Earth in Human Hands Page 21

  If we can ensure our own survival over (or even muddle through) the next few centuries, then we will eventually want to employ more obtrusive planetary engineering and learn to engineer our planet’s climate, intentionally pulling it toward stability. So, if we have a long-term vision for ourselves, and I really don’t think that is optional anymore, then it should include starting to learn what we’ll eventually need to know to do that kind of geoengineering. That will include a great deal of self-knowledge as well as more sophisticated planetary science and engineering. When the technology is understood well enough to be deployed without unintended consequences, the most challenging aspect may be developing the global capacity to make these decisions. If we do, then we will have become a new kind of entity on the planet: self-aware world changers with the good sense to work with the planet and not against it.

  Home Movies

  We have to get a handle on ourselves, learn to act consciously as the global entity we are. Yet look at us now. How are we ever going to get from here to there? When people express despair at the possibility of change, I like to remind them how fast our relationship with the world is changing right now, in precisely some of the ways we need. The first step is awareness, and our awareness of our world is exploding.

  I’ve described how our visits to neighboring planets have given us needed perspective to see how climate and life have evolved with Earth, but at first our forays to worlds beyond Earth were few and far between. Most of the hardware we launched off Earth in the early space age stayed very close to home, circling our planet in low Earth orbit, the first thin threads in a thickening satellite web we’ve been weaving ever since. On April 1, 1960, the TIROS (Television and Infrared Observation Satellite) was launched and began sending back the first continuous images of our planet’s weather patterns. Earth began to self-monitor. From that point on, we’ve photographed and measured our planet with increasing coverage, detail, and instrumental acuity.

  In 1961, there were half a dozen active artificial satellites orbiting Earth. By 1970 the number had grown to 164. In the early ’70s, for a teenage space geek like me, a satellite launch was still a big deal. Today, they remain fun to watch, but they’ve become routine, with only the occasional dramatic mishap providing enough mayhem and novelty to make the news. In 1972, the first Landsat was launched, beginning a continuous program of orbital surface monitoring. This gave us a baseline from which to measure changes in the planet and an ability to catch unfolding natural disasters such as floods, hurricanes, and droughts anywhere on the globe. Starting then, we have had a nonstop photo album of planetary changes. We’ve now had some decades to become familiar with the fluctuations Earth goes through on her own, the hemispheric patterns of weather fronts and storms, and the somewhat predictable cycles of change on seasonal and longer timescales. Against this complex and shifting, but increasingly recognizable, background, we’ve become more adept at picking out longer-term changes and tracking our own activities (urbanization, dam building, and deforestation), which are all recorded with unblinking orbital eyes. The Landsats and other Earth observers gave us more than just the ability to perceive Earth whole and in unseen, revealing colors. Over the years and decades, the unbroken archive of images from these sky cams have given us a fast-forward “this is your life” view, where we can see clearly how the land, seas, and ice of our world, partly in response to our own incitements, have been changing.

  The global weaving continues; the orbital web grows. In 2014, the European Space Agency launched a rocket from its spaceport in French Guyana, carrying Sentinel 1A, the first satellite in its Copernicus project, which is in many ways the most ambitious Earth observation program to date. Copernicus will include a fleet of orbiting craft to be launched over the ensuing decade, which will obtain continuous coverage of the entire planet in unprecedented detail over multiple wavelengths. Sentinel 1A can monitor any location on the globe using radar imaging, a technique we’ve employed with great success elsewhere in the solar system, allowing us to map places that cannot be photographed from orbit using sunlight, because they are obscured by clouds or the dark of night. On cloud-covered worlds such as Venus and Titan, radar mapping from spacecraft has allowed us to uncover the form and history of otherwise unseen landscapes. It’s like flash photography, only the illumination source is not visible light, but a microwave blast sent toward a planetary surface from a spacecraft antenna. This same antenna then captures the signal reflected back from the ground, and beams the pattern earthward, where our computers reconstruct it into new images and maps. These radar flash cameras can see in the dark, but even better, microwaves are unfazed by clouds and hazes. So Sentinel 1A can observe patterns and changes through all kinds of weather anywhere on the ground or ocean, day or night. This makes it an incredibly powerful new tool for monitoring sea ice or ground motion, or keeping track of long-term trends, momentary natural disasters, or even humanitarian crises.

  As sensors improve and coverage expands, we, as a component of a planet, do a better job of self-observation and reflection, obtaining the data we need to understand better what effect our activities are having, and become better equipped to take care of ourselves.

  By 2015 about 7,000 satellites had been launched. Of these, about 3,600 remain in orbit and around 1,000 are functional.10 We are still in an early phase of this planetary self-monitoring, still integrating this powerful new view of ourselves. It’s as if Earth has been evolving a diffuse new organ, a sky-high mycelium of floating mechanical sensors growing far above its surface, to keep a continuous eye on itself and develop a new infallible digital photographic memory of its own changing visage.

  The Apollo program gave us our first widely seen self-portraits—from Apollo 8 in December 1968, the Earthrise image we all know and love—our planet as a deep and lustrous blue jewel, moist and alive, swathed in bright cloud, lingering over the barren, lifeless, alien lunar horizon. [See here of the photo insert.] From Apollo 17 in 1972, the Blue Marble: our first clear view of a full Earth, the entire illuminated hemisphere overwhelming us with its vivid, kinetic beauty. These will always be treasured, the baby pictures of a newly space-faring species. They changed us profoundly.

  The Moon shots gave us our first snapshots, but it was satellite remote sensing that provided our first scratchy home movies, revealing and animating the seasonal changes on the continents and ice caps and the swirling daily circulation of Earth’s atmosphere and oceans. The space age brought home to every living room moving pictures of Earth’s pirouetting cloud patterns. More and more, we learned to connect our local quotidian experiences of the changing weather with the global motions of the roiling atmospheric sea. A hurricane was no longer merely something that happened out of the blue, an intense storm that sometimes engulfed your hometown with terrible wind and rain, but a beautiful and sometimes menacing spiral of clouds that swept across open ocean, swiping vast arms toward vulnerable islands, and threatening a run at the coast. By now, a couple of generations into the space age, aided in no small part by the ubiquitous satellite imagery in TV weather reports—so familiar we’ve long since stopped marveling at its origins—we’ve internalized this radical shift in scale and perspective so that, in our mind’s eye, we seamlessly connect these two views, from orbit and from the ground.

  To see what a difference a satellite network and computer models can make, compare the Great Galveston Hurricane to Hurricane Katrina. In the days leading up to September, 8, 1900, the people on Galveston Island, which juts into the Gulf of Mexico southeast of Houston, had absolutely no idea a monster storm was approaching. They stayed put as the weather worsened to the point where most structures were destroyed and much of the populace was swept away and drowned in the massive storm surge. It was the deadliest natural disaster in U.S. history. The final death toll is not known but is estimated to be around eight thousand.

  If the same hurricane were approaching the Gulf Coast today, we would see it developing weeks ahead and have good predicti
ons of its path. People would have time to head inland to higher ground. Property would still be destroyed, but loss of life would be minimal. Katrina, which struck the Gulf Coast near New Orleans on August 29, 2005, was terrible and shocking for a great many reasons. Still, at least we knew it was coming, and evacuations were ordered days in advance. The failures were organizational, bureaucratic, and cultural. There was loss of life and massive suffering because the authorities did not get their act together and organize an adequate response, because large neighborhoods were poor and disenfranchised, and because the infrastructure of the city had been neglected. These consequences fell disproportionately on the underprivileged. New Orleans is forever changed, many lives are permanently disrupted, and some communities may never bounce back. Yet Galveston can give us some idea how very much worse such a disaster would have been in 1900 before we had the orbital imaging and meteorological models to accurately predict the path and magnitude of such a storm. Can you imagine how vulnerable modern New Orleans, with its eroded barrier islands and rising sea level, its degraded coastal wetlands and increasingly taxed system of levees, would be without a constantly vigilant network of global satellites? This comparison illustrates two somewhat ironic, and cautionary, aspects of our increased reliance on scientific sensors and models to safeguard our cities and our society—both of which are important for understanding the situation and future prospects of human civilization as we enter the Anthropocene epoch.

  First, we’ve made ourselves more vulnerable, created new problems that make us more dependent on our new solutions. By overdeveloping coastal regions and pushing the agricultural carrying capacity of our lands closer to possible limits, we have placed ourselves more in harm’s way, made ourselves more susceptible to catastrophic disruptions of daily life by impulsive natural events (which are also becoming more erratic as they become less “natural,” forced by a changing climate). Yet we have also built up safeguards that we increasingly depend upon, though we easily take them for granted. Giant coastal megacities without satellite remote sensing would be a recipe for disasters that would make Galveston look like a Gulf Coast clambake.

  Second, with Katrina we could see what was coming but were unable to effectively act upon this knowledge. This shows that although science and technology have become indispensable survival aids, they can provide only so much protection if we don’t have the institutional, educational, and cultural resilience to defend ourselves.

  The ability to monitor our planet and our surroundings continuously has changed us, and changed our planet into something entirely new. Yet this aspect of our planet is in its infancy. We take it for granted, but now our Earth-observing capacity comes and goes with the launch and failure of different satellite systems. If we are going to build the capacity to avoid dangerous climate changes and asteroid impacts, then we will need long-term, stable, space-based infrastructure. We’ll need monitoring capability that can be ensured to last over the lifetime of such a project. Right now we are obsessed with innovation, but at some point we will need to focus more on stability. Not that innovation shouldn’t be welcomed if better ways are found to accomplish our goals, but at the very least the baseline plan must be undertaken with technology that can be built to finish the job at hand. We will need systems built to last for centuries, and the institutions to reliably maintain them.

  We’ve shrouded our world with three thousand satellites with which we are watching our planet, spotting previously hidden patterns and constantly firing instantaneous signals around the globe, like cells in a restless planetary superbrain. With these compound orbital eyes and this self-assembling cyborg mind, we perceive with new depth and acuity that we are deeply embedded in complex global systems and cycles of matter, energy, and (increasingly) information. Augmented by satellite senses and terabyte memories, our cave-evolved intellect, supersized with supercomputers, is just now attaining vast new abilities to comprehend the global present and to model and anticipate the future.

  The Bright Old Sun Problem

  Let’s assume we get a handle on our self-induced climate problems in the next century, and learn to manage Earth’s climate cycles gracefully over the next thousand centuries. Then over a much longer timescale, we will be forced to deal with another kind of climate change, one that also goes in the category of planetary changes of the fourth kind.

  When we look farther ahead, even our star, the Sun, cannot be expected to be a reliable, steady partner. As it ages, it is slowly brightening. It’s just what happens to stars like our Sun as they evolve. This is why trying to understand the ancient climate of Earth presents us with the “faint young Sun problem” I write about in chapter 1. Well, in Earth’s far future we’ll have the opposite: a “bright old Sun problem.”

  Our climate automatically adjusts to the gradually warming sun, slowly lowering the average CO2 content in the air, converting it to carbonate rocks in such a way as to balance the slight increases in solar radiation. Earth has been doing this over its entire lifetime, but eventually it won’t work anymore. All the CO2 will be drawn down, Earth’s thermostat will be stuck, and the Sun will keep warming. Then, inevitably, Earth will go the way of Venus. It will become so hot that the oceans will boil and the hydrogen will be swept into space. Left to its own devices, Earth will experience a runaway greenhouse. We’ll lose our water, and all carbon-based life will perish. Earth will be left completely uninhabitable.

  Ultimately, somebody is going to have to step up and deal with this if our biosphere is to survive. As the Sun brightens we’ll want to interfere more strongly because, as the slogan goes, there is no planet B. If we (or our descendants, or our creations, or even somebody else who’s come along and made a home of this planet in the intervening eons) want to remain here we will have to take action and engineer the mitigation of the eventual, inevitable runaway greenhouse. This is not going to be necessary for a billion years, but for long-term survival, it will be absolutely necessary.

  Who knows if anybody will still be around here? This is a timescale much longer than the lifetime of our civilization or even our entire species, or even all animal life. Yet if we think of the life of our biosphere, we see that this is not such a long time. Depending on how you measure it, we, Gaia, are perhaps three billion years old. So this will become a problem when we are only 30 percent older than we are now.

  If we make it that far, given billions of years of engineering prowess, we will be able to solve this problem and even help Earth’s biosphere outlive the Sun. Someday we may be the best thing that ever happened to life on Earth.

  5

  TERRA SAPIENS

  It is far better to grasp the universe the way it really is than to persist in delusions, however satisfying and reassuring.

  —Carl Sagan

  The Great Promotion

  Understandably, the term Anthropocene is disturbing to many people. We are both drawn to and repulsed by the idea that we are the harbingers of a new geologic era. I’ve seen this in response to numerous talks I’ve given and public conversations I’ve led on the topic, and in vigorous, unending debates on social media. People recognize the validity of the concept, but many also find it deeply troubling. The notion of a time in which we are somehow responsible for the world sets off alarm bells.

  This is good. If you’re not disturbed, you’re not paying attention because—wait, isn’t the whole notion just narcissistic and arrogant? Species come and species go, shuffling on and off the stage. Who are we to impart such importance to our own sudden entrance that we name a geological epoch after ourselves? Isn’t it more than a little self-aggrandizing to declare our brief ascendance to be its own chapter in the multibillion-year book of Earth? It even seems to carry the obnoxious implication that we are elevating ourselves to a godlike status, that maybe we think we deserve to be in charge of this place. The conceit that this is somehow our world smacks uncomfortably of a biblical worldview, a world just for us, a universe in which we are the stars of the show. Hasn
’t science led us in exactly the opposite direction, in an exodus from self-centered delusions about our own significance, toward freedom and clarity about our insignificance? Yes, it has, but maybe we need a slight course correction.

  For hundreds of years, science has driven us toward a view in which human existence is less and less central. Our discoveries have repeatedly and persistently pushed us to the margins, revealed us to be just another kind of animal, recent arrivals on an unbelievably ancient planet that is not the focus, or the point, but an insignificant dust bunny tossed in a random corner of a nearly incomprehensible cosmic vastness. It’s been a process of knocking humanity off various pedestals. Four centuries ago Galileo liberated us from the tiny prison of geocentrism, by revealing that Earth, which we’ve always called not just a world but the world, is only one of many planets. Our loss of a privileged place was compensated for by a massive enlargement of our universe. Darwin then showed us that we are not the chosen species, but close kin to all life on this planet, and that we were not made in anyone’s image because biological innovation does not require an intelligent creator. Modern geology and cosmology have affirmed that the story really can’t be about us, because nearly all of it happened long before we showed up, and the size of our physical domain shrinks to insignificance against the immense, expanding clusters and superclusters of galaxies.

  Now the recent exoplanet revolution is finishing the physical decentering of humanity, confirming that planets around all kinds of stars are nothing special. And we feel poised on the edge of a discovery that could pull us off our last pedestal. My own field, astrobiology, is pushing hard against the notion that life is unique to Earth. Soon, in subsurface aquifers on Mars, in a global ocean on Europa, or in the atmosphere of a nearby exoplanet, we will be able to test the proposition that our universe, given liquid water, carbon, and energy, easily makes life. Confirming this suspicion would destroy one of the last refuges of geocentrism.