As you probably know, the actual oceans are rising — almost eight inches since 1880, and that’s only going to accelerate. They’re also acidifying, because they’re absorbing significant amounts of the carbon we continue to pump into the atmosphere at record levels. The ice that covers the polar seas is shrinking, while the ice shields that cover Antarctica and Greenland are melting. The water locked up in all the polar ice, as it’s unlocked by heat, is going to raise sea levels staggeringly, possibly by as much as 200 feet at some point in the future, how distant we do not know. In the temperate latitudes, warming seas breed fiercer hurricanes.

The oceans are changing fast, and for the worse. Fish stocks are dying off, as are shellfish. In many acidified oceanic regions, their shells are actuallydissolving or failing to form, which is one of the scariest, most nightmarish things I’ve ever heard. So don’t tell me that we’re rocking a stable boat on calm seas. The glorious 10,000-year period of stable climate in which humanity flourished and then exploded to overrun the Earth and all its ecosystems is over.

But responding to these current cataclysmic changes means taking on people who believe, or at least assert, that those of us who want to react and act are gratuitously disrupting a stable system that’s working fine. It isn’t stable. It is working fine — in the short term and the most limited sense — for oil companies and the people who profit from them and for some of us in the particularly cushy parts of the world who haven’t been impacted yet by weather events like, say, the recent torrential floods in Japan or southern Nevada and Arizona, or the monsoon versions of the same that have devastated parts of India and Pakistan, or the drought that has mummified my beloved California, or the wildfires of Australia.

The problem, of course, is that the people who most benefit from the current arrangements have effectively purchased a lot of politicians, and that a great many of the rest of them are either hopelessly dim or amazingly timid. Most of the Democrats recognize the reality of climate change but not the urgency of doing something about it. Many of the Republicans used to — John McCain has done an amazing about-face from being a sane voice on climate to a shrill denier — and they present a horrific obstacle to any international treaties.

Put it this way: in one country, one party holding 45 out of 100 seats in one legislative house, while serving a minority of the very rich, can basically block what quite a lot of the other seven billion people on Earth want and need, because a two-thirds majority in the Senate must consent to any international treaty the U.S. signs. Which is not to say much for the president, whose drill-baby-drill administration only looks good compared to the petroleum servants he faces, when he bothers to face them and isn’t just one of them. History will despise them all and much of the world does now, but as my mother would have said, they know which side their bread is buttered on.

As it happens, the butter is melting and the bread is getting more expensive. Global grain production is already down several percent thanks to climate change, says a terrifying new United Nations report. Declining crops cause food shortages and rising food prices, creating hunger and even famine for the poorest on Earth, and also sometimes cause massive unrest. Rising bread prices were one factor that helped spark the Arab Spring in 2011. Anyone who argues that doing something about global warming will be too expensive is dodging just how expensive unmitigated climate change is already proving to be.

It’s only a question of whether the very wealthy or the very poor will pay. Putting it that way, however, devalues all the nonmonetary things at stake, from the survival of myriad species to our confidence in the future. And yeah, climate change is here, now. We’ve already lost a lot and we’re going to lose more, but there’s a difference between terrible and apocalyptic. We still have some control over how extreme it gets. That’s not a great choice, but it’s the choice we have. There’s still a window open for action, but it’s closing. As the Secretary-General of the World Meteorological Society, Michel Jarraud, bluntly put it recently, “We are running out of time.”

New and Renewable Energies

The future is not yet written. Look at the world we’re in at this very moment. The Keystone XL tar sands pipeline was supposed to be built years ago, butactivists catalyzed by the rural and indigenous communities across whose land it would go have stopped it so far, and made what was supposed to be a done deal a contentious issue. Activists changed the outcome.

Fracking has been challenged on the state level, and banned in townships and counties from upstate New York to central California. (It has also been banned in two Canadian provinces, France, and Bulgaria.) The fossil-fuel divestment movement has achieved a number of remarkable victories in its few bare years of existence and more are on the way. The actual divestments and commitments to divest fossil fuel stocks by various institutions ranging from the city of Seattle to the British Medical Association are striking. But the real power of the movement lies in the way it has called into question the wisdom of investing in fossil fuel corporations. Even mainstream voices like the British Parliament’s Environmental Audit Committee and publications like Forbes are now beginning to question whether they are safe places to put money. That’s a sea change.

Renewable energy has become more efficient, technologically sophisticated, and cheaper — the price of solar power in relation to the energy it generates has plummeted astonishingly over the past three decades and wind technology keeps getting better. While Americans overall are not yet curtailing their fossil-fuel habits, many individuals and communities are choosing other options, and those options are becoming increasingly viable. A Stanford University scientist has proposed a plan to allow each of the 50 states to run on 100% renewable energy by 2050.

Since, according to the latest report of the U.N.’s Intergovernmental Panel on Climate Change, fossil fuel reserves still in the ground are “at least four times larger than could safely be burned if global warming is to be kept to a tolerable level,” it couldn’t be more important to reach global agreements to do things differently on a planetary scale. Notably, most of those carbon reserves must be left untapped and the modest steps already taken locally andad hoc show that such changes are indeed possible and that an encouraging number of us want to pursue them.

We can do it. And we is the key word here. The world is not going to be saved by individual acts of virtue; it’s going to be saved, if it is to be saved, by collective acts of social and political change. That’s why I’m marching this Sunday with tens or maybe hundreds of thousands of others in New York City — to pressure the United Nations as it meets to address climate change. That’s why people who care about the future state of our planet will also be marching and demonstrating in New Delhi, Rio de Janeiro, Paris, Berlin, Melbourne, Kathmandu, Dublin, Manila, Seoul, Mumbai, Istanbul, and so many smaller places.

Mass movements work. Unarmed citizens have changed the course of history countless times in the modern era. When we come together as civil society, we have the capacity to transform policies, change old ways of doing things, and sometimes even topple regimes. And it is about governments. Like it or not, the global treaties, compacts, and agreements we need can only be made by governments, and governments will make those agreements when the pressure to do so is greater than the pressure not to. We can and must be that pressure.

The Long View from One Window

I lived in the same apartment for 25 years, moving into a poor but thriving black community in 1981 and out of the far more affluent, paler, and less neighborly place it had become in 2006. A lot of people moved in and out in that period, many of them staying only a year or two. Those transients always seemed to believe that the neighborhood they were passing through was a stable one. You had to be slower than change and stick around to see it. I saw it and it helped me learn how to take a historical view of things.

It’s crazy that anyone speaks as if our world is not undergoing rapid change, when the view from the window called history shows nothing but transformation, both incremental and dramatic. Exactly 25 years ago this month, Eastern Europe was astir. Remember that back then there was still a Soviet bloc, and a Soviet Union, and an Iron Curtain, and a Berlin Wall, and a Cold War. Most people thought those were permanent fixtures, but in the summer of 1989, Hungary decided to let East Germans (who were permitted to travel freely to that communist country) stream over to the West.

Thousands of people, tired of life in the totalitarian east, fled. Poland, Czechoslovakia, and Hungary, as well as East Germany, were already electrified by a resurgent civil society and activist communities that had dared to organize in the face of repression. At the time, politicians and pundits in the West were making careers out of explaining, among so many other things, why German reunification wasn’t going to happen in anyone’s lifetime. And they probably would have been proven right if people had stayed home and done nothing, if they hadn’t begun to hope and acted on that hope.

The bureaucrats on both sides of the Berlin Wall were still talking about the possibility of demilitarizing it when citizens showed up en masse and the guards began abandoning their posts. On that epochal night of November 9, 1989, the people made whole what had been broken. The lesson: showing up is half the battle.

British Prime Minister Margaret Thatcher had been so unnerved by developments in the Soviet Union’s Eastern European holdings that she went to Moscow, two months before the fall of the wall, to implore Soviet leader Mikhail Gorbachev to prevent any such thing. That was early September 1989. “No dramatic change in the situation in Czechoslovakia can be expected,” predicted a Czech official two months before a glorious popular uprising, remembered as the Velvet Revolution, erupted and abolished the government in which he was an official.

There are three things to note about those changes in 1989. First, most people in power dismissed the possibility that such extraordinary change could happen or deplored what it might bring. They were comfortable enough with things as they were, even though the status quo was several kinds of scary and awful. In other words, the status quo likes the status quo and dislikes change. Second, everything changed despite them, thanks to grassroots organizing and civil society, forces that — we are now regularly assured — are pointless and irrelevant. Third, the world that existed then has been largely swept away: the Soviet Union, the global alignments of that time, the idea of a binary world of communism and capitalism, and the policies that had kept us on the brink of nuclear annihilation for decades. We live in a very different world now (though nuclear weapons are still a terrible problem). Things do change.

Maybe, in fact, there’s a fourth point to note as well. That, important as they were, the front-page stories about the liberation of Eastern Europe weren’t what mattered most all those years ago. After all, hidden away deep inside theNew York Times that autumn, you can find a dozen or so articles about global warming, as the newly recognized phenomenon was then called. And small as they were, anyone reading them now can see that so long ago the essential problem and peril to our world was already clear.

The thought of what might have been accomplished, had a people’s movement arisen then to face global warming, could break your heart. That, after all, was still a time when the Earth’s atmosphere held just above 350 parts per million of carbon dioxide, the maximum safe level for a sustainable survivable planet, not the 400 parts per million of the present moment (“142% of the pre-industrial era” level of carbon, the World Meteorological Organization notes). In other words, we’ve been steadily filling the atmosphere with greenhouse gases and so imperiling the planet and humanitysince we knew what we were doing.

The Great Smog and the Big Wind

In that fall a quarter of a century ago, the world changed profoundly right before our eyes. Then we settled back into the short-term, ahistorical view that things are really pretty stable, that ordinary people have no power, and that the world can’t be changed. With that in mind, it’s worth looking at Germany today. Maybe because Germans know better than us that things can change for the worse or the better fast, that the world is not a stable and settled place, and that we do shape it, they have been willing to change.

At one point last spring, cold, cloudy Germany managed to get almost 75% of its electricity from renewable sources. Scotland — cold, gray, oil-rich Scotland! — is on track to achieve 100% renewable electrical generation by 2020 and has already hit the 40% mark. Spain now generates about half its electricity through clean and renewable sources. Other European countries have similar accomplishments. In fact, many of the changes that we in the United States will be marching for this Sunday have already begun happening, sometimes on a significant scale, elsewhere.

To remember how radical this new Europe is, recall that most of these places were burning coal not just in power plants or factories but in homes, too, not so many decades ago. Everyone deplores the horrific air of Beijing and other Chinese cities now, but few remember that many European cities were similarly foul with smoke and smog from the industrial revolution into the postwar era. In December 1952, for instance, the “Great Smog” of London reduced daytime visibility to a few yards and killed about 4,000 people in three days.

A decade before that, in response to the war Germany started, North Americans radically reduced their use of private vehicles and gasoline and planted more than 20 million victory gardens, producing vast quantities of food by non-industrial means. We have done that; we could (and must) do it again.

At least, we don’t burn coal in our homes any more, and in the U.S. we’veretired 178 coal-fired power plants, phasing out many more, and prevented many new ones from being built. The renewable energy sources that were, people insisted, too minor or unreliable or expensive or new are now beginning to work well, and the price to produce energy in such a fashion is dropping rapidly. UBS, the European investment giant, recently counseledthat power plants and centralized power generation are no longer good investments, since decentralized renewables are likely to replace them.

Of course, Germany and Britain are still burning coal, and Poland remains agiant coal mine. Europe is not a perfect renewable energy paradise, just a part of the world that demonstrates the viability of changing how we produce and consume energy. We are already changing, even if not fast enough, not by a long shot, at least not yet. The same goes for divesting from fossil-fuel investments, even though dozens of universities, cities, religious institutions, and foundations have already committed to doing so, and some have by now actually purged their portfolios. The excuse that change is impossible is no longer available, because many places and entities have already changed.

Last Glimmers

If you want to know how potentially powerful you are, ask your enemies. The misogynists who attack feminism and try to intimidate feminists into silence only demonstrate in a roundabout way that feminism really is changing the world; they are the furious backlash and so the proof that something meaningful is at stake. The climate movement is similarly upsetting a lot of powerful people and institutions; to grasp that, you just have to look at the tsunamis of money spent opposing specific measures and misinforming the public. The carbon barons are demonstrating that we could change the world and that they don’t want us to.

We are powerful and need to become more so in the next year as a major conference in Paris approaches in December 2015 where the climate agreements we need could be hammered out. Or not. This is, after all, a sequel to the Copenhagen conference of 2009, where representatives of many smaller and more vulnerable nations, as well as citizens’ groups, were eager for a treaty that took on climate change in significant ways, only to have their hopes crushed by the recalcitrant governments of the United States and China.

Right now, we are in a churning sea of change, of climate change, of subtle changes in everyday life, of powerful efforts by elites to serve themselves and damn the rest of us, and of increasingly powerful activist and social-movement campaigns to make a world that benefits more beings, human and otherwise, in the longer term. Every choice you make aligns you with one set of these forces or another. That includes doing nothing, which means aligning yourself with the worst of the status quo dragging us down in that ocean of carbon and consumption.

To make personal changes is to do too little. Only great movements, only collective action can save us now. Only is a scary word, but when the ship is sinking, it can be an encouraging one as well. It can hold out hope. The world has changed again and again in ways that, until they happened, would have been considered improbable by just about everyone on the planet. It is changing now and the direction is up to us.

There will be another story to be told about what we did a quarter century after civil society toppled the East Bloc regimes, what we did in the pivotal years of 2014 and 2015. All we know now is that it is not yet written, and that we who live at this very moment have the power to write it with our lives and acts.