No one can say whether Superstorm Sandy was a direct result of the Earth’s changing climate. For the Northeast, big storms such as Irene and Sandy foreshadow dangerous times if climate change goes unaddressed, according to scientists.
They also say that the region is already experiencing an increase in intense rainfall events likely caused by warming global temperatures. “This has been a trend for the past 30 years,” said Chris Thorncroft, chair of the Department of Atmospheric and Environmental Sciences at the University at Albany. “The probability of extreme weather events occurring is increasing, and those types of events lead to flooding.”
Scientists cannot say for sure whether any particular storm was directly caused by climate change. But they can describe the type of storms that will become more common in a world where the air and oceans are warmer, there’s more moisture in the air (warmer air can hold more moisture), and the sea levels are higher. Hurricane Sandy, which was especially large, aligns with their expectations.
Technically, climate change will not lead to an increase in storms, according to New York State Climatologist Mark Wysocki.
What it will do, he said, is make storms more intense and the weather more extreme in general. Because of a warming ocean, hurricanes that would have died out before reaching the colder waters of the Northeast are more likely to reach states such as Massachusetts and Maine, and more likely to be stronger when they do. As a result, people in the Northeast are experiencing more storms. Warmer water provides more energy for storms.
“Hurricanes will live longer,” Wysocki said. For coastal regions in the Northeast, which are likely to see a rise in sea level, this could be a big problem. “All you’ll need is a small storm to see a powerful increase in [coastal flooding],” he said. Inland communities on rivers and streams will also experience more flooding, because there will be more precipitation.
Wysocki said that the weather has a “natural variability” that causes extreme weather such as droughts and tornadoes, and that when climate change is added to the mix, such events, from snowstorms to tropical storms, will become even more damaging. He said that the Earth is at the beginning of a period of climate change.
Last week, Gov. Andrew Cuomo caused a stir when he said that violent storms such as Hurricane Sandy can be connected to climate change.
“We have a 100-year flood every two years now,” Cuomo said. “We have a new reality when it comes to these weather patterns. We have an old infrastructure and we have old systems and that is not a good combination.”
According to a 2009 report from the U.S. Global Change Research Program, the Northeast experienced a 67 percent increase in very heavy precipitation between 1958 and 2007.
John Garver, a professor of geology at Union College, organizes the annual Mohawk Watershed Symposium, where issues affecting the Mohawk Watershed are discussed.
physical and political
At this year’s symposium, topics of conversation included flood frequency, causes of floods and flood mitigation strategies, and the flier for the event noted that “While the upper basin has been recovering from the 2006 floods, the lower basin sustained tremendous damage from the one-two punch of flooding from Hurricane Irene and Tropical Storm Lee. Historic and epic flooding in the Schoharie Creek has changed the political, economic, and physical landscape in a deep and profound way.”
Garver said that the Schoharie Creek is discharging into the Mohawk River at a much higher rate than in the past, according to data from the U.S. Geological Survey, and that this higher rate of discharge can be attributed to increased precipitation from storms such as hurricanes and nor’easters.
“There are more and more big weather events,” Garver said. “There are more weather events doing things to the Catskills, and this is affecting the Schoharie Creek. Even before Sandy, and even before Irene, we knew we were getting more extreme weather events.”
“Anybody who thinks they have crystal clear clarity about what is going to happen in the future is going out on a limb,” Garver said. “But we have a pretty good notion of what’s happened in the past, and if those trends continue, it won’t be good. The data suggests a clear trend.”
Among scientists, “there was a big buzz about what Cuomo said,” Garver said.
Wysocki said that he had hoped Hurricane Katrina — which swamped New Orleans in 2005 — would wake people up to the dangers posed by climate change, but that perhaps the various regions of the United States were starting to understand that the extreme weather they’re experiencing has a common cause. “We’re seeing more extreme droughts, more wildfires, more tornadoes,” he said.
Thorncroft said that climate change “shouldn’t be a partisan issue.”
But it is.
Climate change skeptics have criticized the scientists and politicians who suggested in the wake of Sandy that global climate change is a problem.
“It is always disappointing to see that there are a handful of global warming alarmists who will rush to promote a far-left political agenda in the midst of a disaster,” said Sen. James M. Inhofe, an Oklahoma Republican who is one of the leading climate change skeptics in Congress. “The American public reacts negatively towards this approach and that is one of the reasons why the issue of global warming has dropped off the radar screen completely.”
Wysocki said that rebuilding areas damaged by Sandy must be a careful process, and that officials must ask tough questions about whether it makes sense to rebuild certain areas, given the likelihood that extreme weather and flooding will increase.
“We have an opportunity here in the rebuilding process to really think about how to rebuild,” said Wysocki, who is a senior lecturer in meteorology at Cornell University.
“We need to rebuild smart,” he said. For example, it might be a good idea to base rebuilding on where the 500-year floodplain lies, rather than the 100-year floodplain. “The 100-year floodplain is a moving target,” he said. “We need to think differently, and there needs to be a public discussion on living in a flood zone.” Ultimately, a concerted effort to move residents away from floodplains might be necessary, he said. For people living in vulnerable areas along the Jersey Shore, “it might be insane not to move them,” he said. “They may not have been in a dangerous situation 10 to 15 years ago, but it’s becoming dangerous.”
“Our infrastructure is having trouble handling the hits its taking time and time again,” Garver said.
In general, hydrologists prefer not to use the terms 100-year and 500-year flood, and instead focus on probability. What would be considered a 100-year flood should be thought of as having a 1 percent chance of occurring in any given year, while a 500-year flood should be thought of as having a 0.2 percent chance of occurring in a given year.
Last year, the New York State Energy Research and Development Authority released a 600-page report that said that New York should begin planning for hotter summers, snowier winters, severe floods and other impacts stemming from climate change. The study predicts that average annual temperatures in New York will rise by 4 to 9 degrees by 2080, precipitation will rise by 5 percent to 15 percent, and that along the sea coast and tidal portion of the Hudson River the sea level will rise by 1 to 5 inches by the 2020s.
Environmentalists cheered Cuomo and Bloomberg’s remarks, and said that Sandy should motivate elected officials to get serious about addressing climate change.
“We cannot always know when or where a serious weather event will occur — or even what impacts such an event may have on our communities or environment — but we do know that we cannot wait until another disaster like Hurricane Sandy before our state takes action to fight climate change and modernize its aging infrastructure,” said Rob Moore, executive director of the Albany-based Environmental Advocates of New York, in a statement.
“At a time when public officials are dodging the issue of climate change or, worse yet, proudly displaying their ambivalence, we applaud our leaders for acknowledging a reality that is unequivocally supported by a preponderance or scientific knowledge: that our climate is warming, and that New York and the country will experience similar, if not more damaging, events more frequently in the future,” Moore said.