Is Hurricane Sandy "The New Normal?"
November 15, 2012 6:30 PM
With the cleanup from Hurricane Sandy continuing and a Nor’easter ravaging parts of the same areas just a week later, many are asking if this is really what we can expect year after year? Is it coincidence or does climate change play a role? Climate change is a very controversial topic, much like politics. Everyone has their opinion and many can be unwilling to see both sides of the equation. I am NOT writing this to persuade your mind one way or another. I became a scientist because I want to educate everyone on the facts of weather and climate.
We have all heard the politicians screaming that this is “the new normal” and that climate change will ultimately affect all of our lives more and more in the years to come. There is no denying that this could be true, but what you may not have heard is there has been research completed over the last couple of years that focuses solely on whether hurricanes will be affected by warmer global temperatures AKA climate change. Before we dive into that, lets just look at the facts of Atlantic hurricanes for a second. Sandy was a dangerous and destructive storm and my heart goes out to all that were affected by its wind and water.
But was Sandy an unprecedented storm? Well actually no it wasn’t. The Northeast United States has been hit by more than 2 dozen tropical systems over the last hundred years and some were actually more powerful. In fact, from 1944 to 1954, there were 3 different major hurricanes to impact the Northeast proving that the Atlantic Seaboard will go through some active Hurricane periods. Don’t forget about “The Perfect Storm” in the 90’s! It was so epic that Hollywood made a movie about it.
There were 2 components that made Sandy so much different than what we have seen since the industrial age began; it was so late in the year, and it followed the “perfect” path to create the most storm surge for the New York City and New Jersey areas leading to never before seen flooding in the most densely populated area of the United States. That’s literally where the “unprecedented” part of the storm ends.
Now, the scientific research I was talking about earlier was highlighted in a blog post by a science blogger working for the Houston Chronicle named Eric Berger. This research concluded that there is no connection between the rise in temperatures, and more frequent and intense hurricanes. Basically, it concludes that this is NOT “the new normal.” This probably just made your head spin, but its nice to see both sides of the spectrum since the debate currently seems to be one sided. I encourage you to read his blog and decide for yourself. Remember, that these are his words and I don’t necessarily agree with everything he says, but the facts in his blog are backed up by scientific research:
"It only took a hurricane striking new New York City, but climate change is finally an issue in the presidential campaign. On Thursday, New York City Mayor Mike Bloomberg cited climate change as a primary reason why he endorsed President Obama.
To his credit, in his endorsement, Bloomberg did not link Sandy directly to climate change, writing:
Our climate is changing. And while the increase in extreme weather we have experienced in New York City and around the world may or may not be the result of it, the risk that it may be — given the devastation it is wreaking — should be enough to compel all elected leaders to take immediate action.
However, others in the political-climate sphere have been far less interested in accuracy. Writing for one of Bloomberg’s publications, under the headline, It’s Global Warming Stupid, Paul Barrett states:
Yes, yes, it’s unsophisticated to blame any given storm on climate change. Men and women in white lab coats tell us—and they’re right—that many factors contribute to each severe weather episode. Climate deniers exploit scientific complexity to avoid any discussion at all.
Clarity, however, is not beyond reach. Hurricane Sandy demands it: At least 40 U.S. deaths. Economic losses expected to climb as high as $50 billion. Eight million homes without power. Hundreds of thousands of people evacuated. More than 15,000 flights grounded. Factories, stores, and hospitals shut. Lower Manhattan dark, silent, and underwater.
And even that kind of rhetoric is timid compared to what some people have been saying about Sandy and climate change. “Global warming systematically caused Sandy,” wrote George Lakeoff at the Huffington Post. And Kevin Knobloch, an Obama campaign surrogate and President of the Union of Concerned Scientists, said the following of Sandy:
“We’re at a place where we have to focus on both mitigation — reducing greenhouse gas emissions — and adaptation — starting to move our vital infrastructure out of harm’s way. We know this is going to be our future. This is our new normal.”
Sandy has injected climate change, which for months has completely been a non-issue with the Presidential candidates, into the campaign.
My concern is whether the end justifies the means. My concern is setting expectations that Sandy, that large, destructive hurricanes striking the United States, is the “new normal.” My concern is that we’re telling people that we’ve entered an era in which super-storms are the new normal and that there will be a mega-disaster every year.
My concern is that we’re not debating facts when it comes to hurricanes and climate science.
IT’S SCIENCE, STUPID
Science tells us this is not a new normal.
Science tells us climate change has not had a discernible impact on global hurricane activity. A warmer climate, of course, is changing hurricanes. But, scientists consistently tell us, that change is so small it cannot be measured at the present and likely won’t be measurable until the middle of this century.
But what about Sandy?
Earlier this week Andy Revkin compiled some opinions of actual hurricane and extreme weather scientists on Sandy. Kevin Trenberth, who in interviews with me has spoken nearly as ardently about the perils of climate change as has James Hansen, said of the idea that a warmer Arctic contributed to Sandy’s intensification, “With respect to the Arctic connection, I don’t believe it.” And later, he said:
It is true that hurricanes normally recurve and head east, especially at this time of year. So we do have a negative NAO and some blocking anticyclone in place, but the null hypothesis has to be that this is just “weather” and natural variability.
Of course Sandy’s effects were exacerbated by rising sea levels. According to NOAA data, the sea level in Manhattan has risen by about half a foot during the last century. Some, but not all, of that rise is attributable to human greenhouse gases. So the surge was a few inches worse because of climate change.
But that’s as far as the science goes. And my purpose here is to follow the science, not an agenda to change U.S. carbon emissions policy nor deny science or climate change.
So where does the science take us in regard to hurricanes and climate?
WHAT SCIENCE TELLS US
I have already posted about an influential paper in Nature Geoscience, published in 2010, that surveyed all of the recent climate science and hurricane literature. In summary, after studying past and present hurricane data the scientists did not conclusively find any detectable human influence on hurricane activity.
Since that paper there has been more research done. One important paper was published in Science — that would be America’s most influential science journal — which modeled a warming climate’s impact on the frequency of intense Atlantic hurricanes.
This is state-of-the-art science using the best-resolution climate models. If you’re a proponent of anthropogenic global warming then, by definition, you pretty much have to have some measure of faith in these models. The following projection, using the “business as usual” A1B climate scenario, predicts the change in hurricane frequency by wind speed between the current climate and what’s expected between 2081 and 2100.
The authors wrote:
Although our internal variability estimate is very uncertain, these results suggest that one would not expect to detect an A1B-like anthropogenic influence on Atlantic basin category 4 and 5 frequency at the present time.
In other words, in the future there might be an increase in the very strongest storms at the end of the century, and that is something we should definitely be concerned about, but there is not now such an increase. Indeed, if we look at Sandy-like storms, which had maximum sustained winds of 110 mph (50 m/s), we would expect to see about a 35 percent reduction in storms reaching that level of intensity in the future.
How is this possible, given that warmer waters fuel more and stronger hurricanes in our experience? The reason is that the warming in the lower and upper levels appears to be such that atmospheric stability remains about the same. Put another way, a sea temperatures rise, so does the temperature needed for convection — thunderstorm activity — rise in the tropics.
A recent study in Nature found a correlation between a rise in sea surface temperature and this temperature threshold for tropical convection during the last 30 years:
Thus there are theoretical reasons to believe hurricane activity is not increasing at the present, and there are good real-world data reasons to believe this.
Finally there’s another, still more recent study in Geophysical Research Letters that used the Japanese Meteorological Research Intitute‘s global model to simulate hurricane activity over a period of 228 years, from 1872 to 2099.
In contrast to talk about climate change spawning more hurricanes — that more hurricane strikes will be the “new normal” — the actual global count of tropical storms and hurricanes decreased in their study from an average of 83 during the last 30 years of the 19th century to 59.6 during the last 30 years of the 21st century.
We can conclude, then, that science tells us three things about climate and hurricanes:
- There is no discernible effect on present activity by climate change
- There will probably be fewer hurricanes in a warmer world
- The very strongest storms may get a bit stronger in a warmer world
My point is far from casting doubt on climate change and humanity’s role in increasing greenhouse gases. My point is that while there are a lot of very good reasons to be concerned about climate change, notably heat, drought and rising sea levels, an increase in “super” storm activity at present is not yet detectable, and science tells us it won’t be until the middle of the century at least.
Yes, sea level rise will make the effects of hurricanes worse. But telling people that Sandy was caused by climate change, or that Sandy is the “new normal” as a result of global warming, or that Sandy is “global warming, stupid,” is, well, stupid. The science does not support any of these positions. Science, in fact, indicates there will be considerably fewer Sandy-like storms in a warmer world. If saying this makes me a “scold” in the words of David Roberts, so be it.
False promises to the contrary will not help climate advocates make their case, it will only undermine their message when there’s a lull in major hurricanes hitting the United States.
It is true that Sandy was a human-caused disaster. We build cities on the coast. We don’t adequately protect them. We don’t heed evacuation warnings. That is where the blame lies for this one, not climate change."