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Honolulu has lost more than 5 miles of its famous beaches to sea level rise and storm surges. Sunny-day flooding during high tides makes many city roads impassable, and water mains for the public drinking water system are corroding from saltwater because of sea level rise.
The damage has left the city and county spending millions of dollars on repairs and infrastructure to try to adapt to the rising risks.
Future costs will almost certainly be higher. More than US$19 billion in property value, at today’s dollars, is at risk by 2100 from projected sea level rise, driven by greenhouse gas emissions largely from the burning of fossil fuels. Elsewhere in Honolulu County, which covers all of Oahu, many coastal communities will be cut off or uninhabitable.
Unwilling to have their taxpayers bear the full brunt of these costs, the city and county sued Sunoco LP, Exxon Mobil Corp. and other big oil companies in 2020.
At stake in all of these cases is who pays for the staggering cost of a changing climate.
Local and state governments that are suing want to hold the major oil companies responsible for the costs of responding to disasters that scientists are increasingly able to attribute to climate disruption and tie back to the fossil fuel industry. Several of the plaintiffs accuse the companies of lying to the public about their products’ risks in violation of state or local consumer protection laws that prohibit false advertising.
The governments in the Honolulu case allege that the oil companies “are directly responsible” for a substantial rise in carbon dioxide emissions that have been driving climate change. They say the companies should contribute their fair share to defray some of the costs.
The gist of Honolulu’s complaint is that the big oil companies have known for decades that their products cause climate change, yet their public statements continued to sow doubts about what was known, and they failed to warn their customers, investors and the public about the dangers posed by their products.
Were it not for this deception, the lawsuit says, the city and county would not be facing mounting costs of abating the damage from climate change.
Importantly, the complaint is based on state – not federal – law. It alleges that the defendants have violated established common law rules long recognized by the courts involving nuisance, failure to warn and trespass.
The city and county want the companies to help fund climate adaptation measures – everything from building seawalls and raising buildings to buying flood-prone properties and restoring beaches and dunes.
Supreme Court could have killed these cases
Not surprisingly, the oil companies have thrown their vast legal resources into fighting these cases.
On April 24, however, they lost one of their most powerful arguments.
The U.S. Supreme Court declined to hear challenges in the Hawaii case and four others involving the seemingly technical question of which court should hear these cases: state or federal.
The oil companies had “removed” the cases from state court to federal court, arguing that damage lawsuits for climate change go beyond the limits of state law and are governed by federal law.
That theory would have derailed all five cases – because there is no federal common law for greenhouse gases.
The court made that position clear in 2011 in American Electric Power Co. v. Connecticut. Several state and local governments had sued five major power companies for violating the federal common law of interstate nuisance and asked for a court order forcing these companies to reduce their emissions. The Supreme Court refused, holding that the federal Clean Air Act displaced federal common law for these gases.
Several coastal communities, including in Honolulu County, facing increasing erosion want oil companies to help pay for protective infrastructure. AP Photo/Audrey McAvoy
To avoid this fate, Honolulu and the other plaintiffs focused on violations of state law, not federal law. Without exception, the federal courts of appeals sided with them and sent the cases back to state court.
What happens next?
The Honolulu case leads the pack at this point.
In 2022, the 1st Circuit Court in Hawaii denied the oil companies’ motion to dismiss the case based on the argument that the Clean Air Act also preempts state common law. This could open the door for discovery to begin sometime this year.
In discovery, senior corporate officers – perhaps including former Exxon Mobil CEO Rex Tillerson, who was secretary of state under Donald Trump – will be required to answer questions under oath about what the companies knew about climate change versus what they disclosed to the public.
In 2019, former Exxon Mobil CEO Rex Tillerson testified in a securities fraud lawsuit brought by the New York attorney general’s office. The judge ruled in Exxon’s favor. AP Photo/Seth Wenig
Evidence from Exxon documents, described in a recent study by science historians Naomi Oreskes and Geoffrey Supran, shows that the company’s own scientists “knew as much as academic and government scientists knew” about climate change going back decades. But instead of communicating what they knew, “Exxon worked to deny it,” Supran and Oreskes write. The company overemphasized uncertainties and cast doubt on climate models.
This is the kind of evidence that could sway a jury. The standard of proof in a civil case like Honolulu’s is “preponderance of the evidence,” which roughly translates to 51%. Ten of the 12 jurors must agree on a verdict.
Any verdict likely would be appealed, perhaps all the way to the U.S. Supreme Court, and it could be years before the Honolulu case is resolved.
Lawsuits don’t begin to cover the damage
It is unlikely that even substantial verdicts in these cases will come close to covering the full costs of damage from climate change.
According to the National Oceanic and Atmospheric Administration, in 2022 alone the U.S. sustained 18 weather and climate disasters that each exceeded $1 billion in damage. Together, they cost over $165 billion.
But for many of the communities most at risk from these disasters, every penny counts. We believe establishing the oil companies’ responsibility may also discourage further investments in fossil fuel production by banks and brokerage houses already nervous about the financial risks of climate disruption.
Sea levels have surged along the coastlines of the southeastern United States, new research finds — hitting some of their highest rates in more than a century.
They’ve risen more than a centimeter a year over the last decade — about triple the global average — and the effects on communities near the Gulf of Mexico and Atlantic Ocean already are being observed in the form of increased flooding, more severe hurricanes and eroding shorelines.
“We have seen the impacts quite significantly,” said Sönke Dangendorf, an expert in coastal engineering at Tulane University and lead author of the new study.
The study, published Monday in the journal Nature Communications, is the latest to point out the trend. Another study, published earlier this month in the Journal of Climate, highlighted a similar pattern — sea-level rise of more than a centimeter per year since 2010 along the Gulf and Southeast coasts.
As part of a broader attempt to visualize future climate risk, insurance companies, federal mortgage managers and consumer financial authorities are partnering with First Street Foundation to bolster the U.S. economy against the rising risk of extreme weather.
Climate exposure represents a serious threat to the U.S. housing market, which may be overvalued by more than $200 billion dollars, according to First Street data published in Nature.
On Wednesday, the Federal Home Loan Mortgage Corporation — better known as Freddie Mac — was the latest to announce that it would join dozens of other federal and private companies in using First Street data to evaluate climate risk to the properties it helps finance.
Hundreds of hazardous industrial sites that dot the California coastline – including oil and gas refineries and sewage-treatment plants – are at risk of severe flooding from rising sea level if the climate crisis worsens, new research shows.
If planet-warming pollution continues to rise unabated, 129 industrial sites are estimated to be at risk of coastal flooding by 2050 according to the study, published Tuesday in the journal Environmental Science & Technology by researchers from University of California at Los Angeles and Berkeley, as well as Climate Central.
After centuries of flooding, Venice has at long last raised seawalls to save itself from high water. They have already protected the city from catastrophic floods. But climate change and rising seas pose a gnawing question. Will Venice one day have to cut itself off from the waters that are its lifeblood?
When a powerful storm flooded neighborhoods in Fort Lauderdale, Florida, in April with what preliminary reports show was 25 inches of rain in 24 hours, few people were prepared. Even hurricanes rarely drop that much rain in one area that fast. Residents could do little to stop the floodwater as it spread over their yards and into their homes.
Studies show that as global temperatures rise, more people will be at risk from such destructive flooding – including in areas far from the coasts that rarely faced extreme flooding in the past.
In many of these communities, the people at greatest risk of harm from flash flooding are low-wage workers, older adults and other vulnerable residents who live in low-lying areas and who have few resources to protect their properties and themselves.
I study the impact of extreme weather on vulnerable communities as an assistant professor of social work. To limit the damage, communities need to know who is at risk and how they can be better prepared.
A warmer atmosphere can hold more moisture, leading to stronger downpours. The resulting deluges can be devastating. These events are expected to increase in frequency and intensity in many regions as greenhouse gas emissions from human activities continue to heat up the planet.
Where extreme precipitation events are forecast to increase under a low-emissions scenario and a high one. National Climate Assessment 2018
When older adults live in these flood-prone areas, they are at even higher risk. Older adults have a higher likelihood of having health needs or some form of disability that could affect their ability to leave quickly during a disaster. They are also more likely to be socially isolated, which may mean they don’t hear timely information or have help to evacuate or quick access to resources for recovering.
Residents walk out of a flooded neighborhood in Fort Lauderdale on April 13, 2023. Joe Raedle/Getty Images
Renters and the impact of housing insecurity
In a recent study, my colleagues and I looked at how prepared people were for disasters of any kind across the U.S. – flooding, tornadoes, hurricanes and others – and how housing security played a role. The numbers were sobering.
Overall, we found 57% of the population, among 29,070 housing units surveyed nationwide, reported they were not prepared with food, water, emergency funds and transportation in case disaster struck. We found that households facing housing insecurity – those behind on their payments for rent, mortgage or utilities – were less prepared for disasters than others, even when the occupants had similar incomes and educations.
For residents with low incomes and without flood insurance, cleanup costs from flooding can be overwhelming. Joe Raedle/Getty Images
People who are struggling to meet day-to-day needs often don’t have the ability and resources to plan for everyday events, let alone for disasters. Our research has shown that households with children, households led by women, and low-income households were less prepared than others for disasters.
Renting adds additional challenges. In the U.S., lower-income families often depend on the rental market. They tend to move more frequently, and since they don’t own the property, they often can’t make upgrades for safety. And landlords might not prioritize those risks that seem rare but carry costs.
How to help communities stay safe
The most effective way to address these challenges is through solutions that are tailored to the community.
That can involve investing in infrastructure, including state-funded priorities like drainage systems and large-scale flood prevention measures, as well as ensuring that people have access to safe and affordable housing. Some communities and federal agencies have bought out properties that frequently flood and changed zoning rules to prevent more people from moving into harm’s way.
Raising community awareness about climate change and extreme weather risks is also crucial, especially among those most at risk, such as older adults. If people understand the risks, know how to prepare their homes, know how to plan for emergencies and know where to find assistance, they’re more likely to be prepared when disasters strikes.
Scientists explain why warming can lead to heavier downpours and flash flooding.
For example, in Columbus, Ohio, the city is working with the Central Ohio Area Agency on Aging, Age Friendly Innovation Center and my team to improve disaster preparedness among older residents. We hope to learn from older adults in affordable housing communities who have experienced extreme weather in recent years to help design action plans for communities with special needs. The goal is to ensure residents are better prepared for climate- and weather-related emergencies in the future.
Most of Yosemite National Park will shut down starting late Friday in anticipation of a massive snowmelt that is threatening to flood the surrounding region in California, the park announced.
The closure will begin on Friday at 10 p.m. and last until Wednesday, May 3, or “possibly longer,” a park spokesperson tweeted, while additional flooding and closures could occur later in May or June.
To get a sense of the enormous amount of water atmospheric rivers dumped on the Western U.S. this year and the magnitude of the flood risk ahead, take a look at California’s Central Valley, where about a quarter of the nation’s food is grown.
This region was once home to the largest freshwater lake west of the Rockies. But the rivers that fed Tulare Lake were dammed and diverted long ago, leaving it nearly dry by 1920. Farmers have been growing food on the fertile lake bed for decades.
This year, however, Tulare Lake is remerging. Runoff and snowmelt from the Sierra Nevada have overwhelmed waterways and flooded farms and orchards. After similar storms in 1983, the lake covered more than 100 square miles, and scientists say this year’s precipitation is looking a lot like 1983. Communities there and across the West are preparing for flooding and mudslide disasters as record snow begins to melt.
Tulare Lake, long dry, begins to reemerge in March 2023 as flood water spreads across farm fields. NASA Earth Observatory
We asked Chad Hecht, a meteorologist with the Center for Western Weather and Water Extremes at the University of California San Diego’s Scripps Institution of Oceanography, how 2023’s storms compare to past extremes and what to expect in the future.
How extreme were this year’s atmospheric rivers?
California averages about 44 atmospheric rivers a year, but typically, only about six of them are strong storms that contribute most of the annual precipitation total and cause the kind of flooding we’ve seen this year.
This year, in a three-week window from about Dec. 27, 2022, to Jan. 17, 2023, we saw nine atmospheric rivers make landfall, five of them categorized as strong or greater magnitude. That’s how active it’s been, and that was only the beginning.
In all, the state experienced 31 atmospheric rivers through the end of March: one extreme, six strong, 13 moderate and 11 weak. And other storms in between gave the Southern Sierra one of its wettest Marches on record.
These storms don’t just affect California. Their precipitation has pushed the snow-water equivalent levels well above average across much of the West, including in Oregon, Nevada, Utah, Idaho and the mountains of western Colorado, Arizona and New Mexico.
Snow water equivalent is a measure of the water in snowpack. Many basins across the West were well over 200% of average in 2023. NRCS/USDA
In terms of records, the big numbers this year were in California’s Southern Sierra Nevada. The region has had 11 moderate atmospheric rivers – double the average of 5.5 – and an additional four strong ones.
Overall, California has about double its normal snowpack, and some locations have experienced more than double the number of strong atmospheric rivers it typically sees. The result is that Northern Sierra snow water content is 197% of normal. The central region is 238% of normal, and the Southern Sierra is 296% of normal.
What risks does all that snow in the mountains create?
There is a lot of snow in the Sierra Nevada, and it is going to come off the mountains at some point. It’s possible we are going to be looking at snowmelt into late June or July in California, and that’s far into summer for here.
Flooding is certainly a possibility. The closest year for comparison in terms of the amount of snow would be 1983, when the average statewide snow water content was 60.3 inches in May. That was a rough year, with flooding and mudslides in several parts of the West and extensive crop damage.
This year, portions of the Southern Sierra Nevada have passed 1983’s levels, and Tulare Lake is filling up again for the first time in decades. Tulare Lake is an indication of just how extreme this year has been, and the risk is rising as the snow melts.
The transition from extreme drought in 2022 to record snow was fast. Is that normal?
California and some other parts of the West are known for weather whiplash. We frequently go from too dry to too wet.
2019 was another above-average year in terms of precipitation in California, but after that we saw three straight years of drought. We went from 13 strong or greater magnitude atmospheric rivers in 2017 to just three in 2020 and 2021, combined.
California relies on these storms for about half its water supply, but if the West gets too many atmospheric rivers back to back, that starts to have harmful impacts, like the heavy snowpack that collapsed roofs in the mountains this year, and flash flooding and landslides. These successive storms are typically referred to as atmospheric river families and can result in exacerbated hydrologic impacts by quickly saturating soils and not allowing rivers and streams to recede back to base flow between storms.
Are atmospheric rivers becoming more intense with a warming climate?
There’s been a lot of research on the impact of temperature because of how reliant California is on these storms for its water supply.
Atmospheric rivers are long, narrow corridors of water vapor in the sky that typically start in the tropics as water evaporates and is pulled poleward by atmospheric circulations. They carry a lot of moisture – on average, their water vapor transport is more than twice the flow of the Amazon River. When they reach land, mountains force the air to rise, which wrings out some of that moisture.
In a warming climate, the warmer air can hold more moisture. That can increase the capacity of atmospheric rivers, with more water vapor resulting in stronger storms.
Research by some of my colleagues at Scripps Institution of Oceanography also suggests that California will see fewer storms that aren’t atmospheric rivers. But the state will likely see more intense atmospheric rivers as temperatures rise. California will be even more reliant on these atmospheric rivers for its snow, which will result in drier dries and wetter wets.
So, we’re likely to see this whiplash continue, but to a more extreme level, with longer periods of dry weather when we’re not getting these storms. But when we do get these storms, they have the potential to be more extreme and then result in more flooding.
In the more immediate future, we’re likely headed into an El Niño this year, with warm tropical Pacific waters that shift weather patterns around the world. Typically, El Niño conditions are associated with more atmospheric river activity, especially in Central and Southern California.
So, we may see another wet year like this again in 2024.
Across California’s long, flat, usually parched and dusty Central Valley, farmers and residents are used to waiting for water to come. But not like this.
Blanketing the Sierra Nevada above them, a historic amount of snow is slowly beginning to melt. The snowpack, more than 230 percent of normal, is the result of an onslaught of atmospheric rivers and storms that deluged the state for weeks in January and March, damaging coastal cities, rural farming communities and mountain towns.
As California’s brutal winter gives way to the warmth of spring, that deep snowpack will eventually melt, sending a massive amount of water into the vulnerable, low-lying valley below — and toward flood control systemsthat in many cases are woefully unprepared to handle it.
The possible slow-moving disaster looming above the Central Valley — a densely populated agricultural powerhouse that produces a fourth of the nation’s food — has the potential to cause billions in loss and damage, submerge towns and affect tens of thousands of residents, many of them farmworkers and families with low incomes who have already this year endured significant flooding and sodden crops.
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