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An interview with journalist and academic Christina Gerhardt, who maps the shifting geographies of islands in her new book Sea Change.

The scattered Pacific islands of Kiribati are famously at the frontlines of climate change.
Two of the nation’s islands disappeared underwater as early as 1999, and in the years since Kiribati’s residents have had to grapple with the likelihood that more will meet the same fate by mid-century. Already, one in seven moves there are due to the encroaching seas.
In an attempt to provide options, in 2012, the president of Kiribati bought 6,000 acres of land on Fiji, as an alternate home for his people. But Fiji itself — larger, more mountainous, but still vulnerable — also faces the need to relocate its own communities. As the world heats up, islanders have had to reorient their lives around fraught decisions and constant change.
Kiribati is just one of the 49 islands (or collections of islands) that environmental journalist and academic Christina Gerhardt details in her book, Sea Change: An Atlas of Islands in a Rising Ocean, out this month from University of California Press. Working with cartographer Molly Roy, Gerhardt paints portraits of what is at stake as each island watches the seas creep gradually higher, from decimated coral reefs to inundated farms.
Sea level rise is not just about a slowly moving line on a map, said Gerhardt when we spoke about the book. It is a dynamic phenomenon that changes everything from coastal erosion to storm surge, high winds to flooding.
“A livable life isn't about whether or not one is underwater,” Gerhardt said.
There’s a huge range in the population and political power of the islands highlighted, spanning Singapore to Pine Island in the Antarctic Ocean. But Sea Change is woven together by what each island has in common: A relationship to sea level rise that is more urgent and more nuanced than those of us on the continents often appreciate.
What follows is the rest of our conversation, edited for brevity and clarity.
There's no shortage of scientific data outlining the latest numbers with regard to sea level rise. And while that data is absolutely vital, my approach was to weave the science in with these other components.
What I'm really bringing to the forefront in Sea Change is an atlas that depicts the histories and the cultures, and the languages, and the flora, and the fauna of islands. How people will connect with and appreciate islands and islanders is through their history and cultures. You have to provide something to engage with, and that’s where the work of the environmental humanities is really important.
Every single island has a different cluster of issues. So for every island, I gave our cartographer, Molly Roy, different elements to focus on. For one island, it might be the fact that what’s imperiled by sea level rise is agriculture: If you have too much salt water in soil, the plants can’t take up the water they need to survive. For another, I had her focus on sea turtle nesting grounds, which can be inundated or destroyed by sea level rise.
Ultimately, sea level rise should not be thought of as a line, but rather as a zone of inundation. The Marshall Islands, for example, are on average six and a half feet above sea level, and three feet of sea level rise is expected by the end of the century. You may think “Oh, well, that’s not going to be an issue then.” But a livable life isn't about whether or not one is underwater. It's whether or not that home has been inundated enough that it's soggy and moldy and just not inhabitable anymore.
No, this was a huge challenge when we started. The inequities that frontline communities suffer also play out in the resources that are allocated for mapping.
We started the map of the East and the West Coasts of North America, from Deal Island in the Chesapeake Bay to islands off the western coast of Alaska. We have no problem finding data for these islands.
And then we moved into the Pacific. The islands that we had the easiest time getting data for are ones that have U.S. military bases on them, like Guam or the Marshall Islands. But when we were talking about independent nations that don't have this kind of relationship to the U.S., we had a really hard time finding the data. To track down this data I would contact ministers of environment, and other government agencies, and they often didn't have it themselves.
First of all, I have some issues with the tendency to frame islands as harbingers of what awaits people who are continental land dwellers. I think the situation facing islands should, in and of itself with no other qualifications, be of concern. Full-stop.
That said, we also have to think about the audience and how to cast a wide net and share stories from one geographic region with people who are predominantly of another geographic region, which happens to be the hegemonic one. It was really important to also underscore that this is not a situation that remains relevant only to people who are living on islands. Almost half of the U.S. population, about 40 percent, live in coastal states and cities. That's about 130 million people in the US that are going to be impacted. And so I think this is something that we really need to grapple with.
The question of how to get movement on a global stage is a really important one. One of the successes coming out of the UN meeting last year was the push for the establishment of a loss and damage fund. It basically lays the blame of creating the climate crisis squarely at the feet of nations in the Global North, and asks them to compensate frontline nations in the Global South for the damages that have been created. The details have yet to be worked out, but it took 30 years to get to that point. Tina Stege, who was climate envoy for the Marshall Islands, was one of the tenacious leaders who really worked intensely to get this across the finish lines.
The UN gets criticized all the time because it’s so slow — which is true — and because even if there is an agreement that comes out of the UN, it’s not legally binding — also true. But I think the UN is a really important vehicle because it’s the one forum in which 198 nations get together and nations in the Global North do have to listen to these speeches from members of nations in the Global South. Before the latter weighs in, they typically describe the situation in their home countries. And so if you go to the UN, you have a really visceral sense of what’s going on around the world — last year was the floods in Pakistan, and then it was the drought in the Horn of Africa. That sharing between nations happens every year, but I don’t see coverage of these issues. The papers don’t really seem motivated.
The first kind of island in Sea Change is low-lying islands or atolls — often just a couple of feet high, a couple yards across, a couple of miles long — which are the ones that are most at risk. And then there are the high islands, also known as volcanic islands, which often still have active volcanoes. Obviously, the atolls are the ones that are most at-risk, but I decided to include volcanic islands as well, which initially puzzled my cartographer and editor: “These aren’t going to be underwater,” they said. That’s right, but that doesn’t mean they aren’t at risk. On those islands, most people and infrastructure are clustered around the coastline, so they’re going to be at-risk from sea level rise.
In terms of solutions, I talk a lot about soft engineering, or nature-based solutions. This would include the preservation and restoration of coral and oyster reef, and of mangroves and wetlands. Coral reefs and oyster reefs buffer waves when they come toward the island, which is important because wave action is responsible for eroding the coastline. Mangroves also provide a buffer, as one of the only trees that can deal with that high salinity of soil. They also provide a really important marine habitat, where little tiny fish swim around their roots and big predator fish can’t get in. A lot of these things have been ripped from the coastlines to set up urban environments, like harbors or airports.
There’s also hard-engineering, like the great U they’re putting around the tip of Manhattan, or the sea walls in Venice. These are so expensive, and often by the time they’re in place sea level rise has increased to yet another level where they’re not enough to do the work they were originally intended to do.
When I was teaching at Princeton, my students were often so despondent because of all of the catastrophes and disasters unfolding. And I always said it's important to just pick your area and do what you can. You don’t need to solve every issue, everywhere. Just pick your thing. Some people love working in their communities; some people like working more at the international level; some people really like engaging with some of the sources of the catastrophe (meaning the fossil fuel industry and the politicians who are supportive of subsidies for fossil fuels); some people work on the shift to renewables, and consider becoming electricians. There’s no shortage of action points to pick.
I think the really important message for people who are in the Global North that I would love to see connected to Sea Change is that we are the source of the emissions. So even as we go about our busy lives, there are things we can do large and small to actually tip the scales and have a direct impact on people who are in frontline communities. And those inequities are not just global, they're also within our own nation. But action is better than inaction. And of course systemic change is more important than individual change, but I don't want to discount the latter.
Exactly.
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The data center boom is everywhere you look in U.S. economic and emissions data.
This is an edition of Heatmap Daily, an evening review of the day’s news written by our executive editor. Sign up for it here.
It isn’t exactly a new thought, but I’ve been struck recently by how many trends in America’s economic and environmental data are fundamentally about the data center boom and the return of electricity demand:
First, the Energy Information Administration reported this week that U.S. emissions grew by more than 2% last year, driven by surging electricity demand and an increase in coal-fired generation. What caused that higher power demand? New factories and data centers — as well as record summertime cooling demand.
Second, many of the new factories driving that higher power demand are themselves producing goods that are … let’s say … data center-adjacent. There are the enormous new semiconductor fabs, of course. But Ford and General Motors have also set up new production lines (or repurposed old ones) to manufacture grid-scale batteries to meet power demand.
Third, take a look at the recent U.S. spending on private non-residential construction — in other words, everything American companies are building that is not houses, condos, or apartments.
The construction industry’s spent almost $60 billion on data centers over the past year, which is more than it spent on all other office buildings combined (and more than it spent building warehouses, too). Just a handful of categories — data centers, power plants, electricity infrastructure, and certain kinds of electronics manufacturing — now make up a third of all U.S. private non-residential construction investment. They’ve never made up such a large share of construction spending since data collection began in 2014.
As The New York Times recently noted, the American economy is unusually dependent on the American stock market right now — and the stock market is unusually dependent on artificial intelligence. This week, investors started to balk at the enormous spending hyperscalers are planning to keep building out the AI boom; Alphabet’s shares dropped 8% this week after it boosted its planned 2026 capital expenditure and signaled 2027 will be even bigger. If the data center boom started to slow down in earnest, then more than just that budget will change.
Speaking of which, my colleague Emily Pontecorvo wrote earlier this week about how many businesses are struggling to even estimate their carbon emissions from artificial intelligence. The carbon accounting startup Watershed recently unveiled a new formula to help companies get a sense of their AI-related emissions.
But even that formula is still limited by the amount of data hyperscalers publish — and they don’t publish that much. Google, for instance, is the only AI company that has (laudably) provided estimates of its emissions on a per-prompt basis. Yet no company has published its per-token emissions, or how emissions sync up with particular models or regions.
So Emily asked Google: Why aren’t you — or any other model provider — disclosing this kind of data yet?
The tech company didn’t get back to us until after we’d published Emily’s story. But its response was interesting enough that I wanted to quote some of it here.
The problem is “industry consensus,” Cooper Elsworth, a Google spokesperson, told us. “There is currently very little consensus on how to comprehensively and fairly measure the serving environmental impact of generative AI (such as text generation),” he wrote. “Without standardized, ‘apples-to-apples’ frameworks, it is difficult to compare different providers accurately.”
That’s partly because energy use — and emissions data — can vary from site to site and depend on “custom-built hardware, software compilers, and advanced inference techniques.” And he claimed Google doesn’t always have the measurement hardware in place to provide such specific estimates: “Providing precise, repeatable data requires highly advanced measurement infrastructure,” he said. “For example, software-based energy monitoring tools often suffer from sampling biases. For our study, we had to step away from top-down averages and directly measure actual energy at the physical power supply unit (PSU) level across our deployed fleet. Not all providers have the telemetry or data sets required to benchmark their operations at this level of granularity.”
Read Emily’s story to understand the other reasons why estimating — or even “guesstimating” — AI-related carbon emissions is so challenging.
A conversation with Emma Uridge of the Kansas Health Institute.
This week’s conversation is with Emma Uridge, analyst with the Kansas Health Institute. Uridge spent copious hours analyzing state and local laws on data center development to best understand how policymakers are responding to the potential environmental public health impacts of large AI infrastructure, including power and water. The report, which came out this week, also goes in depth into those health impacts. I reached out to her to discuss what she sees as must-watch territory for our readers on this emerging policy arena.
Our conversation was lightly edited for clarity.
What is actually being done on policy when it comes to data centers — beyond moratoria of course?
So first I’d like to just talk about the point of moratoria. It’s helpful to talk about how these policies emerge in the first place. One area where moratoria are helpful is when a data center is proposed but the county has no approach for how they’d like to potentially regulate them. That’s temporary, most of the time. It lets local governments conduct research on the various impacts and also negotiate community benefits, ones that can mitigate any potential negative impacts — like Lancaster Pennsylvania, which instituted a community benefit agreement that maximized the potential benefits of development while mitigating what large data centers can do. That agreement looked at capping municipal water use at 20,000 gallons per day and requiring 100% clean energy. It had financial penalties for non-compliance. The company also committed $20 million to their local economic development and clean energy fund. There are ways to negotiate with developers.
We also see amendments to existing zoning. Data center proposals are increasingly popping up in rural areas, many of which are unzoned, so there’s no way a county can negotiate unless there’s a moratorium in place.
Other policy solutions include different performance standards or requiring on-site renewable energy, like what Jefferson County, Missouri, looked at. Also setback requirements, mandatory noise buffers, ending by-right zoning.
Where are local governments getting ideas for regulating data centers?
A lot of the technical information comes from developers. That can in cases be seen as a biased source of information. I wouldn’t say there’s a dedicated group providing assistance to local governments when a project is proposed — which is a similar story to wind industry development, where we have only a handful of consultants who provide technical advice. It can be really helpful to get a multi-disciplinary approach to hearing information. It can be helpful to have the utility commission, public health folks, those in academia, as well as the developer.
As of right now, especially in rural areas, local governments have a hard task of balancing pushback while getting the most accurate, evidence-based, neutral information to make decisions. That balance can be contentious.
What is the federal government doing on data center policy? How is the Trump administration approaching it?
A few things there. In the early days, the drive was for AI expansion and to be competitive with foreign adversaries. Now due to the amount of public pushback in red and blue localities and a more cautious approach.
I’m not seeing a lot of actual policy movement at this time.
I know the EPA is looking at the chemicals used in cooling data centers because when that water is cycled through the system, some of it is discharged into the water system, so they’re looking at the Toxic Substances and Control Act for monitoring that.
How much of an impact does this minimal federal role have on industry behavior?
Y’know, this isn’t specific to data centers. This is true for all kinds of large-scale development: there’s a need to require some sort of federal monitoring and regulation.
That’s where I see an emerging role for public health. At the federal level, there could be policy movement towards requiring some sort of environmental monitoring at data centers to make sure they’re operating responsibility. Looking at specific water use relative to water availability and what happens when there’s a time of severe, persistent drought. With air quality too — we’ve seen areas where the grid isn’t as reliable so their diesel generators are kicking on more and affecting air quality for residents.
We’re just not seeing all of that right now. We need corporate disclosure.
What do you see as the most important public health impacts from data center development?
It varies by localities. The most discussed obviously is water usage. One thing I’d note about my conversations with folks enthusiastic around emerging tech is, there are still questions that need to be asked about the capacity of localities to support a data center. Like a small town in Kansas may only be using 40% of their water for their utility needs. If a data center came online, how much of that water goes to the data center?
One area underexplored within the public health discipline is energy poverty and energy security. The ability of a household to meet the needs of everything energy provides in our lives. It’s known we have an aging electric grid but we’re not talking enough about large-scale blackouts when the grid is not sufficient to support some of these new data centers.
Plus more of the week’s big development fights.
1. Laramie County, Wyoming — Meta is fighting the fine it received in the Cheyenne data center water pollution controversy, and the conflict between the tech giant and the city’s small board of public utilities is continuing to spill out into the public.
2. Niagara County, New York — This county just rejected a solar project’s highway work permits in a show of retaliation against the state’s Office of Renewable Energy Siting.
3. Barron County, Wisconsin — The anti-solar protest is the new campaign stop in deep red Wisconsin.
4. Chesapeake, Virginia — A large battery storage project on the Virginia coastline is on the rocks amidst rampant local opposition.
5. Lewis County, West Virginia — West Virginia is now a key battleground in the fight over transmission, as a line spanning all of West Virginia and Maryland — and cutting through Data Center Alley in Virginia — causes compounding consternation.