The following excerpt is from the introduction to Alex Steffen's new book, Carbon Zero. The rest of the book is available as chapters on Grist and in ebook form on Amazon. You can learn more about Steffen at his website AlexSteffe.com or follow him on twitter @AlexSteffen.
Forewarned
On
 Monday the 29th of October, 2012, a tidal surge 13.9 feet high (the 
highest ever recorded) washed up and over the waterfront in Lower 
Manhattan, pushed forward by the superstorm Sandy. That same week, the 
storm destroyed large swathes of coastline from the New Jersey shore to 
Fire Island, while driving torrential rains, heavy snows, and powerful 
winds inland across the eastern U.S. and Canada. By the time the storm 
blew out, it had killed more than 100 Americans, made thousands 
homeless, left millions without power, and caused at least $50 billion 
in damage. Sandy was, by any reckoning, one of the worst natural 
disasters in American history.
Maybe, though, the word “natural” 
belongs in quotes. Because what was surprising about Sandy wasn’t that 
it happened (indeed, many had predicted that rising sea levels and 
storms intensified by warmer oceans would make something like Sandy 
inevitable), but that it was seen so clearly, and so immediately, for 
what it was: a forewarning of what a planet in climate chaos has in 
store for us.
Sandy was far from the first sign that climate 
change is here — scientists have been warning for decades of the dangers
 of a heating planet, and in the last 10 years we’ve seen a flurry of 
unprecedented storms, droughts, floods, melting glaciers, and wildfires,
 as well as record-breaking heat waves following one after another. 
Sandy, though, knocked down walls of denial and inattention that have 
kept us from admitting what’s happening to our world.
What’s 
happening is that we’re losing the climate fight. Climate change is 
here, it’s worsening quickly, its effects are more dire than many 
thought they would be, and — if we continue with business as usual — 
we’re on a track to unleash an almost unimaginable catastrophe on 
ourselves, our children, and our descendants.
“Part of learning 
from [Sandy] is the recognition that climate change is a reality,” said 
New York Gov. Andrew Cuomo at the time. “Extreme weather is a reality. 
It is a reality that we are vulnerable.” He added later, ”Anyone who 
says there is not a dramatic change in weather patterns is denying 
reality.”
Our choice: “extremely dangerous” or “catastrophic”
To
 not warm the planet at all no longer remains an option. The Earth is 
already dangerously hotter than it was before the Industrial Revolution.
We
 used to think that warming up to 2 degrees C fell within a sort of 
“safe zone,” where we could expect change but not crisis. But in a world
 we’ve warmed only by about 1 degree C above the historical baseline, 
we’re already seeing massive climate impacts across the planet. These 
unexpected impacts, along with new projections from ever-improving 
climate models, tell us that the climate is not nearly as forgiving as 
we’d like it to be. As the Tyndall Center for Climate Change Research’s 
Kevin Anderson puts it, “1 degree is the new 2 degrees.” Two degrees, 
meanwhile, now appears not just dangerous, but extremely dangerous.
That
 means the menu of choices in front of us no longer includes a 
completely safe and stable climate. Instead, our choices come down to 
two options: a world in which climate change becomes extremely 
dangerous, or one in which it becomes totally catastrophic.
To 
keep climate change within that merely “extremely dangerous” range, 
scientists say, we must limit the rise in global temperatures to 2 
degrees C. Allowing warming to accelerate beyond 2 degrees C to 4 
degrees C takes us beyond extremely dangerous into downright insane.
Yet
 that’s where our current emissions trajectory is leading us: to a world
 4 degrees C hotter, perhaps as soon as 2050; and perhaps even 6 degrees
 C hotter by the end of the century. Four degrees global temperature 
rise involves so many utterly catastrophic impacts — permanent droughts,
 large-scale shifts in agriculture, megastorms, rapid sea-level rise, 
ecosystem collapses, and so on (all triggering social instabilities) — 
that we can’t expect our global civilization to avoid serious 
disruptions, and in many places, long-term ruin. A world 4 degrees C 
hotter is, as some put it, “beyond adaption.” (A world 6 degrees C 
hotter is almost beyond comprehension: To conceive of a world 6 degrees 
warmer, imagine alligators in the Arctic.)
A world that’s 4 
degrees C hotter would also be vulnerable to nonlinear climate feedbacks
 — ways in which the effects of warming (like the melting of the Arctic 
permafrost) could rapidly worsen warming itself (by, in this case, 
releasing enormous volumes of CO2 and methane now trapped in frozen 
soils). Some worry these feedbacks could lead to “runaway” climate 
change, wherein a cycle of warming and greenhouse-gas releases and more 
warming spirals viciously out of control. At that point, even the 
wildest “geoengineering” ideas — for example, creating artificial 
volcanoes to fill the stratosphere with sulfate particles, blocking some
 of the sunshine headed towards Earth — would be, at best, “Hail Mary” 
strategies (and would do nothing to address other catastrophic effects 
of rising emissions, like the acidification of the oceans and the 
resulting mass die-offs of ocean life). Spiraling climate chaos of this 
severity would leave us on a profoundly different planet than the Earth 
we now call home.
There is simply no way to put a cost to those 
kinds of impacts: Their magnitude transcends economic reckoning, because
 their impact could be greater than the entire human economy is worth. 
Four degrees of warming, Anderson and many others say, is therefore 
something we should avoid literally at all costs, because no economic 
cost we pay will be greater than the losses we risk in a climate 
catastrophe of that magnitude.
Now, all of this is the sort of 
thing that can bum you right the hell out, and it’s not irrational to 
let it get to you — there’s a real chance we may destroy civilization 
and much of the natural world in the decades ahead, and that’s a valid 
reason for being a bit glum. There’s just no shiny side to extreme 
climate chaos.
It’s not too late to avoid catastrophe
If
 that were the end of the story we could all just start drinking now. 
Hell, I’d buy the first round. But it’s not. We still have a choice. We 
still, just barely, have the option of choosing to limit warming to 2 
degrees and then working hard to restore the climate once we’ve 
stabilized it. We can, yet, pause at “extremely dangerous” and pull back
 from the brink of chaos.
To do that, we have to limit the total 
amount of carbon dioxide and other greenhouse gases in the atmosphere. 
What’s the limit? Drawing on the scientific consensus, 350.org, the 
world’s leading climate advocacy network, puts the number at 565 more 
gigatons of CO2 (or about 450 parts-per-million [ppm] of CO2 in the 
atmosphere). That’s the most humanity can emit and still, probably, hold
 global warming to 2 degrees C.
That means we need to face a fact 
almost no one likes to discuss: We need to hit zero. That is, we need, 
as a species, to bring our global climate emissions into balance with 
what nature can safely absorb (actually, because we need to start 
rolling greenhouse gas concentrations backwards, we almost certainly 
need to emit less than nature can absorb, in order to take CO2 back out 
of the atmosphere and get back to safer greenhouse gas levels, of 350 
ppm or less — but one shocking reality at a time is enough). This means 
that all the expressions of commitment we’ve heard from politicians 
about reducing greenhouse gas emissions by 50 percent off 1990 levels, 
say, or 80 percent by 2050 or whatever — all of those numbers are 
meaningless. The meaningful number is simple: zero, as soon as possible.
Zero, worldwide
A
 worldwide transition to a climate-balanced global economy (one which 
adds zero CO2 each year to the total CO2 in the atmosphere) lies 
completely within our reach. But to achieve it, we’ll need to be honest 
with ourselves about geopolitics and reality. Because we have some tough
 decisions to make.
Climate change is global, with people 
everywhere worsening the crisis. But we are not all equally responsible 
for the crisis we face now. Those of us who live in the wealthier 
nations got our wealth by cutting down forests, and burning coal and oil
 to fuel our industrialization. We are wealthy, to be blunt, because 
we’re the ones who put most of the greenhouse gases up there in the 
first place.
In the last century, to get wealthier, you needed 
smokestacks and clearcuts and coal mines. Poorer nations — whose 
economies rely more on older, more polluting technologies — argue that 
they have a right to grow their economies to help their people escape 
poverty and achieve prosperity. These nations are mostly willing to 
negotiate with wealthier countries on lowering their climate emissions 
rapidly, but they will need time to transition to low-carbon economies, 
and they expect that we in the wealthier countries will lead the way on 
cutting emissions rapidly to buy them time. Essentially, the poorer 
nations are saying, they have a right to the lion’s share of those 
remaining 565 gigatons of CO2.
Even ambitious plans for global 
emissions reductions take time. Poorer countries now emit less overall, 
but their economies are inefficient and largely dependent on dirty 
energy. Lots of work will need to be done for those countries to level 
off their emissions, and more work after that for their economies to 
become carbon neutral, even with really aggressive innovation — 
innovation bolder than any we have seen anywhere in the developing 
world. For example, one recent credible scenario by Kevin Anderson and 
Alice Bows would have emissions in poorer countries leveling off in 
2025, then declining 7 percent per year thereafter, until the global 
carbon balance was restored. Seven percent a year, it should be noted, 
would be extremely bold: but even that extremely bold goal would demand 
that the wealthier countries buy time by zeroing out their own emissions
 first. The poorer countries argue this is a matter of “climate equity.”
Since
 we need their agreement, and their action, it’s probably smart to just 
go ahead and admit they’re right. It would be unjust to ask the world’s 
poor countries to absorb the costs of taking actions we ourselves avoid,
 in order to solve a problem we mostly created. We need to go first in 
zeroing-out our emissions.
But here’s the thing: far from being 
some unbearable burden, rapid reductions to net-zero emissions may in 
fact offer wealthier nations our best opportunity to rebuild our 
economies to prosper in the 21st century. To understand why, we need to 
look at the kind of planet we’re becoming: an urban planet.
Our urban future
Humanity
 is already an urban species, with more people living in cities than in 
the countryside. By the middle of the century, we will likely have as 
many as 9.5 billion people living on the planet, with 70-75 percent of 
us (around 7 billion people), demographers estimate, living in cities 
themselves, and 95 percent or more of humanity living within a day’s 
travel of a city. By the 2050s, the overwhelming majority of humanity 
will be participating in urban systems of health care, education, 
communication, commerce, and government that only a few decades ago were
 limited to the “developed” world.
Growth is transforming the very
 nature of cities. Every day, at least 200,000 people move to cities or 
are born in them. That’s like building a city the size of San Francisco 
every four days. Then doing it again, four days later. Then doing it 
again — and repeating the process several thousand times in the next 40 
years. By 2050, we will have an estimated 3.5 billion more urbanites, 
and to house them we will have built a constellation of thousands of 
large cities, including a scattering of extremely large megacities, each
 home to tens of millions of people. The largest city-building boom in 
human history will happen in the next four decades, with each decade 
experiencing more change than the one before.
This urban boom 
won’t be wonderful for everyone; for many, it may be tragic. Unless we 
change our priorities quickly, as many as a billion people — climate 
refugees, the rural and destitute, victims of conflict and deep 
structural poverty — will live on the very edge of existence. Perhaps as
 many as 3 billion people will live in informal settlements — in the 
huge slums springing up around many developing world cities. Hundreds of
 millions of these slum-dwellers will live in abject poverty. 
Inequalities will strain our societies. In the midst of widespread 
poverty, 3 or 4 billion others may rise out of poverty to enter the 
global middle class, living what we today would consider a “modern” — if
 modest — life. A billion may well live in even greater affluence than 
we experience today. And the one thing the vast majority of these people
 will have in common is their cities, and the ways in which those cities
 are linked together.
How we build this coming wave of cities will
 largely decide not only the quality of life of the people living in 
them, but also the future of our planet. Because how we build our cities
 will decide, more than any other factor, how much we heat the planet.
Our urban opportunity
Climate
 emissions are a byproduct of the global economy; but the links that 
connect that economy together are forged in our great cities. In this 
book, we’ll see how the choices cities make about how they grow will 
largely determine whether their economies will be clean or dirty; and 
the choices these cities make, in aggregate, will largely determine 
whether the global economy as a whole will be catastrophic or full of 
possibilities.
In 40 years, humanity will live in thousands of 
these major cities, each stamping the global economy with its own 
character — and burdening the planet with its consumption and pollution,
 to greater or lesser degrees. But right now, the economies of only 
about 200 cities define the global economy. These cities and the regions
 surrounding them are responsible for the vast majority of their 
countries’ prosperity, and also of their countries’ greenhouse gases.
Most
 of these cities are still in the wealthier nations. If our cities 
reinvent themselves, finding pathways to low-to-no-carbon futures, our 
nations can rapidly cut climate pollution, even if most of our 
compatriots lag behind in reducing emissions. Building cities that 
produce no net emissions — that reduce emissions to the extent that the 
greenhouse gases generated can be balanced through other actions that 
draw CO2 out of the atmosphere (what I call “carbon zero” cities) — may 
in fact be the smartest, quickest pathway to lowering national 
emissions.
Furthermore, the options that will be available to 
those thousands of emerging cities over the next 40 years largely depend
 on the choices we in the world’s wealthiest cities make today. The 
reason is that innovation and invention move slowly, yet are critical. 
When no new solution is available, business as usual is a given. Once a 
better solution to a given problem has been found, its spread can be 
hastened, though innovation diffusion still takes time. As the wealthier
 cities design away their own emissions, many excellent new solutions 
will be created, resulting in zero-emissions pathways poorer cities will
 be able to follow as they get wealthier.
There’s no time to lose.
 The costs of action will rise, not fall, with time. Many big 
investments have long life spans: They can operate for decades — and 
need to, in order to pay back the costs of their construction. This 
makes it politically very hard (and sometimes economically expensive) to
 shut down new infrastructure and industrial systems, even when those 
systems are producing unwanted results. What we build in the next two 
decades will probably be with us for decades more. Making new 
investments in old, dirty ways of doing things (like coal-fired power 
plants, highways, and suburban sprawl) retards change, and commits us 
either to continued pollution or to costly retrofits and replacements in
 the near future. But also, the longer we wait, the more the 
consequences of climate change already set in motion will hamper our 
progress and make us less able to act. All of the impacts of climate 
change have human costs, in many cases quite large. Few have any benefit
 at all. The longer we wait, the more our economic capacity for change 
will be damaged by droughts and floods, rising oceans and spreading 
diseases, climate refugees, and political instability. This is not even 
to mention the increasingly heart-wrenching human costs or the 
psychological trauma caused. Sandy was just a taste of what climate 
change could cost us.
Our cities as climate solutions
So,
 changing how our cities work proves to be a pretty vital job. 
Fortunately, our comparatively massive wealth has left us with a number 
of capacities the rest of the world simply doesn’t have: The majority of
 the world’s research universities, think tanks, engineering and design 
firms, advocacy groups, investment funds, venture capitalists, and so 
on, are all concentrated in the wealthiest cities — and even with China,
 India, and Brazil growing by leaps and bounds, this central fact of the
 concentration of the capacity for innovation in a relatively small 
number of rich cities is unlikely to change overnight.
Leading the
 way into a carbon zero future will be good for business. Cities that 
innovate in design, planning, policy, and products will equip their 
citizens with exportable skills and marketable experience before those 
in slower cities even know they exist. With thousands of large and small
 cities about to boom, the markets for urban innovations are almost 
inconceivably vast. There’s a 40-year boom on its way; cities that lead 
the way into a carbon zero future will be its great success stories.
Many
 of the most important kinds of innovations, policies, and plans needed 
to create such urban success stories are local — or are, at least, the 
kinds that don’t demand bold national action to succeed. In countries 
like the United States, where dirty energy companies have managed to 
clog the works of government, the ability to innovate meaningfully at a 
local level represents a huge advantage. Our major cities are small 
enough that committed people can actually change them, and large enough 
that changing them can produce big impacts.
Americans, Canadians, 
and Australians, in particular, sail now on a collision course with 
planetary realities. Our sprawling suburbs and low-density cities depend
 on abundant resources, cheap oil, and low costs for pollution, none of 
which the future holds. No amount of political grandstanding will change
 that fact. Sprawling, auto-dependent suburbs are unsustainable, and 
that which cannot be sustained does not long continue. For the size of 
their populations, our cities are the most climate-damaging in the 
world.
Even Northern European cities, with their older, more 
compact urban forms, better transit, and reputations for climate 
leadership, are far from sustainable — they, too, need a lot of change —
 but I have chosen to focus on North American cities precisely because 
that is where we need the biggest change in the shortest time. (Readers 
from the rest of the world should find a few ideas worth mulling over — 
much of what applies to North America applies without too much 
translation to Australia and New Zealand, as well as in parts to much of
 Europe and the prosperous parts of Asia, especially Japan and Korea. 
Around the world, leadership will take different forms: the imperative 
to lead will be the same.)
I’m writing most directly to my fellow 
Americans, though. That’s because I care deeply about my country, as do 
most Americans. I believe that if we truly love our country, we must 
care about its future; and we can’t care about its future without taking
 into account the ways our nation’s actions today are shaping that 
future; without attempting to steer a course that will leave our 
countrymen better off in the future. To love our country today is also 
to wish to see it secure and prosperous tomorrow. So to be patriots, we 
have to want to be good ancestors to those who are coming after us. And 
being good ancestors today means, perhaps above all else, fighting 
climate change. No greater threat faces America in the coming years than
 climate chaos. We learned that with Katrina; we’ve learned that with 
droughts and floods and wildfires; and now we’re learning it afresh as 
our nation recovers from the assault of a superstorm of unprecedented 
size. And the biggest storms are still ahead.
Building carbon zero
 cities means not only greater prosperity, but more security. Almost 
everything we need to do to drop our climate emissions also leaves us 
more rugged and resilient to disasters and global instability. Carbon 
zero cities mean future-proof cities, or as close as we’re likely to 
get.
Our choice could not be clearer, to my mind: Remake our 
cities into central hubs in the global climate-neutral economy we’re 
moving towards (and ready ourselves for the tough times to come), or 
shirk our responsibilities and leave ourselves even more vulnerable to 
the onrushing chaos. As a patriot, the right choice for America is plain
 to me.
Imagining carbon zero cities
How do
 we get to work? Well, we can’t build what we can’t imagine, so the 
first task in building carbon zero cities is to reimagine the cities we 
have.
Reimagining is hard work. It requires both a robust 
conversation about what carbon zero cities might be like, and a far more
 creative approach to envisioning the kinds of innovations and solutions
 that could get us there. This little book is my attempt to outline one 
version of a carbon-neutral city; to get a conversation going about what
 kind of change a 90 percent cut in emissions might entail; and to point
 out some of the main areas of possible innovation.
It’s worth 
emphasizing that this is a sketch, not a blueprint. I wouldn’t even 
attempt to ordain a model for zero-carbon development that every place 
should adopt. Every city is unique, with its own character, geography, 
civic culture, and history. Regional economies and politics have left 
every metro area with different workforces, institutions, and business 
cultures. The implementation of national policies and local capacities 
vary widely. No one set of innovations applied in a specific way will 
suit the needs of every city. Large teams of professionals and engaged 
citizens should (and I hope, will) take up the actual work of upgrading 
their cities. I’m not interested in dictating approaches to anyone.
Indeed,
 it seems to me that what we need most right now are not conclusive 
answers, but good hypotheses put immediately to the test; and good 
hypotheses spring first from reframing our understanding of a given 
challenge. I hope that my reframing of this challenge will influence 
readers to begin to see their own cities’ challenges in a new light.
But
 don’t expect things to look normal, illuminated by the demands of the 
future. We have, again and again, mistaken what we think of as “normal” 
for “best” and “permanent.” Normal as we knew it in the second half of 
the 20th century is already a thing of the past. Already, many of our 
older systems are crumbling, revealing themselves to be unsustainably 
expensive or indefensibly harmful. Even the timescales of the 20th 
century are out of date. Changes that took half a century before are 
erupting in a few years now.
The speed of change will not slow. It
 is both pulled along by the dire necessity of quick action — for, as 
Donella Meadows has written, on a planet full of limits, “Time is in 
fact the ultimate limit” — and driven along by the unleashing of 
innovation, collaboration, and competition on a planetary scale that 
dwarfs anything our great-grandparents could have comprehended. If the 
ultimate limit turns out to be time, the last infinite resource turns 
out to be creativity.
I believe that planetary limits and human 
creativity are now inextricably bound together. I doubt we’ll reinvent 
the physical limits of this world, at least in the next few centuries. I
 would bet against the emergence of any technologies that allow us to 
exceed our planetary boundaries on both a global scale and a sustained 
basis. But I would also bet we can build a civilization that works 
within our planetary limits, and furthermore, that the realm of 
possibilities for human experience within those ecological limits is 
essentially infinite.
Indeed, as we cease trying to maximize the 
volume of material growth and start emphasizing sustainable prosperity, I
 think we’ll find that what we’re able to do with energy and materials 
becomes more and more brilliant, meaningful, and enriching. Design 
constraints often deliver better results than a belief in complete 
freedom. Quite the opposite of imposing hardship, carbon zero targets 
may very well spur a renaissance in urban creativity.
The 
straining limits that pressure us to remake our cities will likely 
produce an unprecedented blooming of applied creativity and civic 
acumen. I find it completely likely that the constraints of climate 
neutrality and ecological sustainability, boldly met, may produce the 
most livable, prosperous, and resilient cities the world has ever seen.
Nothing
 in this book is utopian: Most of what I suggest is already being 
implemented or experimented with somewhere, though no city I know of has
 put all the pieces together in one place. Some of what I suggest still 
lives in the realm of conjecture, but that realm is not as far away as 
it used to be.
I hope you will take my sketch, use what makes 
sense to you, discard what doesn’t, and begin your own drawings of what 
the future’s possibilities can be — they are bound to be better than 
mine, and the world needs every well-grounded, well-crafted vision it 
can get. Please, don’t just read: reimagine.