Saving Us

by Katharine Hayhoe

  HUMANS ARE THE BIGGEST UNCERTAINTY

  The concept that we have a choice to make is surprisingly new. Back in the 1990s, nearly all regional and sectoral climate assessments treated climate impacts as essentially inevitable. They were just looking ahead to see what was going to happen, so people could prepare. By doing so, they cast humans as the archetypal victim in an old western, tied to the tracks while the locomotive steamed around the corner. There’s no altering the speed of the train, this metaphor suggested, but if you could see it coming at least you could prepare to minimize the impact.

  This view isn’t just unhelpful—it’s wrong. Why? If disaster isn’t inevitable, and we can do something about it, understanding the difference our choices make becomes absolutely critical. This simple concept is the key to everything I do, and everything I talk about in this book.

  What are our choices? As John Holdren, senior science advisor to President Obama, declared in his 2008 address to the U.S. National Academy of Sciences, we have three of them. We can reduce the heat-trapping gas emissions that are causing climate to change; we can build resilience and prepare to adapt to the changes that we can’t avoid; or we can suffer. “We’re going to do some of each,” he said. “The question is what the mix is going to be. The more mitigation we do, the less adaptation will be required, and the less suffering there will be.”

  To correct the train metaphor, we humans are actually on the locomotive’s footplate, with our hand on the throttle. The train is heading for a bridge that’s down. We can assume protective positions to ride out the crash, but we can also stop accelerating (stop increasing our emissions) and hit the brakes (decrease our emissions) to minimize the damage. We’ll have a lot better chance of surviving, the more we do.

  So while localized information on how impacts affect us helps people understand why climate change matters, it’s essential to pair this information with an understanding of how our actions matter, how impacts depend on the carbon emissions we produce. This information is time-sensitive: it presents us with a choice to make now. If we don’t act, that in and of itself is also a choice; and it’s one that makes the worst-case scenario, with all of its attendant suffering, virtually inevitable.

  We humans are the greatest uncertainty in the climate system.

  THE DIFFERENCE OUR CHOICES MAKE

  When the Union of Concerned Scientists invited me to help lead a new regional climate assessment for the state of California in 2002, I knew that we couldn’t just use the same mid-range, middle-of-the-road scenarios previous assessments had. We had to show the difference that human choices can make. So we decided to compare two very different climate futures: First, what if humans continue to depend primarily on fossil fuels for the rest of the century and emissions continue to rise? And second, what if we accelerate the transition to clean energy with climate-friendly policies, bending emissions down? What would California look like in those two different futures?

  The all-star project team included Steve Schneider, one of the most experienced climate scientists of our time. A physicist who’d served as advisor to U.S. administrations since the Nixon era, Steve’s outspoken advocacy over the decades has encouraged many of us scientists to also speak out about the risks of climate change. A California resident, Steve wanted to know the answers to these questions as much as anyone.

  The two scenarios were first fed into the complex global climate models that capture the physics and chemistry and, increasingly, the biology of the planet, to see how the Earth’s climate system would respond to each possible future. Global models and top colleagues weren’t enough, though. Global model output is notoriously coarse and would not give a precise enough picture of the impacts of climate change on California’s varied terrain. I had to figure out how to “downscale” the global climate model output into high-resolution, finely gridded information. I called Ed Maurer, a hydrologist who’d recently moved to California’s Santa Clara University. “I’m not sure about this,” Ed said cautiously, “but it sounds important. Let’s see what we can do!”

  I collected the temperature and rainfall projections from the global models. Ed gathered the historical observations. Together, we bias-corrected and downscaled them. Then we parceled the data out to the team of over thirty researchers who were studying climate impacts on California’s water, wildfire risk, health, wine industry, air quality, and more. For the first time, everyone’s analysis was based on the same climate projections, and everyone was quantifying the difference between a high-carbon versus a low-carbon future. And when the results started to trickle in, they were even more shocking than I’d expected.

  It turns out that for our modern world, the difference between a higher versus a lower emissions future is nothing less than the survival of our civilization. In the lower emissions scenario, our agriculture, our water, and our economic systems can continue, albeit with significant and often costly adaptations. The higher emissions scenario predicts the end of many of these systems as we know them. For example, the city of Sacramento could experience a Tucson-like climate before the end of the century, and up to 90 percent of California’s winter snowpack (which supplies half its water) could disappear.

  The results of our work, published in the Proceedings of the National Academy of Sciences, hit home. A year later, California governor Arnold Schwarzenegger signed the very first law in the history of the United States requiring mandatory greenhouse gas emission targets. Standing behind him at the ceremony were the California authors of our study. The law, executive order S-3-05, listed the impacts we’d found were projected to occur under the higher scenario as justification for why California was taking action. “I say the debate is over. We know the science. We see the threat. And we know the time for action is now,” the governor said.

  The message had been received, loud and clear: we have a choice, and now is the time to act.

  I. Given the interconnected nature of our world and our tendency as scientists to underestimate the extent of climate impacts, I feel this is unlikely. But since I’m a scientist, I have to say it’s at least hypothetically possible.

  11 THE SICKNESS AND THE CURE

  “Why do you fight for our planet? For me, it’s to save lives, protect our children’s future, fight for social and racial justice, and support people’s health and human rights around the world.”

  GAURAB BASU, CAMBRIDGE HEALTH ALLIANCE

  “There is no Planet B.”

  CLIMATE ACTIVIST’S PLACARD

  A few years ago, I received an invitation to an event that sounded so improbable I almost deleted the email, suspecting it was a fake. A festival held in the Canary Islands organized by Queen guitarist Brian May and his former PhD advisor, which had featured Brian Eno as a musical guest the previous year… could that be real? Fortunately, I decided to look it up before deleting it. I learned that Starmus was indeed a real festival of science communication and art, and they really were inviting me to speak at it. I accepted, and was flabbergasted to end up with a front-row seat at one of Stephen Hawking’s final talks.I I’d read the British physicist and Nobel Prize winner’s best-selling 1988 book, A Brief History of Time, as an astrophysics undergraduate. His grandiose vision of the universe injected meaning and life into the endless and often tedious equations required to understand quantum probabilities and nonlinear fluid dynamics, so seeing him speak had been on my bucket list for years.

  Hawking’s talk, like his posthumous book, focused on the future of the human race. He repeated his concern that climate change was one of the greatest threats facing this world and stressed the urgent need to avoid catastrophic impacts. “There is no new world, no utopia waiting around the corner,” his computerized voice said, its very lack of inflection making the warning even more ominous. I agreed—but my jaw dropped in surprise when Hawking concluded by saying humans will have to populate a new planet to survive climate change. As a climate scientist, I know the speed of climate change far exceeds our ability to terraform Mars.
Unchecked, climate change will overwhelm our civilization long before anywhere near the number of people required to “save civilization” could be transported to another planet where they’d thrive. And even if a few hundred or even thousands did manage to make it to Mars, they wouldn’t be the poorest and most vulnerable of us, who are already suffering the greatest impacts. It would be the Jeff Bezoses and Elon Musks of the world who could afford to buy their own ships and load them with their favorite people like a real-life version of the black comedy Kingsman.

  Two days later, I was waiting backstage for my own talk. The speaker immediately before me was Martin Rees—Lord Rees—Astronomer Royal of the United Kingdom, whose groundbreaking work on galaxy clustering and quasars I’d also read as a student. As technicians labeled our identical laptops with different colors of tape to make sure they didn’t get confused, I finally asked him the question that had been gnawing at me since Hawking’s talk. “Do you agree that we may have to terraform Mars to escape climate change here on Earth?”

  “Oh no,” he replied categorically. “Stephen and I are old friends. But fixing climate change is a doddle in the park compared to terraforming Mars.”

  That was a mic drop if I’d ever heard one.

  CLIMATE SOLUTIONS ARE HEALTH SOLUTIONS

  There is no backup planet in the wings; whether we like it or not, this is our world. That’s why, when it comes to our choices, it isn’t only about avoiding the worst: it’s also about making our planet a better place to live. And nowhere is the contrast between the risk of inaction and the reward of action more evident than when it comes to our health.

  Ed Maibach is a runner. He’s also a public health researcher who directs George Mason University’s Center for Climate Communication. And Ed’s research confirms, time and time again, that our health depends on the planet’s health. Just as smart individual choices in diet and lifestyle benefit our short- and long-term health, so, too, smart societal choices can reduce both the severity of climate change and its impact on our health.

  “Americans tend to see global warming as a distant threat,” one of Ed’s 2018 articles begins. But he’s found that giving people information on how climate change affects their health makes them more engaged and more willing to support climate action. What kind of information? How climate change affects us directly, through heat waves, stronger storms, flooding, and indirectly, through air pollution, disease, and contamination. It affects the quality of our food, the safety of our homes, and even our mental health. And what type of action can we take? First, mitigation: cutting air pollution, heat-trapping gas emissions, and climate change. And second, adaptation: preparing to weather the impacts we can no longer avoid.

  “The health benefits of climate solutions,” he told me, “are profound, nearly immediate, and local—which in turn helps to address the psychological conundrum of climate change being perceived as distant. Climate solutions are health solutions; and not just in the distant future, but today, here, for us. They pay for themselves almost immediately, so their future benefits are essentially free.”

  BEATING URBAN HEAT AND AIR POLLUTION

  When we think of climate change and health, our minds often jump right to the most obvious connection: stronger and more frequent heat waves. And these are a big deal. As I mentioned before, in July and August 2003, the then hottest summer on record in Europe caused more than 70,000 premature deaths across the continent. Even back then, climate change had already doubled the risk of such a heat wave occurring. And as the mercury ticks up, tempers also flare. Psychologist Craig Anderson has been studying this phenomenon since the 1980s. “Hot temperatures increase aggression by directly increasing feelings of hostility and indirectly increasing aggressive thoughts,” he wrote in a 2001 paper called “Heat and Violence.” That’s why warmer cities have higher rates of violent crime than cooler ones, and violent crime tends to spike in the summertime.

  A national report from the Union of Concerned Scientists found that if emissions continue unchecked, by midcentury the U.S. will see twice as many days with a heat index above 38°C or 100°F as today, and four times as many days with a heat index above 41°C or 105°F. “Failing to reduce heat-trapping emissions would lead to a staggering expansion of dangerous heat,” the authors wrote. This heat would be worse in cities, thanks to the urban heat island effect—created by high concentrations of concrete, asphalt, and buildings in cities. It’s also worse in poorer neighborhoods, which are less likely to have many trees. Trees cool their local environment by releasing water vapor and providing shade. And the more air-conditioning we use, powered by fossil fuels, the higher the emissions and the hotter the planet will get. It’s a cruel feedback loop.

  Then there’s the fact that burning fossil fuels doesn’t only produce heat-trapping gases, it also generates air pollution. Air pollution from burning fossil fuels is responsible for nearly 9 million premature deaths per year. To put those horrifying numbers into context, by spring 2021 there had been 3 million deaths from COVID-19, worldwide. That’s why the World Health Organization (WHO) has called air pollution the “single largest environmental health risk” facing humanity; and climate change only makes it worse. Higher temperatures speed up the formation of hazardous ground-level ozone that forms from tailpipe and industrial emissions. Ozone, particulates, and other pollution makes it hard to breathe deeply, causes coughing, and damages our lungs, leaving them vulnerable to infection. Those who suffer from lung conditions such as asthma, emphysema, and bronchitis are especially at risk, but high ozone days can harm even healthy people. And air pollution exacerbates coronavirus, by making people’s lungs more vulnerable to the infection.

  In the Netherlands, researchers found that even a 20 percent increase in exposure to particulate pollution doubled the risk of COVID-19 infection. A U.S. study found that people living in polluted areas were much more likely to die of the virus. Analyses in China, Italy, Europe, and elsewhere found similar results. Not only that, but those who were already impoverished or disadvantaged were more likely to have been exposed to more air pollution prior to the pandemic, worsening their vulnerability. In Chicago, Illinois, African Americans make up less than a third of the population but more than two-thirds of COVID-19 deaths; Harvard researchers believe that air pollution may account for some of that disparity. And just as scary are new findings on how air pollution harms our brains. It can increase the risk of dementia and other neurodegenerative disorders that so many older adults experience. It can also affect the newly developing brains and nervous systems of babies before they are born, delaying or impairing cognitive development and increasing risk for autism.

  At this point you might be tempted to assume the fetal position yourself. How are we supposed to prevent such hideous, pervasive, yet invisible harms? Ed has the answer to that: implement solutions that help today, and tomorrow. For example, tackling the urban heat island effect, the very factor that makes extreme heat and air pollution worse in urban centers, can reduce climate impacts and make us better prepared to weather them.

  Take the city of Chicago, for example. It’s classified as a “severe ozone nonattainment area” by the Environmental Protection Agency due to its endemic air pollution. It also experienced deadly heat waves, responsible for hundreds of deaths, in 1995 and again in 1999. In 2008, the city’s mayor announced an ambitious Climate Action Plan for Chicago. In it, the city identified the most vulnerable people and neighborhoods and worked with me and other climate scientists to determine how these risks were likely to change under a higher and lower emissions future. For example, the city’s first responders told me that they staffed by the thermometer in the summer. As heat spiked, health emergencies, violence, and crime in the South Side of the city rose a noticeable amount. Then they identified key things they could do today that would make people’s lives better now, reduce carbon emissions, and ensure the city did its part toward achieving a lower emissions future. To mitigate summer heat, they identified “hot spots” where
trees, “green roofs” planted with vegetation, and reflective surfaces would cool temperatures during the hottest days. This would slow down the reactions that create ozone pollution and reduce energy use and carbon emissions at the same time.

  How are they doing today? As of 2019, Chicago has hundreds of green roofs around the city, including an expansive one on its city hall where 150 species of plants now grow. They’ve shut down the two local coal-fired power plants that were a big source of air pollution and carbon emissions. They are well on the way to building one of the largest electric bus fleets in the U.S. and have increased the number of bicycle trips people take to over 45 million each year. There’s still a ways to go in meeting their goal of six thousand green roofs and a million trees, but they are heading in the right direction.

  Heat isn’t their only problem. More frequent and more intense heavy rain events have been flooding the city, shutting down the public transportation system. It’s also leading to sanitary sewer overflows into the Chicago River and beach closures on Lake Michigan. Flooding is so severe that, in 2014, Farmers Insurance sued the county and the city’s water district, stating that they “knew or should have known that climate change… has resulted in greater rainfall volume, greater rainfall intensity and greater rainfall duration.” As a result, the city has built two new reservoirs to hold the storm water. And most importantly, everything they’ve done has helped cut costs, clean up the air people breathe, make the city a safer place to live, and reduce carbon emissions. It’s a win-win-win.