells you that small perturbations grow and gradually change the sequence of
the weather, sometimes in a very constrained way, and sometimes in a very broad way. But, you can also argue – of course – that,
if you take that concept, there are lots of worlds that might have been, during the period
in which we’ve observed the planet. But, we haven’t observed them because we didn’t
get a flap of seagull’s wings one place or another. So, we have to remember that the observations
– is only one plausible realization of what the world’s weather could have done – say
in the last 30 years. And, when you accept that, you then say, well,
actually, could I use then multiple realizations of the weather from simulation, as paths that
the world’s weather could have taken, but we happened not to observe. So, this idea that there might be Black Swans
out there – very extreme events – that just could have happened, if the weather had set
up in a different way, because of chaos theory, if we chop down a different bit of forest
or done something different with our cities, that – that’s the flap of the seagull’s wings. So, what we were able to do is actually to
take – we had 1,400 years of simulated weather from 1980 to 2010, because of part of another
project. So, we had 1,400 simulated winters that were
all perfectly plausible versus 35 observed winters that were from 1980-2015. And, then you can say – well – here this is
the South East of England. These are the range of the observed monthly
rainfalls during the winter. I mean, when you’ve got 30-35 samples and
you can sort of plot a distribution, but quite frankly the tails are not well populated. Here’s the model simulations. And, they were quite plausible simulations. Model was quite good – actually – surprisingly
good. It’s quite a high resolution model. We’ve put in red the ones that lie outside
anything that’s been observed. And, so, you’ve actually filled up the distribution
function – much more effectively both at the dry end but, here we’re interested in the
wet end, and you’ve got quite a large number of events, though wetter than anything you’ve
observed in the current climate, just from natural variability. There’s January 2014, the Thames flooding,
which was an extreme outlier compared with the previous years. But, actually, if we’d had this information,
we might not have been so surprised that it happened. And, this one – that’s actually worse than
that. So, then you can go away and answer the question
that the Minister wanted with.. well what’s the chance? And, he wanted a 1 in 100 year chance. Well, I don’t know how you do a 1 in 100 year
event when you’ve got that 50 years maximum data, not sure. But, actually, you can do the 1% risk. So, here we’ve got… this is the percentage
increase in rainfall above the maximum that we’ve currently observed. And, this is the chance of the event. So, and, here is the probability taken from
the simulations. And, we can say that actually at the 1% level
there’s a chance of having between 25 – 30% more rainfall, 20 – 30% more rainfall. It’s not zero, and it’s not a 100. It’s actually quite well constrained. And, every year you might expect there’s a
reasonable chance that you’ll break a new record… it’s between 5 and 10%. If we had done that with only 35 years of
data, which is what we’ve got for the observations for the current climate with CO2 forcing you
can see how unconstrained the tails of the distributions are… you can’t really talk
about the risk of a 1% event. It’s anything across here. And, this is a big problem for most of the
things to do with the insurance industry and many of the infrastructure investments. We’re having to work on 100 year events. The insurance industry works entirely on the
tails of distributions, which are not well characterized from observations. So, there’s a real role here, now, for simulation
to provide synthetic event sets that can allow us to populate or fatten up the tail, as the
insurance industry says, to give better estimates of risks of extremes. So, this is a very exciting development. And, I think – you know – we’re just beginning
to explore this, applying it to all sorts of aspects of the world’s climate, from heat
waves in China to heavy rain in the U.K. and elsewhere. So very exciting. That’s only one bit of the story though, because
actually what we really want to know is at the regional local level, what are we going
to do? This is the Thames barrier. “Is it good at 2100?” is a good question. In 2014-2013, the Thames barrier was closed
more than it was open. It was closed most of the winter because of
the extreme rainfall and extreme storms that we had. So, it was a bit of a wakeup call. How well do we know these things? And, this is our number one risk in the U.K. It’s an east coast storm surge. But, how do you manage to how can you characterize
that risk? Well, we started a really groundbreaking project
while I was at the Met Office, having experienced that those extreme events, thinking about
how we are going to get a better understanding of the fully coupled near surface environment. So, the U.K., the Thames is exposed to river
flooding, storm surge, tides, all those things. So, this was a project we started, an integrated
couple prediction for the U.K. at the convective scale.relevance to people, ecosystems, and
infrastructures. This is what people really want to know about
if we’re going to manage our risks. So, this is what we’ve built in the last 3
or 4 years, published in Geoscientific Model Development by Huw Lewis. He worked very closely with me when I was
Chief Scientist. And, we’ve built this 1.5 kilometer model
of the atmosphere, the land, the waves and the coastal shelf sea. I think it’s a first. It’s very, very innovative. This is not going to be operational – I don’t
think – for another 5 to 10 years – but very exciting – just a little snippet of what we
get out… well…this is sea surface height. Many of you won’t know, but the U.K. experiences
incredibly high tides. This is the tidal range, here in meters, from
more than 8 meter tidal range in many parts of the country. This is the tide propagating around the shelf
sea, around the U.K. And, so, tides are an integral part of our
environment, not necessarily others. The tides, here are from the shelf sea model. This is surface currents. And, we can see, they speeded up a bit. The tides also drive very, very strong surface
currents around the coast and some very interesting coastal currents. You can see when you’re down at 1.5 kilometers
and the interaction of with the shelf here is fascinating. And, there’s been a lot of analysis of this. We’ve added waves and here’s a couple of examples
of extreme wave height, one upon the east coast here, which is in the North Sea. This is an uncoupled simulation of the wave
height. This is the coupled in red, and the observations
in black. So, a fully coupled atmosphere ocean wave
tide model gives you estimates that are at least a 0.5 meter bigger than you would get
from an uncoupled model. And, 0.5 meter, when you’re thinking about
sea defenses, is quite significant. This is actually Hinkley Point, where we’re
building a nuclear power station. And, this is another example. I was asked, “What a 1 in 10,000 year event
was for Hinkley Point?”, when I was Chief Scientist. That was interesting – didn’t know how to
do that, really. But, here’s Hinkley Point – very, very different
wave of spectrum. But, again, if you’re concerned about extreme
wave height – really it’s the only the couple system that gets anywhere near the observations. Here is the work we’ve done. We have a very complex river systems in the
U.K. This is our interactive now coupled hydrology
and river flows. This is part of developing a much better estimate
of river flooding and how we manage rivers. From them from this very high resolution model,
some very exciting stuff… we have a lot more to do, including also the coastal biology
and the health of the coast. And, we’ve started to work with other countries,
particularly Singapore, where the local environment is also very complex. So, I think this is a really exciting breakthrough. So, if we think about what the 21st century
is going to require of us, then I think – you know – thinking of environmental risk is going
to pose major challenges to society. The science of weather and climate lies at
the core of managing many of these risks, whether it’s through simulated event sets,
a narrative, sorts of things I’ve given you a sense of. So, we have to get a better understanding
of the coupled local environment in which we live. And, that I think is the next step, for a
lot of our science is getting down to that local environment level. But, I just wanted to end up, because I’m
here at J.P.L. and it’s NASA, I want to turn that by, just saying a little bit about…
from theses last words almost to Piers Sellers. Because he was very – I think – inspirational. Many of us knew him in his early years as
a land surface modeler. And, he went on to be – of course – an astronaut. And, here he is in the space shuttle. And, he died as many of you will know of pancreatic
cancer about 2 years ago. And, the year before, he wrote a really – I
think – fantastic piece in The New York Times. And, this is what he said. “When we think about the challenges we face
for the future” He said, “New technologies have a way of bettering our lives in ways
we cannot anticipate. There is no convincing demonstrated reason
to believe that our evolving future will be worse than our present, assuming careful management
of the challenges and risks. History is replete with examples of us humans
getting out of tight spots. The winners tended to be realistic, pragmatic,
and flexible. The losers were often in denial of the threat.” I met quite a lot of those losers when I was
Chief Scientist, people who – senior people – who denied that climate change existed and
that it was all a hoax. They were in denial of the threat. He then goes on to say, “As an astronaut,
I spacewalked 220 miles above the Earth, floating alongside the International Space Station,
I watched hurricanes, cartwheel across the oceans, the Amazon snake its way to the sea
through a brilliant green carpet of forest, and gigantic nighttime thunderstorms flash
and flare for hundreds of miles along the equator. From this God’s-eye-view, I saw how fragile
and infinitely precious the Earth is. I’m hopeful for its future.” Wonderful piece by him. There is so much more in that to read, actually. And, so, I think – you know – coming back
to the beginning, climate science is about helping us to live safely and sustainably
on our planet. And, I just want to end with a bit of what
might look like triviality, but it’s not. I think it’s quite a profound message. This is Linus from Peanuts, and he’s out there. And, he’s on the beach. And, he’s building this fantastically ornate
sandcastle. And, I often think about that when I see climate
impact assessments and the sort of information we sometimes give back to Ministers. We’ve built this fantastically complicated
assessment with social scientists and engineers and so forth. And, it looks a bit like that we’ve all seen
them. But, the problem is, as he finds out, is that
the rain comes down. And, he says at the end “There’s a lesson
to be learned here somewhere, but I don’t know what it is.” And, those of you who remember going to Sunday
School might well remember what the lesson is – of course – is that “A foolish man built
his house on sand. The rain came down; the streams rose; and
the winds blew and beat against that house, and it fell with a great crash.” And, of course, what did the wise man do? “The wise man built his house on the rock. The rain came down; the streams rose; the
winds blew and beat against that house; yet, it did not fall, because it had its foundation
on the rock.” And, what’s really important here and one
of the things that concerned me when I was Chief Scientist is that whatever advice we
give to people who have to make decisions and set policies that we need to ensure that
the bedrock of science is there. And, this is a really important message…
climate and where the science is not done… it’s a long way from being done. And, we have to be aware, as I often wasn’t
talking to Ministers in government, to be very honest with them and say I can’t answer
that question because the science isn’t good enough yet. As we move into this world where we’re going
to be asked, challenged time and time again about environmental risk, we have to be absolutely
honest and ensure that we get the investment in the bedrock science… the sorts of stuff
that you’re doing here with Earth observations, the sort of stuff that my folk at the Met
Office are doing with building better and better models. We have a long way to go if we’re going to
provide the quality of information that we need to deal with 21st century challenges. So, that may seem like a bit of frivolity,
but a message – I think – has to be very clear. So, thank you very much for listening. I’ve run on far too long. We are going to take some questions for about
5 minutes. I know it is lunch time. We’re going to run over a bit, about 5 minutes
or so for questions. Wait for the mic because it’s being recorded. Hi, I wonder if you have an opinion on what
I perceive to be the fundamental problem which you’re getting at here, which is, you know,
my brother was in the Australian Civil Service and eventually became fairly high up as in
2nd Term Minister, and his perception of the problem goes something like this: Technical
person says to Minister “We have a perception of a problem with a certain amount of uncertainty”. Yes. And the minister says, “You want me to commit
how much money to your confidence level.” Yes. “Go away.” Yes. Is there an answer to them? Yes, I mean this was obviously, this is the
root of a lot of the work that we were doing in the Met Office. And, to some degree, it’s about language that
we use. So, we shouldn’t use the word uncertainty
because that’s not what this is. I mean chaos theory is not uncertainty, it’s
about probabilities and confidence. So, that’s the first thing. And, then you have to – sort of – actually
start to work with these people and look at the cost benefit ratios. Where is their decision point? So, that it’s not just there’s an uncertainty. Where is it that it makes it important for
you to make a decision pending on how much it costs? And, actually, it’s a lot about just educating
people about how we produce these probabilities and how they should use them. After all, every decision we make in life
is based on… we make a risk assessment. You may not realize it, but we will make risk
assessments with everything, everything we do. But, it’s about… you’ve got to have that
dialogue with the Minister. And, actually, this one was the example I
showed of flooding was a very, very interesting discussion. I actually sat with the Minister. He wanted to know how climate models work. Once he understood all that he understood
what we were doing and how we were catching it, he could actually describe it. Not all Ministers are as good at this. I think we can’t get around this – that we
have to work with probabilities. But, I would like to think that we can use
better words, positive words – like confidence. There are messages where you can say I am
absolutely confident that it will be like this, and we can use narratives. I mean, I didn’t talk about that too much. But, I’m actually very keen on taking some
of the tails of the distribution of building a narrative from what the simulation is telling
us about how the weather evolved. And, therefore, you can run almost like a
test case of what your response would be to… within that narrative. I’m not sure I’ve really answered your question
very well. But, I mean this is the fundamental thing
that we have… in all walks of life. As, we go through, we are going to have to
deal with probabilities and risk. And, it’s about having the right dialogue
at the right level. And, I think the main thing for me, when I
was Chief Scientist, was to be absolutely clear that anything I said whether it was
a probability or whatever, I could justify the scientific basis for. So, I think this is still for me the key thing
that we have to be sure that we can go back to the science and say I can or I can’t answer
that question yet – but not try and give a half-baked answer on probabilities that you
don’t believe in. I can give you a more difficult question. So you’ve tied climate change to weather extreme
events, which are local in space and short in time – what about structural changes – like
abrupt changes – which happened in the past, like Younger Dryas, and, so one. Yes. What about this? Well, they would have been the same sort of
thing – I mean Younger Dryas was driven by a completely different process, and we would…� Pardon? It’s was global. That’s right. But, the point here is that what we feel as
individuals is not the global change but the change where we live and the weather that
we experience. That’s absolutely true. The Younger Dryas, yes, was a global change,
was a massive change. And, everybody will feel it. But, actually, the place where… there was…
at the individual or the country level, it’s about the weather. It’s not about the global mean change, how
that manifests itself in the weather that you experience. If you work for the government. Yes
We will take two more. One from Duane -I think- there is one of the
top there. I developed, for example, the sea ice in the
Arctic going away. That’s how weather extremes in more along
the lines with what he is talking about, for example. Yes. I mean, that is a good example because, but
then who is going to be impacted? Well, it’s probably going to be the Arctic
– the Inuits and the Arctic ecosystems and maybe the loss of Arctic sea ice could have
an impact on U.K. weather, for example. So, that’s an example of a big change. But, actually, most of the changes that we’re
going to see are going to be along the lines of more extremes, whether we want to call
them weather extremes or extremes of climate variability. One last question and we break for lunch. I’m just curious. Can we engineer favorable scenarios by having
seagulls flap their wings? What did she say? She said, can we engineer favorable scenarios
by more seagulls flapping their wings? Probably not. Chaos – chaotic system – doesn’t quite work
like that – unfortunately. You probably have equal chance of it being
unfavorable as favorable. Yes. So, I think we will thank you again Julia
again for her wonderful talk.


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