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Summer headlines have screamed of climate extremes: Record temperatures, an ocean heat wave, and rampant wildfires, including Canadian blazes that have funneled dense smoke into major U.S. cities.

For Loretta Mickley, a Harvard wildfire expert, the fires present a dual problem: Not only are they a symptom of climate change — becoming bigger, hotter, and more common in regions where they can affect large population centers — but they also make the crisis worse. By burning vast layers of partially decomposed vegetable matter called peat, fires like those in Canada release even more greenhouse gases into the atmosphere.

The Gazette spoke with Mickley, who will chair a National Academies workshop next month on wildfires as a driver of greenhouse gases, about the science behind the threat. The interview has been edited for clarity and length.

Q&A

Loretta Mickley

GAZETTE: How do we expect wildfires to change in the decades to come?

MICKLEY: The consensus is that wildfires will increase in what we call boreal regions —Siberia, northern Canada, and Alaska. With climate change, these regions are warming more rapidly than elsewhere on the globe, and the warmer temperatures will dry out the fuel, leading to increased fire activity. Fire is also predicted to increase in the western U.S. The climate in the western U.S. is historically very variable, prone to dryness, and climate models suggest that we’ll have more frequent droughts and more fire activity there.

In Australia as well as the Mediterranean, there’s also a strong view that fires will increase, again because of warmer or drier conditions under climate change. The fires in Australia in 2019-2020 and in Greece this summer are consistent with these projections.

GAZETTE: So the general sense is more fires and shifting locations?

MICKLEY: Yes, but with a caveat: human activity. While human activity can ignite fires, human changes to the landscape — like roads, cities, even cropland — can impede the spread of wildfires because there’s less fuel. Efforts to suppress fires in populated regions such as the western U.S. have also played a role in this decline. In fact, in the early 2000s, observations showed that fire was decreasing over much of the globe. But there are also these emerging, climate-driven trends, and there is a consensus that out-of-control, intense wildfires will increase in some regions of the globe, imperiling people, animals, and vegetation.

GAZETTE: And the fires we’ve seen in the U.S. and around the world this summer are consistent with that consensus?

MICKLEY: For the most part. The fires in Quebec and the fires in the western parts of Canada are totally consistent with climate change. The drivers of the terrible fires in Maui are complex and include recent drought as well as a change in vegetation from native species to more flammable invasive grasses.

GAZETTE: The September workshop will focus on greenhouse gas emissions from these fires. Why is that a concern?

MICKLEY: In the natural world fires are ignited by lightning. With no humans around, fires release greenhouse gases — mainly carbon dioxide — into the atmosphere, which over time are taken up again by the regrowth of very similar vegetation. The natural world has a neutral carbon balance.

But with a changing climate, two things can happen to disrupt that balance. First, the fires in boreal regions become more intense, and, because of the tremendous heat being generated, peat, which has stored carbon for thousands of years, can start to burn and contribute massive amounts of carbon to the air. That carbon will take at least another 1,000 years to go back into the peat. Second, in boreal regions, fires can thaw permafrost, beginning a cascade of microbial processes that may also generate greenhouse gases.

GAZETTE: So there’s little debate that burning peat will release large amounts of carbon?

MICKLEY: No question. There’s also peat in Indonesia, where human activity has really perturbed land cover. The government there made a big attempt to grow rice in the 1990s, which failed but left lots of peatland drained, making it much more vulnerable to fire. More recently, fire in Indonesia has been used to clear land to plant different crops, including timber and palm oil, leading to the drainage and exposure of still more peat. When an El Niño brings dry weather to the region, fires in the region can go out of control for several weeks or more, with lots of peat burning. For example, there was a big El Niño in 2015 and the amount of carbon released by fires in Indonesia that year was equivalent to the amount emitted by the European Union. These are sizable amounts.

GAZETTE: The concern with peat, specifically, is that you’re taking it from long-term storage and releasing it into the atmosphere. And it takes a long, long time to rebuild that storage. Is there an analogy here to fossil fuels?

MICKLEY: It’s very much like that. The timescales are shorter for generation of peat compared with, say, oil, but it’s similar. So burning peat is a big problem for the carbon budget.

Then there’s the problem of climate change affecting the succession of vegetation in an ecosystem. This is a very new area of research and we’ve done a little work on it. If you burn, for example, the conifers in Sierra Nevada, you may not get conifers back. It’s too dry and too warm during certain times of the year. That could be another source of carbon into the atmosphere. There is some concern that after the recent very large fires in the western U.S., like the Camp Fire and some of the fires in the Columbia River Gorge in Oregon, given the changing climate, we won’t see the same dense vegetation return.

GAZETTE: What are some of your goals for the workshop?

MICKLEY: It’s a public workshop and the goal is to assess the problem of greenhouse gases being emitted by wildfires. We don’t have to come to consensus or have a list of recommendations, but there will be a strong emphasis on what we can do besides stop emitting carbon dioxide.

In Australia, there has been a successful program that has empowered Indigenous people to recreate their traditional fire practices and has led to big changes in fire activity. Our former graduate student Tianjia Liu has investigated the effect of Indigenous controlled burning in northern Australia early in the fire season, when fuels are less dry. This initiative has reduced available fuel and decreased fire activity later in the season, when fires are typically more intense and harder to control. The area burned there has decreased by about 30 percent since 2003.

But it’s a very hard problem. Typically fires in remote regions in Canada and Alaska are just allowed to burn, but now we’re thinking, “This isn’t working. There’s all this smoke. Carbon dioxide is being released. Peat is burning. We need to do something.” But there’s a fine line between wise fire management and fire suppression. In the western U.S. during the 20th century, there was a huge effort to limit the size of fires. That approach got us into trouble because now, when fires do occur, the accumulated fuel can lead to large, out-of-control burning. I’m hoping that this workshop will illuminate prudent ways to manage these and other remote regions. The fires are a terrible calamity, an outcome of climate change that can’t easily be controlled. It’s akin to hurricanes and sea-level rise. You can prepare for sea-level rise, but then along comes a Hurricane Irene. It’s frightening.

Dakota Law cradled a small shark as two fellow student researchers leaned in to touch it. Before this summer, Law had never worked in a lab or held a shark. Now she’s done both, thanks to an undergraduate research program geared to students with disabilities.

The rising senior in engineering sciences at Smith College is one of three students studying sharks for eight weeks this summer through the Research Experience for Undergraduates program Accessible Sharks, funded by the National Science Foundation. She worked in the lab of Harvard’s George Lauder. Scientists from Woods Hole Oceanographic Institution and the University of Florida also took part.

Law, who has an invisible disability, talked about what the experience has meant for her. “I have been very hesitant and, honestly, kind of nervous about both going into the industry or continuing my journey through academia and how my disability might hinder my experience.”

None of that hesitation was evident in late July when Law’s peers in the program visited her in Lauder’s lab, and she showed off that chain catshark — and its denticles. The flat V-shaped shark scales, also known as “skin teeth,” have an enamel coating, dentin layer, pulp cavity, and blood vessels. They are of particular interest to researchers, Lauder included, because they help sharks swim more efficiently by reducing the drag around their bodies.

A group of international researchers led by the Center for Astrophysics | Harvard and Smithsonian (CfA) achieved the once-unimaginable four years ago: using a groundbreaking telescope to capture an image of a black hole.

Last month some of those researchers, engineers, and physicists convened at Harvard to consider and begin drawing up plans for the next step: a closer study of the photon rings that encircle black holes in glowing orange. The mission has been dubbed the Event Horizon Explorer (EHE), and the group hopes it will offer additional insight into black holes, which sit at the center of galaxies.

The $300 million project examining the nature of space and time builds on the success of the Event Horizon Telescope (EHT) project of 2019, when researchers took the first-ever picture of a black hole, a focal point so tiny “the biggest ones on the sky are only about the same size as an atom held at arm’s length,” said Michael Johnson, an astrophysicist at the CfA.

“What we are trying to do now is launch a space mission that would improve the sharpness of the EHT images by a factor of 10,” Johnson said. This would reveal photon rings — rings made by the light orbiting a black hole. Johnson described these as similar to “a tiered wedding cake, where each time the light goes around, it piles up a sharper ring.” Currently, “We can’t see those in the EHT images. They’re too narrow to distinguish from the rest of the light near a black hole,” he said.

It’s a huge undertaking, but for the recently gathered team of more than 70 researchers, the project is beginning to look possible. “We were trying to figure out if there were any showstoppers. Was there any reason that we can’t launch this within the next 10 years? And the exciting thing was that there weren’t,” said Janice Houston, a systems engineer at the CfA. “We think that we can keep our foot on the gas and actually get this built within the next decade.”

The concept seems drawn from a Hollywood space odyssey. “Detecting the photon ring requires recording huge volumes of data on the spacecraft. We plan on using laser light to beam the information equivalent of the entire Library of Congress down to Earth,” said Peter Galison, Joseph Pellegrino University Professor in the History of Science and Physics and director of Harvard’s Black Hole Initiative.

However, the payoff could be hard proof of what once seemed impossible. Photon rings, for example, would provide proof that black holes at the centers of galaxies are spinning, and that they are dragging their space-time along with them as they rotate. Space-time is a mathematical model that describes the four-dimensional fabric of the cosmos — length, width, height, and time.

“If a black hole is spinning, it would distort the shape of the photon ring, squeezing it into an oval,” Galison said. If the EHE is able to measure the photon ring, “that will be a rock-solid measurement of the effects of the rotating black hole to bend the path of light itself.”

Before the EHE can launch, it faces immense challenges, from building sensitive receivers that are cooled to nearly absolute zero to record the light hitting the telescope, to launching a dish several meters in diameter with an exquisitely precise surface. “At NASA, we are always pushing the boundaries of engineering to explore entirely new parts of the universe,” said Eliad Peretz, a mission and instrument scientist at NASA Goddard Space Flight Center. “This is a chance to bring together breakthrough technologies in many different systems to bring us closer than ever before to seeing the edge of the universe.”

Dominic Chang, who is studying physics in Harvard’s Griffin Graduate School of Arts and Sciences, is one of the scientists working on the theoretical physics driving the project. For the last two years, he’s been building physics-based models that “are quick to compute and can be fit to data to describe what’s happening in the 3D geometry of the space-time.” During the workshop, Chang focused on science applications for the EHE, coming up with proposals that engineers would be able to reasonably construct.

“Basically, we wanted to come up with a set of ideas that we knew we could support with lots of simulations. And the workshop led to a flurry of new ideas. It’s amazing to be part of this project on the ground floor and to contribute to the burst of progress that is tied to a potential new experiment,” Chang said.

“This mission would have profound implications for multiple priority areas identified by the U.S. astronomy community in the last decadal survey,” said Peter Kurczynski, chief scientist of cosmic origins at NASA Goddard. “This is an extraordinary opportunity for us to finally understand how the enormous black holes in the centers of galaxies actually formed.”

FAS Dean of Science Christopher Stubbs addressed the workshop on one of its early days, giving the team guidance in a talk called “Going Big: A Scientist’s Guide to Big Projects and Large Collaborations.”

“It’s remarkable that this group, along with others, has managed to accomplish the paradoxical thing of imaging a black hole,” he said. “Leveraging that and moving forward is significant.”

Black holes, warming seas, new treatments for disease: No matter how you approach it, the news is full of science-based stories. For those of us who aren’t scientists, however, understanding the context — not to mention the technical jargon — can be a challenge. With that in mind, we asked Harvard science faculty in various fields to recommend their favorite science book for nonscientists. Ideally these accessible reads will give the rest of us a leg up on understanding our changing world.

William “Ned” Friedman

Arnold Professor of Organismic and Evolutionary Biology, Director of the Arnold Arboretum

“Immediately, one book comes to mind: My favorite book by Charles Darwin (and his last — published in 1881): ‘The Formation of Vegetable Mould Through the Action of Worms.’ While some of his books changed the world (‘On the Origin of Species,’ ‘The Descent of Man’) and some were highly technical (‘Orchids,’ ‘Barnacles,’ ‘Power of Movement in Plants’ …), his book on worms, which reflected a lifelong interest (beginning in the 1830s and ending with his death in 1882) in the slow but steady effects of earthworms on the terrestrial world is one of the most charming and heartwarming books I can imagine in the world of natural history books.

“It reveals the loving father, grandfather, and husband experimenting with earthworms with his family (wife Emma, son Francis whose wife had died in childbirth and was now living with his parents, and grandson Bernard) at Down House. Imagine the science: Darwin with a pot of worms trying to determine if they can hear. To conduct this experiment, his wife Emma is called upon to play the piano loudly, his son to play his bassoon, and his grandson to play a whistle! Darwin’s personification of the worms shows the true extent of his feelings for the intelligence of fellow creatures and his sly sense that something quite wonderful is lurking behind even the lowly earthworm. Truly, if one is going to read only one book by Charles Darwin, this is the one!”

David S. Ludwig

Professor of Nutrition, Harvard T.H. Chan School of Public Health

Ludwig, who is also a professor of pediatrics at Harvard Medical School, went with the science fiction novel “Seveneves” by Neal Stephenson, which imagines a catastrophic event that has rendered the earth uninhabitable — sending humans on a desperate race to re-create a habitable environment in space.

“A fascinating thought experiment in how humans might evolve and adapt to extreme changes in their environment. Although science fiction, the narrative is grounded in plausible biology and physics. A wonderful, long read,” he said. “Start now, should last the rest of the summer.”

Daniel E. Lieberman

Edwin M. Lerner II Professor of Biological Sciences

Lieberman, who also serves as chair for the Department of Human Evolutionary Biology, offered two reads:

“The Body: A Guide for Occupants” by Bill Bryson: “As someone who studies and teaches human anatomy and physiology, I was utterly charmed and delighted by Bryson’s entertaining tour of the human body from head to toe and from the inside out. Bryson combines his trademark style that mixes old-fashioned journalism with wry humor and anecdotal stories to explore at breakneck speed how our bodies work and why that matters.”

“Zoobiquity” by Barbara Natterson-Horowitz and Kathryn Bowers: “‘Zoobiquity’ is another entertaining, eye-opening, and engaging read that puts human disease into perspective. Natterson-Horowitz and Bowers eloquently explore how so many of the medical conditions we confront — from cancer to obsessive-compulsive disorder — also occur in other species. Although the book’s goal is to examine what animals teach us about being human, I found the book also made me think about how human health can teach us more about other animals.”

Jacqueline Olds

Associate Professor of Psychiatry, Harvard Medical School

Olds, a psychiatrist who specializes in couples, had several suggestions:

“The Angel and the Assassin: The Tiny Brain Cell that Changed the Course of Medicine” by Donna Jackson Nakazawa: “This book discusses the role of microglia in the brain for good and ill! Nonscientists would like this clear explanation of why some of these mysterious neurological diseases occur and new theories about how the immune system may get involved! The fact that the microglia were seen as irrelevant by doctors and scientists but now are seen as crucial might intrigue nonscientist readers.”

“Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding” by Daniel Lieberman: “This is a very personal story about a paleo anthropologist who got ‘hooked’ on exercise (running) and decided to incorporate the study of exercise and running into his work. He found that some of the best runners in the world do it for fun, which was counterintuitive because here in America so many people are so serious and exhausted by their attitude toward exercise as a kind of ‘castor oil’ cure, which is good for them even if they hate doing it. He essentially advocates that people find an enjoyable way to make exercise part of their life so it can be a more pleasant road to health!”

“Under A White Sky: The Nature of the Future” by Elizabeth Kolbert and “How to Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need” by Bill Gates: “A clear-eyed introduction to the science of climate change by a science journalist who writes well for The New Yorker (Kolbert) paired with a book that describes in an optimistic way the work we still have to do to change our carbon emissions worldwide. Nonscientists will find these books very comprehensible and lucid.”

“The Good Life: Lessons from the World’s Longest Scientific Study of Happiness” by Robert J. Waldinger and Marc Schultz: “This book takes the longest-running study of a large group of people and makes it digestible by telling individual stories and distilling the major lessons of the study into guidelines for living. It is already written in lay language yet pays good attention to the evidence-based results of this study without drowning the reader in statistics!”

David Emil Reich

Professor of Genetics, Harvard Medical School

Reich nods to “my colleague Joe Henrich,” the Ruth Moore Professor of Biological Anthropology Professor Of Human Evolutionary Biology, choosing his book, “The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous.” “It’s really a masterpiece and quite thought-provoking.”

Stuart Harris

Associate Professor of Emergency Medicine, Harvard Medical School

“The single most important book I have read in the last 18 months is Scott Reynolds Nelson’s ‘Oceans of Grain: How American Wheat Remade the World,’” says Harris, who also leads Mass General Hospital’s Division of Wilderness Medicine. “He’s an ecologist/economist and this book looks at the fundamental biologic underpinnings that lead to wealth and political stability. In short, empire (from the ancient Greeks on) as ecological phenomenon. Specifically, looking at the 2,000-plus-year history of the Ukrainian grain production and how in feeding the world they have made or broken empires for the last 2,500 years. The inability of the land to produce stable, storable calories is what led to the French Revolution, Russian Revolution, and the Arab Spring.

“This was written before the Russian invasion. Given the current reimposition of embargo by Russia, it is especially pertinent now. (It also gives a fascinating reassessment of the U.S. Civil War.)”

Anyone can look up into the sky at a galaxy. A powerful telescope can help. But how much of it can you really see, much less understand, this way?

That’s where computer simulations come in, according to Andrew Pontzen, professor of cosmology at University College London.

Pontzen spoke Friday, as part of the series Harvard Science Book Talks, about his recent book “The Universe in a Box: Simulations and the Quest to Code the Cosmos,” which he wrote for a general audience. The book focuses on how simulations help scientists study the mysteries of the universe.

Computer simulations have become critical tools for cosmologists and astrophysicists. By modeling complex astrophysical phenomena that are impossible to observe in a lab or any other way we currently have available, simulations provide a glimpse into the formation of galaxies, stars, black holes, and the workings of the cosmos.

With the help of modern supercomputers that can run massive calculations, simulations have enabled scientists to do what they couldn’t do with pencil and paper, Pontzen said.

“The question that we have as cosmologists is twofold: First, how did the universe come to be structured in this way?” said Pontzen. “And how does it relate to the story of our own solar system, the sun, and the earth? It turns out computer simulations are a great way to get to grips with these kinds of questions.”

Cosmology, the study of the universe, has been revolutionized in the last few decades by the development of faster, more powerful supercomputers. One hurdle for researchers in the past has been the immensity of the universe. There might be trillions of galaxies, each with hundreds of billions of stars. To the naked eye the galaxies appear scattered at random, but simulations show they are organized in a pattern, the so-called cosmic web.

But as much as simulations provide insights into the structure of the universe, they also reveal only “the tip of the iceberg,” said Pontzen.

Visible materials in the universe, such as stars, planets, and the Milky Way and Andromeda galaxies, can be seen directly through telescopes, but they comprise only about 5 percent of the total mass and energy of the universe. The remaining 95 percent includes materials such as dark matter and dark energy, which at the moment scientists are unable to probe in any laboratory.

Simulations have proven to be effective in predicting the behavior of dark matter, an extra material in the universe that can’t be seen but can make its presence felt through gravity.

The story of how simulations came to be goes back to the 19th century, said Pontzen. In his book, he pays tribute to computer pioneers Charles Babbage and Ada Lovelace. An English mathematician, Babbage is considered the “father of the computer” for having built a computing machine in 1821. Lovelace, also an English mathematician, wrote a set of operating instructions, or an algorithm, for Babbage’s machine, years later.

Simulations couldn’t exist without computers, Pontzen said.

“Ada Lovelace wrote a really beautiful description of what a simulation essentially is,” he said. “She said, ‘Those who view mathematical science not merely as a vast body of abstract and immutable truths will regard with special interest all that can tend to facilitate the translation of its principles into explicit practical forms.’”

As an example of a pioneering use of simulations, Pontzen highlighted the role of meteorologist Lewis Fry Richardson, who applied math and physics to weather forecasting in the early 1900s. “He attempted to do simulations of meteorology to make weather forecasts before computers were even available,” said Pontzen. “He was trying to do this by hand, using what looked like a giant spreadsheet he was filling in, doing loads of calculations by hand in order to translate theoretical physics into something really practical.”

With its alluring ability to visually replicate systems or phenomena impossible to study in a lab or outer space, computer simulations have been embraced in medicine, climate science, economics, and epidemiology, among other disciplines.

Simulations have also captured people’s imaginations and popular culture. In “The Matrix,” a science fiction movie released in 1999, humans are trapped inside a simulated reality created by intelligent machines. In 2003, Swedish philosopher Nick Bostrom published a paper titled “Are We Living in a Simulation?”

In his book, Pontzen deals with the question. During the talk, the event’s moderator, Atınç Çağan Şengül, Ph.D. ’23, didn’t miss the chance to ask whether it’s possible that we are living in a simulation. The cosmologist was quick to dismiss it, saying that even if it’s a fun idea to toy with, scientific evidence does not support the existence of “some external reality.”

“I think we’re in quite a lot of trouble when we start believing in that kind of thing because then, by implication, everything we’re doing in cosmology is a bit of a waste of time, because all that stuff out there is not real,” said Pontzen. “It’s first at all a problem for cosmologists, but it’s also a problem for all of us, as humanity, because it’s creating a sort of doubt on the nature of reality … To me, this set of ideas is quite antithetical to scientific progress. It’s almost like encouraging us just to give up on knowing what’s really going on.”