Last summer, Ryan Coonerty, a county supervisor in Santa Cruz, got word that the neighboring county of San Mateo was about to take a bold step in adapting to climate change. Rising seas are already eroding San Mateo’s coast, and the county will need to spend billions of dollars on new sea walls and other infrastructure to protect itself in the years to come. So in July, San Mateo, along with Marin County and the city of Imperial Beach, sued 37 fossil fuel companies, arguing that they should help pay for the damage their products cause.
Santa Cruz had also been feeling the effects of climate change. Waves were taking chunks out of coastal roads, Coonerty says, destroying utility pipes beneath them. The sea wasn’t the only problem: there was a years-long drought, followed by historic wildfires, followed by unusually intense winter storms, which triggered landslides causing $140 million in road damage and cutting off entire neighborhoods. “We’ve never had storm damage like that before,” Coonerty says. “At the end of the day, this is going to be billions of dollars in damage to public infrastructure. And the question is, are the oil companies going to stick the public with the bill after they’ve reaped untold profits and lied to us?”
In December, Santa Cruz filed a suit of its own. Nine cities and counties have now brought similar lawsuits, including San Francisco, Oakland, and New York. In recent weeks, officials in Los Angeles and Florida have discussed joining the fray.
There are several reasons why this wave of litigation is happening now. Frustration with the Trump administration’s opposition to climate action has led states and cities to take matters into their own hands. Recent floods, storms, and fires have also created a sense of urgency. Because of climate change, such events will only get more severe, and if cities are going to be prepared, they need to begin the expensive process of adapting their infrastructure now.
These lawsuits are also a sign that the science connecting climate change to damaging events has greatly improved. Santa Cruz, for instance, is suing not just for sea level rise, but for drought, wildfires, and other disasters, armed with recent research showing that climate change is already making them worse.
Not long ago, the phrase “no single event can be attributed to climate change” was repeated like a catechism. This is no longer true. Though scientists still warn that it’s inaccurate to speak of weather events being “caused” by climate change — weather always has multiple causes — better climate models, more powerful computers, and refined methodologies now allow researchers to quantify how climate change has increased the likelihood or severity of heat waves, droughts, deluges, and other extreme events.
The American Meteorological Society now publishes an annual compendium of studies examining the role of climate change in the previous year’s weather. This January’s issue marked an ominous milestone. For the first time, researchers found phenomena that couldn’t have happened in a world without industrial greenhouse gases. The record global heat of 2016, a strangely warm patch of water off Alaska known as “the blob,” and deadly heat waves in Asia weren’t just more likely because of climate change — they were only possible because of it.
Meanwhile, new research is quantifying the amount of carbon dioxide that energy companies have added to the atmosphere over the course of their entire existence. Combined with attribution science, the two fields form a sort of climate forensics, enabling communities to point to an ostensibly natural disaster, find the fingerprints of climate change, and trace them back to an Exxon or BP.
If the current volley of lawsuits over adaptation costs are successful, they will likely be followed by others: Phoenix might sue over deadly heat, Boulder over its shrinking ski season, or Houston over torrential rain. The list of disasters exacerbated by climate change keeps getting longer. Recent attribution studies have found that climate change played a major role in everything from violent avalanches in Tibet to the bleaching of coral reefs in Australia.
Plaintiffs compare their cases to the pivotal tobacco litigation of the 1990s, hoping for a similar outcome but foreseeing similarly daunting obstacles. Like the states that brought the tobacco lawsuits, they face fantastically well-funded opponents and must convince courts of the causal link between major companies and widespread harm. No climate lawsuit has made it to trial in the US before.
Vic Sher, a partner at the firm Sher Edling LLP, which is leading several of the California lawsuits, says that one reason he believes the cities have a shot now is the science. “All of these earlier cases didn’t have the benefit of current attribution science, in terms of drawing the link between emissions and impacts, and emissions during a particular period, and attribution to particular corporations,” Sher says. “We have all that information now.”
Scientists have been able to quantify the effect of greenhouse gases on global average temperature for decades, but identifying their effect on specific weather events is far more challenging. Weather varies drastically by the day, season, and year before you even get to large-scale shifts like El Niño. It’s one thing to take all that data and find the trend of rising average temperature, and another to figure out how late June heat waves in the Mediterranean have changed and why.
There are two main steps to detecting climate change’s role in an event. The first is to look at historical data and determine the likelihood of the event in the current climate, and how that likelihood has changed over time. If there’s a trend, the next step is to see whether it’s due to greenhouse gases or one of the countless other variables that affect weather.
That’s done using computational models that simulate temperature, sea ice, moisture, and other elements of the climate system. Typically these models are used to predict how the future climate will respond to rising greenhouse gases, but attribution researchers use them to compare the current climate with a hypothetical one where greenhouse gas emissions never occurred. In a sense, we’re currently conducting a planet-wide experiment in what happens when you pump billions of tons of carbon dioxide into the atmosphere, but there’s no control group — an untouched planet against which we can measure the effects — so attribution researchers use models to simulate one.
Friederike Otto, a senior researcher at the University of Oxford and a lead scientist on the World Weather Attribution project, compares the process to figuring out whether dice are loaded. You roll a clean die and a loaded one over and over and compare the results. You won’t be able to point to a particular winning roll and say it happened because the die was loaded, but you can quantify how much more likely loading made it.
The first major attribution studies were done on heat waves, like the ones that killed tens of thousands of people in Europe in 2003 and Russia in 2010. The studies captured public attention and scientists began researching more events and delivering results more quickly. Since 2014, researchers at the World Weather Attribution project have been publishing assessments of heat waves, droughts, floods, and other events often weeks after they occur.
Attribution science is still new and there’s much room for improvement. In a 2016 report, the National Academies of Sciences declared that the field had advanced rapidly but needs better models and common standards for evaluating their quality. Even high-end models only simulate the climate system at a resolution of 25 square kilometers. That’s enough to capture large-scale phenomena like heat and rain, but not enough to handle weather with complex local dynamics, like thunderstorms or hurricanes.
These limitations will likely be raised by fossil fuel companies in court, as will general questions about the accuracy of the models. Models can be tested and fine-tuned by seeing how well they reproduce the recent past, but there isn’t always good historical data to test against and, of course, there’s none for the counterfactual, low greenhouse-gas version of the planet.
But when it comes to large-scale events, attribution research can be a useful tool for measuring how risk has changed. After Hurricane Harvey swamped Houston, two independent studies found that climate change had made the storm’s Earth-bending rainfall more likely and more intense. The year before, a study found that climate change had increased the odds of a catastrophic deluge in Louisiana. These studies show that torrential rain in the Gulf is no longer a freak event, and that flood maps need to be redrawn, building codes updated, and infrastructure made ready.
The better attribution science gets, the easier it will be to argue that governments should have foreseen climate risks and prepared for them — and to hold them liable if they fail to. In the journal Nature this fall, a group of environmental lawyers listed a range of actors, from local governments to construction companies, that could face litigation for continuing to operate under a 20th century understanding of risk. “Advances in the science of extreme weather event attribution have the potential to change the legal landscape in novel ways,” they wrote.
The science can also bolster litigation against greenhouse gas emitters themselves. Robert Glicksman, a professor of environmental law at the George Washington University Law School, points out that when states sued tobacco companies, they relied on a form of causation similar to that provided by attribution studies. They couldn’t say definitively that a particular cancer was caused by smoking, but states could say smoking increased the probability of cancer among their residents, which was translating to higher health care costs that the tobacco companies were liable for. An analogous case is now being made by a growing number of cities and counties around the US: climate change has made certain disasters more likely, and local governments are bearing the costs.
By Josh Dzieza. Source: The Verge