How to Change Everything Page 3

  Our modern way of life is constantly emitting these heat-keeping greenhouse gases into the air. This means that we are constantly heating the planet in a way the Earth has never seen before.

  You’ll find out more about the links between human activity, energy use, greenhouse gases, and climate in chapter 4. First, though, you deserve to learn who is at greatest risk if we continue on our current path. You’ll then see why this moment of danger is also a moment of great opportunity.

  The bad news is that we are responsible for climate change. The good news is that we can do something about it. We already have the knowledge, tools, and technologies we need to do amazing things.

  PREDICTING THE CLIMATE FUTURE

  Scientists know that some climate disruption is going to happen no matter what we do, because warming that has already begun will not stop overnight. But we also know that if we do not act, climate change will be a lot worse. So climate scientists are constantly working on ways to measure our effect on the climate and to predict, or project, what the climate will be like in the future, to help us determine how to keep that warming to a minimum.

  Climate scientists rely on two things: data and tools. The data is mountains of information. Over many years, measurements have been made of temperatures, wind speeds and directions, rainfall amounts, levels of salt in the oceans, sizes of glaciers, and much more. The tools are computer programs called models that are designed to mimic our planet’s complex climate system. Researchers test a model by having it reproduce past changes in the climate, then comparing the results with the historical record. Next, they make predictions about the future, to show us what changes we can expect from specific changes in the climate system.

  By changing the data that goes into a model, scientists can answer “what if?” questions. What if humans started reducing greenhouse gas emissions? What if they started emitting more? What role do clouds play in a given prediction? What if the amount of wildfire smoke increased every year?

  Modeling is challenging because the climate system is so complex. Many programs for doing it exist, and they work in a variety of different ways. In addition, not all researchers use the same sets of data within these programs. This is why projections of the climate’s future differ. Projections also change when scientists gather new data or create new, more precise models. When research showed that the oceans are warming faster than expected, for example, or that Greenland’s ice is melting faster, that information changed many climate projections.

  Two other things that can impact climate projections are tipping points and feedback loops.

  Tipping Points:

  The climate does not change in a steady, smooth line. Something that has been changing slowly can suddenly change quickly. This may happen because conditions have reached what is called a tipping point.

  Imagine yourself slowly, steadily leaning to one side. At a certain point you will simply fall over. You have reached the tipping point. The remainder of your sideways movement will be swift and possibly catastrophic. And once you reach the point of falling, you cannot raise yourself back to your upright position.

  The same thing can happen with climate change. For example, in 2014 scientists at NASA and the University of California in Irvine broke some disturbing news. They had been studying the West Antarctic Ice Sheet, part of the massive coat of ice that blankets the south polar continent. On an area the size of France, they said, glacier melt now “appears unstoppable.” What had once been a slow flow of melt into the sea was significantly speeding up because the water where the glaciers meet the sea is getting warmer, melting them from beneath.

  According to these researchers, a tipping point may have been reached, probably signaling the end of the West Antarctic Ice Sheet. If it keeps melting, as they predict, it will eventually raise sea levels some 9.8 to 16.4 feet (3 to 5 meters). “Such an event will displace millions of people worldwide,” one of the scientists said.

  While reaching a tipping point like this is serious, it still could take centuries for the ice sheet to collapse completely. Even if we can no longer completely prevent the disaster, we have time to delay it. The only way to do that is to slow the rate at which the ice sheets are melting and moving, which means slowing the warming of the planet. And the only way to do that is to cut the amount of the greenhouse gas emissions that are raising temperatures and fueling global warming.

  Feedback Loops:

  Another complication of climate projections is feedback loops. These happen when one process speeds up or slows down another process, and then the second process speeds up or slows down the first process, and on and on.

  Sea ice shows us a feedback loop in action. Ice floats on water in the Arctic Ocean and on the edges of Antarctica. Warming temperatures cause some of it to melt in the summer. When it melts, a surface that was once covered by white ice is covered by dark water instead. White ice reflects the sun’s heat away from the Earth’s surface, but dark water absorbs heat. So when the warming trend melts some ice, there is less ice to reflect heat and more open water to absorb it. This boosts the warming trend, which now melts more ice faster. If nothing happens to break the loop, it will go on until the summers are ice-free.

  Feedback also happens with permafrost, the soil that stays frozen year-round beneath the surface in cold places, such as high mountains and the polar regions. Permafrost contains material from things that were once alive, such as dead plants and bacteria. When temperatures rise high enough, permafrost starts to thaw, and that once-living material decays. This releases methane and carbon dioxide, two greenhouse gases. Putting more greenhouse gas into the atmosphere speeds up the warming, which speeds up the thawing… and another feedback loop is under way. Such loops add to the challenge of climate modeling because they cannot always be predicted.

  Permafrost is permanently frozen soil—until temperatures rise, and it melts.

  All of this means that climate change is a fast-moving field of study, and scientists must keep developing new and more accurate tools for gathering data and modeling projections. These researchers are a vital source of information about what will happen to our climate if we do nothing—and also about the changes we can make that will lead to better outcomes.

  A melting section of permafrost has broken off into the sea.

  EARTH TOMORROW?

  Scientists’ climate models may produce a range of possibilities for the future, but many of them start at the same point in the past.

  That starting point is the average world temperature in the late nineteenth century—around 1880. From that point, scientists measure the temperature today, then project future increases of 1.5°C (2.7°F), 2°C (3.6°F), and more.

  Why those numbers? Because in 2016 nearly two hundred nations signed the Paris Agreement, part of the United Nations Framework Convention on Climate Change. The Paris Agreement set a goal of cutting greenhouse gas emissions to prevent the global temperature from increasing more than 2°C above preindustrial levels, but with efforts to keep the increase below the even better target of 1.5°C. These were believed to be the lowest targets that had a chance of being achieved.

  The difference between 1.5°C and 2°C may seem small, but it means a lot. In September 2018, the Intergovernmental Panel on Climate Change (a large international team that the United Nations created in 1988 to provide the world with scientific information about human-caused climate change) published a report that compared the effects of 1.5°C of global warming to the effects of 2°C. The differences are huge.

  At 2°C of warming, 1.7 billion more people would be at risk of severe heat waves one out of every five years than they would be at 1.5°C. Sea levels would rise by an additional four inches (ten centimeters). So for these reasons and more, 1.5°C of warming is a much better goal than 2°C.

  How is the world doing on meeting that target?

  At the time this book was written, the world had already warmed 1°C since the nineteenth century. The World Meteorological Organization,
which tracks temperature, projects that we still are on a path to warming the world by 3°C (5.4°F) to 5°C (9°F) by the end of this century. And as we’ve already seen, 2019 was the second-warmest year on record. As this book was being finished, 2020 was on track to be in the top five.

  Temperature isn’t the only way to measure climate change, though. In November 2019, a NOAA report revealed that the global sea level had risen eight to nine inches (twenty-one to twenty-four centimeters) since 1880. For most of the twentieth century, the sea level rose at a rate of 0.06 inches (1.4 millimeters) a year. From 2006 to 2015, though, the ocean rose an average of 0.14 inches (3.6 millimeters) a year. This means the rise of the oceans is speeding up, just like the rise in temperature.

  Why 1880?

  The Baseline for Measuring Change

  Most nations of the world have signed the Paris Agreement, which says that they will try to limit the planet’s warming to 2°C (3.6°F) above preindustrial levels—or, better yet, to 1.5°C (2.7°F), if possible. But what does “preindustrial levels” mean?

  The Paris Agreement doesn’t define “preindustrial” precisely, but in general terms, it means “global temperature before the rise of modern industries powered by fossil fuels.” As you’ll see in CHAPTER 4, that rise began around 1770, so the ideal baseline for measuring climate change would be the temperature of the world at that time.

  Unfortunately, only a few good records exist of temperature measurements made before 1850. Scientists can estimate earlier temperature ranges from physical evidence, such as growth rings in trees and ice cores, long tubes of ancient ice carefully drilled from places such as Greenland and Antarctica. They can use computer models to estimate past temperatures based on things such as the position of Earth relative to the sun and the amount of ash and other particles in the atmosphere from volcanic eruptions. But for practical reasons, most climate models use the years 1850–1900 or 1880–1900 as their baseline, because that is when people began keeping reliable global temperature records.

  Some amount of future warming is already locked in, so the sea will not stop rising entirely. In the worst case, if greenhouse gas emissions remain at their current levels, the sea level in 2100 could be as much as 8.2 feet (2.5 meters) higher than it was in 2000. This would flood huge areas of the world’s low-lying coastlines and devastate dozens of major cities. It would turn millions, maybe billions, of people into climate refugees who would be forced to flee to new locations in other cities or even other countries.

  Unless we do something about it.

  NOAA projects that if humans reduce their emissions of greenhouse gases as much as possible to slow the warming of the planet and the melting of its ice, the global sea level in 2100 will likely be a foot (0.3 meters) higher than it was in 2000, instead of 8.2 feet (2.5 meters) higher. That is a huge difference, and it’s why young people like Greta Thunberg are so frustrated that politicians aren’t doing what is required to dramatically reduce the level of climate change.

  Keeping the warming below 1.5°C, however, will be like turning an enormous ship around. The authors of the Intergovernmental Panel on Climate Change study found that it would mean cutting global carbon dioxide emissions almost in half by 2030, and bringing global emissions to zero by 2050. Not just in one country but in every major economy on the planet.

  What would we have to do to cut emissions by that much? Carbon dioxide (CO2) is the greenhouse gas that is doing the most to drive global warming. It is emitted when we burn wood, coal, oil, and gas. Deforestation, driving, flying, and many industrial activities such as drawing energy from fossil fuel–burning power plants all release carbon dioxide emissions.

  Already the amount of CO2 in the atmosphere is far past safe levels, so meeting the 1.5°C limit on warming would mean removing a great deal of it. This could be done through technology designed to capture and store carbon dioxide, but that technology has limits, as you will see in chapter 7. Or we could do it the old-fashioned way, by planting billions of trees and other plants. They draw CO2 out of the atmosphere and add oxygen to it. Still, no one solution is quite enough on its own. The Intergovernmental Panel on Climate Change report says that to meet our targets, we need to make rapid “changes in all aspects of society.”

  We must decide to immediately change how our societies produce energy, how we grow our food, how we move ourselves around, and how our buildings are built. Among other possibilities, we could replace fossil fuels with clean, renewable energy sources such as wind and solar power, build networks of fast electric trains to take the place of some driving and flying, and design houses and office buildings that will require less energy to heat and cool.

  But we need to think about deeper changes, too. We could use less energy, rather than just switching where we get it from. We could reduce the number of miles people drive by improving public transit, even making it free. And because every product we buy represents energy used at every step of making or shipping it (even “green” products!), we could all decide to shop less and consume less.

  It is the biggest challenge we humans have faced. Are we up to it?

  There is still time to reach that target of 1.5°C, but only if we act now.

  IT’S NOT JUST THE HEAT

  Warming is not the only factor stressing our planet. Many other human activities are changing the natural world, rapidly making it look very different from the beautiful and bountiful places you have all seen in nature documentaries about rain forests and oceans.

  The difficult truth is that many of the life forms that share our planet are in a state of crisis. Some of them are losing their homes because human activity is filling in the wetlands, plowing the prairies, polluting water with chemicals and plastic, and smashing the reefs where they live. Some creatures are unable to adjust to the changing temperatures. Various bird species cannot find their seasonal foods, for example, because plants now flower before the birds return from migration. Other animals are being hunted toward extinction. And because humans have only begun to explore the deep ocean, whole species will be lost before we have even learned that they exist.

  We are also cutting down trees at an alarming rate. People and corporations harvest trees for fuel, to make paper and other products, and to clear land for ranching cattle or growing plantations of cash crops such as corn, soybeans, and sugar.

  Large stretches of forest on the Southeast Asian island of Borneo, for example, have been destroyed by the demand for palm oil, which is used in many foods, vitamins, beauty products, and other consumer goods. Natural habitat that was once home to countless plant and animal species has been replaced by rows of palm trees that can be harvested for this oil. In other places, such as vast areas of the Amazon rain forest, trees are cut down or deliberately set on fire to make room for cattle pastures.

  Climate change worsens the effects of these bad choices. For example, forests that are already under threat of human deforestation are also dying more rapidly as tree-destroying insects move into new territories that have grown warmer because of climate change. And, of course, this creates a feedback loop of warming, because when trees die, they stop drawing CO2 out of the atmosphere. Dead trees are also drier than living ones. They are more likely to catch fire.

  Our actions don’t just hurt the planet, the environment, and other living things, though. They harm us, too, and not always in ways that are easy to see. One example is the effect of carbon dioxide on our food.

  Scientists have discovered that when the amount of CO2 in the atmosphere goes up, the nutritional quality of food crops goes down. In experiments, researchers surrounded open-air plots of rice and wheat with machines that added CO2 to the air. The grains of those plants had lower than normal levels of protein, iron, zinc, and some B vitamins.

  If greenhouse gases keep increasing, our food crops may become less nutritious overall, adding to problems of hunger and disease. Even more serious, if climate change continues on its current path, heat and drought could also make it impossible to
farm large areas of food-producing land.

  All of us can do things in our daily lives to slow down climate change and ensure that this doesn’t happen. We could follow Greta Thunberg’s example and convince our families to give up meat and airplane travel. Even two meatless days a week, or one less flight per year, is a start. But while our individual choices make a difference, individuals alone cannot bring about the sweeping changes we need. If we are to make those changes, then government, business, and industry—including the major sources of greenhouse gases—must also make very different choices.

  This is the knowledge that drove young climate activists into the streets. This is why it is so important for us to join together and make our voices heard, telling our leaders that we care passionately about the future and helping to shape a better way forward. Now that you know what those climate activists know, this book will show you how you can get involved too.

  Because by speaking up together to say no to rising temperatures, we also say yes to a more fair and equal world.

  CHAPTER 3 Climate and Justice

  Not everyone experiences the effects of climate change to the same degree. We live in a world of racial, economic, and climate injustice, with some people having far more than they need and many others not having close to enough. This chapter will show you how these injustices began and how they are often interconnected—and also some of the ways people are working to end them.