Fredi Otto

Friederike Otto, known to most people as Fredi, is a British scientist renowned for studying the effects of climate change on the weather. From her base at Imperial College London, she leads World Weather Attribution—a resource that can prove, within a matter of days, whether a storm, flood, heat wave or drought was caused by the climate crisis. Not so long ago, people used the malignancy of nature or the whims of gods to explain why the weather careened between dangerous extremes. We now know these extremes are often caused by climate change—but until Otto’s research, it took scientists months or even years to gather the evidence that would definitively prove the link.

When I meet Otto at a café close to her home, not far from the banks of the River Thames, the sky is finally calm. In the preceding days, Storm Eunice had dragged the roofs from buildings and toppled trees across Britain. Otto tells me in her characteristically frank manner that, contrary to popular perception, the storm was not caused by climate change. “If you measured the wind speed of the recent storm, there was no evidence that climate change [made it] worse,” she says. Otto is frustrated by the tendency to blame every extreme weather event on our planetary crisis, in part because it leads to world-weary apocalypticism that obscures the capacity those in wealthy countries have to change course. 

In her book, Angry Weather, Otto describes what she calls a “new way of doing climate science”: one that is not confined to specialist journals or reports, but instead equips activists and policymakers with the evidence needed to dispel myths and pin responsibility on those who have “profited most from not acting on climate change earlier.” Angry Weather is propelled by a stark cadence and urgent conviction that humans aren’t condemned to forever suffer the effects of volatile weather, our homes repeatedly flooded as the seas rise. Instead, Otto believes that adapting to this uncanny new climate is an entirely possible—albeit political—choice. The feeling you get when you listen to her speak is not a sense of quickening dread about our shifting, malevolent weather, but optimism about the possibility of tangible action. 

Hettie O’Brien: On a basic level, how does climate change affect the weather?

Friederike Otto: There are essentially two ways. One is the warming effect. Because you have global greenhouse gases in the atmosphere, it gets warmer. A warmer atmosphere can also hold more water vapor, which needs to escape as rain. So across the world, we see more heavy rainfall. But then there is a second effect, which I call the “dynamic effect.” Because we have changed the composition of the atmosphere, this affects atmospheric circulation. So that means that how weather systems develop, how they move and where they move works together with the warming effect. If you have fewer low-pressure systems bringing rain in the winter in an area like southern Africa, for example, which is really dependent on getting rain in the winter, it increases the risk of several-year droughts quite dramatically. These things may sound mundane, but they can have extreme consequences.

HO: You’re known for pioneering “attribution research.” Can you explain what that means?

FO: Every time there is an extreme weather event, journalists and policymakers immediately ask: What’s the role of climate change? With World Weather Attribution, we try to provide the scientific evidence as soon as possible—ideally within days, while the public discourse is still happening. Before this project, it was only people with political opinions or incentives who would give their opinions about a weather event being linked to climate change. So we thought, we really need to change this.

HO: I can see huge political implications for the research you’re doing. It could, for example, be used as evidence for the harm particular industries have had on the atmosphere.

FO: That’s not an accident. It’s definitely been part of the thinking behind doing this. We wanted to really put the causes and facts together to build a causal chain between individual emitters of greenhouse gases—which can be countries or companies—to global temperatures and actual concrete damages. Of course, it’s important to understand how much climate change affects the weather in order to build resilience and adapt to climate change. But this research is also important for questions of responsibility, and ultimately of retribution and compensation.

“The questions
scientists ask are
never apolitical.”

HO: Do you think scientists have a responsibility to make their political views clear and to persuade others of them?

FO: We always have this idea that science is neutral or objective. But that’s never been true. Science is testable hypotheses and transparent assumptions. That’s how science produces facts—by having an idea, testing it over and over again, and at some point it becomes a fact. But the questions scientists ask are never apolitical. Because science is the people who do science, and those people ask questions that are of interest to them and are shaped by their values. So I think it’s quite dangerous to believe that science is neutral. For me, it’s important that the science I’m doing is actually of practical relevance to the questions we have in society.

HO: How are you able to attribute a specific weather event to climate change so quickly? 

FO: It took us nine days to prove that the Canadian heat wave last summer was linked to climate change. We first look at the observational data to find out what aspects of the weather have led to the impact of the extreme event—what we call the “event definition.” For a heat wave, it might be that hospital admissions drastically increased after three days of heat, so we’d take those three days and use this period to define the extreme event. And then we would ask: What kind of event is this in the world we live in today? Is it a one-in-100-year event, or a one-in-10-year event? To answer this, we’d look at observational data and statistical climate models. Then we would ask what kind of event this would be in a world without climate change—removing the greenhouse gases and aerosols that we know have been put in the atmosphere since the industrial revolution. The volume of greenhouse gases that have been emitted since the industrial revolution is very well documented and measured, as we have reports of how much coal and oil and gas have been dug out and burned. 

“Yes, climate change is a
really big problem. But we
have a lot of agency to
deal with it.”

HO: There must be parts of the world where observational data isn’t so freely available.

FO: Oh yes. We have a very good picture [of data] when it comes to countries like the UK. I’m just starting a new project with colleagues in the Kenyan Met Office to find out about heat waves. When you look at the official records, no heat wave in Kenya has ever happened. But that is not the case. And many countries sell their weather data to the highest bidder, rather than making it publicly available. 

HO: Are some weather events particularly indicative of the effects of climate change?

FO: For heat waves, climate change is an absolute game-changer. Heat waves have become several orders of magnitude more likely: not just twice as likely, but hundreds of thousands of times more likely. Heat waves are where we see the fingerprint of climate change most strongly. They are also by far the deadliest extreme events in Europe. But of course what turns a weather event into a disaster depends on the vulnerability of the society. So if you have a highly vulnerable population that is only adapted to a small range of possible weather conditions, and you change that even slightly, this can lead to catastrophe. Even if the climate change effect is not big in absolute terms, it can be really dramatic because of peoples’ vulnerability. 

HO: It seems there is a perception problem when it comes to thinking about the effects of climate change on the weather. We’ve always had extreme weather events and it’s really tricky to disentangle what has always been the case from what is new, alarming and scary.

FO: That’s why we do this work: to disentangle these drivers of disaster. Because you can’t feel it. You have to actually look at the data. Events that might have been really damaging in the past might not be so damaging now because populations have adapted. But this is also true the other way round. If we have lots and lots of people who have built houses on floodplains or are living in informal settlements, weather events that have happened before are suddenly a lot more damaging now because of our increased vulnerability or exposure to them. That has nothing to do with climate change.

HO: There is a disorienting sense of scale in thinking about all this. We talk about abstract, one-degree rises in average global temperatures, alongside sudden bursts of catastrophe, such as the floods in Germany last year. 

FO: Yes. It’s also very difficult to communicate this. Climate change played a role in the floods in Germany, for example, but even without climate change these floods would have been an absolute disaster. A lot of the damage was due to people living on floodplains, and the geography of the area features lots of small rivers that flooded easily and quickly. And there was little information about how to evacuate. There are lots of layers in how we portray the effects of climate change on the weather. On the one hand, you want to communicate that climate change is already costing lives. But of course, climate change is also not behind everything bad that is happening.