Planet Earth, creation, the world in which civilization developed, the world with climate patterns that we know and stable shorelines, is in imminent peril. The urgency of the situation crystallized only in the past few years. We now have clear evidence of the crisis, provided by increasingly detailed information about how Earth responded to perturbing forces during its history (very sensitively, with some lag caused by the inertia of massive oceans) and by observations of changes that are beginning to occur around the globe in response to ongoing climate change. The startling conclusion is that continued exploitation of all fossil fuels on Earth threatens not only the other millions of species on the planet but also the survival of humanity itself—and the timetable is shorter than we thought.

How can we be on the precipice of such consequences while local climate change remains small compared with day-to-day weather fluctuations? The urgency derives from the nearness of climate tipping points, beyond which climate dynamics can cause rapid changes out of humanity’s control. Tipping points occur because of amplifying feedbacks—as when a microphone is placed too close to a speaker, which amplifies any little sound picked up by the microphone, which then picks up the amplification, which is again picked up by the speaker, until very quickly the noise becomes unbearable. Climate-related feedbacks include loss of Arctic sea ice, melting ice sheets and glaciers, and release of frozen methane as tundra melts.

There is a social matter that contributes equally to the crisis: government greenwash. I was startled, while plotting data, to see the vast disparity between government words and reality. Greenwashing, expressing concern about global warming and the environment while taking no actions to actually stabilize climate or preserve the environment, is prevalent in the United States and other countries, even those presumed to be the “greenest.”

The tragedy is that the actions needed to stabilize climate are not only feasible but provide additional benefits as well. How can it be that necessary actions are not taken? It is easy to suggest explanations—the power of special interests on our governments, the short election cycles that diminish concern about long-term consequences.

I am aware of the claims that I have become a preacher in recent years. That is not correct. Something did change, though. I realized that I am a witness not only to what is happening in our climate system, but also to greenwash. Politicians are happy if scientists provide information and then go away and shut up. But science and policy cannot be divorced. What I’ve seen is that politicians often adopt policies that are merely convenient—but that, using readily available scientific data and empirical information, can be shown to be inconsistent with long-term success.

I believe the biggest obstacle to solving global warming is the role of money in politics, the undue sway of special interests. “But the influence of special interests is impossible to stop,” you say. It had better not be. But the public, and young people in particular, will need to get involved in a major way.

“What?” you say. You already did get involved by working your tail off to help elect President Barack Obama. Sure, I (a registered Independent who has voted for both Republicans and Democrats over the years) voted for change too, and I had moist eyes during his Election Day speech in Chicago. That was and always will be a great day for America. But let me tell you: President Obama does not get it. He and his key advisers are subject to heavy pressures, and so far the approach has been, “Let’s compromise.” So you still have a hell of a lot of work ahead of you. You do not have any choice. Your attitude must be, “Yes, we can.”

I am sorry to say that most of what politicians are doing on the climate front is greenwashing—their proposals sound good, but they are deceiving you and themselves at the same time. Politicians think that if matters look difficult, compromise is a good approach. Unfortunately, nature and the laws of physics cannot compromise—they are what they are. Policy decisions on climate change are being deliberated every day by those without full knowledge of the science, and often with intentional misinformation spawned by special interests. Citizens with a special interest—in their loved ones—need to become familiar with the science, exercise their democratic rights, and pay attention to politicians’ decisions. Otherwise, it seems, short-term special interests will hold sway in capitals around the world—we are running out of time.

In 2001, when I spoke to Vice President Dick Cheney’s cabinet-level Climate Task Force, I was more sanguine about the climate situation. It seemed that the climate impacts might be tolerable if the atmospheric carbon dioxide amount was kept at a level not exceeding 450 parts per million (ppm; thus 450 ppm is 0.045 percent of the molecules in the air). So far, humans have caused carbon dioxide to increase from 280 ppm in 1750 to 387 ppm in 2009.

During the past few years, however, it has become clear that 387 ppm is already in the dangerous range. It’s crucial that we immediately recognize the need to reduce atmospheric carbon dioxide to at most 350 ppm in order to avoid disasters for coming generations. Such a reduction is still practical, but just barely. It requires a prompt phaseout of coal emissions, plus improved forestry and agricultural practices. We need to acknowledge now that a change of direction is urgent. This is our last chance.

How, though, can today be a critical moment when we do not yet observe great changes in climate? So far, the effects of climate change have been limited in the near term because of climate system inertia, but inertia is not a true friend. As amplifying feedbacks begin to drive the climate toward tipping points, that inertia makes it harder to reverse direction.

The ocean, ice sheets, and frozen methane on continental shelves—all have inertia, resisting rapid change. Heat is pouring in the ocean, and ice shelves are starting to melt. Continued emissions growth will surely cause destabilization of at least the West Antarctic ice sheet.

How close we are to destabilizing frozen methane which would exacerbate warming is unclear. There are already signs of an accelerated release of methane from high-latitude tundra and from the larger reservoir on continental shelves. So far the amount of methane released has been small. But if we continue to increase greenhouse gas emissions, the eventual destabilization of large amounts of methane is a near certainty. We must remember that the human-made climate forcing—changing the planet’s energy balance in a way that alters temperature—is not coming on just a bit faster than natural forcings of the past; on the contrary, it is a rapid powerful blow, an order of magnitude greater than any natural forcings that we are aware of.

Cataclysmic storms—what I call storms of my grandchildren—when will these hit with full force? Already the air holds more water vapor than it did a few decades ago. The strongest of the storms that derive energy from water vapor—including thunderstorms, tornadoes, and tropical storms—are becoming stronger, and the associated winds and floods are becoming more extreme.

But qualitatively different storms will occur when ice sheet disintegration is large enough to damp high-latitude ocean warming, or even to cause regional ocean cooling, while low latitudes continue to warm. Global chaos will ensue when increasingly violent storminess is combined with sea level rise of a meter and more. Although ice sheet inertia may prevent a large sea level rise before the second half of the century, continued growth of greenhouse gases in the near term will make that result practically inevitable, out of our children’s and grandchildren’s control.

Several uncertainties will affect the speed at which more obvious climate changes emerge. One is uncertainty about whether and how solar irradiance will change during the next few years and next few decades. As of October 2009, the sun remains in the deepest solar minimum in the period of accurate satellite data, which began in the 1970s. It is conceivable that the sun’s energy output will remain low for decades, as it apparently did a few centuries ago, which may have been the largest contributor to the Little Ice Age. But contrary to the fervently voiced opinions of solar-climate aficionados, such continued low irradiance would not cause global cooling and would not stop the continued progression of global warming. This does not mean, however, that the solar effect is negligible. Indeed, if the sun pulls out of its current minimum soon, resuming a typical solar cycle, there may be an acceleration of global warming in the next six to eight years. But whatever happens with solar irradiance, the world is going to be warmer during the next decade (the 2010s) than it was in the present decade, just as the present decade is warmer than the 1990s.

The other major uncertainties that will influence how rapidly climate change effects become obvious are the amount of human-made aerosols and the planet’s energy imbalance. Aerosols are the biggest source of uncertainty in terms of the overall forcing that humans are applying to the climate system. The planet’s energy imbalance is our best single measure of the state of the system, helping us define how much of a change in atmospheric composition is needed to restore climate stability. Both require improved data.

But our imperfect knowledge of these quantities does not imply uncertainty about the direction that global climate is headed—the world is getting warmer, and it will continue to do so during the next few decades.

You need to be well informed, to understand these matters, because you cannot count on governments, the people paid to protect the public, to deal properly and promptly with the climate matter. The problem with governments is not scientific ability—the Obama administration, for example, appointed some of the best scientists in the country to top positions in science and energy. Instead, the government’s problem is politics, politics as usual.

U.S. government scientists, at least those at the highest levels, cannot contradict a position taken by the president. And President Obama’s assertion that he would “listen to” scientists did not mean that he would not listen, perhaps with even sharper ears, to political advisers.

When you learn of a lightly publicized agreement with Canada for a pipeline to carry oil squeezed from tar sands to the Unites States, when you learn of approval for plants to squeeze oil from coal, when the president advocates an ineffectual cap-and-trade approach for controlling carbon emissions, when our government funnels billions of dollars to support “clean coal” while treating next-generation nuclear power almost as a pariah, you can recognize right away that our government is not taking a strategic approach to solve the climate problem.

The picture has become clear. Our planet, with its remarkable array of life, is in imminent danger of crashing. Yet our politicians are not dashing forward. They hesitate; they hang back.

Therefore it is up to you. You will need to be a protector of your children and grandchildren on this matter. I am sorry to say that your job will be difficult—special interests have been able to subvert our democratic system. But we should not give up on the democratic system—quite the contrary. We must fight for the principle of equal justice.

One suggestion I have for now: Support Bill McKibben and his organization It has the most effective and responsible leadership in the public struggle for climate justice. McKibben has done a remarkable job of helping young people get organized.

But as in other struggles for justice against powerful forces, it may be necessary to take to the streets to draw attention to injustice. There are places where action has begun to have some effect. The government in the United Kingdom, for exampled, may be turning against coal plants that do not capture carbon emissions—strong activism there is surely playing a role. There have been some locally effective actions in the United States as well. But overall, results are small in comparison to what is needed. The international community seems to be headed down a path toward inadequate agreements at best. Civil resistance may be our best hope.

It is crucial for all of us, especially young people, to get involved. This will be the most urgent fight of our lives.