Government Office For Science
Good evening. Thanks very much, great to be here.
What a fantastic week with Generation Hope. I know its been really lively, really exciting, and of course really important.
I wanted to start by reminding us, if we need reminding, that the world has just lived through a pandemic. That pandemic affected every country, affected populations around the world, and science was absolutely essential in terms of trying to understand how to deal with that.
If governments thought that was a big challenge, which it was, then when we think about climate, it is a challenge that is going to go on for many, many years. And its an enormous challenge for every single government around the world.
Just as in the pandemic, science is going to be crucial to combatting the problem that we face.
Greta Thunberg says listen to the scientists. I want to spend a bit of time in this talk just thinking about what that actually means in practice. What is it that scientists need to say to government in order to get governments to act? Because the way this climate crisis that were living in is going to be sorted out is through action from everybody but it has to be action from government. Governments must do something.
When I think about giving science advice to governments and Im going to be deliberately not very campaigny. What are the things science advisers need to say, need to think about, when theyre giving advice to government?
I think there are four things that they need to think about.
The first is: is the evidence base, is the science, adequate. If it is not adequate, what are you going to do about it? Thats question number one.
Question number two then becomes: has that science base, has the evidence base, actually been understood by politicians? Thats a difference. I can tell somebody something, and say Ive done my job, but that isnt my job done. It isnt the job of people trying to get governments to change just to tell them something. Its really important that you then assure that theyve understood it. And not only if theyve understood it, but they understand where the uncertainties are and where the gaps are.
The third thing is: has that science advice been given in a form thats actually relevant to policymaking? Because governments have to make policy. They have to make policies that then impact the way businesses behave, the way we do things, the way things get done, in terms of implementing technologies or whatever it might be. So has that science advice actually been given in a form thats usable by a policymaker.
The fourth is: if youve done all that, and somebodys made a policy, how can you use the science to track whether the policy is having the impact that you think it needs to have.
I want to cover that for climate.
So the first question: is the science base adequate?
Lets tackle first of all the question of is it adequate in terms of the nature of climate change being a real thing. Well, its pretty unarguable that the temperature has gone up.
This is the temperature from 1850 to 2021 and its gone up by 1.2 degrees centigrade. So yes, its warmer on average than it was all those years ago.
The second is: does that relate to carbon in the atmosphere? Does it relate to greenhouse gases? (Specifically Im going to concentrate on carbon dioxide). Here there is a really important graph that will be familiar to lots of you. This is the carbon dioxide content that goes back 800,000 years.
How do you know what the carbon dioxide content was 800,000 years ago? The answer is from ice cores. Taken in the Antarctic, where you can go down a very long way and you can find an ice core from 800,000 years ago. In fact, theyre going back now to 1.2 million years, because there were some quite important climatic changes that took place between 800,000 and 1.2 million [years ago]. But at the moment weve got it from 800,000 years. In that ice core, there are trapped air bubbles which you can then measure the carbon dioxide content in.
What you can see is that the carbon dioxide content has dotted around up and down over those 800,000 years. Homosapiens appear somewhere say up to 200,000 years ago. Then you get to the far right of this and today is right off the scale.
So [the concentration of CO2] has been pretty constant, going up and down, around 200 225, and now its up to over 400. And the reason its gone up like that is the industrial revolution.
Theres very little doubt that carbon dioxide has gone up, theres very little doubt that its happened very recently and theres very little doubt that its linked to human activity.
So temperatures gone up, carbon dioxides gone up. Are those two things related?
We know from physics that those two things are related. In other words if you have greenhouse gases, you will get warming. But you can also see it in terms of the modelled projections. You overlay those two things the temperature increase and the carbon dioxide increase, so the bar chart again is the temperature and the line is the carbon dioxide. There is a relationship between the two things.
So the evidence base, in terms of is this a real phenomenon, is it man-made, of course. Look at it. Its very clear that this is going on.
This impact on the climate is real in terms of the effects it has. You can look at it in terms of sea level we know that Kiribati for example, you can see the increase in sea levels has actually led several islands to be underwater. This isnt just a phenomenon in the pacific ocean, its happening elsewhere. Were seeing more extreme events as well as sea level rise. Those extreme events include wildfires.
Several years ago I asked the question should the UK be thinking about wildfires? The answer that came back was not really, we dont have that sort of problem in the UK. But we do. Were going to have wildfires. In Australia, where they have wildfires every year, there has been a linear increase in wildfires during the summer and spring months. Its gone up year-on-year, the number of wildfires and the extend of wildfires.
But if you look at the edge of those periods, when you normally didnt see wildfires, so going into Autumn and Winter, theres been an exponential increase, a massive year-on-year exponential increase in wildfires.
So were seeing more extreme weather events, and that is linked to the warming that Ive just discussed.
The science base must be adequate to know theres a problem. There has to be a recognition its real. And theres evidence also that you might be able to do something about it.
We know at an individual country level, you can see reduction in the emissions of carbon dioxide, and the UK certainly has reduction in the emissions of carbon dioxide. But here is an observation from what happened in a rather enforced way during the pandemic.
Human activity and travel slowed down. What you can see is theres an annual increase in CO2 emissions and then right at the end, you can see the covid pandemic and theres a decrease. And that decrease is because of reduced human activity during the period. So this is a reversable phenomenon. You dont want to reverse it by having everybody stay at home and not doing anything, but it is a reversable phenomenon.
So what are we seeing? Temperatures up. CO2s up. Theres a relationship between the two. There are consequences in terms of sea level, in terms of extreme weather events, and that this is a reversable phenomenon.
Where do the uncertainties lie? Where are the things that actually youd still like more science to be able to inform future decision making and future planning?
Well, we know that there are potential tipping points. Things that become really potentially irreversible if we go beyond where they are now.
This picture which came from a paper published last year was asking the question what happens if we go up to 2 degrees warming, 2 to 4, and above 4? And it looks at a load of tipping points around the world. So the west Antarctic ice sheet collapse can occur before 2 degrees rise. A really big ice sheet, an east Anta