The power of future storms hard to predict
Big storms are fed by energy from warm seas, and experts say that with warmer oceans there's a lot more of that energy today at their disposal then there used to be.
The jury is still out on whether this will mean a future of more frequent and more powerful storms, but experts can agree that we're in for changes to what was once considered the norm.
"Are storms getting stronger? That's a tough question to answer," said Angela Fritz, an atmospheric scientist with Weather Underground. "But what we do know is that research is telling us that storm patterns are getting more weird."
She said that because of the shrinking sea ice at the North Pole, the jet stream has become more sluggish in moving storms along. This means that large Atlantic storms, such as Sandy and the February blizzard, will linger over the East Coast's populated regions longer than they used to, wreaking a good deal more havoc.
The `balding' Arctic: Scientists in the summer of 2012 witnessed a record for the smallest North Polar ice cap ever witnessed -- 3.5 million square kilometers, or less than half the area typically occupied four decades ago, according to the National Snow & Ice Data Center.
"What we're going to see is more destruction -- more rainfall and, paradoxically, more snowfall, because warmer air carries more moisture," Fritz said. "And rising sea levels will also come into play here, because just a few inches can mean the difference between flooding and no flooding."
She notes that now, the jet stream seems to be more in the business of creating blocking patterns than moving things along and out of harm's way.
"This blocking pattern was what caused Sandy to make that left hook toward land," she notes.
Whether that will mean that we're entering an era of Sandy-sized tropical storms is a matter of debate for meteorologists and climatologists. This is because large storms are complex beasts and warmer oceans alone might not guarantee that the state's shoreline is in for a succession of storms like Irene and Sandy every year or two.
Homes in harm's way: Complicating the picture is coastal development. Today's storms are more destructive because there are more buildings along the shore to destroy. Not only are there many more homes along the shore today, but they're also far more elaborate and costly to replace than the beach cottages of yore.
"We have greatly increased the risk by the population density and the value of the properly that we have put in harm's way," said Timothy Reinhold, senior vice president of research and chief engineer for the Insurance Institute for Business and Home Safety. "There were a cluster of really bad hurricanes in the early 1900s, and when you run the figures of what kind of damage you would see with those storms and today's development, the numbers are just astronomical."
He said that despite huge losses from mega-storms like Katrina and Andrew, the building industry has pushed back on efforts to tighten building codes, with North Carolina and Louisiana actually relaxing their codes.
Hard question to answer: "Part of our problem is that we're trying to collect data where our methodology of collecting this data has changed over time," said Thomas C. Peterson, a research meteorologist at NOAA's National Climatic Data Center in Asheville, N.C., who said that whether the storms themselves are getting stronger is a difficult question to answer.
"Some ingredients have become more favorable to the increase in severe storms over the years, but some have not," Peterson said. "We understand that as the ocean warms, there's a greater likelihood of increases in hurricanes, but, on the other hand, the warmer water heats the upper atmosphere, and this will work against developing strong coastal storms"
There is consensus, he said, that extreme precipitation events in general are increasing, with more rain falling in downpour events than there used to be.
"Human-induced global warming is causing this increase in precipitation," he said. "We're also seeing a decrease in the amount of snow compared to rain," Peterson said. "As it gets warmer, there's a greater chance that what used to be a snowstorm is now a rain event."
Plenty of data: Just about everywhere you look, the numbers point to a hotter Earth.
According to the National Oceanic and Atmospheric Administration, the number of months with below-average temperature readings have been few and far between. July 2013 was the 341st consecutive month, since February 1985, that the global monthly temperature has been higher than the long-term average, month-to-month. And nine of the 10 warmest Julys on record have occurred since the beginning of the 21st century, NOAA says.
These are just two in the long line of data points telling us that we're living on a planet that's getting hotter.
But it's the temperature of the oceans that concerns storm experts, and most of the Earth's vast seas are a lot warmer than they used to be 50 or 100 years ago.
NOAA says that many ocean regions are now much warmer than average, with part of the northeastern Atlantic off the coast of North America, sections of the southern Indian Ocean, and various regions in the western Pacific observing record warmth.
"One thing that all scientists who study sea ice agree upon is that under increasing temperatures, the overall long-term declining trend will continue and some summer in the future, we will look down on the North Pole and see a blue Arctic Ocean," said Walt Meier, a scientist with the National Snow & Ice Data Center.
" It's not a matter of if, but when."
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