We are losing the battle to save our planet, and we have no one to blame but ourselves.

As the United Nations opens its 25th climate change summit in Madrid, leaders are seeking to put a brave face on a dismal situation. “My message here today is one of hope, not of despair,” U.N. Secretary-General António Guterres told journalists Sunday.

Hope, unfortunately, is not a plan.

“The last five years have been the hottest ever recorded,” Guterres said. “Sea levels are at the highest in human history.” And as for the crusade to keep global warming below the level of utter catastrophe, Guterres reported that “the point of no return is no longer over the horizon. It is in sight and is hurtling toward us.”

History will condemn a host of villains, starting with President Trump. The United States, as the globe’s leading economic power, is uniquely positioned to lead the world toward climate solutions. Instead, Trump is deliberately worsening the problem by pulling out of the Paris climate accord and actively encouraging the increased burning of fossil fuels, including coal. Decades from now, we may well see this as the Trump administration’s worst legacy.

Chinese President Xi Jinping, unlike Trump, understands and accepts the scientific consensus about climate change. But China’s greenhouse gas emissions continue to soar and are now nearly double those of the United States. Xi continues to value rapid economic growth — fueled, in part, by new coal-fired power plants — over humanity’s well-being in the long term.

Indian Prime Minister Narendra Modi has sharply boosted his nation’s carbon emissions as well. The European Union has seen its emissions decline but only modestly.

At least China, India and Europe are projected to meet their initial emissions targets under the Paris accord; the United States is not. But those targets were meant to be just a beginning. If warming is to be held to 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels by the end of this century — a level scientists consider awful but manageable — carbon emissions worldwide need to start dropping rapidly. Like, right now. Yet emissions last year reached an all-time high.

Despite what Trump and other ignoramuses might say, there is essentially no scientific disagreement about the fact that climate change is occurring or the fact that humankind is the cause.

A bulletin last week from the World Meteorological Organization, a U.N. agency, reported that the concentration of heat-trapping carbon dioxide in the atmosphere has risen by an incredible 47 percent since the Industrial Revolution. By examining the levels of various isotopes of carbon in the air, WMO scientists were able to show that the added carbon is of the kind emitted when coal and other fossil fuels are burned.

In other words, we’ve been found standing over the victim with the murder weapon in our hands.

At the Madrid climate summit — where House Speaker Nancy Pelosi (D-Calif.) is the highest-profile U.S. attendee — the assembled leaders will hear that prior assessments of climate change catastrophe were understated. Global warming is happening faster than predicted, with more dramatic consequences than previously imagined. Glaciers are melting. Seas are rising. Weather patterns have shifted in unpredictable ways, making monsoon rains unreliable, generating supercharged hurricanes and exposing once-temperate regions such as Northern Europe to deadly heat waves.

The Earth is immensely large, while each of us individually is very small. It may be difficult to imagine that we could have such a big impact on the environment. But look at photographs of the planet taken by astronauts and note how thin the atmosphere is. The air we breathe extends upward only roughly 10 miles — the distance many of us commute each day in our carbon-spewing SUVs and pickup trucks.

That issue of scale is one impediment to the kind of climate action we desperately need. An even bigger problem is the question of time.

We of the boomer cohort will long have returned to dust before climate change begins to feel like an everyday five-alarm crisis. Our children will feel it, though, and our grandchildren will suffer in ways we can only begin to grasp. Future generations will be mystified and furious. They will see from the historical record that we knew what was happening, that we knew of ways to at least slow it down — a carbon tax, for example — and that we did almost nothing.

Our benighted leaders fail to give us meaningful action on climate change because we fail to demand it. We can’t look to the Madrid conference to save the planet. We must look within.

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