How science could help sue big polluters — BBC News

[0:00] Tremendous devastation caused by Hurricane Melissa. [0:05] Terrifying the worst day of my entire life. [0:08] Once a village, now an island. [0:11] There's no food. [0:17] The most destructive wildfires ever to hit Los Angeles. [0:22] This was a beautiful home. I had a lot of good times here. [0:26] These are just a few of the major extreme weather events [0:31] that have hit the headlines in recent years. [0:33] And the evidence is stronger than ever that many of these kinds of disasters [0:37] were directly influenced by climate change. [0:40] And that's thanks to a branch of climate science called Attribution Studies. [0:44] See that? It was really hot here this year. [0:50] World Weather Attribution, or WWA, is a global organization [0:57] that studies individual extreme weather events. [1:00] What we are doing is basically answering the question, [1:04] whether and to what extent has human-induced climate change [1:08] made an extreme event more likely or less likely [1:11] or more intense or less intense. [1:13] Extreme weather events are selected for study based on their impact. [1:18] For example, a high death toll or significant damage to infrastructure. [1:22] I wondered if you could walk me through the process [1:26] of how do you do an attribution study? [1:28] The first step is to find out what has actually happened. [1:32] And that sounds trivial, but it's sometimes actually quite difficult. [1:36] Ideally, we would look at weather station data. [1:40] In many countries, there are only a few weather stations, [1:43] and that is a big limitation. [1:46] Satellite data is also used to establish where the weather hit [1:50] and how intense it was. [1:52] And then we would, in the next step, find out what kind of event is that [1:57] in the world we live in today. [1:59] This is done using climate models, simulations run by huge supercomputers. [2:04] They estimate how variables like temperature and rainfall behave [2:09] in the world's climate system. [2:11] Attribution studies use different climate models [2:14] to compare how extreme weather events might turn out [2:17] in different global warming scenarios. [2:20] Temperatures are now 1.3 degrees warmer than they were [2:24] before we started burning fossil fuels. [2:27] Is the event we have just observed in the warmer world, [2:32] is the one and two year event, is the one and ten year event? [2:36] We compare that with the same event if it had occurred [2:42] in a world without climate change. [2:44] Is it still a one and ten year event, [2:48] in which case climate change wouldn't have any influence, [2:51] or would it have been a one and a hundred year event, [2:54] in which case then we could say, because of climate change, [2:57] this event has been made ten times more likely. [3:00] Hurricane Melissa was one of the most powerful storms [3:06] in modern history. [3:08] It caused at least 95 deaths across the Caribbean, [3:11] making it a strong candidate for an attribution study. [3:14] Tropical cyclones in general are more complex types [3:20] of extreme events to study. [3:22] The climate models, they are relatively good [3:25] in simulating rainfall. [3:27] They are very bad at simulating wind. [3:31] Tropical cyclones are also relatively rare, [3:35] so there's not much data to use in studies. [3:38] To overcome these problems, [3:40] researchers at Imperial College London [3:42] have created the IRIS model, [3:44] a database of millions of synthetic tropical cyclone tracks. [3:48] WWA's attribution study examining Hurricane Melissa [3:52] found that climate change made a storm of this strength [3:55] five times more likely, [3:57] and increased the intensity of its winds and rainfall. [4:00] Jamaica was bang in the middle of the path of this hurricane, [4:10] and they had very good early warning system. [4:13] They evacuated people as best as was possible. [4:16] Still, people did die. [4:20] The destruction of the houses and infrastructure is enormous, [4:24] and that shows there is just a limit of what you can do. [4:31] You can't just move the island out of potential pathways [4:37] of ever increasingly intense hurricanes. [4:40] Attribution science has been evolving since the 1990s, [4:47] and it's increasingly being used to strengthen climate lawsuits. [4:53] This is Saul Luciano Yuya. [4:58] He's a farmer who lives in the Peruvian Andes, [5:01] and his home is under threat from melting glaciers. [5:04] In 2015, he sued the German energy company RWE, [5:10] arguing that its emissions contributed to melting the glaciers, [5:16] and he wanted them to pay for flood defences. [5:19] Attribution science was key in strengthening the case [5:22] as it moved through the court system. [5:25] Las montañas, los glaciares están derritiéndose, [5:28] y eso ha provocado que haya riesgos, riesgos a la vida, [5:33] y pido estoy aquí para pedir justicia climática. [5:38] Dr. Noah Walker-Crawford helped bring the case to court. [5:44] We've had a growing wave of climate litigation [5:47] over the past two decades. [5:49] Attribution science has advanced so much [5:51] that that's providing the kind of evidence for cases [5:53] that wouldn't have been possible 10 or 20 years ago. [5:56] Saul's case was ultimately dismissed in 2025. [6:01] The court ruled that the specific risk of flooding to his home [6:05] was not high enough to investigate whether RWE should pay out. [6:09] However, the court has found that in principle [6:13] these major fossil fuel companies can be held liable [6:16] for their contribution to climate change. [6:18] That means, in principle, major polluters can be made [6:21] to pay for climate change impacts. [6:23] So it may only be a matter of time [6:26] until one of these cases is successful, [6:28] until we have a precedent, [6:30] and that could really open the door [6:32] to a large number of future cases. [6:34] Once fossil fuel companies have to pay out for climate damages, [6:39] that raises serious questions about their business model [6:42] because it means that greenhouse gas emissions [6:45] equate to a financial liability, [6:48] and that will put significant pressure on investors [6:51] to move their money away from fossil fuels [6:54] and toward renewable forms of energy production, [6:57] and it will also put a lot of pressure on politics [7:00] to find more sustainable long-term solutions [7:02] to address climate change. [7:04] To be continued... [7:10] ... [7:14] ... [7:16] ... [7:18] ... [7:22] ... [7:23] ...