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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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Rob takes Jesse through our battery of questions.
Every year, Heatmap asks dozens of climate scientists, officials, and business leaders the same set of questions. It’s an act of temperature-taking we call our Insiders Survey — and our 2026 edition is live now.
In this week’s Shift Key episode, Rob puts Jesse through the survey wringer. What is the most exciting climate tech company? Are data centers slowing down decarbonization? And will a country attempt the global deployment of solar radiation management within the next decade? It’s a fun one! Shift Key is hosted by Robinson Meyer, the founding executive editor of Heatmap, and Jesse Jenkins, a professor of energy systems engineering at Princeton University.
Subscribe to “Shift Key” and find this episode on Apple Podcasts, Spotify, Amazon, or wherever you get your podcasts.
You can also add the show’s RSS feed to your podcast app to follow us directly.
Here is an excerpt from our conversation:
Robinson Meyer: Next question — you have to pick one, and then you’ll get a free response section. Do you think AI and data centers energy needs are significantly slowing down decarbonization, yes or no?
Jesse Jenkins: Significantly. Yeah, I guess significantly would … yes, I think so. I think in general, the challenge we have with decarbonization is we have to add new, clean supplies of energy faster than demand growth. And so, in order to make progress on existing emissions, you have to exceed the demand growth, meet all of that growth with clean resources, and then start to drive down emissions.
If you look at what we’ve talked about — are China’s emissions peaking, or global emissions peaking? I mean, that really is a game. It’s a race between how fast we can add clean supply and how fast demand for energy’s growing. And so in the power sector in particular, an area where we’ve made the most progress in recent years in cutting emissions, now having a large, and rapid growth in electricity demand for a whole new sector of the economy — and one that doesn’t directly contribute to decarbonization, like, say, in contrast to electric vehicles or electrifying heating —certainly makes things harder. It just makes that you have to run that race even faster.
I would say in the U.S. context in particular, in a combination of the Trump policy environment, we are not keeping pace, right? We are not going to be able to both meet the large demand growth and eat into the substantial remaining emissions that we have from coal and gas in our power sector. And in particular, I think we’re going to see a lot more coal generation over the next decade than we would’ve otherwise without both AI and without the repeal of the Biden-era EPA regulations, which were going to really drive the entire coal fleet into a moment of truth, right? Are they gonna retrofit for carbon capture? Are they going to retire? Was basically their option, by 2035.
And so without that, we still have on the order of 150 gigawatts of coal-fired power plants in the United States, and many of those were on the way out, and I think they’re getting a second lease on life because of the fact that demand for energy and particularly capacity are growing so rapidly that a lot of them are now saying, Hey, you know what, we can actually make quite a bit of money if we stick around for another 5, 10, 15 years. So yeah, I’d say that’s significantly harder.
That isn’t an indictment to say we shouldn’t do AI. It’s happening. It’s valuable, and we need to meet as much, if not all of that growth with clean energy. But then we still have to try to go faster, and that’s the key.
Mentioned:
This year’s Heatmap Insiders Survey
Last year’s Heatmap Insiders Survey
The best PDF Jesse read this year: Flexible Data Centers: A Faster, More Affordable Path to Power
The best PDF Rob read this year: George Marshall’s Guide to Merleau-Ponty's Phenomenology of Perception
This episode of Shift Key is sponsored by …
Heatmap Pro brings all of our research, reporting, and insights down to the local level. The software platform tracks all local opposition to clean energy and data centers, forecasts community sentiment, and guides data-driven engagement campaigns. Book a demo today to see the premier intelligence platform for project permitting and community engagement.
Music for Shift Key is by Adam Kromelow.
They still want to decarbonize, but they’re over the jargon.
Where does the fight to decarbonize the global economy go from here? The past 12 months, after all, have been bleak. Donald Trump has pulled the United States out of the Paris Agreement (again) and is trying to leave a precursor United Nations climate treaty, as well. He ripped out half the Inflation Reduction Act, sidetracked the Environmental Protection Administration, and rechristened the Energy Department’s in-house bank in the name of “energy dominance.” Even nonpartisan weather research — like that conducted by the National Center for Atmospheric Research — is getting shut down by Trump’s ideologues. And in the days before we went to press, Trump invaded Venezuela with the explicit goal (he claims) of taking its oil.
Abroad, the picture hardly seems rosier. China’s new climate pledge struck many observers as underwhelming. Mark Carney, who once led the effort to decarbonize global finance, won Canada’s premiership after promising to lift parts of that country’s carbon tax — then struck a “grand bargain” with fossiliferous Alberta. Even Europe seems to dither between its climate goals, its economic security, and the need for faster growth.
Now would be a good time, we thought, for an industry-wide check-in. So we called up 55 of the most discerning and often disputatious voices in climate and clean energy — the scientists, researchers, innovators, and reformers who are already shaping our climate future. Some of them led the Biden administration’s climate policy from within the White House; others are harsh or heterodox critics of mainstream environmentalism. And a few more are on the front lines right now, tasked with responding to Trump’s policies from the halls of Congress — or the ivory minarets of academia.
We asked them all the same questions, including: Which key decarbonization technology is not ready for primetime? Who in the Trump administration has been the worst for decarbonization? And how hot is the planet set to get in 2100, really? (Among other queries.) Their answers — as summarized and tabulated by my colleagues — are available in these pages.
You can see whether insiders think data centers are slowing down decarbonization and what folks have learned (or, at least, say they’ve learned) from the repeal of clean energy tax credits in the Inflation Reduction Act.
But from many different respondents, a mood emerged: a kind of exhaustion with “climate” as the right frame through which to understand the fractious mixture of electrification, pollution reduction, clean energy development, and other goals that people who care about climate change actually pursue. When we asked what piece of climate jargon people would most like to ban, we expected most answers to dwell on the various colors of hydrogen (green, blue, orange, chartreuse), perhaps, or the alphabet soup of acronyms around carbon removal (CDR, DAC, CCS, CCUS, MRV). Instead, we got:
“‘Climate.’ Literally the word climate, I would just get rid of it completely,” one venture capitalist told us. “I would love to see people not use 'climate change' as a predominant way to talk to people about a global challenge like this,” seconded a former Washington official. “And who knows what a ‘greenhouse gas emission’ is in the real world?” A lobbyist agreed: “Climate change, unfortunately, has become too politicized … I’d rather talk about decarbonization than climate change.”
Not everyone was as willing to shift to decarbonization, but most welcomed some form of specificity. “I’ve always tried to reframe climate change to be more personal and to recognize it is literally the biggest health challenge of our lives,” the former official said. The VC said we should “get back to the basics of, are you in the energy business? Are you in the agriculture business? Are you in transportation, logistics, manufacturing?”
“You're in a business,” they added, “there is no climate business.”
Not everyone hated “climate” quite as much — but others mentioned a phrase including the word. One think tanker wanted to nix “climate emergency.” Another scholar said: “I think the ‘climate justice’ term — not the idea — but I think the term got spread so widely that it became kind of difficult to understand what it was even referring to.” And one climate scientist didn’t have a problem with climate change, per se, but did say that people should pare back how they discuss it and back off “the notion that climate change will result in human extinction, or the sudden and imminent end to human civilization.”
There were other points of agreement. Four people wanted to ban “net zero” or “carbon neutrality.” One scientist said activists should back off fossil gas — “I know we’re always trying to try convince people of something, but, like, the entire world calls it ’natural gas’” — and another scientist said that they wished people would stop “micromanaging” language: “People continually changing jargon to try and find the magic words that make something different than it is — that annoys me.”
Two more academics added they wish to banish discussion of “overshoot”: “It’s not clear if it's referring to temperatures or emissions — I just don't think it's a helpful frame for thinking about the problem.”
“Unit economics,” “greenwashing,” and — yes — the whole spectrum of hydrogen colors came in for a lashing. But perhaps the most distinctive ban suggestion came from Todd Stern, the former chief U.S. climate diplomat, who negotiated the Kyoto Protocol and the Paris Agreement.
“I hate it when people say ’are you going to COP?’” he told me, referring to the United Nations’ annual climate summit, officially known as the Conference of the Parties. His issue wasn’t calling it “COP,” he clarified. It was dropping the definite article.
“The way I see it, no one has the right to suddenly become such intimate pals with ‘COP.’ You go to the ball game or the conference or what have you. And you go to ‘the COP,’” he said. “I am clearly losing this battle, but no one will ever hear me drop the ‘the.’”
Now, since I talked to Stern, the United States has moved to drop the COP entirely — with or without the “the” — because Trump took us out of the climate treaty under whose aegis the COP is held. But precision still counts, even in unfriendly times. And throughout the rest of this package, you’ll find insiders trying to find a path forward in thoughtful, insightful, and precise ways.
You’ll also find them remaining surprisingly upbeat — and even more optimistic, in some ways, than they were last year. Twelve months ago, 30% of our insider panel thought China would peak its emissions in the 2020s; this year, a plurality said the peak would come this decade. Roughly the same share of respondents this year as last year thought the U.S. would hit net zero in the 2060s. Trump might be setting back American climate action in the near term. But some of the most important long-term trends remain unchanged.
OUR PANEL INCLUDED… Gavin Schmidt, director of the NASA Goddard Institute for Space Studies | Ken Caldeira, senior scientist emeritus at the Carnegie Institution for Science and visiting scholar at Stanford University | Kate Marvel, research physicist at the NASA Goddard Institute for Space Studies | Holly Jean Buck, associate professor of environment and sustainability at the University at Buffalo | Kim Cobb, climate scientist and director of the Institute at Brown for Environment and Society | Jennifer Wilcox, chemical engineering professor at the University of Pennsylvania and former U.S. Assistant Secretary for Fossil Energy and Carbon Management | Michael Greenstone, economist and director of the Energy Policy Institute at the University of Chicago | Solomon Hsiang, professor of global environmental policy at Stanford University | Chris Bataille, global fellow at Columbia University’s Center on Global Energy Policy | Danny Cullenward, senior fellow at the Kleinman Center for Energy Policy at the University of Pennsylvania | J. Mijin Cha, environmental studies professor at UC Santa Cruz and fellow at Cornell University’s Climate Jobs Institute | Lynne Kiesling, director of the Institute for Regulatory Law and Economics at Northwestern University | Daniel Swain, climate scientist at the University of California Agriculture and Natural Resources | Emily Grubert, sustainable energy policy professor at the University of Notre Dame | Jon Norman, president of Hydrostor | Chris Creed, managing partner at Galvanize Climate Solutions | Amy Heart, senior vice president of public policy at Sunrun | Kate Brandt, chief sustainability officer at Google | Sophie Purdom, managing partner at Planeteer Capital and co-founder of CTVC | Lara Pierpoint, managing director at Trellis Climate | Andrew Beebe, managing director at Obvious Ventures | Gabriel Kra, managing director and co-founder of Prelude Ventures | Joe Goodman, managing partner and co-founder of VoLo Earth Ventures | Erika Reinhardt, executive director and co-founder of Spark Climate Solutions | Dawn Lippert, founder and CEO of Elemental Impact and general partner at Earthshot Ventures | Rajesh Swaminathan, partner at Khosla Ventures | Rob Davies, CEO of Sublime Systems | John Arnold, philanthropist and co-founder of Arnold Ventures | Gabe Kleinman, operating partner at Emerson Collective | Amy Duffuor, co-founder and general partner at Azolla Ventures | Amy Francetic, managing general partner and founder of Buoyant Ventures | Tom Chi, founding partner at At One Ventures | Francis O’Sullivan, managing director at S2G Investments | Cooper Rinzler, partner at Breakthrough Energy Ventures | Gina McCarthy, former administrator of the U.S. Environmental Protection Agency | Neil Chatterjee, former commissioner of the Federal Energy Regulatory Commission | Representative Scott Peters, member of the U.S. House of Representatives | Todd Stern, former U.S. special envoy for climate change | Representative Sean Casten, member of the U.S. House of Representatives | Representative Mike Levin, member of the U.S. House of Representatives | Zeke Hausfather, climate research lead at Stripe and research scientist at Berkeley Earth | Shuchi Talati, founder and executive director of the Alliance for Just Deliberation on Solar Geoengineering | Nat Bullard, co-founder of Halcyon | Bill McKibben, environmentalist and founder of 350.org | Ilaria Mazzocco, senior fellow at the Center for Strategic and International Studies | Leah Stokes, professor of environmental politics at UC Santa Barbara | Noah Kaufman, senior research scholar at Columbia University’s Center on Global Energy Policy | Arvind Ravikumar, energy systems professor at the University of Texas at Austin | Jessica Green, political scientist at the University of Toronto | Jonas Nahm, energy policy professor at Johns Hopkins SAIS | Armond Cohen, executive director of the Clean Air Task Force | Costa Samaras, director of the Scott Institute for Energy Innovation at Carnegie Mellon University | John Larsen, partner at Rhodium Group | Alex Trembath, executive director of the Breakthrough Institute | Alex Flint, executive director of the Alliance for Market Solutions
The Heatmap Insiders Survey of 55 invited expert respondents was conducted by Heatmap News reporters during November and December 2025. Responses were collected via phone interviews. All participants were given the opportunity to record responses anonymously. Not all respondents answered all questions.
Plus, which is the best hyperscaler on climate — and which is the worst?
The biggest story in energy right now is data centers.
After decades of slow load growth, forecasters are almost competing with each other to predict the most eye-popping figure for how much new electricity demand data centers will add to the grid. And with the existing electricity system with its backbone of natural gas, more data centers could mean higher emissions.
Hyperscalers with sustainability goals are already reporting higher emissions, and technology companies are telling investors that they plan to invest hundreds of billions, if not trillions of dollars, into new data centers, increasingly at gigawatt scale.
And yet when we asked our Heatmap survey participants “Do you think AI and data centers’ energy needs are significantly slowing down decarbonization?” only about 34% said they would, compared to 66% who said they wouldn’t.
There were some intriguing differences between different types of respondents. Among our “innovator” respondents — venture capitalists, founders, and executives working at climate tech startups — the overwhelming majority said that AI and data centers are not slowing down decarbonization. “I think it’s the inverse — I think we want to launch the next generation of technologies when there’s demand growth and opportunity to sell into a slightly higher priced, non-commoditized market,” Joe Goodman co-founder and managing partner at VoLo Earth Ventures, told us.
Not everyone in Silicon Valley is so optimistic, however. “I think in a different political environment, it may have been a true accelerant,” one VC told us. “But in this political environment, it’s a true albatross because it’s creating so many more emissions. It’s creating so much stress on the grid. We’re not deploying the kinds of solutions that would be effective."
Scientists were least in agreement on the question. While only 47% of scientists thought the growth of data centers would significantly slow down decarbonization, most of the pessimistic camp was in the social sciences. In total, over 62% of the physical scientists we surveyed thought data centers weren’t slowing down decarbonization, compared to a third of social scientists.
Michael Greenstone, a University of Chicago economist, told us he didn’t see data centers and artificial intelligence as any different from any other use of energy. “I also think air conditioning and lighting, computing, and 57,000 other uses of electricity are slowing down decarbonization,” he said. The real answer is the world is not trying to minimize climate change.”
Mijin Cha, an assistant professor of environment studies at the University of California Santa Cruz, was even more gloomy, telling us, “Not only do I think it’s slowing down decarbonization, I think it is permanently extending the life of fossil fuels, especially as it is now unmitigated growth.”
Some took issue with the premise of the question, expressing skepticism of the entire AI industry. “I’m actually of the opinion that most of the AI and data center plans are a massive bubble,” a scientist told us. “And so, are there plans that would be disruptive to emissions? Yes. Are they actually doing anything to emissions yet? Not obvious.”
We also asked respondents to name the “best” and “worst” hyperscalers, large technology companies pursuing the data center buildout. Many of these companies have some kind of renewables or sustainability goal, but there are meaningful differences among them. Google and Microsoft look to match their emissions with non-carbon-power generation in the same geographic area and at the same time. The approach used by Meta and Amazon, on the other hand, is to develop renewable projects that have the biggest “bang for the buck” on global emissions by siting them in areas with high emissions that the renewable generation can be said to displace.
Among our respondents, the 24/7 “time and place” approach is the clear winner.
Google was the “best” pick for 19 respondents, including six who said “Google and Microsoft.” By contrast, Amazon and Meta had just three votes combined.
As for the “worst,” there was no clear consensus, although two respondents from the social sciences picked “everyone besides Microsoft and Google” and “everyone but Google and Microsoft.” Another one told us, “The best is a tie between Microsoft and Google. Everyone else is in the bottom category.”
A third social scientist summed it up even more pungently. “Google is the best, Meta is the worst. Evil corporation” — though with more expletives than that.
The Heatmap Insiders Survey of 55 invited expert respondents was conducted by Heatmap News reporters during November and December 2025. Responses were collected via phone interviews. All participants were given the opportunity to record responses anonymously. Not all respondents answered all questions.