The Weather of the Future: Heat Waves, Extreme Storms, and Other Scenes from a Climate-Changed Planet - Heidi Cullen (2010)
“What’s the forecast?”
I heard this question a lot when I first started at The Weather Channel in 2003. People figured that if I worked at a 24-7 weather network, I must be a meteorologist. That was fine by me, I’ve always been a closet weather geek, and besides, who doesn’t secretly want to be a meteorologist? There is something so appealing about going to work every day and predicting the future without the use of tarot cards or constellations.
I’m not sure how many people secretly want to be climatologists, but that’s what I really am. And for anyone wondering what a climatologist is, here’s a rough answer: Climatologists pick up where meteorologists leave off. We focus on weather timescales beyond the memory of the atmosphere, which is only about one week. And I guess you could say we also focus on timescales beyond human memory, which is shorter than you might think.
Climatologists look at patterns that range from months to hundreds, thousands, and even millions of years. The single most important and most obvious example of climate is the seasonal cycle, otherwise known as the four seasons. The seasons, a result of the 23.5° tilt of the Earth’s axis, affect the weather dramatically. And the physics behind the seasons are well nailed down. Summer, the result of one hemisphere’s being tilted closer to the sun, is warmer. And winter, the result of the other hemisphere’s being tilted away from the sun, is colder. The forecast for the seasons follows the physics; this is why, if I issue a forecast in January that says it will be significantly warmer in six months, you probably won’t think I’m a genius, but you’ll believe me.
There are countless other patterns on our planet that influence the weather. Take El Niño, for example. Nicknamed by fishermen along the coast of Peru after the Christ child, El Niño is a warm ocean current that typically appears every few years around Christmastime and lasts for several months. From its home in the tropical Pacific Ocean, El Niño is powerful enough to influence weather across the entire world. Unlike the seasons, which are controlled by astronomical forces, El Niño results from processes that happen here on Earth and that don’t come and go like celestial clockwork. Climatologists have come to understand that the physics of El Niño result from a series of complex interactions between the ocean and the atmosphere. Technically, El Niño (EN) describes the ocean component, whereas the atmospheric component is known as the Southern Oscillation (SO). That’s why climatologists generally refer to it as ENSO.
During an ENSO event, the easterly trade winds weaken and the surface water off the coast of Peru and Ecuador warms up several degrees. This warmer water leads to increased evaporation, causing the air above it to rise and thereby affecting the winds. This conversation between ocean and atmosphere is nuanced and far-reaching. The atmosphere feels the influence of the warm ocean surface below it and conveys the message by shifts in tropical rainfall, which in turn affect wind patterns over much of the globe. For example, most El Niño winters are milder over western Canada and parts of the northern United States, and wetter over the southern United States from Texas to Florida. In other parts of the world, ENSO can bring drought to northern Australia, Indonesia, the Philippines, southeastern Africa, and northern Brazil. Heavier rainfall is often seen in coastal Ecuador, northwestern Peru, southern Brazil, central Argentina, and equatorial eastern Africa.
El Niño is just one of the ways climate can work itself into the weather. You might say meteorologists are obsessed with the atmosphere, whereas climatologists are obsessed with everything that influences the atmosphere. But in the end, we’re all obsessed with this notion of predicting the future. The atmosphere may be where the weather lives, but it speaks to the ocean, the land, and sea ice on a regular basis. Consider them influential friends that are capable of forcing the atmosphere to behave in ways that are sometimes, as in the case of ENSO, predictable. The hope is that if scientists can untangle all the messy relationships at work within our climate system, we should be better able to keep people out of harm’s way. The farther we can extend human memory, the longer out in time a society can see, and the better prepared we’ll be for what’s in the pipeline.
And that is where global warming enters the picture. If the four seasons are Mother Nature’s most prominent signature within the climate system, then you might say that global warming, the term that refers to Earth’s increasing temperature due to a buildup of greenhouse gases in the atmosphere, is humanity’s most prominent signature. The big difference between global warming and other climate and weather phenomena is that in this case, we’re the ones doing the talking. And greenhouse gases are the chatter we use to influence the behavior of the atmosphere.
Decades of study suggest that this conversation will slowly drown out all others, its influence cutting across all timescales and all regions of the planet. Global warming has already begun pushing around the timing of the four seasons, and ongoing research shows that it is also influencing the weather. Meanwhile, climate scientists have developed a robust understanding of the physics of this human interaction with the atmosphere. They have collected data and built predictive models of the climate system that are capable of looking into the past and—more important—the future. The forecast for Earth is in, and it’s not good.
Part I of this book explains the cutting-edge science behind this long-term climate forecasting, demonstrating why the predictive models for next century should be trusted in the same way that you trust the forecast for tomorrow on your local news. Here we’ll examine the relationship between our weather today and our forecasts down the road, looking at how climatologists assess the changing statistics of extreme weather events and how these changing statistics play into the long-term forecast.
We’ll also look at the history of weather prediction and how it serves as the foundation of climate forecasts today. Weather forecasts and climate forecasts are based on the same principles of mathematics and physics. Yet they have inherent differences that allow weather forecasts to focus on short-term changes in the atmosphere, whereas climate forecasts focus on long-term changes to the entire system of ocean, land, and ice. Keep in mind: just as my initial forecast that July would be hotter than January didn’t involve the weather on a specific day, so too a climate forecast for 2050 or 2100 looks at the big picture and not a specific day. A forecast for the year 2050 has the potential to be as meaningful and as useful as tomorrow’s weather forecast; it’s just used in a differ- ent way.
All this is important because if you don’t trust the models, you won’t believe the forecasts—and the forecasts are what Part II of this book is all about. In Part II, we’ll look at the forty-year forecasts for a few important places around the world. To start, I asked climate scientists to list the places they thought were most vulnerable to the threat of global warming.
I then narrowed the list down to seven key examples. (I’ve included a fuller list of hot spots identified by climate scientists in Appendix 3.) I chose these seven places not necessarily because they’re the most endangered places or because the stories they offer are the most dramatic, but instead because collectively they demonstrate a spectrum of risks that exist with climate change. By mid-century, not every part of the world will be affected by global warming in the same way. Each location I’ve chosen has its own Achilles’ heel, a vulnerability that unabated climate change will expose and exploit until the place is forever altered. Taken together these vulnerabilities show the breadth of repercussions that climate change will bring. It is my hope that whether taken as individual stories or as a whole, the predictions found in this book will demonstrate that global warming will hit all of us in the places we love and the homes where we live.
If Hurricane Katrina taught us anything, it is that the worst-case scenario can happen. For the first time in human history, science has given us the ability to peer into a crystal ball of numbers and models and see what kind of a climate we’ll be living in by mid-century if we continue to emit carbon at our current levels. I share this look at the future with people outside the scientific community not as a scare tactic or as hyperbole, but because only through such sharing will the world come to understand precisely what is at stake.
Let me show you what I mean. For several years, I’ve been giving lectures and seminars about climate change to a variety of groups all over the world. Sometimes I speak to scientists; sometimes the audience is primarily students and their parents; sometimes it’s politicians and business executives. After one of my first seminars, several years ago, I was standing at the front of the lecture hall, putting my computer away, when I was approached by a man—probably in his late forties—who had a question. He had enjoyed my lecture and found that it opened his eyes to several new aspects of the science and impacts of climate change, but what he really wanted to know was this:
“Do you think I should sell my beach house?”
After he said this, I thought for a moment about how best to calculate the risk associated with owning beachfront property in the United States, factoring in our best estimates of impacts such as sea level rise, storm surge, and saltwater intrusion—just to name a few. The man waited patiently with an earnest, if slightly bemused, look on his face. I suspect he may have been joking with me, but I felt I owed him an answer.
It was then that something hit me: This is the only way a lot of people can truly connect to the issue of climate change—via a long-term investment like real estate.
The more I thought about his question, the more I realized that the scientific community had failed to communicate the threat of climate change in a way that made it real for people right now. We, as scientists, hadn’t given people the proper tools to see that the impacts of climate change are visible right now and that they go far beyond melting ice caps.
I can honestly say that real estate is what comes up most often when I talk to people about global warming. While I’ve spent much of my research career looking at the global impacts of climate change, I fully understand that people want to see the local impacts. If people are going to understand what is really at stake, scientists have to find new ways to communicate the science, using data, images, and computer scenarios that convey more completely what climate change really looks like—both now and in the future. Beachfront property is only the tip of the iceberg.
This book is written with precisely that goal in mind. It’s a book about climate science and climate scientists, but ultimately it lays bare the true stakes of climate change. It illustrates that doing nothing and remaining complacent are tantamount to accepting a future forty years down the road in which your town, your neighborhood, and even your backyard will not look the same. It is not an exaggeration when I say that no place on the planet will look the same forty years down the road if climate change continues. All weather is local, and as you’ll see, in the future all climate change will be local, too.