Sandy: Act of God or act of man?

Is global warming to blame for Sandy the “Frankenstorm�? Pundits and politicians were arguing about that even before the massive storm struck the Atlantic coast; now that it has moved on, after killing 50, flooding the New York subway system, ripping away chunks of New Jersey’s coastline and causing myriad other damage that will place Sandy among the most expensive natural disasters in U.S. history, it’s a more pressing question. After all, if the storm were an act of man rather than an act of God, we might be able to prevent such disasters from recurring.

Unfortunately, though, there’s no easy answer. Climate change is measured in terms of observed changes in temperatures and weather patterns across broad swaths of territory over long periods of time. Scientists are reluctant to attribute any single weather event to man-made global warming. So how come such experts as Al Gore are telling us that Sandy was “strengthened by the climate crisis�?

In part, it’s because Sandy involved a highly unusual confluence of weather events, some of which may have resulted from a widely documented rise in global ocean and surface temperatures. Waters in the mid-Atlantic, for example, are unseasonably warm, which may have made the storm stronger. It might have headed harmlessly out to sea if not for a rare blocking pattern caused by a high-pressure system near Greenland, which may have arisen because Arctic temperatures are going up.

THEN AND NOW: Devastation from super storm Sandy

But more important than the exact causes of Sandy’s fury is the fact that it was so predictable. Climate scientists have warned for years that we can expect more extreme weather events such as storms, cyclones, droughts and floods as the greenhouse effect takes hold. They have predicted that rising sea levels would cause severe flooding in low-lying areas such as Manhattan and erode coastlines in such places as Florida and New Jersey. These predictions aren’t just theoretical worries about the future; they appear to be happening now. “Anyone who says there is not a change in weather patterns is denying reality,� said New York Gov. Andrew Cuomo on Tuesday.

Opponents of efforts to curb greenhouse gases complain that weaning ourselves off fossil fuels would cost too much. But property damage from Sandy is estimated at $20 billion, and it’s just one storm; climate change will ravage infrastructure along the coasts, burn up forests and homes, and wreck crops, just for starters. The cost of adapting to a warmer world — building sea walls and levees, constructing dams, moving homes and businesses to safe ground — will be breathtaking. The question isn’t whether we can afford to clean up our energy sources, it’s whether we can afford not to.