This year, Las Vegas, Nevada broke its all-time heat record, reaching 120° F.
The temperature was recorded at Harry Reid International Airport on July 7, 2024. That week, between July 6 and July 12, was the new hottest 7-day period on record, with an average high temperature of 117.5° F.
This is the daily reality for Vegas residents in the summer. Record-breaking temperatures are hard to bear, but so were all the hot days and nights that came before. Commuters frequently see temperatures above 120 flash on their vehicle dashboards, and outdoor workers struggle to do their daily tasks under the hot sun.
“There’s a disconnect between climate science and the people who live here,” says Woodwell Climate Research Associate, Monica Caparas. “Vegas residents know our summers are hot and unbearable. Understanding climate change is driving the extreme weather we’re experiencing is where the disconnect lies. ”
Caparas moved to Las Vegas as a child. She grew up there, left for college, and returned to settle into her adult life. Today, she works for Woodwell Climate’s Risk team remotely from her home in the city. Caparas knows the ins and outs of local life. These include Vegas’s rapid population expansion, the groups of people experiencing homelessness sheltering in underground stormwater infrastructure, and the heat that was unbearable before it started making headlines.
Experiencing climate change without shelter
Caparas’s work with the Risk team aims to provide communities like Las Vegas with an accurate picture of the climate-driven changes in their future. These “risk assessments” are provided through Woodwell Climate’s Just Access program, which uses the most accurate climate models, in collaboration with local knowledge, to anticipate future community safety threats. The analyses have brought to light growing threats from flooding, heat, storms, and more. The team provides assessments, free of charge, to states, cities, and countries across the world.
Just Access serves what Risk Program Director Christopher Schwalm calls “frontline communities.” The term describes groups of people who are over-exposed, under-resourced, underserved, historically marginalized, and therefore the most at-risk to the repercussions of climate change. In the risk assessment for Las Vegas, people experiencing homelessness are front and center.
“Between May 20th and the first week in July, about 20 people who were experiencing homelessness died of heat,” says Dr. Catrina Grigsby-Thedford, Executive Director of the Nevada Homeless Alliance (NHA) and community partner in Las Vegas.
The NHA estimates that almost 8,000 people are experiencing homelessness on any given night in southern Nevada. The number is only growing. Grigsby-Thedford says that this year’s unhoused population is up 1,300 people compared to 2023.
“Often our shelters are full,” Grigsby-Thedford says, “We’re limited by shelter beds and space.”
The NHA’s shelters do open all day in extreme heat, but so many people packed tightly together is still unsafe.
With nowhere to go, some seek shelter underground in Las Vegas’s stormwater infrastructure. While the tunnels are cooler out of the sun’s reach, they are at risk from flooding. Across the region, extreme precipitation is expected to increase by 12-14% by 2050, raising flood risk in the city and especially within the tunnels.
To combat lack of space and shelter, the NHA hosts 4-8 one-stop resource fairs per month. The events, called Project Homeless Connect, serve both people experiencing homelessness and low-income residents in Las Vegas. Grigsby-Thedford says these events “fill in gaps”—offering housing assistance, medical care, hygiene care, and other resources.
Despite all of this work, many unhoused people are hesitant to engage with organizations like the NHA. Grigsby-Thedford says “choice is often a challenge,” and that when people grow accustomed to the way things are, they often accept it and choose to stay.
Picturing risk
Building trust with communities, especially those predisposed to mistrust outside actors, is essential in this work. Which is why, Schwalm says, Woodwell Climate approaches risk work with the goal of “meet[ing] people where they are.”
That means “scoping,” the team’s word for listening to what community and government leaders want out of the risk analysis—what concerns they have, weak points they’ve identified, and what help might be needed post-analysis.
“Two-thirds of the time we spend from start to finish falls into this scoping idea, rather than doing analysis itself,” Schwalm says.
Scoping frames the data the risk team collects, as well as who their partners will be during the risk analysis process.
“We find people who are practical and recognize that there’s a problem,” Schwalm says, “We only work with communities who want to work with us.”
Following the scoping process, the Risk team compiles an analysis of extreme weather events and subsequent risks each community will face as climate change progresses.
“We perform a stress test of that particular geography to identify weak points,” Schwalm explains.
Then, the Risk team uses the most up-to-date climate models possible to predict changes in extreme weather and regional climate. By using predictive models, the team focuses efforts on what the future will hold, as opposed to using past strategies.
“We need to use the future to predict the future,” Schwalm says simply.
Making climate risk data accessible to all
Over the past three years, Just Access has provided 50 communities—that’s about a quarter billion people—with risk analyses. These communities span the U.S., Central and South America, Africa, Asia, and Oceania. They’ve worked with countries, like the Democratic Republic of Congo, where they helped update the country’s National Adaptive Plan, states like Chiapas in Mexico, groups like Cree Nation in Canada, and other communities, now including Las Vegas.
Despite all of this work, though, Schwalm says there is still room to grow.
“Fifty communities is kind of only a drop in the bucket,” he says, “We’re not going to make a huge dent in this unless we move beyond working community-by-community.”
Two major roadblocks for Just Access are finite resources: time and money. Individual risk analyses require a lot of time and communication to address risks in relatively small areas.
The other obstacle, money, is something climate research could always use more of. Grants and donations are crucial in order for analyses to remain free, and those sometimes come with limitations.
“There’s a tension from the funder to work in a specific geography sometimes,” Schwalm says, “It’s a juggling act.”
Climate change can also be a politicized topic. In order to meet people where they are, sometimes the Risk team implements changes in language used to communicate with community leaders. This can be a change as simple as using “extreme weather” instead of “climate change.” As long as everyone in the room is ready to confront what the future holds, they’re all working on the same page towards the same goal.
“We’ve done red states, blue states, rural, urban,” Schwalm continues. “We’ve learned how to read the room.”
Creating the foundations for change
Woodwell Climate’s involvement in Las Vegas brings to light the way justice issues, like homelessness, interact with growing threats from climate change.
“In the Las Vegas risk assessment, we are focusing on the disproportionate impacts of the climate crisis on communities already facing systemic socio-economic inequity,” says Caparas. “We must think about intersectionality in order to address climate justice.”
Not only does climate change represent a current crisis for those experiencing homelessness, communities with fewer resources are now at greater risk of being made homeless by future climate-related disasters. Accurate climate risk information can support organizations like NHA as they develop strategies to serve people experiencing homelessness in a more extreme future.
Grigsby-Thedford says that NHA members, especially those with lived experience of homelessness who work as Lived X Consultants, are always looking to be involved in projects like the one Caparas leads.
“We always talk about weather in our meetings,” she says, “So this is perfect, someone’s actually doing research about this. Anything that impacts [Las Vegas’s homeless population], we want to make sure we’re involved in that.”
For the Las Vegas risk assessment, Caparas is working with the NHA and Southern Nevada Lived X Consultants to understand climate risks around cooling stations in public buildings, which are a vital, air-conditioned shelter when the heat index is too high. Grigsby-Thedford says there were many more cooling stations in 2023 and 2024 compared to previous years.
Caparas also forged a connection with Miguel Dávila Uzcátegui, Southern Nevada’s Regional Transportation Commission (RTC) Senior Planner and board member of Help Hope Home. Together, they are developing a database of flooding infrastructure and updating the city’s flooding model with future climate projections. The RTC will integrate the Risk team’s model into regional planning work, updating Las Vegas’s flooding and transportation infrastructure for community safety.
None of this work would have been possible without Caparas’s diligent bridge building between the scientific resources of Woodwell Climate and the needs of people in her own community. Those connections allow science to be informed first and foremost by those most affected by climate change.
“The people closest to the problem are the people closest to the solution,” says Grigsby-Thedford.
The city of Chelsea, Massachusetts persevered through the American Revolution and two great fires. Now its resilience is being tested by climate change, as rising sea levels and more intense storms have begun sending frequent flood waters into the city.
Woodwell Climate Research Center recently conducted a thorough analysis of flood risk in Chelsea, identifying where flooding is likely to increase with climate change. The picture it paints is one where the city’s most vulnerable citizens get hit the hardest.
Located north of Boston where Chelsea Creek merges into the Mystic River and the Boston Harbor, Chelsea is vulnerable to two forms of flooding— storm surge from the harbor and extreme rainfall events. Currently, 15% of the city falls within an area of potential flooding. That number will more than double to 34% by 2081.
The return interval of high intensity flooding events will also increase. Scientists use the term “1-in-100 year events” to refer to the kind of large-scale flooding that has a 1% likelihood of occurring over the course of a century. Woodwell calculated that today’s 1-in-100 year rainfall events could become three times as likely by mid-century, and 1-in-100 year storm surge events could be annual occurrences by 2081. That would be like the city of Chelsea experiencing flooding proportional to Hurricane Sandy every year.
Heavy Industry, Low Incomes, High Risk
Chelsea was settled on a salt marsh punctuated by five hills. The city was developed from the high ground down, and much of the marsh and wetlands around Island End and Chelsea Creek were filled in over the city’s history. These low lying areas form the city’s vulnerable floodplain.
According to Woodwell’s analysis, that floodplain contains much of the city’s vital industry. Two oil terminals sit on Chelsea’s waterfront— the Chelsea Sandwich and Gulf Oil terminals. Here, petroleum, natural gas, and other petrochemicals are stored before being transported to their final destinations. The southeastern waterfront is also a designated port area for commercial shipping.
On the western side of the floodplain is the New England Produce Center, a massive regional hub for food distribution, as well as a major employer.
“Our waterfront has been industrial for 200 years and will continue to be industrial. But we’re very concerned that industry and flooding aren’t compatible,” says Karl Allen, a planner in Chelsea’s Department of Housing and Community Development who worked with Woodwell on the analysis.
Affordable housing is also at risk. Much of the city’s affordable housing was built in the 50’s and 60’s in the lowest-lying areas of the city, where marshes were filled in to create land for their construction. These communities are already familiar with bearing the burden of environmental damages— a rail line bisects the city through a designated environmental justice corridor. At only a few feet above sea level, the rail line serves as a major inundation pathway. Without adaptation measures, climate change will hit these lower income areas hardest.
Climate-Proofing Chelsea
“I can say that the one thing that’s been very common for municipal and state agencies is a sense of moving goalposts,” says John Walkey, the Director of Waterfront and Climate Justice Initiatives for GreenRoots. GreenRoots is a community organization dedicated to improving urban environmental and public health in Chelsea. Walkey and Greenroots facilitated the collaboration between Woodwell and the city.
“We are now at the stage where climate processes are moving faster than our bureaucracy can,” said Walkey. That could have been a paralyzing realization, especially backed up with analysis results outlining the intensity of increased flooding. Instead, the City’s planning leaders have decided to confront the floodwaters head on, using the analysis to change the way they think about implementing routine infrastructure updates.
Of course, Water doesn’t care where one municipality begins or ends; it will flow into any accessible space. The success of Chelsea’s adaptation measures will depend on collaboration with nearby localities— Everett, Revere, Boston. For example, there are plans in the works to construct a flood defense between Chelsea and nearby Everett that sits across the Island End River. Both cities hope this landscaped wall will protect the area from major flooding until at least 2070.
Having a thorough flood risk analysis also puts the city in a good position to lobby for adaptation on a larger scale. In mid-April, Woodwell and Chelsea hosted a briefing for the offices of Massachusetts Senators Ed Markey and Elizabeth Warren and Congresswoman Ayanna Pressley on the results of the flood analysis and the regional security issue it represents.
“Chelsea is facing a severe threat from climate change over the course of the next 50 years,” said Chelsea City Manager, Tom Ambrosino during the briefing. “So we are working hard to try to be prepared for it. But a lot of these projects are beyond our immediate capability.”
Chelsea is one city of hundreds
There are hundreds of Chelseas across the United States facing similar, and increasingly urgent, threats from flooding, drought, heat, or extreme weather. Many communities are scrambling to adapt as disasters hit, without knowing how much more change is on the horizon. Replicating climate risk analyses like the one in Chelsea could help them get a more specific picture of what they are facing.
“When you tell people well, ‘you’ve got to design for conditions in 2070’, they say ‘what does that mean? What kind of storm are we designing for?” says Allen. “This analysis has given us a better understanding of what kind of disasters we’ll be looking at, and with what frequency, so we have a design target.”
Risk analyses are invaluable to a municipality’s ability to plan for the shifting goalposts of climate change. Yet the availability of these analyses is uneven. Cities with more resources are able to pay private companies for risk assessments, while non-profits like Woodwell work to fill in the gaps. The Center has already partnered with 14 communities in the U.S. and abroad to produce tailored analyses. But there are nearly 20 thousand municipalities in the U.S. alone. Each will experience their own unique version of climate change.
“It really highlights the need for a national climate service,” said Woodwell Research Associate Dominick Dusseau who worked on the analysis for Chelsea, “something that can provide a nationwide standard service, rather than a piecemeal thing.”
Woodwell’s analysis is a prototypical version of what could be possible with more uniform risk assessment services, as well as a model of successful community engagement. Woodwell will continue to grow its partnerships with individual cities, but the scope of climate change will require a larger, more coordinated response.
“We’re doing a lot, there’s just so much more to do,” says Dusseau.
A warmer world means snow, rain will be much less predictable
When and where precipitation falls can determine whether or not people have enough drinking water, aquifers can support agriculture, and rivers keep running. Climate change is breaking down the predictability of weather patterns across the globe. Two new releases this week, from the Woodwell Climate Research Center and Probable Futures, flesh out our understanding of how the shifting seasonality of precipitation might impact our future.
Rainy seasons are fluctuating more
A new volume of maps, data, and educational materials launched on the Probable Futures platform today. The volume provides information that helps readers better understand local, regional, and global precipitation trends, showing how they will change with climate change.
The impact of a warmer world on precipitation patterns is not uniform—in some places dry spells will become more common, in others, intense storms, and some places will fluctuate between both. Rainy seasons may start earlier or later in different parts of the world, which will have impacts on growing seasons and agricultural yields.
“Climate change is reshaping both local precipitation patterns and the global water system—and everyone on Earth will be affected,” said Alison Smar, executive director of Probable Futures. “It may seem counterintuitive, but knowing that the future is less predictable is a valuable forecast. Communities need to be more resilient, adaptable, and prepared. It’s within our power today to prepare for the events that are probable, and prevent those with irreversible impacts.”
Snow is melting earlier
Woodwell Associate Scientist, Dr. Anna Liljedahl and Assistant Scientist Dr. Jenny Watts, were co-authors on a paper also released today that documents the impacts of earlier snowmelt in the Arctic. The Arctic is warming more rapidly than anywhere else on earth, which has led to earlier snow melts and longer growing seasons in the tundra.
Conventional hypotheses have predicted that lengthening summers would allow more time for vegetation to grow and sequester carbon, perhaps offsetting emissions elsewhere.
“Our results show that the expected increased CO2 sequestration arising from Arctic warming and the associated increase in growing length may not materialize if tundra ecosystems are not able to continue capturing CO2 later in the season,” said Dr. Donatella Zona, lead author on the paper from the University of Sheffield’s School of Biosciences and the Department of Biology at San Diego State University.
Dr. Liljedahl says that the results highlight the fact that the impacts of climate change will be complex across ecosystems.
“This work shows how important it is to continually assess our assumptions and terminology on how the Arctic system will respond to warming. We often say that warming will lead to a “longer growing season”. We need to be more careful in making that connection,” said Dr. Liljedahl.