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A podcast by GBH News reporter Ian Coss gives this notorious project a long-overdue reappraisal. Bonus: The show comes with lessons for climate infrastructure projects of the future.

If you’ve lived in Massachusetts at any point in the last 50 years, you’ve heard of the Big Dig. It’s infamous — a tunnel project that was supposed to bury an elevated highway in Boston to the tune of $2 billion that eventually ballooned in cost to $15 billion and took a quarter of a century to finish.
The Big Dig was more than just a highway project, though. It was a monumental effort that Ian Coss, a reporter at GBH News, calls a “renovation of downtown Boston.” The project built tunnels and bridges, yes, but it also created parks, public spaces, and mass transit options that transformed the city. In a nine-episode podcast series appropriately called The Big Dig, Coss dives into the long, complicated history of the project, making a case for why the Big Dig was so much more than the boondoggle people think it was.
I talked to Coss about how the Big Dig came to be and the lessons we can learn from it as we continue to adapt our built environment to a changing climate. Our interview has been edited for length and clarity.
I moved to Boston for college in 2010, and I remember going to the North End and being struck by how beautiful it was. I didn’t realize how recently that view had changed until I listened to your podcast — I mean, the Big Dig had only wrapped up a few years earlier.
It’s easy to forget how quickly it transformed. I grew up in Massachusetts, so when I would come into the city I would see [the Big Dig] being built — I have vague memories of the elevated artery. And when I moved to Boston Proper in 2013, which was less than a decade after the project wrapped, it was stunning for me to be like, “oh, this is what that project was,” because I definitely didn’t understand it at the time.
What made you decide to create an entire podcast about this “renovation” of Boston?
I think part of it was this disconnect where I grew up hearing about the Big Dig and mostly hearing bad things about it — it was behind schedule, it was a disaster, a boondoggle, etc. — because that really was the reputation of the project, nationally and locally. And then moving to the city and seeing the fruits of it, it was hard to reconcile those things. Like, this “disaster” created a greenway through the middle of the city. Now you can actually get to the airport.
What was driving that narrative of its being a disaster?
The Big Dig went on a very long emotional journey. It started as this kind of visionary, idealistic project championed by activists and supported by politicians of both parties. And then, after navigating the process of funding, permitting, contracting, managing, and designing, by the time it's in construction, it really is not a source of pride.
There are a number of technical things about the Big Dig that could have been done better, and we can learn lessons from it. The way it was contracted could have been done better. The management structure could have been done better. There were flaws in the design, including a fatal flaw that cost the life of a driver in the tunnel.
I think a lot of it is about the storytelling. Just to give one example, so much of the negative narrative around the Big Dig was around the cost. You often hear about how it started with an estimated cost of $2 billion and wound up costing $15 billion. But I think that narrative misses a few things.
One is that it was never going to cost $2 billion. That was not a realistic estimate. But in our country, it is so hard to get approval, political support, funding, and permitting in place that there is a very strong incentive all throughout the process to downplay the costs, downplay the risks, downplay the disruption, make it sound like this is going to be quick and easy and painless and cheap, just to get to the starting line. Because the paradox of it is that if we had known in 1983 or 1987 or 1991 that this was going to be a $15 billion project, it would have never happened. And yet, in hindsight, there are many smart people who told me that this project was a bargain at $15 billion because of what we got in terms of economic benefits, transportation improvements, and environmental improvements.
There’s almost an element of asking for forgiveness rather than permission here, but that forgiveness is inevitably laced with anger because of those expectations.
Right. If only it were just forgiveness.
The Big Dig had its roots in the National Highway Program. Were all those projects going constantly over budget?
There’s a great paper that I cite in episode four where the authors studied the cost of highway building per mile every year from the 1970s through the 1990s, and it’s actually a great sample set because we’ve built so many highways of different sizes in different states. Basically, what they found is that highway costs per mile really ramp up significantly in the 1970s. And that’s, of course, the period when the [Big Dig] was first getting conceived.
So the short answer to your question is, it was cheaper once. But there were other costs, in that those early highways in the ‘50s and ‘60s largely did not consider the impact on communities or on the environment. They did not make a lot of mitigation efforts to minimize the day to day disruption caused by those projects. So I think part of what the Big Dig captures is this really historic change in the way we build things in this country that was ushered in by the anti-highway movements, by citizen activism, and by the National Environmental Policy Act. Over the course of the 1970s we made it much harder to build things, for very good reasons.
I think the Big Dig — which some people describe as the last great project of the interstate era — captures an attempt to do a massive, ambitious infrastructure project that is also loaded with environmental mitigation and also has a robust community process. Part of what we learned through that is that you can have a project that’s cheap and efficient, you can have a project that’s democratic and humane, but it’s tough to have it all. And the Big Dig was trying to have it all, and we did get it all, but at enormous cost. That was the thing that could never be solved.
You make a connection between the Big Dig and climate change right from the first episode. What are the climate lessons we can learn from the Big Dig?
In some ways, it’s ironic to hold up the Big Dig as a case study for climate change because it’s a highway project. My point is not that the Big Dig is, like, the future of infrastructure. But what it offers is a recent case study on a massively ambitious building project. We have some distance, and you can see the whole arc of it, but it very much lives within our era. It’s not the Hoover Dam or the Golden Gate Bridge or any of those other big projects built in a different time under different conditions.
The way I see it is that in order to mitigate or prevent the worst effects of climate change — and you can feel free to disagree with me — we’re going to need to build a lot of stuff. This is not a problem that we’re going to solve by riding bicycles and growing vegetables in the backyard, both of which I do and hope everyone does. And of course, those projects might look different than the Big Dig because building a wind turbine isn’t exactly analogous to building a downtown tunnel. But I think there are relevant analogies, especially things like coastal mitigation in cities, improving mass transit, building high energy transmission lines — these large scale projects that will affect people but also are an important public good.
You talked on the show about the Big Dig as an attempt to make this process more democratic at some level. People on both sides had very strong feelings about it. This reminded me of the NIMBY/YIMBY dichotomy of climate projects. Did anyone mention any best practices that could be applied to future projects of this kind?
I’ve talked with Fred Salvucci [former Massachusetts Secretary of Transportation and driving force of the Big Dig] about this. He mentioned this biblical parable — he’s full of parables — about Jesus walking across the water and then turning to his disciples and telling them to follow. But they step into the water and fall right in, and when they get back out they say it’s impossible. And then Jesus says, “It’s easy to walk across the water. You just have to know where the stones are.”
And Fred said the lesson there is that, in order to navigate this kind of process, you have to know where the flashpoints are, what the issues will be. That way you can anticipate them rather than just going in and saying “this is my project, I’m going to do it this way and you can fight me on it.”
Part of what I think is really interesting about this, which I think speaks to present-day projects like offshore wind, is that in that fight, you have very well-intentioned actors who are trying to make the project better and using the environmental process to do that. And you also have bad actors who are weaponizing and manipulating the environmental process to their own personal ends. And those two things get all mixed up.
You know, I’m an environmentalist. I believe in environmental review. I don’t want to sit here and say that we need to get rid of all environmental permitting because it makes it too hard to build things. But I think it’s also important to recognize that these things can be weaponized.
Scheme Z, which proposed this big spiral loop of ramps and a bridge over the river, is a good example. Politically, that became very messy — they were trying to impose concentrated harm in the name of a public good. And I know, strategically, maybe there are things [Salvucci] could have done to mitigate that or circumvent that, but given the structures in place, the logical outcome is that it spends a decade in lawsuits and review committees and you wind up with something that’s okay, that everyone can live with.
The funny thing about that is that it turned into the Zakim Bridge, which is now a Boston icon.
Right. I mean, that’s part of the communication piece, too.
I was biking under the Zakim bridge the other day, and I biked through where there’s a nice pedestrian and bicycle bridge and this skate park that is always filled with people. Truly, that is maybe the best utilized public space created by the Big Dig.
It’s easy for me to play Monday morning quarterback and say “oh, you should have communicated that better, you should have told the story better.” I mean, he was saying all the right things. But then all you had to say on the other side was “it’s 18 lanes and five ramps,” and that sounded terrible and looked terrible on the page. And I mean, sure, I wish there weren’t all those ramps there, but like you said, ironically, the bridge became an icon of the city.
I think a big part of the lesson for me is how hard it is to build infrastructure democratically because the timescales are all wrong. These things have short-term costs and cause short-term disruption and bring very long-term benefits.
I was constantly struck by this issue of scale, both in terms of time and money. It’s hard to wrap your head around the idea of billions of dollars and projects that span decades. These are just things that are impossible for any regular person to really plan out.
I was talking to someone who said that their dad was in his 70s when the Big Dig was just getting started. And for him, it was like, “my city’s going to be torn up for the rest of my life,” right? That’s what this project meant for him — he would live with this mess of a project and never see the results. And he had to deal with that so that you could move to Boston in 2010 and never know the city another way. The cost of that benefit is borne by another generation.
And it’s the same thing with climate change. It moves on a scale that is so much longer than politics. The Big Dig took almost 40 years from conception to completion. So if you’re thinking about political capital, if you’re thinking about two- and four-year election cycles, it’s very, very hard to conceive, plan, and deliver a project on that kind of time scale.
The benefits and costs are almost inverted in climate change, in a way. We’re talking about future benefits, yes, but we’re also talking about future costs if we don’t do anything. But it’s so hard to make people think in a 40- or 50-year timescale.
If the Big Dig was so hard to make happen politically with what I think was a more genial political environment overall, it feels kind of impossible to think of building anything on that scale right now.
I gave a talk at City Hall a few weeks ago and I was talking with some of the young planners there, people who are in their 30s. Some of them have been listening to the series, and they told me they could not imagine what it would be like to get that kind of federal funding out of Washington, get all the local players on board, get it through the permitting process, and get it contracted. Because right now if they try to take away one parking spot and put in one bike line, they’re bogged down in meetings for a year.
I think climate change is also the inverse of projects like this because with the Big Dig, for example, you can feel the tangible benefits of a quicker commute and a more beautiful city. But with climate change, if the projects work, you’d actually feel nothing.
Exactly. Climate change is way, way harder. A road project or a rail project will have benefits. You get ribbon cuttings and photo ops. But if we make Boston resilient to flooding or something, you know, do some big project that would improve the shoreline or whatever ideally, that historic storm surge may never come, or it’ll come and we’ll be prepared for it and nothing will happen. But yeah, you’re working with long term counterfactuals.
It feels to me like climate change was designed in a laboratory to flummox institutions. It takes all of our cognitive biases, our ingrained social and biological blind spots and weak points and just flicks them all at us at once.
All nine episodes of The Big Dig are out now. You can listen on the WGBH website, Apple Podcasts, Spotify, or wherever you get your podcasts.
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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.