Column: How do we get there from here?

For the September issue of Physics Today, I wrote about the so-called climate connectivity of the world’s tropical forests: the extent to which forest species can find paths across a fragmented landscape to suitable new homes in a warming world. The analysis didn’t consider this year’s fires in the Amazon rainforest—the forest-cover data the researchers used allowed comparisons only through 2012—but it found that deforestation had done plenty of damage already. Even if habitable forested regions exist in 50 or 80 years, many species won’t be able to get to them from where they are now.

It was an emotionally taxing story to write. Stories about climate change always are. Most of our content in the Search & Discovery department comes from a place of enthusiasm: We write about research because we think it’s exciting, and we hope you’ll be excited by it too—whether it’s about the march of technological progress , the big questions of the universe , or a wacky new result that piqued our curiosity . Climate change research is different: We cover it not because we want to but because we have to. This is the greatest crisis of our time, and understanding its manifold consequences is important. But thinking about those consequences for a month straight is not a lot of fun. I don’t envy the researchers who work in this field full-time.

Miller’s Diary

Physics Today editor Johanna Miller reflects on the latest Search & Discovery section of the magazine, the editorial process, and life in general.

At least this month’s story leaves some room for optimism that we can still undo the damage we’ve already done. Not all climate change stories do. A few years ago, I wrote about a pair of studies that came to a particularly bleak conclusion : that the glaciers of West Antarctica are beyond saving. Their ultimate collapse may take a century, or it may take a millennium, but it’s going to happen sooner or later, the researchers concluded, even if ocean temperatures and greenhouse gas levels were to immediately go back to normal. That’s pretty grim.

For the sake of my sanity, I wrote a second story that month on a less depressing topic: By analyzing the isotopes of lead in harbor sediments outside Rome, researchers traced the use of the city’s lead-lined aqueducts over the better part of a millennium, from the harbor’s construction in about the year 112 until well into the Middle Ages. An ancient people inadvertently poisoning their own water supply might seem like a strange choice for a nondepressing story—but the researchers explicitly found that there wouldn’t have been enough lead in the water to do much damage to anyone’s health. And their analysis spanned a chapter in the history of Western civilization that’s long fascinated me, if only because most general history overviews have so little to say about it: First the Roman Empire was there, then it wasn’t, and then somehow, centuries later, the map of Europe was completely reorganized into something much closer to its present form.

How did we get here from there? The lead-isotope researchers didn’t find anything new to answer that question, but they did confirm a key turning point that’s documented in the historical record. In the middle of the sixth century, the Constantinople-based Byzantines (successors to the eastern half of the Roman Empire) wanted to get the old empire back together, and they set out to conquer the Italian peninsula from the Ostrogoths. They eventually succeeded—and when they reached Rome, they started up the long-disused aqueducts—but the two-decade war took such a toll that it left them vulnerable to subsequent attacks. (For an alternative-history take on the events of that era, I recommend Lest Darkness Fall by L. Sprague de Camp.) I never thought I’d have anything to say about Byzantine history in a physics magazine. But because of climate change, I did.

And in a way, it’s because of climate change that I have a job at a physics magazine at all. In my final semester of college, I found myself with a gap in my schedule, so I signed up for a class in scientific writing. One of our assignments was to write a paper about a controversial issue. “How about global warming?” I asked. “You know, like whether it’s happening or not.”

“Oh, OK,” said the instructor, probably inwardly rolling his eyes at me like I am now.

That class—and that assignment—planted the first seed in my mind that writing about science would be an enjoyable thing to do; without it, I likely never would have gotten the idea, seven years later, to answer a job ad in Physics Today. But the paper itself is long lost to the mists of time (or at least to a pile of dusty boxes in a closet at my parents’ house), as is surely all for the best. I was a naive undergraduate determined to give both sides an equal voice, whether that balance was warranted or not. I probably didn’t make a whole lot of sense.

But that was in 1999. We’d only just gotten the news—or maybe we didn’t even have it yet—that 1998 had been by far the hottest year on record to date. Before then, you could perhaps be forgiven if you looked at the temperature records and convinced yourself that they showed nothing but natural fluctuations. Now it’s 20 years later, and there’s no more room for doubt. The 1998 record temperature anomaly has been exceeded many times, including by all five of the years since 2014. July 2019, we’ve just learned, was the hottest month ever recorded. Climate change is happening. Humans are causing it . The ramifications are already bad, and they’re going to get worse.

It’s clear by now where we need to go on this. We need a wholesale switch to renewable energy. We need to cut way back on things that don’t yet have sustainable equivalents, like airplane flights . We need to pull as much carbon back out of the atmosphere as we can. We need to make major changes in the way we use land . And we need to steel ourselves—and the rest of the world—for the effects of climate change that, despite our best efforts, are coming anyway.

But knowing our destination isn’t enough; we also need a path to get there, and I don’t know if we’re going to find one in time. We already have a lot of the energy technology that we need, but rolling it out on a large scale has been far too slow. We have the collective ingenuity to develop the technologies that don’t yet exist, but most of our greatest minds are otherwise employed; saving the world doesn’t always pay the bills. And we have some politicians with some good ideas, but their voices are too often overpowered or drowned out by distractions. We’re on course to do way too little, too late, and it’s hard for me to imagine what could radically alter that trajectory anytime soon.

How are we going to get there from here?