As I write this, it’s been nearly a week since Hurricane Sandy roared ashore on the East Coast of the US, leaving devastation in its wake. On day six after the storm, there are many communities still waiting to get their electricity restored.

If there’s one overarching lesson to be learned from Hurricane Sandy, it’s that the old standard, still publicized by emergency planning agencies all over this country—that people need to prepare for a disaster by stocking up on three days’ worth of emergency supplies—is woefully inadequate.

On day six, many residents of Long Island, the New Jersey shore, and outlying communities still have no electricity, which means they have no heat in November, no clean water flowing from their taps, no hot water to sterilize or clean anything, and no electricity to cook food. Which means they’re still eating food out of cans, nearly a week after the storm, if they have that much canned food left. No electricity means no ability for gas stations to pump gas, which means people can’t get in their cars and drive to buy more supplies. If they followed the advice of their local emergency planning agency, then they ran out of food three days ago.

And now comes the announcement that many of these communities won’t get their power restored until two weeks after the storm, leaving these people stranded and living in pre-civilization conditions for an inhuman amount of time.

The fault may lie with FEMA or with Congress, which has been so focused on the budget deficit and partisan gridlock that the money tap has been nearly cut off for essential federal government services like emergency rescue and management. In spite of Republican anti-government theory, no private business can step in and manage assistance on the same scale over the same wide area as the federal government. Yet Republican theory has shaped federal government policy and forced us into a brave new world of no government help in the face of disaster.

And today’s disasters are like nothing we’ve known in the past. This is lesson number two that we can take away from this disaster. While Hurricane Katrina was terrible and other hurricanes have borne stronger winds and higher waves than Hurricane Sandy, this storm was bigger in area and contained more kinetic force than anything to ever hit the Northeast Coast in our lifetimes, and possibly in recorded history. It was big enough and powerful enough to reshape the entire coastline, creating new bays, inlets, and lakes. Hurricane Sandy literally changed the shape of the eastern seaboard, and mapmakers will spend years catching up.

Of course, people had time to prepare for the storm, but they could only prepare for what they knew. New York City took a direct hit from Hurricane Irene just last year. Most folks assumed that Sandy couldn’t be much worse, even though meteorologists were telling them to expect a 12 to 13-foot wall of water driven by 80 mile-per-hour winds to hit New York City. When the storm surge hit, the actual size was closer to 15-feet, higher even than the worst-case scenarios proposed by the experts.

Yes, Hurricane Sandy was a “perfect storm,” where many variables contributed to the overall size and ferocity of the storm: a high tide, a full moon, the convergence of a northward moving hurricane with a southward moving nor’easter, etc. But one contributing factor makes modern storm predictions particularly difficult:  global warming.

As global temperatures rise, oceans heat and expand. Ocean levels in New York City have been rising one inch each decade, and the pace is accelerating. It’s no coincidence that during the week that Hurricane Sandy hit New York, the residents of Venice, Italy (which sits at sea level) have been wearing waders and dealing with rising floodwaters.

Warmer oceans also mean more water vapor in the air, which adds more fuel to storms and boosts the size of storms. Larger and more frequent storms have long been an expected outcome of global warming.

And that means storms like we’ve never seen before. The human race is engaging in a vast uncontrolled experiment with our planetary climate, and we’re seeing the effects of that now.

The final lesson we can take from Hurricane Sandy became evident when New York Mayor Michael Bloomberg finally announced on Thursday that he supports Barack Obama for president, because Obama is the only candidate who has done anything to address global warming. Both candidates in the race for the presidency have solicited Bloomberg’s endorsement because he has a lot of influence in national politics: he’s wealthy, he’s smart, he runs the nation’s largest city, and he manages the financial heart of America. People listen to him.

Don’t get me wrong, we should commend Bloomberg for coming out and saying what’s important: the biggest economic risk, the biggest security risk, the biggest risk to the future of Americans is not terrorism. It’s climate change. But why does global warming have to hit this man’s front yard and wreak havoc on half his city before he’s able to wake up and say “yes, this is a problem”?

Bloomberg just proved to those of us who’ve been crying in the wilderness that Americans are not willing to make even minor changes in their daily lives—for example, driving an electric car instead of an SUV—in order to save themselves from the ravages of a super-storm like Hurricane Sandy.

And that’s going to be our undoing. If we can’t admit now, after what’s happened to the East Coast, that global warming is real, that it’s impacts are happening now, that it is the biggest threat we face, not just as a nation but as a planet, then we deserve all the future “perfect storms” that are headed our way.