Thanks very much. I'm delighted. Honoured.
So you'll come to. To hear this lecture? I, I very much hope you enjoy and gets me out of it.
And, ah, of course, I'm very grateful to the the ECI and the Smith School in particular, for hosting this event.
And crucially, that means providing free drink afterwards.
So I know why most people are here to guarantee a good turnout and so on.
But but I, of course, particularly should start off by thanking the school geography,
environment and the Department of Physics School of Environment for giving me the opportunity
to to talk to you today as the driver entrusting me with one of their statutory chairs.
I have to try not to break it, I suppose, and and the Department of Physics for having shepherded me this far and also continue
allowing me to continue my involvement in the department as as we go forwards.
I am joining in a sort of inaugural lecture like this.
I gather it's customary to start off with a sort of bit of an autobiographical spin on on why I got to where I am.
And also a lot of people here looking around the room know me anyway, so I think I'll spare you that embarrassment.
But I will make one little comment on along those lines, because I'm joining a department where I've discovered unnervingly that.
So the researcher is often the subject of investigation as well as the thing the researcher is investigating.
And I also wanted rather unnerving talking to Sarah Watt more than 9 a.m.
I might really talk to her. Is she just analysing who I am, so to speak, or what I'm doing?
And so I'm going to struggle with this anyway.
So the, the, the reason I thought I should therefore start off with a declaration which I thought would prompt a theme for this lecture,
is that, as many of you know, mines the second career in our family.
My wife Irene got her statutory chair a few years ago, and partly as a result,
I have the privilege of meeting our kids at 3:00 every afternoon at the primary school gates.
And it's very striking how working on climate change and big planetary environmental
problems doesn't fit in with my role as a parent in a North Oxford primary school.
And that's kind of what the title of the lecture is all about.
When I it's a it's a classic North Oxford Primary School.
People are concerned about the environment. People several parents are here have seen and they sort of asked me plenty what I do.
And they're interested. Oh, yes. Climate change and and and they're concerned about that.
Several have solar panels on their roofs and so on. And we talk about them.
We move on and talk about other things. And then I go to conferences and people talk about, you know,
is it a 10% or 2% probability of a third headline shut down affecting the climate of Europe in 50 to 100 years time?
And it just doesn't connect up at all.
And it's this disconnect between what we do as climate scientists and indeed what politicians do without climate science.
So it's this some sort of triangle we have to try and reconnect that I'm thinking about in this inaugural lecture.
We've got the sort of stuff we do as climate scientists making these projections of the
world which look disturbingly predictable and wander off into the future at some alien date,
a long way away. We have politicians making, you know,
pronouncements about their commitment to avoid more than two degrees of warming and so forth at these big international conferences.
And then we have reality. We have actual people at the school gates getting on with their lives.
And there's very little connection between between these three.
The lack of connection between climate science and climate policy has been very heavily discussed,
and I've been engaged in some of those discussions and I'm enjoying continued discussions as we go forward.
But it's this disconnect between what we do as scientists and the questions people are really interested in that I want to focus on in this lecture,
because one of the things I one of the conclusions I guess I'll try and convince you of is that if as a scientific community,
we've done a better job of focusing on the questions ordinary people really are interested in,
we might not be in quite such a pickle as we're in as regards climate science and its role in them in policy.
As you probably know,
the rules of the lecture are that you're allowed to ask questions and it all has to proceed in complete silence until the privacy and myself file out.
And so when when I heard these rules, I thought, this, this, this is never going to work.
And it's going be very boring for everybody, which is why I'm also so.
So that's why we sort of introduced this format and a panel discussion afterwards.
And I'm, of course, very grateful to the panel for coming up.
David, Bob, Sarah and Richard. And you'll be hearing from all of them after the lecture, and that'll be an opportunity for everybody.
There'll be roving mikes and everybody can join in and discuss what we've been what we've been talking about.
So to make notes of the things you wish to disagree with, because I hope there will be plenty.
So this is the challenge we face and the situation we're in,
sort of being realistic about climate and about the way the climate issues evolved over the past 20 years.
What's been achieved? I said very little.
What's been achieved in the sense of doing anything about climate change, in the context of the problem as a whole is very little.
An enormous amount has been achieved over the past 20 years in terms of understanding the problem and to some extent how.
I'll try and convince you in understanding how relatively simple it is, at least on the large scale.
And then we can come on to how potentially complicated it might be on smaller scales.
And then I'll talk about in the context of what has been achieved, in the context of what needs to be achieved.
And that's the challenge we face of an eventual phaseout of anthropogenic greenhouse gas emissions.
And the problem we have having facing that 50 to 100 year time scale challenge is facing where most people's priorities lie,
which is essentially present day climate understanding, today's climate and current climate trends.
And most people who I talk to at the school gates are not really that interested in forecasts of the
climate in 2100 or estimates of the probability of events happening in their grandchildren's lifetimes,
or even our ability to make marginally skilful, multi-decade climate predictions.
So this is it's that it's that connection that we want to try and remake in this.
And that's the sort of direction that I'm going in terms of making the link between
the physics departments and the School of Geography as part of this research.
Just in terms of giving you the context of where we're at, in terms of emissions.
We've been doing some work with Corinne le Carré in the Tyndall Centre, UEA Tyndall,
and she has a very nice way of framing the problem of understanding how emissions are evolving.
Thinking from the top down in the big picture, how emissions per head emissions per person in different parts of the world are evolving.
I find this very intriguing figure. So that's the UK there.
So the black line is real data, that's emissions tonnes of carbon per person.
Okay. So you can see in the UK and it starts in 1750 here and goes up to 2050.
So the UK, we sort of peaked a few decades ago and it's now perhaps coming down in emissions per person.
But you know, perhaps that's just noise. So we have to sort of consider the possibility that this might just be a noise about a stabilisation.
The USA has shot up faster, may be coming down faster.
Or is it just noise and it's about to stabilise. Okay.
So so this is the sort of range of uncertainty in where emissions might go next given the amount of information we've got so far.
But most of these mature countries, we're seeing at least some sort of inflation,
which gives you a bit of a constraint on what might be happening next.
Of course, somewhere like China, you're very much in a very different situation.
You know, we've got emissions per head taking off. You can basically fit any function you like to this sort of curve.
And you could go. So, so then of course, you've got to use more information to try and put some bounds on what might happen in the future.
And so Koreans considering the possibility that China might tap out.
It's an American style cap of six odd tonnes per person, per head or cap out of the European style maximum of two and a half.
And these are sort of the point is here is to sort of use the sort of the overall shape
of the way emissions are evolving as a way of giving bounds on emissions in the future.
The normal way of doing this kind of thing, by the way, is very different, is to set up something called an integrated assessment model,
which has a model of the transport sector, a model of the power sector and so forth, and and sort of try and model everything into the future.
This is very much a much more sort of top down, data driven approach, which I like.
I mean, certainly it's certainly much closer to the sort of things we've been trying to do with climate.
But of course, because there's less information going in, you end up with a lot of uncertainty in what comes out.
However, because of the properties of CO2, which will come back to a lot of these uncertainties,
in effect integrate out because CO2 accumulates in the climate system.
And what we find is the what matters really for the climate system is the total integrated amount of CO2 we dump in the atmosphere over all time,
not the amount we dump in any given year. We'll be coming back to that theme fairly frequently.
And so the process that even given these very large range of possible behaviour in emissions per head of population,
when you multiply that by what we actually know,
rather with considerable confidence, which is actually how the population is going to evolve between now and 2050,
because those those trends, you know, there's a lot of inertia in population.
You can actually make projections that far ahead with a reasonable amount of confidence.
You end up with a relatively small range of uncertainty in accumulated carbon emissions from fossil sources out in 2050.
And it's in the ballpark of the upper end of the ranges of onset, of the projections of the scenarios that are out there at the moment.
So the this sort of approach points towards a future at least over the next 40 to 50 years where we're following the high end scenarios of emissions.
And that is certainly consistent with the emissions data that's been released relatively recently,
although of course, you shouldn't read too much into just one or two years.
But certainly the bounce back from the recession in emissions was such that most people are saying that does appear to be the sort of path we're on.
So on the sort of area of what's happening to global emissions, there's absolutely no sign of a slowdown in fossil carbon emissions at the moment.
If anything, we're seeing a modest acceleration in the rate of CO2 emission into the atmosphere.
What what a lot of people are reporting as having slowed down is the climate.
Response. You'll read a lot in particularly in certain newspapers,
but also on the Internet and blog sites and so forth, about how global warming stopped in 1998.
If it if if it were true that more than we more than we thought of the warming that occurred prior to the year 2000 was a natural fluctuation.
And if the current shorts relatively short period of relatively stable temperatures were to continue, that would, of course, be reassuring.
It wouldn't mean that everything we've done so far is wrong,
but it would mean we'd start to be able to rule out some of the upper end of the possible responses of the climate system to these rising emissions.
At the moment, however, there isn't that much reassurance in what we've seen so far because we can, in fact explain what's happened since 1998.
That's 1998 here, the spike in temperatures. The grey here is the data and the various colours are different authors attempts at explaining what's
happened in the data due to different factors affecting global temperatures over the past 50 to 100 years.
This is a figure that trembles here in maths and physics has been putting together as part of the preparation for the next IPCC assessment.
And what it shows is, is that it's possible to explain, not necessarily this is the correct explanation,
but this is a possible explanation of what's happened to global temperatures over the past 50 years.
And these explanations typically involve, from 1998 onwards, quite a bit of cooling due to the non-recurrence,
if you like, of an extreme El Nino event such as the one we had in 1998.
So we've we haven't seen another El Nino like the one in 1998 or indeed the one in 1982.
Those were those are very strong El Nino events. They give a big upward spike into the global temperature series.
We haven't seen another one. So that record is for that reason yet to be broken.
We've also seen the El Nino occurred at a time when there wasn't the cooling due to the early nineties
volcano had largely dissipated and it also occurred at a time when solar activity was relatively high.
And we've seen a little downturn in temperature due to solar activity over the past ten years.
So we're now at a relatively weak part of the solar cycle, whereas ten years ago it was a little bit stronger.
You're pretty finding it irritating if you're at the bank. Why have I got one of these scales so big and these lines so small?
Well, that's kind of the point here, is these are not big wiggles.
And they're not particularly they're not in terms of at the school gates.
These are not particularly important wiggles.
They matter for scientists because, of course, if we couldn't explain what was happening since that time,
if there was a genuine evidence of a problem with our understanding of the way the climate system was responding to those emissions,
then, you know, we'd perhaps be backing off the whole projections we're making about further warming in the future, but there isn't such a problem.
We can see that. We can explain what's going on as a combination of these natural factors affecting
climate and the anthropogenic influence estimated from these different studies.
And you can see all of them agree we're seeing a substantial anthropogenic warming over the past over the past few decades.
And one one question is which which comes out of this, of course,
is there is an element this is sort of explaining after the event things have happened.
So we go out and look for reasons why they've happened.
Scientists are disturbingly good at this, as Sara will point out, and we were very often brilliant with hindsight.
And we do need to be careful about the possibility or indeed the sort of formal statistical
danger of overfitting when we're trying to explain every wiggle in the Time series like that.
And I wouldn't suggest that we should expect to be able to explain all the wiggles
in global temperature and the sort of detail that those studies have demonstrated.
So just to convince you, though, that it isn't all just being wise after the event,
I thought I'd show you one genuine prediction of global mean temperature of global climate made in a paper submitted in the last millennium.
And this is a prediction of global temperature based on data.
Banks in the data available was only available up until 1996.
Although we submitted the paper in 1999, we weren't quite as good in those days, that sort of gathering data together.
And so. And so we are now in a position more than 14 years later to look at how good that
forecast was of the decade following the point at which the forecast was made.
I and the reason I like the number 14 is there's a precedent for 14 year climate forecasts.
And you'll notice how seriously in those days people took the climate scientist.
And if only the same were true today.
So the crucial point here, this was the article in question.
And if I just zoom in, you'll notice they did receive it in the last millennium.
And I'd just like to publicly apologise to Irene for submitting a paper,
and thank you for giving me the opportunity of doing so and rather just spoiling our Christmas that year, as I recall.
But I was kind of obsessed with getting this thing in. And it is satisfying that it went in just with one view.
This is we can we can stand up and say hand on heart. The forecast of the next decade was completely out of sample.
Okay. Yes, the paper was published in 2000. We didn't fiddle with the figures.
Okay. So everything. And so this is what happened. That was 14 years later.
That's the validation, I think. Now, of course, there's an element of luck in this.
It could have. It could have been basically, we were saying could have been anywhere inside that great curve.
But the point is that the actual average temperature over the past decade was exactly
what we expected it to be based on the information we had back in the 1990s.
It's not that we can explain it after the event. It was it was explained before the event.
And this is one demonstration, of course, which I'm fond of because I played a role in it.
But there's other papers out there.
You can go back to what the IPCC was saying in the 1990s and say, you know, what would they have forecast for where we would be today?
And it is remarkable how close we are to where we were predicted to be.
So that's sort of telling you that there's certainly no evidence that global warming is stopped.
We do understand why the 1998 record is yet to be broken.
And we shall. And some people, in fact, argue that it, in fact, has been broken, or at least is a statistical tie and emissions continue, if anything.
So they the the trends are pointing towards an acceleration and the climate is responding much as expected.
One of the questions I get often, often get asked is, is it true that it's sort of turning out worse than we thought?
My impression is the evidence is coming in, some of it worse than we thought, some of it.
But it's sort of you know, it's not obvious that in many ways what's remarkable is the evidence is coming in so
close to what we expected that the system is evolving and in some ways surprising,
surprisingly simply compared to us at a global level.
Tim. Tim is frowning there. There's any suggestion this is a simple system at a global level on in response to changing greenhouse gases.
And we're not seeing any imminent reductions in fossil CO2 emissions.
So in that sort of rather depressing context,
could we make more progress perhaps on alternatives to CO2 and other drivers of carbon dioxide of climate than than CO2,
which is something which has been proposed and is will, I'm sure, receive a lot of coverage in the next couple of years.
There's a lot of because we're basically not making any progress on CO2.
This has led to a lot of enthusiasm for trying to do something about climate change by reducing emissions of black carbon.
So soot from a lot of it from burning biomass in developing countries.
Tropospheric ozone generated by photochemical pollutants and and and many other many other kinds of blue pollution and methane,
of course, from agriculture and natural gas reductions. I promise to members of the audience at least one reference to trans fats in this election.
So that is one gratuitous reference to the farting cow.
These are we want to emphasise bad things.
We agree with the unit report's assessment completely that it would be very good for the world and good for women
in developing countries in particular to do something about the things that cause emissions of black carbon.
These things poison a lot of people in developing countries, a lot of very good reasons for cutting them, unfortunately for political reasons.
A lot of people want to say that meeting the target of avoiding more than two degrees of warming is one of these reasons,
because they've made this commitment. They made a commitment to avoid more than two degrees of warming.
They want to be seen to be doing something about it.
And this appears to be something easy they can do. However.
And the you know, the early drafts of the unit report.
I don't know what they're going to say in the version of the report which is released tomorrow.
In fact, I didn't even know it was going to be released tomorrow until which you told me earlier on today.
But in the executive summary of this report, which they released earlier this year,
it contained the statement reducing short lived climate forcings will help keep global temperature rise below two degrees.
And that's a politically very convenient thing to be able to say,
because we're trying to do that and we want to reduce these short lived climate forcings.
So you put the two together and it all looks very good. The only problem is it's not true.
Okay. The reason it's not true is that these things are short lived.
They don't live. They don't survive in the atmosphere for very long.
Which means that emissions we make of these short lived forcing agents today make very little difference to the risk of going over two degrees.
It's a relatively obvious point, but one which we've been in prompted by this unit document to look into.
And Neil Bauman, one of one of my graduate students, has been working with Steve Smith of the UK Climate Change Committee on this problem.
And what this plot, which Neil's produced, shows how in one particular little model the emissions in different decades impact on peak warming.
Okay. So what you're seeing here is the emissions we make in the 2000 in the in the 20 tens.
Would that column be. No, that would be the 20 tens again.
So in this decade, the the the emissions we pump into the atmosphere under this scenario,
which is a scenario in which temperatures are expected to peak around two degrees,
the emissions we make in this decade contributes about 2/10 of a degree to that two degrees.
Okay.
And so if somehow magically we followed this scenario, but we just didn't emit anything this decade, okay, then the peak would be 0.2 degrees lower.
Yeah. These sort of with more or less what we're talking about.
So so what we're saying here, this gives you an idea of which gases are most important when for peak temperatures.
And notice, plain carbon, tropospheric ozone and methane are these quite small bars up at the top here, entirely dominated by CO2.
I think they become important out in the future as you approach the peak.
And at a time when you virtually eliminate your CO2 emissions anyway.
But the bottom line is cuts in these other gases make very little difference to your risk
of dangerous climate change in the future unless you've already got CO2 under control.
And I hope I convinced you with Corinne's work, we haven't got CO2 under control.
We shouldn't pretend that we have. So it's a convenient fiction, but sadly not true.
The reason carbon dioxide is so important, of course, is that it's the one which builds up in the system.
It's like a heavy metal toxin, so to speak.
The dose of CO2 accumulates in the climate system, unlike the others, where if you cut emissions of methane within 10 to 20 years,
the methane you've released into the atmosphere has oxidised into CO2 and
therefore has much less impact on the planet than it would do as methane alone.
The sort of demonstration of this point about the fact that it's the total amount of
CO2 you dump in the atmosphere that matters is just illustrated by this figure here,
which shows three different scenarios for future CO2 emissions on the left and the temperature response on the right.
And so you've got a blue scenario which has emissions rising rapidly and then peaking suddenly in the early 2020s.
Nobody is pretending these scenarios are plausible. They're just you know, we're physicists here.
We're just sort of trying out to see what happens and then plummets at 8% per year and end up at a very low level by 2100.
Again, alternate scenario here, the green one where they start falling soon and go down is only 3% per year.
But crucially, the area, this green area is the same as that one.
That blue area is the same as that one. So all of these curves have the same integral does the same area under the curve.
Okay. So the same total amount of carbons released into the atmosphere.
And by the time you get on to the 22nd century, the climate response is identical.
Okay. And certainly, considering the uncertainty in the climate response,
there's no there's no perceivable there's no perceptible difference between emitting carbon early and emitting carbon later.
And there's more. It's the total amount of carbon. It's the carbon.
It's the total carbon. Sorry, missing word. That's the total carbon that matters.
And the other important point to make is there's plenty more where that came from in the sense that if we put past emissions here I'm sorry,
this is slipped slightly, that should come to about half a trillion tonnes if we include conventional oil and gas reserves.
That takes us up to a trillion tonnes. Oil, gas and coal.
And so you can read off from this figure basically what temperature you would expect to peak at from the total amount of carbon you put in.
So you release a trillion tons, you'd expect to peak around two degrees, which is what governments are aiming to try and keep the total figure to.
If you burn all conventional oil, gas and coal, you've got plenty of carbon down that to take you up towards the four degree mark.
And if you include all the shale gas reserves and so forth that people are now creatively uncovering,
there's plenty of carbon there to take us into well territory we wouldn't want to explore with the simple climate model,
at least possibly not with the real world either. So that's that's the situation we're in.
And so the sort of brutal reality we're facing is that, yes,
emissions over the next few decades will determine the risk of dangerous climate change because it's all building up in the system,
it's emission and it's CO2 emissions that are doing that. But frustratingly, for politicians who really want a statement from the scientists saying,
tell us what to do now, its emissions next year don't determine the risk of dangerous climate change.
And so this is again, this is the tension we face.
Is that the kind of statement politicians want scientists to be able to make, which is, you know,
you have to peak by this state, simply can't be made because it's not the way the system works.
You know, you could take.
Either of any of those three trajectories and end up with the same climate outcome, probably a very different economic outcome, but some.
So it's it's simply not true to stand up and say.
From the point of view of as a as an ecological imperative, emissions have to peak by a certain date.
Um, how can how can we, as climate scientists in this situation, how can we help us towards a sort of a lower regrets future?
And this brings me back to the point about these very abstract projections of climate over the next century,
following these idealised curves of emissions and temperature responses and so forth.
There are an awful long way away from anything any normal person cares about, if you like.
And one one question we need to ask ourselves is perhaps climate science could help more if we were to focus more on what people really care about,
what what most people get most exercised about. When they're talking to me about climate, then the long term projections for 2100 and beyond.
And those things are are not what's going to happen in 100 years time, but they're overwhelmingly what is happening now and why.
So here's one example. The 2010 heat wave in Russia estimated to have caused around 50,000 deaths and around 15 billion loss to the Russian economy.
The event in question was this massive heat wave where temperatures were up to 12
degrees above normal over an extended period of weeks in western central Russia.
And Moscow is clouded in data for weeks on end in this grey haze.
Another event which goes very much in the public mind, the 2010 Pakistan floods.
A really interesting question. Was it part of the same event?
We don't really know that the answer to that question yet, but it's an interesting one to consider.
This one caused fewer deaths, although and happening in the poorer country, probably fewer billions in terms of economic losses.
But as a fraction of the wealth of that country was equally serious and of course, was followed up with further floods in 2011.
And to get really serious, the 2003 floods of the I mean, the road, which may in fact, have had an impact on house prices, this.
All of these are weather events.
And to address this, the problem people the concerns people have about whether we have to understand how climate and weather are linked.
And so the crucial. Little rhyme to take away with you to remember how this link works.
Climate is what we expect. That's in the physicist or the statisticians sense of expectation.
So it's the the average you would get from many, many realisations of the system you're studying.
Weather is what we get and this particular realisation that we live in.
And then of course when we're studying how external factors affect climate and whether it's climate that we affect and weather is what gets us,
it's weather that actually does damage and affects people.
And in making the link between climate and weather,
we're perennially we're perpetually faced with the challenge illustrated beautifully by this cartoon,
which I'll just read to me, because you can't visit the banks and the guy on the left saying he's very hot today,
and the guy on the right says, yes, global warming. And the chances are, but it'll be cold next week.
That's due to the unpredictable weather patterns caused by global warming. And then he says, if it's hot, it's global warming.
If it's cold, it's proven global warming, too. And he says, yes, modern climatology is an easy science.
So this is the challenge we face is that people definitely have a feeling that absolutely
every weather event that happens around the world gets blamed on human influence,
on climate, well, gets blamed on climate change. And of course, that's not justified.
That's and the science that we're really interested in,
in building on and through this link between the School of Geography and the Department of Physics
here is actually making that link objective and robust so that we can say in quantitative,
quantitatively, how climate change is affecting people around the world.
I'll just take you through quickly, through the example of the Russian heat wave of the kind of analysis we do,
because it illustrates the sort of tools we use to address this kind of question whether when a weather event happens,
how can we say what the role of external drivers was in making that event either larger or more or less probable?
This is what happened in 2010.
We had what's called a blocking anti cyclone. You can see the flow around this high pressure system over western Russia and that's that
the arrows show the flow of wind around that and this high pressure in the centre there.
And the temperate surface temperatures rose to on average over the month of July, an average of six degrees above normal for that time of year.
That was the characteristics of the heat wave we were looking at. There've been a couple of papers published already this year on the 2010 heat wave,
interestingly reaching apparently diametrically opposite conclusions.
So there's a paper by a group of American authors which report concluded that the heat wave was mainly due to natural,
internal atmospheric variability.
And another paper by a couple of German authors, which appeared more recently and said with an approximate 80% probability,
the heat wave would not have occurred without climate warming.
These are both very heavily reported papers. What was interesting was there was almost no overlap in who reported which paper, as you might imagine,
but some that sort of as long as you have those kind of completely contradictory signing statements appearing,
you're left with a challenge as to what the winner where is the scientific community at on this?
We've been working on this. Friedrich, also in my group,
has been working in particular on this problem to try and to try and disentangle what these authors had really
found and see whether or not their conclusions were quite as contradictory as they first appear or indeed,
as the authors appear to have thought. This is what happened July.
Temperatures in western Russia and these are the observations they're bouncing around.
And this red curve here is following a suggestion of John Von Oldenburg and I came to in the Netherlands.
It's an empirical way of seeing how much you can explain the in a statistical sense,
explain what's happened to central Russia temperatures in terms of what's happened to large scale temperatures around the world.
And you can see that this sort of explained estimates,
explained components of the central Russian temperature involves a small warming about two degree or so.
But the anomaly that happened in 2010 was way bigger than that.
I guys,
we had this big excursion on the against the background of what you might on the basis of this empirical analysis think was a small warming trend.
If you just take this data alone, the Russian data alone, and then you just take the full century and fit a straight line to it, you.
Don't see a warming trend so.
So you it does the signal I should stress if all you do is look at the data the signal is relatively weak and and unconvincing.
What we've been and that's not particularly surprising if you're looking at a hundred
years of data and in an event which might only happen once every hundred years.
You're not going to see very many of them in order to be able to work out what's going on.
So what we've been doing as saw over the past year is as part of the sort of sequence of experiments we've been doing under the Climate Prediction
Dot Nets initiative is simulating the year 2010 and indeed all of the years since 1960 with our weather models just to see simulating many,
many times to see how in the models, the frequency of extreme events changes over time.
Okay.
So it's in a sense doing a little bit better than the real world because if we've got a model, we can actually run it many times as the real world.
We only got to run it once. So you can't. It's hard to tell if the statistics of extreme events are changing.
We're doing this using these. If you're trying to study changing statistics of rare events, you need to simulate the system so many times.
We certainly can't afford to run it on our own computers. And so with the support of Environment Guardian,
we're doing the only way we can do this experiment is actually by recruiting our members of the public to do these runs for us.
And we're obviously grateful to Guardian of supporting this.
I'd have to say Damian Carrington is here this evening and has been instrumental in helping get this experiment off the ground.
I should, of course,
stress that further back climate action on it also had a lot of support from the BBC when we were doing longer term climate prediction experiments.
These this is all laboratory. These are the people around the world who are doing these runs for us and
continue to provide a an extraordinary computing resource to climate science.
And if any of them are here in this room,
then I'm very much hoping that one of our heroic board moderators who keeps an eye on all the rest of the participants is here.
So if Mo is here, thank you very much indeed for all your work.
I nearly fell off the dice at that point. Okay.
So this is just some evidence of the models working, but in view of the time, I can I ask you to take my word for it.
And but some evidence, more interesting evidence of the models not working.
If we look here at the sorry, the models models, simulated temperatures and observed temperatures over the same period in time.
You'll notice we have many more models and observations because we are, of course, able to run the model many, many times.
And there's an obvious bias between them. Even though we haven't got that many observations, we can see the models too warm.
It's over. It's too too far to the left. I think that's typical for these kinds of models.
And we have to in this particular study, we can't do anything else but just correct that bias.
What we would rather do, of course, is use a better model which doesn't have that bias.
And we're hoping working with collaborators here and also ECOWAS, to move on from the relatively crude models we're using here,
to use the most sophisticated models available to redo this kind of analysis.
But at this point, all we can do is correct for these biases and see what happens and use our models to assess how the risk of an extreme heat wave,
such as happened in 2010 in Russia has changed over the years.
And what we find is quite an interesting it's quite an interesting conclusion because we can kind of say that both of these papers,
which appeared over this year, are, in a sense, right?
It just depends on how you frame the question of how much of that event was anthropogenic
or how much of it was externally driven versus how much was an internal fluctuation.
This plant shows the return time of monthly temperatures as simulated by the model after bias,
correction and so forth in the 1960s in green here and the 2000s in blue.
Okay. So these are preliminary results.
And, you know, there's still work to do to work out how uncertain we are in these curves.
But they do serve to illustrate an important point.
The heat wave was a big departure from average conditions whichever decade you were looking at.
Okay, so six degrees above normal of which.
So that's this big black arrow here, of which maybe only a degree was due to the background warming.
Okay, so on that way of thinking about the problem, the heat wave was indeed mostly natural.
Okay. So be careful. Now, watch.
I'm not. This is the conjuring trick. Okay. On the other hand, if we think in terms of the probability of the heat wave occurring.
This was the magnitude of the heat wave itself. This threshold here in the 1960s, it would have been a one in 100 year event.
But by the 2000s, it was down to a one in 30 year event.
So it had become three times more likely to occur in terms of its probability of occurring in 2000.
Most of the risk of it occurring at the time it did was due to the external trends.
So you got one event. If you think about it in terms of magnitude, it was mostly natural.
If you think about it in terms of probability, it was mostly driven by the external forcing.
Okay. Now, that's not a convenient conclusion for a reporter to take away, but it's just the way it is, I think.
I don't think anybody saw me attempting to explain this to Emily Maitland on NEWSNIGHT last week.
It did not go well, although actually in self-defence.
The dice, it was it was my fault, not the dice for the dice. She did a very good job.
It was the it was it was me fluffing my lines over what to say because the dice did actually roll six more often than she had done.
But okay. Never mind. But she thought that she'd roll six every time.
But that's that's the problem we always face. People think if it's global warming, we should get a heatwave every summer.
So anyway. Never mind. I guess that's a feature of NEWSNIGHT, isn't it?
You always realise what you should have said as soon as the microphone goes off. Anyway, so.
But there we are. So, so. So this. I've got a little bit more time to explain this to you here.
So that's that's the situation we're in, which is the question we're more interested in the magnitude.
How much is human influence increased the risk of a heat wave of a given magnitude?
So these are two ways of thinking about it.
There's a sense in which it was mainly natural in terms of magnitude or a sense in which it was mainly caused by the external trend.
If you think in terms of occurrence probability, I think it's not really a scientific question, which is the right way to think about it.
I'm afraid Sam is nodding at this point because I'm you know, I'm aware that, you know,
we scientists tend to tend to think that we know how to answer those kinds of questions, but we don't.
It depends who's using the information, which which question they will they will be most interested in.
We are able to do this using the weather at home approach, using these large ensemble simulations to large numbers of different events.
And it's important to stress that as we're looking at the impacts of large scale warming on events in different parts of the world.
Not all events are being made more likely you often will get.
It's often said climate change is making the weather more extreme.
I'm never quite sure what that means,
but it's certainly not true that every kind of extreme weather event is being made more likely by more likely by climate change.
Here's to the floods that occurred in North in 2000, which we reckon were made somewhat more likely as a result of past greenhouse gas emissions.
And this is an interesting result from Alison K in C H Wallingford, where she looked at a a flood.
That didn't happen in the spring of 2001.
Okay. So this sound doesn't slightly academic, doesn't it?
But it's an interesting question. We didn't have a flood in the spring of 2001, but we might have done.
And the risk of having one was substantially reduced by human influence on climate.
Because why in spring, the big floods that happen tend to result from accumulated snow melting fast.
That doesn't happen anymore because we don't get those sorts of accumulations of snow again.
So this kind of thought it was completely academic because this kind of part has happened in the past.
Back in 1947 and 1963 and those kinds of flood, the floods are becoming less likely.
So when you're making a statement about human influence on flood risk in the UK,
I'm always careful to sort of preface this with a sort of British Rail style.
It's got to be the right kind of flood. Okay, so this is why we've argued we need this sort of work.
Probabilistic event attribution. Most present day impacts of climate change are related to extreme weather,
and quantifying how risks are changing does allow us to better quantify and indeed insure against present day risk.
It allows us to build resilience and also to justify that adaptation funds are really
spent on adaptation to climate change and not just building resilience to bad weather.
There's been some criticism of this idea that I'm going to skip over that to the just in view of the time,
just to show where it gets it gets really interesting.
And this is sort of tends to be the point where juices get. In this debate.
And this is a quote not from a scientific paper, but from a paper in the Columbia Journal of Environmental Law by David Grossman in 2003.
And he pointed out that for lawyers, it is the contribution to risk way of thinking about the problem that matters,
not the magnitude and the threshold. For lawyers getting interested in the possibility of liability is an increase in risk of roughly a factor of two.
Now, of the events we've been talking about, the European heatwave in 2003 exceeds that threshold.
The UK floods of autumn 2000 probably don't.
So if you're thinking of suing an oil company for your house being devalued, you probably well, you probably don't want to talk to me.
You'll have to find another expert witness for that one. And we're still working on the 2010 heatwave.
What does this mean and where might all this go? I'm at present,
people have started raising the question of whether victims of climate change could secure compensation
as a matter of legal rights rather than simply because they're poor and they're entitled to some help.
And the main of the main obstacle in these cases, most of which have been filed in the states,
of course, is the political crisis, the political question.
The point is there is a political process going on. The courts are therefore reluctant to get involved in assigning liability.
But what if and this you know, what if that process in the next couple of weeks, for example,
were to collapse completely and we were to sort of emerge from Durban with sort of politicians
simply giving up and saying that they were just not going to they couldn't reach agreement.
As indeed, people have wondered if this might happen on a number of occasions through the process so far.
The total cost vary. Lots of, you know, where how far might liability extend?
What sort of numbers are we talking about?
If fossil fuel producers and this is why it's good to have David home from Shell on the panel to talk about this.
If fossil fuel prices were actually be to be held liable for the climatic consequences of the products they sell, how big might the bill become?
Well, it's interesting.
The estimates that are available suggest the bill, which is not that different from the size of carbon taxes people are talking about.
So it might not in the end, it could wash out in a very similar way to an imposed carbon tax.
But this is the kind of thing I would hope we will get talking about in the panel discussions.
I won't dwell on that. Are those those numbers here? I'm a puzzle, though.
Each time I just want to leave you with is that most environmentalists, I'm confident,
would object strongly to the idea of resigning ourselves to a future where fossil fuel producers and and those who benefit
from the use of fossil fuels simply pay their way and compensate people who are adversely affected by climate change.
And yet, so so although environmentalists would typically say this would be a bad outcome,
and yet ask yourself, which you think would have more impact on the share price of a major coal company?
And remember, coal companies have on their books far more carbon than we can possibly afford to dump in the atmosphere.
If we're actually going to meet the targets, the politicians say we're going to meet in avoiding dangerous climate change.
If an an if a deal was announced in Durban that we were actually going to set up a global cap and trade system,
would that actually affect the share price of a major co-producer?
My guess is it would not. The share price wouldn't even flicker because people know that the politicians will
never have the bottle to actually see it through and keep that carbon underground.
On the other hand, if Durban works to collapse completely and it to be announced that as of now,
anyone handling fossil fuels was fully liable for all the consequences that they have on the climate for the indefinite future,
that actually might make a bit more of an impact on share prices.
And that suggests we're revealing what we really believe about both the capability of the political process to deliver as it's going at the moment,
and the potential of private sector remedies to have more impact in the future.
The real the reason for this asymmetry is the point that under the second scenario,
it's those who benefit from the production and use of fossil fuels today that
bear the risk of climate change turning out to be worse than currently expected.
So as of next week, the world's attention on this issue will be focussed on Durban and gathering of scientists
and politicians to discuss how they're going to negotiate their way out of climate change.
What many fewer people will know is that another event happens on Monday, which is all the testimony begins in the case of Kivalina versus ExxonMobil.
Kivalina being an Arctic village that is suing Exxon Mobil for the products Exxon Mobil sells,
causing global warming and resulting in the village essentially sliding into the sea.
I have no idea what the outcome of Kivalina versus Exxon Mobil will be,
but I suggest to you that the Ninth Circuit Court in California is where our attention
should be focussed next week and not the intergovernmental negotiations in Durban.
Thank you.