Understanding predictions of risk better

The real challenge with communicating climate predictions is how far away it feels. To many people, especially in richer countries where they are not feeling severe impacts of extreme weather at the moment, it feels very distant in the future. It feels very distant on our planet. Extreme weather seems like something that affects less developed countries, or people generations from now. And it’s hard to communicate what the risks of climate change will look like when many of them seem to be subtle shifts and a lifetime away.

One of the things that has helped me to understand predictions of risk better, and the tangible sense of risk, is that a couple of years ago, I was diagnosed with bowel cancer. I was lucky that it hadn’t fully spread around my body, but it was still advanced enough that there was a significant chance that even after chemotherapy, it could come back. Not only that, but the chemotherapy was damaging my body in sometimes permanent ways, like causing neuropathy to my fingers. It brought to light how it feels to be at risk, how it feels to live with uncertainty, how it feels to have two different possible futures – of the cancer returning or not returning – and also, how it feels to have a treatment for that cancer with negative consequences as well, which have to be balanced with the positive impact that they have.

Why we must plan for multiple futures

So, for me, that encapsulated the challenge of climate change, which is not so immediate. It doesn’t feel so personal, especially if we are living in better developed countries where we can protect ourselves with air conditioning and sea defences and strong, resilient infrastructure and strong healthcare services and so on – we’re not going to suffer the impacts of extreme weather or changes in coastal flooding as quickly or severely. It’s a useful position to put yourself in, to have that very uncertain future, because you can understand the way that you have to plan for two different futures.

We don’t know what future greenhouse gas emissions will be. We don’t know how quickly we will limit them. And therefore, there are effectively two different scenarios, or several different scenarios, of a rapid decrease in greenhouse gas emissions to try and meet the Paris Agreement targets or a slow decrease in greenhouse gas emissions, where we see some of the serious consequences of climate change. At the moment, we have to plan for both futures. We don’t know which it’s going to be. For me, at that time particularly, I had to plan for two futures of the cancer coming back or not. And it made very tangible that idea of sometimes having to make difficult changes to treat the problem.

Gaining perspective on benefits and drawbacks

People often think about the challenges of a low-carbon transition or limiting our greenhouse gas emissions because we think we don’t want to change our way of life. We don’t want to consume less. We don’t want to have upheaval and uncertainty and change. And we think we might lose out on our quality of life. We worry about the impact on the economy, but for me, because I had this trade-off of a negative consequence of neuropathy and my chemotherapy, I could see how it was to weigh up those different things. And obviously, the benefits of the treatment, of the longer lifespan, of the greater probability of not having the cancer return, was worth the temporary negative side effects of the chemotherapy.

Now, I still have some neuropathy, and luckily, it has faded a bit. I’ve been lucky that some of those consequences have decreased with time. But also, some of it is psychological. I’ve adapted to it. I don’t notice the sensations as much. And I’ve learned to perhaps avoid triggering the sensations, or I expect them, so they don’t worry me so much. Again, the parallel with climate change mitigation of emissions is clear: we might have some temporary challenges, things that we don’t know how to deal with, things that might feel like a loss or a change. That’s difficult, but we will adapt to that as humans. We do adapt. We always adapt. We’re resilient. We will have a new world that we construct.

An incredible opportunity to choose the future

Photo by Derick Hudson

Hopefully we’re aware enough and knowledgeable enough to mitigate and reduce our emissions in ways that also improves the quality of life for people around the world. Think of the Sustainable Development Goals of equality, regarding gender, race and poverty. We have this opportunity to design a world where we do limit the negative consequences of a low-carbon transition or improve the equality of opportunity around the world. So, it’s an incredible moment in time – we can choose the future.

And we have the information. We have the tools. We have many of the technologies – we have to work out which ones to scale up, how to make them efficient, how to make them cheap, how to rapidly move to new technologies in a short space of time. But we know from the pandemic how quick we are to adapt to new situations and how resilient we can be psychologically. And in terms of the way we live our lives, the changes that we’ll make for climate change will not be as rapid. They will not be occurring over days and weeks, like for the pandemic. They will be over months and years. So, there will be time to get used to the changes, to adapt, to find the advantages as well as the challenges. Having cancer and having chemotherapy made it really tangible for me how to weigh up uncertainty about the future, and also the challenges of addressing climate change.

The role of the Intergovernmental Panel on Climate Change

If there were three things I wanted people to know about the reports of the Intergovernmental Panel on Climate Change, the IPCC, the first is that they’re written by ordinary scientists – not a special different body of people – who are not paid. It’s voluntary. We spend our evenings and weekends doing this. I have weekly meetings at nine o’clock at night with my international collaborators. So, it’s not a paid job, and it’s written by ordinary scientists.

The second thing about the IPCC reports and the IPCC itself is it is intended to be policy-relevant, but not policy-prescriptive. We are summarising the evidence and assessing that evidence and how strong the evidence is for different predictions of climate change, but not making recommendations. There might be, for example, a prediction of how greenhouse gas emissions would need to decrease in the future in order to meet the Paris Agreement. But that’s not the same as a political statement that we should or shouldn’t try and meet the Paris Agreement. It just lays out the different possible paths that we can choose and what the consequences would be.

Extreme predictions and strength of evidence

The third thing that’s important to understand about the IPCC, which comes up when I talk to environmental activists and people who are particularly concerned about climate change, is that some people worry or express a concern that the IPCC is very conservative, that it favours predictions of small climate change and ignores the most dramatic predictions. And activists, understandably, will often focus on the worst-case predictions, partly because it’s what they’re concerned about, and partly because it helps to motivate change.

But just because the IPCC is not purely focusing on those predictions, it doesn’t mean it’s not doing its job. The IPCC’s job is to assess the strength of the evidence. And what that means is if you have a very bad prediction or a very good prediction, if they’re outliers, it’s quite possible that there’s less evidence for those predictions. Perhaps just one or two studies or one particular method has come up with that prediction, and in the central range, where there’s most evidence, there are lots of studies, lots of different methods, lots of different scientists, lots of replication over the years. Those are the most likely predictions. And those are the ones that it’s the IPCC’s job to weigh up.

How different viewpoints can still be valid

So, we present to policymakers the predictions of climate change that have the strongest evidence to support them and that we are most confident about. And we still mention the extremes and the outliers and the worst case and the best case. But those typically have less evidence to support them. It’s not clear how likely they would be. They might be low-probability predictions. It’s really important to think about the difference between those two roles.

Photo by Nancy Beijersbergen

For the activist who wants to worry about the worst case, it’s a precautionary principle. It’s saying, well, we haven’t ruled this out. We don’t know that this couldn’t happen. So therefore, we want to act to prevent it from happening. And that’s a perfectly valid viewpoint, versus the IPCC, whose job is to say this is the most likely future, and this is the strongest evidence for the future, where most studies agree. And those two things don’t conflict if you understand where they’re coming from. But that’s sometimes the reason why we get different predictions being mentioned by different groups. Some are focusing on the worst case and some are focusing on the most likely, and they have different aims and different places in decision-making in our future. So, those are both valid but different viewpoints.

How will policymakers respond to scientific evidence?

It’s impossible to predict how policymakers will respond to scientific evidence to some extent. Of course, it changes with time; it changes by country; it changes with political will. Environmental activism has influenced politicians, as well as scientific evidence itself. A lot of it is about reaching a particular tipping point, a certain momentum, certain acknowledgement that the science is very clear on the human causes of climate change and the broad-brush picture of what future climate change will be under high or low greenhouse gas emissions. And there’s broader public acknowledgement and concern about those changes and an acceptance that the way we live our lives is changing, and we’ll have to change to avoid the worst consequences of climate change.

It’s very difficult to predict the response of individual politicians. Politicians don’t always act in accordance with their values. Anecdotally, I hear of politicians concerned about climate change but not putting policies into practice because they can’t see how to do it, because they find it challenging, because they feel there might not be local public support. It’s not easy to summarise, but I’m very heartened to see that, in general, in most parts of the world, we are seeing that momentum now to act on climate change.

Why it’s time to do everything to address climate change

But, of course, that’s only the beginning of the story, because how you act is challenging. There are always pros and cons to every method. I rarely advocate particular policy options or technologies. I talk about the pros and cons of each. But the main thing I do say, which is quite a palatable message for politicians as well, is that to some extent we can’t choose one method over another, one policy over another – we have to do everything. We’ve left it too late to pick and choose between one kind of energy source and another, or one technology and another. We have to do everything. We have to throw everything in the kitchen sink at it.

In a way, that shows there’s a path for everything, whether it’s for people who favour renewable energy or nuclear, or reducing consumption, or carbon dioxide removal techniques from the atmosphere. And all of these have their challenges. There are many others that I haven’t mentioned, of course. But it shows that people can to some degree focus on and specialise in the areas where they think they can most make a difference, that they think are most promising if there are more investments and advances in technology. People no longer have to fight about choosing this approach, or that. We have to do everything.

We all need to tackle climate change

The most important thing about tackling future climate change is that not only can we not choose one method over another, but we can’t choose one nation over another. We can’t say one group of people has to act and the others don’t have to, because it has to be systemic. The people who are emitting a lot of greenhouse gases now have to change. For the people who are not emitting many greenhouse gases now, we need to help them to progress and develop in their societies in a way that’s going to maintain lower greenhouse gas emissions. So, there are different changes involved in that, but it’s still all part of the same picture. And if we don’t all do that as humanity, then we won’t have and maintain the changes that we need.

The idea that “my actions won’t have consequences” — that they’ll be negligible, or the UK’s actions will be negligible compared with China, for example — is a false logic. The only reason China has more emissions than other countries is that there are more people. If you look at the emissions per person, they are lower than many other countries. So we often see unhelpful comparisons like this used as an excuse, when people don’t want to act.. So, we’re often using subdivisions and chunking it up in different ways as an excuse if we don’t want to act. Or sometimes, conversely, this induces a certain despair or helplessness, too: people want to act, but they feel that their actions aren’t causing change.

The mechanisms of future change

Photo by Frederick Hornung

But there are those two ways of looking at that. One is that we have reached the stage where the scale of the transformation in our society has to be widespread and systemic – and absolutely everyone on the planet will be affected. But also, more prosaically, the individual actions of consumers, of votes, in aggregate, do persuade the big businesses, the finance industry, the governments. When they see lots and lots of small citizen actions indicating that they want to support action on climate change, then the bigger levers of business and governments and finance will act.

Something that I have become quite interested in and quite optimistic about is the role of law in acting on climate change, thinking about what the risks are to different companies of climate change and of a low-carbon transition. And, potentially, what are the risks of being sued by shareholders or by the public in the future for not acting in a way that either conserves their financial assets or conserves the planetary health and resources? Sometimes the mechanisms for change in the future aren’t where we expect. We might not think of lawyers as the people who are going to save the planet, but maybe they will be. But it’s very much a collective effort because the transformation has to be so thorough and systemic that no one can sit it out.

Discover more about

The future of climate change

Golledge, N. R., Keller, E. D., Gomez, N., et al. (2019). Global environmental consequences of twenty-first-century ice-sheet melt. Nature, 566, 65–72.

Siegert, M., Atkinson, A., Banwell, A., et al. (2019). The Antarctic Peninsula Under a 1.5°C Global Warming Scenario. Front. Environ. Sci., 7(102).

Edwards, T. M. (Guest), Heap, T. (Host). (2020, April 15). Covid-19: the environmental impact [Audio podcast]. In Costing the Earth. BBC Radio 4.

Being a climate scientist