Panel one - Q&A - part 1

Facilitator: And if I'm gonna ask, give you questions in groups? But if you need me to repeat questions at any point, just say. So first question's for you then, are about ice. So there's been a reduction in size of Arctic ice, and it seems very drastic over the last 15 years, more so than before. Was there any specific reasons for that? Either man-made or naturally? I'm with the after ice having melted, how so drastically? How can we recover even if we reduce our emissions now? Start with those two. Yes.

Ed Hawkins: Thank you for the questions. Very interesting questions.

May I start with the 1st one. As I said in my talk we've seen the Arctic Sea ice declined by about 40% in ice cover. There're lots of variations from year to year, which are caused by the weather. So if the weather is particularly bad for the ice one year, you'll get a particularly low extent that year. And, if the weather is slightly colder that year, you'll get slightly more. But we're seeing this long term trend downwards. Most of that trend is due to the warming of our planet so that there may be a small contribution from very long time to go variations in the ocean. But most of it is due to the fact that we're warming the world. And as the world continues to warm up, the amount of ice in the summer season will continue to decline until there's very little left in the summertime. If we get about two and 1/2 degrees above where we were the pre-industrial times, then there'll be very little there in the summer and as we go higher and higher will then get very little in other months, expanding outwards from the summer to the autumn and to the spring. Unless we bring temperatures down, thie ice will not come back.

Facilitator: Great. So a final question on ice and one other. So, someone says, I think the waxing and waning of the icing in the Arctic has happened before and I believe scientists have proven this. I do feel the water is rising and the ice melting faster. What's your opinion on what I've said? On the other question, is seawater becoming more acidic slowly down to humans? And if so, how?

Ed Hawkins: So, as Joe described in her talk, we have information about how the climate's changed a long time in the past. And yes, we have seen other times in the deep past where there was almost zero ice on the planet. You know, there was no ice in Greenland and no ice in Antarctica and sea levels were about 100 metres higher than they are today. So we know there are natural factors which affect the climate as Joe described. We see changes in the Earth's orbit, which is the main one. But what we're seeing now the changes are very rapid compared to the changes that have occurred in the past and we know -- we understand the basic physics and chemistry behind those changes. And yes, the ice has varied in the past, but it's much slower than it has been at the moment.

Seawater acidic, yes. So the reason that seawater is becoming more acidic is because there is more carbon dioxide in the atmosphere. And so more carbon dioxide has been absorbed by the ocean in the surface waters and as it does that it becomes a very weak carbonic acid. And so, yes, the ocean acidification is entirely due to our emissions of carbon dioxide. That's humans. Yes.

Facilitator: So people would like to understand, relatively, how much does it cost to tackle climate change versus how much does it cost if we don't? Essentially due to economy, infrastructure failures, wildfires, and other catastrophes? It says here to the relative costs. Do that one first?

Ed Hawkins: I'm not sure, that's the question, actually, I know much about. Yeah, that the costs are something important for the other panel. Actually...

Facilitator: We'll stick it on the chair and we'll ask Chris Stark. And what fact factors do climate deniers disagree with?

Ed Hawkins: There's a long list. I guess the one -- the question I get most in my engagement is about understanding the causes of the recent trends. And of course, climate has changed before, and so that is used as a way of saying, "Well, it can't be humans this time, because climate's changed in the past". And, of course, we study, climate scientists have studied all these other reasons, like the volcanoes, the variations in the sun, variations in the earth's orbit. But this time is different because we understand the physics of how increasing greenhouse gas levels in the atmosphere warm the planet. It's happened far faster now than in the past. So yeah, I guess that's the question I get asked most.

Facilitator: Is there a risk of a runaway greenhouse effect?

Ed Hawkins: No.

Facilitator: When I said pithy that's what I had in mind. So a few questions here they're similar. So if sea levels continue to increase this way, when will the Earth be flooded? Is the most recent UK flooding due to climate change or human involvement? So, for example, is it just cause we've built on traditional flood plains? And is the UK more at risk than countries such as the US and Russia from flooding? Because we're a small island.

Ed Hawkins: it's-- on sea-level rise first of all. We know that there is roughly 100 or 120 metres worth of sea-level rise locked up in the ice caps at the moment. That's Greenland and Antarctica is about seven metres on Greenland, seven metres on the west Antarctic Peninsula and the rest on the Antarctic ice cap. So that there have been times in the very distant past where all of that has melted and we can see that sea levels were 100 metres or so higher. That takes a very, very, very long time to happen. So we are seeing sea levels rise. We, if temperatures continue to rise globally, then that-- we suspect to see up to a metre of sea-level rise over the next century. And the important thing to know about sea-level rise is that it's very, very hard to stop it. Even if we stabilise temperatures, global temperatures, sea level will continue to rise for centuries and this is because we're committed to losing part of Greenland because of the rising temperatures and also because the warming in the oceans take time to propagate down to depths, reckon warmer depths and warm-- and therefore raise sea-levels. So sea-levels is-- will continue to rise for centuries even after we stabilise global temperatures. But it will occur at a slower rate, but it's still be up to a meter over the next century or so, so low lying areas will face increased risk of flooding in the UK.

There are already talking about whether we do have to abandon certain villages on the coast because of increased risk of flooding. We'll potentially need to build a new Thames barrier to protect London, for example, cost of a large amount. So, obviously, for countries like Bangladesh or Holland, those risks are even greater, probably. So, flooding of people's houses. There are numerous factors involved with that. And of course, if we're building on floodplains, that puts those living on the flood plains at risk of flooding. We are seeing increased frequency of heavy rainfall in the UK, so that increases the risk. But you can't just you can't talk about climate change alone. There are a whole load of factors, but how we use the land in the mountain regions as well as on the lowlands, about where the water ends up. And the reason for flooding are very, very complex we're affecting the chance of heavy rainfall and so, therefore, affecting the chances of flooding.

So, yeah, the UK, we live in a part of the world where we get a lot of storms in the wintertime. You know, we've had a lot of storms this winter so far, for example, that will continue to happen, will continue to get storms, and so we'll continue to face risk flooding. Other areas where they have less storms have left fewer risks. Places which get typhoons and hurricanes, for example, will still face those threats, and they will also, like in the UK storms, dropping more rain. That will also happen with hurricanes and typhoons. And so in those parts of the world America, Philippines, Thailand, those types of area which get hit by those storms will face greater risk of flooding from increased rainfall from the storms. But also the fact that sea level is higher and so inundation from the winds and the storms are associated with those extreme weather events will also be greater.

Facilitator: Great. Can oil and gas to be replaced by renewables to solve climate problems? And is it affordable?

Ed Hawkins: I'll pass that on to the other panel.

Facilitator: Is there also evidence of increased, accelerated, increasing the size of desserts with recent climate changes. You can pass that to Joanna.

Ed Hawkins: Yeah, I don't know the answer to that one, do you know the answer to that one?

Joanna Haigh: I don't know precisely the answer to that one. But I think that the -- in sub-Saharan Africa that the dry regions are spreading, so that means there's less vegetation. So I guess that means desertification.

Facilitator: Thank you. Is there any evidence that climate change has caused migration?

Ed Hawkins: That's a very, very difficult question. I think I tried to highlight through my talk, which had to be very brief. There are numerous risks and reasons for migration and these other risks. Climate change could potentially be a factor in those decisions. So, for example, if there is widespread crop failures for heatwave, for example, like we had in Russia in 2012, that caused a spike in crop prices and therefore, bread became more expensive in many regions and that, I believe, started some protests in some countries. So that may be one reason.

There may be other reasons, such as farmers struggling to survive. And if there is a change in the climate, they may not be able to get to grow the crops that they used to growing and that may influence decisions. But there are so many other reasons why people might move and migrate. That -- climate change is an added factor, but there are so many other factors involved as well.

Facilitator: Has there been any research regarding the sun getting warmer naturally?

Ed Hawkins: So the sun does have a regular cycle, it postulates that goes up and down in brightness slightly every 11 years. We don't see a strong effect of that on our global climate. Over the last 150 years, we have pretty good measurements of the sun's brightness, fire, recording sunspots. And in the early part of the 20th century, the sun did get a little bit brighter. But over the last 40 years, overall, the sun has been getting dimmer while temperatures have been rising at the same time so we can very confidently rule out the sun as a contributor to the recent warming of our planet.

Facilitator: And your last question was the last question. The other question here is actually for me, and I'll do that when the speakers swap rooms. So I'm going slightly change this question with your permission, because I know the answer to this question, which is, does Ed have a graph with him of the population of Oxford for the same period as the temperature was warming?

So I know you don't have a graph of that with you, so I changed that question. So is the increase in temperature that you showed on your graph due to an increase in the population of Oxford during the same period?

Ed Hawkins: That's a very good question. So the -- my colleague who has produced that record for Oxford, says that roughly 0.1 degree of the rise in Oxford, so Oxford was increased by about 1.6 degrees Celsius warmer, 0.1 or maybe 0.2 of that is due to the urban heat island effect due to increased population. But the rest is due to the fact that the planet is warming.

Facilitator: Thank you very much. If you could pass the mic to Jo. Jo, we have an even more questions for you. So pithy..

Joanna Haigh: I can take some of them.

Facilitator: Yes. How do you measure the carbon dioxide levels?

Joanna Haigh: How do you CO2 in the atmosphere? Well, there's various sort of chemical techniques. You can put up samplers and sampling in the atmosphere from a balloon or something light, or you can capture amounts of air and bring it down to the surface and analyse it in the laboratory.

Facilitator: Great. Thank you. That was lovely and pithy. And so, if you-- a couple of questions together here similar enough/ So what will happen if we go over 1.5 degrees? Also, what will happen if we don't reach net-zero emissions by 2050?

Joanna Haigh: So the 1.5 degrees has come out of the United Nations Framework Convention on Climate Change meetings. They started off by thinking that two degrees was enough and they were trying to stick to two degrees. But at the Paris agreement, the countries that were in particularly the low lying states in the Indian Ocean said, "No, we want it to be one and 1/2 degrees because we can see that above one and 1/2 degrees, we're going to be flooded. So that was adopted as a preferable, if possible, sort of target. Subsequently, there's been quite a lot of studies on the difference between one and 1/2 and two degrees, and I -- actually are more than you might think, given it seems to be quite small amount.

So particularly, for example, if you look in the Mediterranean region, which is going to be one of the regions, its most hit by lack of rainfall, is quite a significant difference between one and 1/2 and two degrees in the drying out of the Mediterranean region. If you go over two degrees, it's not a question of on and off, it's just a question of things getting worse and worse. So I mean, I can't precisely what say what will happen in the Mediterranean, but I guess it will just get drier in the countryside and if to get wetter it will get wetter. So it's just more extreme.

Facilitator: And if we don't reach net-zero by 2050?

Joanna Haigh: So, the net-zero is that -- is what is shown to be the best thing that we can do to try and keep the temperatures below one and 1/2 degrees. If if we don't hit net-zero by 2050 then it'll make things warmer, or we'll have to suck more CO2 out of the atmosphere after 2050 to get the balance back.

Facilitator: And what would happen to the Earth if all the heat radiation was absorbed by the atmosphere?

Joanna Haigh: So at the moment, it's 90% and the rest is going out. If it was all absorbed, it wouldn't be possible to really have an equilibrium situation, or it would just be getting hotter and hotter and hotter. So I guess we end up with a very, very hot service. It's not gonna happen.

Facilitator: Okay. How can humans decrease CO2 emissions rather than just - hold on - how can humans decrease CO2 emissions rather than just stopping increases in C02 emissions?

Joanna Haigh: That's the sort of engineering question which I'm not very good at. There's various techniques for getting CO2 out of the atmosphere. One is artificial trees, which have sort of carbonates. chemical stuff in them that can absorb the CO2. Or you can just plant more trees, which, of course, is a very nice natural solution. But that means you might be challenged by the amount of land that you need to plant all these trees. And you know you're taking that land away from, for example, agriculture. That's not going to help. Can you think of any more? Decarbonisation?

Ed Hawkins: No, no.

Facilitator: Fine, okay. And sort of similarly, what needs to be done to reduce CO2? And how are we going to educate people to achieve this?

Joanna Haigh: So reduce CO2 in absolute terms and reduce the emissions. I mean, I think how to reduce the emissions is the question that we're putting to you actually. You'll be given all the different sort of options to discuss, and you're going to tell the UK government how to do it.

Facilitator: Great. So when are the USA and China going to bring their carbon emissions down?

Joanna Haigh: So this is a question we often get. I know. Why do we bother in the UK when we've got China and US, and other countries doing much more? So each of those countries, of course, is different. Every country has got its own issues, its own history, and its own way of doing things. So each of the country's needs to do its own thing. If we take China, of course, is a huge population and they've been growing their economies, and that's been a huge increase in their CO2 emissions, which have just started to flatten off. Now, of course, one good thing about a command economy rather than a democracy. If the government decides to do something, then it happens. And so the Chinese government has decided it's not going to build any more coal-fired power stations, and it's going to try and get things going down, partly because it can see the effect on public health. So if you look at the air quality in for example, Beijing, it's absolutely dire and that is largely due to fossil fuel. So I don't think the Chinese will be doing for sort of altruistic reasons, you know, to be part of the global club. But they say it's necessary and so they're acting, not fast enough, but they are acting. [Please note additional information at the start of this transcript]

I think, completely or not completely different but somewhat different situation is in India, where the standard of life, on average, across the population is very much lower. And so clearly the government wants the people to have a better quality of living, and why should they not? We enjoy it. And the question is how they can get from the poor standard of living to a better standard of living without burning all the fossil fuels, which is what we've done to get to where we are. And there is a huge development in India of renewable energy, particularly solar. Of course, you know, they've got a good place for doing solar energy. So interesting things, like small local networks of solar powered -- solar power stations. So instead of having a big power station that gets the electricity and distributed to across the people. You have just little networks with lots of solar power and joining together in villages and towns. And this stuff is just beginning to get developed. It's not -- it's certainly not solved yet and India's going to be a problem, but they are working in the right area.

USA, well, obviously, they got Trump and he has withdrawn from the International Climate Agreement, which is shocking. But let's put him to one side. Maybe he'll be out of a job soon, we never know. But what's happening in the US, is that many of the individual states and the individual cities have decided that they're going to go to net-zero by 2050 anyway. So, you know the federal government could just get lost and they're doing it. So in California and also some other states, they have decided to have a net zero target by 2050 and they're working on how to do it themselves. So I think that's a positive thing.

Facilitator: Okay, so we have lots more questions here about how you remove CO2 from the atmosphere and whether it's just about trees. I think we've had as much as we're gonna get from this panel on that, so what I'll do is carry over to the next panel having to see what they have to say about that. Jo, why 2050, not earlier?

Joanna Haigh: So what happens is that we run these big computer models. So the models are the same ones that are used to forecast the weather, and you can also use them to look into the future of the climate. And you can chuck a lot of CO2 into these models and see what happens, and you can take it out again and see what happens. And what we find is that if you want to get to net-zero by 2050 you have to peak CO2 fairly soon and then start declining it sharply to get through 2050.

What was the question again? So why not sooner? I think it's if you can peak sooner and you can cut faster, then that wouldn't do any harm. But it's just a question of whether it's possible.

Facilitator: Okay. And why did the global average temperature flattened off between circa 1930 and 1970 before increasing again?

Joanna Haigh: So this is an interesting question and you could see on that temperature graph. Of course, the temperatures wobbling around all the time, and it's influenced by all sorts of natural factors, as well as the greenhouse gases. I mentioned the volcanoes and the sun, but another very important aspect is the heat that's coming in and out of the oceans, and there are certain time scales on that. So when the temperature flattens off, it's sometimes because there's just that reason in that particular period is more energy has gone into the oceans, and then it subsequently come out again.

Also, during the middle of the century, there was -before that period- there was lots of industry putting lots of particles into the air, so the industrial particles was cooling it off and sort of rather strangely, well not strangely, but unfortunately, when there was clean air acts, and trying to clean the air up, took the particles out. And then, of course, that made the heating come back again.

Facilitator: Okay, so you talked about the fact that carbon is maintained in the atmosphere for 200 years. Does that mean that if we stop producing carbon emissions now, it will take a long time for us to notice any effect? And also is there anything we can do to speed up that process?

Joanna Haigh: Absolutely yes. I said 200 years, and that's the sort of average amount. In fact, you know, some of it will last a lot longer and some of it will last less long. But on average, it's going to last 200 years. And that does mean precisely that that even if we stopped emitting CO2 today, it takes a long time for the temperature to come back down because of CO2 stays there, and you've got to get it out of the atmosphere again to make the temperature come down faster.

Facilitator: So you're model panelists. We've got through all those questions with four minutes left. That means that I can take a couple of extra questions. So did any tables. Did you have questions that got a lot of votes but didn't quite make it into your top two for these speakers that you'd like to ask? Just hand up? Yes.

Table Speaker: So this is for Ed. So, because of the very specific temperature conditions needed to create tropical storm, will increases in temperature increase the surface area of the ocean where the storms can develop increasing the frequency of storms?

Ed Hawkins: So the frequency of tropic storms is a very hot topic in climate science. I'm not sure there is huge consensus yet about- just the number of storms. I suspect that if there was I'm-- my role here is to try and express the scientific broad scientific view. So my understanding is that we may well get more of the intense storms because there's more energy in the atmosphere. We may get slightly fewer overall, but they on an average day, maybe more intense. I think that's the consensus of the community. Although there was a wide range of views on that.

Facilitator: Any other questions you would like to ask? One over here. Too slow, going over here and then I'll come back.

Table Speaker: This one was for Ed and you've got your list of risks.

Table Speaker: You've got disease and movement of disease across the world. And so my table was interested in how would diseases come into the UK due to climate change? And has it happened before?

Ed Hawkins: So again, diseases transmission is another one of these very complicated risks where climate probably plays a role, but it's not the by no means the only role. So, for example, I'm going to talk outside the UK, probably to start with. But malaria is one that's been much discussed in the scientific literature. That type of disease, as far as I understand, it thrives in certain temperature conditions. And as we warm the planet, the area in which those temperature conditions are right for the mosquitoes will grow. And so there is the potential risk, therefore of increased transmission of those types of diseases. So it's a very complex field. Um, whether any of you know, the recent diseases that come to the UK like ash dieback, for example, whether that's got nothing to do with climate, I don't know the answer to that. But scientists are concerned about the risk of increased transmission of diseases such as that.

Facilitator: Okay, and final question. I saw a hand up here, so I'm going here.

Table Speaker: For the countries with the highest CO2 emissions, do you know which one has the most emissions per person?

Ed Hawkins: Um, so I know that Australia is near the top of the list, as are countries like Saudi Arabia and then the USA. I think of -- are some of the ones, that there are some very small countries which have very high per capita ones. But those I think are the three bigger economies, which have the highest per capita emissions.

Facilitator: Okay, so we're now out of time. Could we say thank you very much to our panelists? If you'd like to get up, hand me back the mic. You're gonna disappear to the other room and Becky and Chris will be in here shortly.