Sandy is a storm without a silver lining. We have lost lives, homes and businesses. Let's not also lose the chance to learn the lesson of our generation, if not our century.
In the storm's aftermath, the question we hear again and again is: Did climate change cause superstorm Sandy? Unfortunately, that is invariably followed with the blanket hand wave of dismissal -- oh, you can never blame any single storm on climate change. That mistaken caveat leads us down the wrong path.
Think about it: Do you know whether your aunt's cancer was caused by the cigarettes she smoked? No -- but we know without a doubt that cigarette smoking causes cancer.
Do you know whether too much weight and too little exercise caused your uncle's heart attack? You cannot say for sure about those extra pounds -- but no one questions the scientific fact that inactivity and excess weight drive up the high rate of heart attacks.
Do we know that the lead paint in a neighbor's house caused his child's developmental delay? No, the cause cannot be tracked that definitively, even though we know exposure to lead at a young age causes measurable developmental problems, and that removing lead in gasoline has seen a big rise in IQ among kids.
So why do we allow the complexity of cause and effect trap us into refusing to answer the right question on climate change? Scientists know that climate change has increased Earth's temperature, and that it has fueled more heat waves, more intense precipitation, more intense droughts and more wildfires.
They're confident those extremes will soon become the new norm.
Hurricanes occur naturally; we know that. So do rainstorms and droughts. And so do cancer, heart attacks and developmental delays.
But don't mistakenly separate the superstorm that hit our coast from climate change. We don't make that distinction between cigarettes and cancer, between obesity and heart attacks, between lead and developmental delay.
What climate change does is make many "natural" events more frequent and worse. By continuing to pump millions of tons of carbon pollution into our atmosphere every single day, we are throwing Earth's complex climate system out of whack, and this is the price we pay.
Science tells us that the destructiveness of this storm was fueled by climate change -- driving higher sea levels that pushed up storm surge, and higher ocean temperatures that contributed to the monstrous size of the storm and loaded extra rain into the clouds.
Science has identified another powerful potential factor: The record-breaking melting of Arctic sea ice's impact on the jet stream may have created the block of high pressure above Greenland that drove Sandy west into the continental United States, rather than allowing it to spin off east into the North Atlantic, as most late-season hurricanes do.
So in short, the answer to the question, "Did climate change cause Sandy?" is: Climate change makes storms worse. Just as smoking cigarettes makes cancer more widespread; as obesity increases heart disease.
But the right answer goes beyond the simple acknowledgment that climate change is having a costly, negative impact on our lives. It leads to a call for action, and a coordination of the overwhelming scientific evidence with business and political leadership that, so far, has been sadly lacking.
Just as our leaders agreed to require smoke-free public spaces, and just as they agreed to remove lead from gasoline that harmed children, our leaders must step up to the climate challenge and call for strong action.
We must demand that they acknowledge the reality of climate change, how we are causing it and how it is changing our world, and agree on a path to solve this problem.
That path means stopping our contributions to climate change -- a cessation that scientists say is possible only if we can agree, as a society, to change the way we extract and use energy.
Answering this question leaves us with another, undoubtedly more important one: How soon will we start?
Catherine Thomasson is an internal medicine physician and executive director of Physicians for Social Responsibility. This is from the McClatchy-Tribune News Service.