Huff and Puff and Blow Your House Down

Under the weight of record snows, roofs across the Northeast have been buckling this winter, raining debris on children skating in ice rinks, crushing cows and tractors in farmers’ barns and even flattening a garage full of antique cars. In December, nearly 18 inches of new heavy snow brought down the roof of the Metrodome in Minneapolis, forcing the Vikings to temporarily relocate to Detroit.

And it was not just American infrastructure that appeared to be under the weather, so to speak. In Brisbane, Australia, January storms ripped apart a riverside boardwalk — turning a concrete section 150 yards long into a waterborne torpedo that threatened downstream bridges. The wall of a Hungarian reservoir holding toxic red sludge crumbled in October after weeks of downpours, sending the waste into nearby villages. The litany of extreme weather events has often left local officials scrambling to respond to each new crisis, looking — by turns pathetic and heroic — like the little Dutch boy with his finger in the dike, trying to fend off nature’s monumental forces.

Global warming is most likely responsible, at least in part, for the rising frequency and severity of extreme weather events — like floods, storms and droughts — since warmer surface temperatures tend to produce more violent weather patterns, scientists say. And the damage these events have caused is a sign that the safety factors that engineers, architects and planners have previously built into structures are becoming inadequate for the changing climate.

Dikes, buildings and bridges are often built to withstand a “hundred-year storm” — an event so epic that there is a 1 percent chance it will happen in a given year. But what happens when 100-year storms are seen every 10 years, and 10-year storms become regular events? How many structures will reach their limits?

Engineers and insurers are already facing these questions. Munich Re, one of the world’s largest insurance companies, says climate-related events serious enough to cause property damage have risen significantly since 1980: extreme floods tripled and extreme windstorms nearly so. (The number of damaging earthquakes — which are not thought to be influenced by climate change — have remained stable.) Statistics show that the frequency of days with heavy precipitation is up in South America, North America and parts of Europe

Your own perception that there are more storms and more flooding causing damage — that is extremely well documented,” said Peter Hoeppe, a meteorologist who is the head of Munich Re’s Corporate Climate Center. “There is definitely a plausible link to climate change.”

For insurers, the challenge has been how to insure structures against the vicissitudes of increasingly extreme and severe weather. For engineers, new weather raises difficult questions about what kinds of safety factors should be built into designs and whether old structures need retrofitting or reinfo