Climate experts have pointed out that Nemo, the very bad nor’easter that just hit the Northeastern US and Maritimes, is partly an effect of global warming. Some meteorologists have responded with an incorrect response, a recitation of a now tired and useless mumbling retort that I’m afraid may even have it origin among scientists who should know better, and at the very least was kept alive by them for far too long: “Well, you can’t really attribute any given weather event to climate change.” Some regular people who are not climate scientists have repeated that faleshood as well. Then there are people making the claim that a bad winter storm is proof that climate change is not real or reversing or some other such thing. This of course is wrong at so many levels that if a scientist (even a non-climate scientist, just anyone who values critical thinking) said it they would be fired and sent off the humanities in a second. I will also mention this, because it helps us to get at a causal mechanism for what is going on here: Many people have stated, quite clearly on TV and Facebook and all those other good places, that “The Upper Midwest” or more particularly “Minnesota” gets more snow than Massachusetts or the Northeastern US. This is incorrect. Plain, simply, untrue. But that people believe this tell us something about people’s beliefs about the weather and helps explain some things. By the way, I’ve lived in New York, Massachusetts and Minnesota and I can tell you that people who live in the Northeast think Minnesota gets more snow, and people in Minnesota think Minnesota gets more snow. So everybody is wrong and in the same way. This isn’t just a mater of each region thinking they get the most snow.
And yes, as I’ve implied, all these things are connected and I’ll show how. The conclusion of this essay, though, will be the following points: Continue reading Finding Nemo→
On June 6th, 1944, some 160,000 soldiers aboard about 5,000 boats of diverse design crossed the English Channel and carried out the Invasion of Normandy, one of the more important events in recent history. Many of the soldiers were so sick from choppy seas that leaving the boats and walking or running into German gunfire seemed like a good idea. The invasion was originally planned for the 45h of June, but a very precise weather forecast told the Supreme Commander, General Eisenhower, to wait until the next day. The forecast for the 6th of June, integrated with the logistical features of the operation, had the landing craft arriving on the German-held beaches just as wave heights were reducing from a level unacceptable for this operation to something that could be managed by most (but not all) vessels.
If you’ve seen “The Longest Day” or any of the other classic semi-documentary dramatizations of D-Day, you may recognize the name Captain James Stagg. Stagg was the meteorologist on Eisenhower’s staff, and as such he was the conduit and translator for the information that came from the meteorology group. That, in turn, was a combination of American and British scientists with very different methods and backgrounds, but both using data and analyses that involves a large number of individuals making observations and crunching numbers, from teams at Scripts Institute in California who developed the primary predictive models in use to British Coast Guard observers making observations at sea several times a day.
The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters by Bruce Parker elucidates the science behind this historic moment in great detail in one of several riveting chapters about the ocean, and stuff the ocean does. Parker is a former chief scientist of the National Ocean Service so he knows something about waves, storms, tides, tsunamis, storm surges, and the like. This book is a nice combination of primer on meteorology ala the ocean and weather-related adventure stories. Throughout the book I kept running into things that I had always wanted to know about … like how exactly did that one huge ship I’ve seen so many times off the Cape Peninsula in South Africa sink? (The ocean did it!), what really was the story behind Stagg’s predictions (as discussed) and what is a future with greater storm surges and rising sea going to look like?
I recommend this book for non-experts who need to know all about ocean related science, who need to better understand the effects and dynamics of storms like Sandy, Tsunamis, and similar events. Parker does not hold back on the science and the detail. This is a very enjoyable way to elevate one’s self to the level of armchair oceanic meteorologist in a few evenings of enjoyable reading!
Earlier this year a paper was published in the journal Nature in which a team of scientists looked at changes in storm surge potential under conditions of global warming, and they used the New York City area in their modeling. Combined with resent research adding to the growing body of data and studies that show increased storminess with global warming, this research suggests that the increased possibility of a hurricane causing a storm surge that would actually flood the subways in Manhattan is not only possible, but pretty likely to happen in the near future. Perhaps as soon as …. earlier this week. More exactly, the research predicts an increase in the frequency of what we think of as “100-year flood” and “500-year floods.” In other words, more bad floods.
One study1 from 1987 indicated that modest warming over the Atlantic Ocean could increase the destructive nature of hurricanes by 40-50%. Subsequent studies showed variable results when modeling hurricane frequency or strength under warming conditions, but part of this had to do with the way models were constructed. Recently, Bender et al2 noted that earlier models showed, enigmatically, a decrease in hurricane activity with warming, but also failed to produce category 3 or higher storms, indicating that something was fundamentally wrong with the models. Their revised look at the question indicated that we could expect “…nearly a doubling of the frequency of category 4 and 5 storms by the end of the 21st century…” and they further noted that the “…largest increase is projected to occur in the Western Atlantic, north of 20°N.” New York City is north of 20°N and adjoins the Western Atlantic.
Future increase in storminess is a serious problem for our society, and should be a great concern. Denying increases in storminess has also become a cottage industry within the larger anti-science climate change denialist community. A year and a half ago or so I suggested that this storminess was a matter of quality of life, and indeed, for some, life and death for our children and grandchildren, and that people who were in the business of denial of climate change today amounted to criminals with people of the future being their victims. This led to a major outcry in the anti-science climate change denailist community, threats of a law suit, a period of continuous harassment on the internet and in private, and a small number of absurd but not entirely discountable death threats against me, apparently organized by the anti-science community at one particular blog that recently came out with the absurd assertion that Hurricane Sandy was in fact not a hurricane and thus, I assume, does not count as a storm in considering the possibility of future hurricanes being larger, farther north, or more frequent, because of global warming. Those science denialists are answerable, of course, to the families of those who died in the Northeastern United states over the last few days as a result of a climate-change enhanced super storm.
The peer reviewed research at hand 3that predicted the flooding of subways in NY was produced earlier this year. From the abstract of the paper:
Storm surges are responsible for much of the damage and loss of life associated with landfalling hurricanes. Understanding how global warming will affect hurricane surges thus holds great interest. As general circulation models (GCMs) cannot simulate hurricane surges directly, we couple a GCM-driven hurricane model with hydrodynamic models to simulate large numbers of synthetic surge events under projected climates and assess surge threat, as an example, for New York City (NYC). Struck by many intense hurricanes in recorded history and prehistory, NYC is highly vulnerable to storm surges. We show that the change of storm climatology will probably increase the surge risk for NYC; results based on two GCMs show the distribution of surge levels shifting to higher values by a magnitude comparable to the projected sea-level rise (SLR). The combined effects of storm climatology change and a 1 m SLR may cause the present NYC 100-yr surge flooding to occur every 3–20 yr and the present 500-yr flooding to occur every 25–240 yr by the end of the century.
Have a look at the following graphic from the paper:
Worst case scenario for storm surge events at The Battery, New York City, under global warming conditions.
It may be helpful to briefly consider how tides work, and what a storm tide is. Tides are the warping of the ocean’s surface in sync with the Moon’s gravitational field and to a lesser extent, the Sun’s gravitational field. Think of the tide as an elongation of the planet that travels around the earth always pointing a long end at the moon, and a secondary, lesser elongation pointing at the sun. When the two are at 90 degrees from each other, the total elongation is at its minimum, and when the two are in sync (during a full or new moon) the effect is strongest. This elongation moves around the earth over the course of a lunar month but the earth spins within that gravitational effect once every 24 hours. For this reason, about twice a day, a given spot on the earth is sitting under one or the other of the two ends of this elongation. That’s high tide.
The total effect on the ocean is actually rather small at sea. But, when the elongated effect passes from sea to land it effectively bunches up the ocean against the land and you can get more tide. The height of the tide depends on the shape of the ocean basin (horizontally, as we would see it on a map), the detailed nature of the shore line, and other factors. So, we get a couple of feet of tide in Florida and 40 feet in the Bay of Fundy, normally. The height of the tide in new york city is something like 3.5 to 4.9 feet depending on the contribution of the sun’s gravity. The city is built with the assumption that the ocean will go up and down by this amount, with a few more feet added to sea walls and barriers to account for waves and such.
A storm tide is mainly one thing: Additional height of the water owing to the blowing of the sea by consistent long term and powerful winds towards the shore. But there are two other factors that also raise the tide during a storm. The lower barometric pressure experienced in a storm raises the water level a measurable amount, and in some cases, the tide can be even higher if there is flood water coming down an estuary or river at a given point.
A worst case scenario involves an “astronomical” high tide (the Moon and the Sun lined up) with a strong wind blowing towards shore and a very low pressure system storm. That was Sandy the other day in New York.
The graphic shows how the harbors and bays around New York City are essentially traps for both tide and storm effects, with the Battery being caught, as it were, between a rock and a hard place, with tidal waters coming in from two directions (against a possibly flooding Hudson River).
The present study notes that earlier studies had indicated that the storm surge threat at the Battery was between 1.24 and 2.78 meters (4 to 7+ feet). The storm surge with Hurricane Sandy topped out at about 14 feet, which was about 7 feet higher than expected, so at the highest end for the present estimate for the so called “500 year flood.” that’s astonishing, considering that for all its strength and bigness, Sandy was not as powerful in the immediate area of New York City as it could have been.
The main outcome of this study is to suggest that the frequency of high flooding of the kind we saw earlier this week will shift, so that multi-century events occur (on average) every few decades, owing to a combination of changes in storm patterns and sea level rise.
As the climate warms, the global mean sea level is projected to rise, owing to thermal expansion and melting of land ice. … The total SLR [sea level rise] for NYC is projected to be in the range of 0.5–1.5m by the end of the century. The effect of SLR, rather than changes in storm characteristics, has been the focus of most studies on the impact of climate change on coastal flooding risk … To our knowledge, this paper is the first to explicitly simulate large numbers of hurricane surge events under projected climates to assess surge probability distributions.
Our study shows that some climate models predict the increase of the surge level due to the change of storm climatology to be comparable to the projected SLR for NYC. … the combined effect of storm climatology change and SLR will greatly shorten the surge flooding return periods. … the present
NYC 100-yr surge flooding may occur every 20yr or less … and the present 500-yr surge flooding may occur every 240 yr or less…
1 Emanuel, Kerry A. 1987. The dependence of hurrican intensity on climate. Letters to nature. 326, 483-485.
2Bender, Knutson, Tuleya et al. Modeled impact of anthropogenci warming oin the frequency of intense Atlantic hurricanes. Science 327(5964), pp 454-458.
3Lin, N., Emanuel, K., Oppenheimer, M., & Vanmarcke, E. (2012). Physically based assessment of hurricane surge threat under climate change Nature Climate Change, 2 (6), 462-467 DOI: 10.1038/NCLIMATE1389
As you know, I’ve shifted some of the topics I have discussed on this blog over to The X Blog. However, some topics can very reasonably go on both. One of these is how we communicate, and argue, and sometimes make progress in this crazy, zany place we call The Blogsophere. Also, as an Anthropologist, I see topics related to gender, sexism, feminism and related topics as fully at home here, as well as at The X Blog. So, I just completed a series of posts over there which I’m sure will be of interest to those of you who tend to hand out here and might not otherwise notice. I hope you visit them, read them, love them or hate them, send them to your family to enjoy for the holiday season, and hopefully scream at me about them in the comments. They are:
This started out as a big-huge blog post which I then decided to break down, and I decided that for a number of reasons. One is that some of the subtopics (i.e., the one on sex positiveness and calibration) may be more of a side issue. Another is that I didn’t want any one of the topics to get sidelined by shifting focus should there be extended discussion. Mainly, though, I wanted to have bite size pieces to avoid the tl;dr effect, and to later have more narrowly defined items to point or link to as appropriate.
People are asking me: Is the recent spate of tornadoes caused by global warming? The usual answer to that question is that you can’t answer the question because a tornado is not caused by climate … it is cause by weather … and global warming (which is real, and which is cause by humans) is climate change.
However, that is not really the best answer to the question. Ultimately, I want to propose an analogy for how to think about this question, but first, a stab at a good answer, which if modified could probably be improved:
Jeff Masters’ WunderBlog is a key source of information on any current weather events:
A stunning tornado outbreak of incredible violence has left at least 202 dead across the Eastern U.S.; injuries probably number over a thousand, with 600 injured in the town of Tuscaloosa alone. The tornadoes carved huge swaths of damage, completely flattening large sections of many towns, and damage from the storms is likely to be the greatest in history for any tornado outbreak. Hardest hit was Alabama, with at least 149 dead…
The best place to donate is probably the American Red Cross. At this moment, their web site does not seem to be aware of the tornadoes, but they are in fact on the scene working now.
Dozens of people died in tornadoes in the US over the last couple of days, and most of those deaths were preventable. The truth is, most of those killed died because of a decision they made, so their death is to some extent their fault. But, for good reason, no one wants to blame the victim, so we see very little discussion about how a death spree like this happened over the weekend could have bee avoided. Also, almost every single feature of avoiding similar deaths in the future touches on a difficult political issue or points to a costly solution. Therefore, those involved and those reporting on the issue tend to avoid talking about the obvious. Finally, there is a small set of commonly used explanations, which are either totally incorrect or partly incorrect, that are easy for loved ones of the dead, reporters, local and state officials, and others to pull out of their nether regions. The main explanations are, of course, “God’s Will” and “Random Chance.”
Either way, someone’s gonna lose themselves a trailer, which brings us to the real reasons people die in tornadoes. They are:
I went to Target to look at weather radios and found out that they don’t carry them. But the three Target employees that were gathered near the cameras and electronics with whom we inquired were interested to know why we were looking for one.
“You’re about the tenth person today who has asked about weather radios. What gives?”
When I was first in the Ituri Forest, I Noticed there were many kinds of plantains grown in the gardens there They varied by size and shape. One version seemed to have numerous black spots on the outside. When asking what it was called, I found its name was the same as the variety without the black spots. Eventually, someone realized that I was asking the wrong question, and gave me the explanation I was unknowingly looking for: “The ones with the black spots were the ones at a certain ripening stage during a storm in which rocks made of water in the form of what you call ice cream, sort of”
That is how you say “hail damage” in a tropical country in a a shared language with limited vocabulary in that shared language for frozen things.
This picture, from a current (as of this writing) accuweather forecast page, is an excellent illustration of what happens here in the upper Midwest the spring.
The overall pattern of movement of air masses at the continental scale is west to east, with extra moist and extra warm air secondarily moving north from the Gulf of Mexico, and cool and usually dry air coming form the Northwest (not shown here but note the “blizzard” part) and with dry Pacific/Rocky Mountain air coming from the west. The main energy flow to keep an eye on is that coming from the Gulf.
by Bruce Parker elucidates the science behind this historic moment in great detail in one of several riveting chapters about the ocean, and stuff the ocean does. Parker is a former chief scientist of the National Ocean Service so he knows something about waves, storms, tides, tsunamis, storm surges, and the like. This book is a nice combination of primer on meteorology ala the ocean and weather-related adventure stories. Throughout the book I kept running into things that I had always wanted to know about … like how exactly did that one huge ship I’ve seen so many times off the Cape Peninsula in South Africa sink? (The ocean did it!), what really was the story behind Stagg’s predictions (as discussed) and what is a future with greater storm surges and rising sea going to look like?
