I could begin a story about the growing human influence on earth鈥檚 climate system with a recap of the effects of an unabated rise in concentrations of heat-trapping carbon dioxide and other greenhouse gases. (The short version, of course, is: centuries of melting ice and rising seas, hotter heat waves and heavier downpours, less predictable storm patterns, disrupted ecosystems and water supplies.) But given that such pieces have been written for decades, including by me, with little evident impact, there may be more value in examining our species鈥 haltingly evolving relationship with the atmosphere and climate. If anything good is to happen, it will happen because of a big change on our side of that relationship.
It should be no surprise, first of all, that humanity is taking its time absorbing and confronting what鈥檚 going on. Our interactions with climate, for far more than 99 percent of history, ran in one direction: Precipitation or temperatures changed, ice sheets or coastlines or deserts advanced or retreated, and communities thrived, suffered, or adjusted how or where they lived. Only a couple of decades have passed since people outside of a tiny community of scientists began to grasp that the human-climate relationship, in measurable but still subtle ways, now runs in two directions.
That slow awakening is part of the broader challenge of confronting the Anthropocene鈥攁n ever-more-popular name for this Age of Us. Earth鈥檚 operating systems are increasingly in our sway, just when our population and development surges are putting unparalleled numbers of people in harm鈥檚 way. In essence, we鈥檝e found ourselves in a race between our awareness and our environmental potency. Potency has been winning so far, whether your concern is climate change or more direct damage to ecosystems.
The basics of human-caused climate change are clear-cut. Human-generated greenhouse gases and other pollutants, along with vast changes in landscapes through the expansion of agriculture and cities, have altered the composition and dynamics of the atmosphere, from poles to equator. Yes, there are variables in the climate equation that are still unsolved. Hurricanes, for instance, are expected to grow more intense, although there could be fewer overall. And our understanding is further complicated by the lag between slow-building environmental phenomena and when we finally become aware of them. But the climate challenge is real, and all the more troubling due to both the difficulty in reversing the process, given the long lifetime of carbon dioxide once released, and the inertia in important components of the system once they鈥檝e been powerfully jogged. For example, most of the heat added to the earth system by the greenhouse effect so far has gone into the oceans. That may sound like a good thing, but that heat will resurface down the line, as the great ocean conveyer belt of currents circulates water from the depths, amplifying atmospheric warming. In other words, even though the ocean may be soaking up a considerable amount of warmth, it also commits the planet to warming for centuries, if not millenniums, as the University of Chicago climatologist David Archer detailed in The Long Thaw, a sobering book that lays out why, despite our focus on real-time weather events, we ain鈥檛 seen nothing yet.
Awareness that substantial warming is already inevitable can produce a feeling of fatalism. That鈥檚 just one facet of what I鈥檝e taken to calling our inconvenient mind. I鈥檝e reported on some unnerving things in more than 25 years of covering just about every aspect of human-driven climate change. I鈥檝e videotaped the cracks forming in shifting sea ice beneath a floating research camp near the North Pole. I鈥檝e had front-porch conversations with murderous ranchers chain-sawing and burning the Amazon rainforest. I鈥檝e stared from a catwalk into the green depths of a nuclear power plant鈥檚 spent-fuel pool鈥攁 great vantage point for considering the risks and rewards of modern energy choices. But the science revealing how the human mind tends to misperceive problems of this scope and time scale, even in the face of accumulating data, is in many ways the most unnerving phenomenon of all. We鈥檙e simply not good at recognizing incremental changes that could pose potentially calamitous risks. Nor is this weakness restricted to climate policy: The overdue brake job. The extra cookie. The rusting bridge. The national debt. Yet it is no less perilous for being pervasive. (As part of 爆料公社's examination of this issue, Elizabeth Kolbert of our tendency toward misperception and miscommunication.)
Our inability to perceive subtle changes and their attendant threats doesn鈥檛 let Homo sapiens off the hook, however. We are different from other life-forms that have become planet-scale powerhouses. Take blue-green cyanobacteria, organisms that began flooding the atmosphere with oxygen some 2.4 billion years ago. Some earth scientists call that atmospheric jolt , because the buildup of oxygen was toxic to most other species at the time. And yes, you could step back and say there鈥檚 not much of a difference between our carbon binge and that oxygen outburst. Except those mats of photosynthesizing slime weren鈥檛 looking up at the sky, measuring and marveling at what they鈥檇 done. Through science, we are. With awareness comes responsibility, at least in theory. I鈥檓 pretty sure cyanobacteria are not self-aware.
Luckily it鈥檚 still too early to describe the ongoing buildup of human-generated greenhouse gases as the Great Carbon Dioxide Catastrophe. Climate scientists say there鈥檚 . They say we can afford to produce roughly another 500 billion metric tons of carbon emissions before the resulting shifts in temperature, weather patterns, and sea level essentially lock in a daunting future for our species and many of our companions on this planet. That buys us about 50 years at our current rate.
The Carbon Cycle: A Finely Tuned Machine
While that may sound like cause to relax, it鈥檚 not even close, for two reasons. One is the sheer mass and momentum of the fossil-driven economies and lifestyles of today鈥檚 prosperous nations. As the physicist and energy analyst John Holdren told me in 2006, before he was President Obama鈥檚 science adviser, 鈥淲e鈥檝e got a $12 trillion capital investment in the world energy economy and a turnover time of 30 to 40 years. . . . If you want it to look different in 30 or 40 years, you鈥檇 better start now.鈥
The other obstacle is the unmet demand for basic energy needs of the some 2.8 billion people who still burn firewood, charcoal, or dried dung for cooking and heating, and of the 1.2 billion who can鈥檛 reach for a light switch. Some can transition to renewable energy choices, but we can鈥檛 simply consign the others to darkness.
Given these climate and human realities, how do we develop a sustainable, two-way relationship with the atmosphere and climate? How do we limit warming and gird ourselves smartly for the future? First, it would help to conceive of global warming less as a problem to be solved and more as a legacy issue to be consistently addressed. Too often we鈥檝e heard calls to 鈥渟eal the deal鈥 (on a binding treaty) and 鈥渟olve the climate crisis鈥 in ways that imply this is the task of a single president or generation. A more realistic view is that we need a new relationship with energy to go with our evolving new relationship with climate. Addressing both sources of emissions and sources of societal and ecological risk is something to do as routinely, and passionately, as we work on poverty reduction and health care. It took a century to get deep into the fossil era; it will take decades to get out.
Second, it would help to abandon expectations that pressing the science case for warming ever louder or more cleverly will build a groundswell of concern that vaults us at last toward clean energy choices. Science literacy matters, of course, but we have to get comfortable with the idea that humans will inevitably have a wide range of reactions to climate change. As , more familiarity with science can amplify differences rather than resolve them. In 2010 I found a Nobel winner in physics to support just about any stance on the issue.
Diving into that body of behavioral science can leave you sapped. But the same science points to productive paths. One Yale survey, for example, has found very broad support for higher fuel-efficiency standards for cars even among people who question global warming. I know conservatives and liberals who enthusiastically agree that the federal government should not be subsidizing development in coastal zones that are increasingly vulnerable to advancing seas, or in Colorado鈥檚 鈥渞ed zones鈥 and other areas in the West where wildfire risks are already high and, according to a host of studies, rising with warming. Another source of optimism is the fast-expanding array of tools for the global sharing and shaping of ideas, observations, and investments that offer great potential for accelerating energy innovation and resilient planning.
The 鈥溾 complexity of the greenhouse challenge, as first described by the young climate analyst Kelly Levin and some colleagues in 2007, guarantees that a mix of approaches鈥攖he 鈥渟ilver buckshot鈥 of Bill McKibben, the veteran climate writer and campaigner鈥攊s needed. In action as in evolution, diversity is adaptive. McKibben has mostly shaped around confrontation, for example, attacking big oil companies and pressing university trustees and politicians to pull . But the group has also staged 鈥溾 in which communities gather together to make such environmentally friendly changes as planting trees and erecting solar and wind energy installations. At the same time, innovators like the Caltech chemist focus on pushing forward photovoltaics and other energy technologies. Entrepreneur is devising new investment models to foster expanded solar panel use. Ban Ki-moon, the United Nations Secretary-General, has wisely approached the world鈥檚 interlaced climate and energy challenges along two tracks, for the world鈥檚 still un-electrified billions.
One of the most exciting signs of a change in thinking came in by two former Democratic senators, Tim Wirth and Tom Daschle鈥攍ong champions of such top-down tools as laws and treaties. They laid out a new approach to climate progress that fits our variegated world:
鈥淲e think the time has come for the international community to alter its collective climate strategy, cease the search for the impossible all-encompassing top-down agreement鈥攄escribed unattractively as 鈥渂urden sharing鈥濃攁nd instead encourage an approach that builds on national self-interest and spurs a race to the top in low-carbon energy solutions. This would change the psychology of the climate change issue from one of burden to opportunity, and change the likely outcome from one of hand-wringing about failure to excitement about tangible action to build a better world.鈥
Their call replaces the unachievable quest of building a binding treaty with an inclusive and sustained search for productive paths on energy and the environment. And as that kind of approach spreads鈥攆rom international diplomacy to household decisions to career choices made by students鈥擨 see solid prospects that we can win this race with ourselves. We can move from awareness to responsibility to meaningful action and pass on a planet to the coming generations that, while unavoidably bearing our footprint, remains something beautiful to behold.
Andrew C. Revkin has covered human-caused climate change since the mid-1980s in two books and hundreds of newspaper and magazine articles. He writes the Dot Earth blog for The New York Times.