by William Hooke, AMS Policy Program Director,
from the AMS Project, Living on the Real World
Reality: Disasters – that is, disruptions of entire communities, persisting after an extreme has come and gone, and exceeding a community’s ability to recover on its own – are largely a social construct. Consider this simple example. Meteorologists call a tropical storm a hurricane when its winds exceed some 75 miles per hour. The strongest hurricanes ever observed show wind speeds about twice this level, 150 mph, say. Physics tells us that the forces on buildings and structures should vary as the square of the wind speed (getting a little technical …). The strongest hurricanes therefore pack a wallop about four times that of the weakest; the area suffering hurricane-force winds also tends to be a bit bigger. But the damages from these largest storms may be 200 times as great. One contributor to this big difference? Building codes. These are county-based, and so vary somewhat across the 3000-some counties in the United States, but in hurricane-prone areas usually require that brick-and-mortar residential construction withstand wind speeds of about 120 mph – right in the middle of the hurricane-force wind range. [Manufactured housing, by contrast, is governed by a less-rigorous federal standard, which requires that such structures only maintain their integrity at wind speeds up to some 70-90 mph.] Change building codes, and you change this loss profile.
Alert! These are our choices, but they’re not necessarily bad choices. When it comes to building codes, we’re simply forced to set a realistic standard. Whenever we wish, we can elect to build homes that will withstand hurricane-force winds, or even the strongest tornadic winds, which might approach 300 mph. But these homes would be considerably more expensive. They might be built largely underground, looking more like World War II “pillboxes” than homes, with narrow slits for windows, etc. Remember, they have to bear up not just to the winds but also to the windborne debris: lumber, roofing, automobiles, etc. Most of us wouldn’t be able to afford them, and wouldn’t want to live in them even if we could. We prefer our views, the connection with the outdoors. So we build a safe room, or a storm cellar, and accept the remaining risk.
Building codes are but one example; here’s another – land use. Simply by choosing to build in the flood plain alongside rivers and on the coasts, we ensure that our future will be punctuated by repetitive loss. Build on an earthquake fault-line? Expect the same outcome. There’s much more to this topic. We’ll return to it down the road.
But, for now, let’s set it aside in order to introduce a more complicated notion. When we choose to urbanize – and over half the world’s population lives in cities now – we expose ourselves to other risks, and different kinds of risk at that. To live in cities requires critical infrastructure, ranging from the elevators that service high-rise buildings to networks of roads, sewage systems, water works, electrical grids, communications, financial services, health care, and so on. As a result, we’re now subject to outages of these systems, from whatever cause. An example from the Midwest flooding of 1993. The city of Des Moines, Iowa remained largely dry; only a small sliver of land along the river was submerged. For a while, business could, and did, go on pretty much as usual. But when the flooding surmounted the city’s water treatment plant, the quarter million area residents, although themselves on higher ground, had to drop whatever they had been doing to find water safe to drink.
A more recent example. We know that the Eyjafjallajokul volcano in Iceland erupted in 920 AD, 1612, and over a two-year period from 1821-1823. While these events were recorded, none caused much of to-do outside of Iceland itself. With the invention of airplane, however, we introduced a new vulnerability. When Eyjafjallajokul erupted in April of this year, it shut down European air travel for nearly a week, and that disrupted travel and commerce worldwide. [Nobody’s recommending that we do away with air travel. The point here is that when we introduce a new technology, we also introduce unintended consequences, and these typically take a long time to show up.]
Reality: our current policy approach to many hazards has the effect of trading frequent, more limited disasters for fewer, more destructive ones. Take the practice of reducing flood threats through construction of levees, for example. This policy succeeded in reducing the damages resulting from relatively more frequent but also more minor flooding events. But for those rarer, larger floods that have succeeded in topping or breaching the levees, the damage tolls and the subsequent disruption balloon – Katrina being a case in point. Look at wildfires. For decades, federal and state agencies held a policy of quickly putting out every fire they could. This practice led to large fuel buildups – dead wood, decaying plant matter – all across the West. As a result, in more recent years when and if fires did get out of control, the resulting burns were of far greater extent and posed far more widespread dangers. Today the policy is to let wildfires burn and run their course, except where they pose an immediate threat to life and property.
Reality: Disasters are mutating in response to rapid social change, and scientific and technical advance. Consider just a few examples. In 1812 the central United States experienced a series of earthquakes exceeding magnitude 8.0 on the Richter scale – three over a period of a few months. These New Madrid earthquakes destroyed the dwellings of the few hundred indigenous people and settlers in the area, created a new lake adjacent to the Mississippi River, and rang church bells in Boston, a thousand miles away. Today the area’s population runs into the several millions. Many of the natural gas pipelines serving the northeastern United States run through this region. The consequences of the next New Madrid earthquake will be far more sweeping than the last.
[A vignette. When I started in meteorology, the conventional wisdom was the buildings and skyscrapers making up urban areas interfered with the boundary-layer inflow needed to form and maintain major tornadoes; hence tornadoes were supposedly a rural phenomenon. There may yet be some merit to this argument, but at that time cities presented a relatively small target to tornadoes, hadn’t been around all that long, and were growing rapidly in extent. Tornadoes now find a target-rich environment, and in recent years have invaded downtown Miami, Nashville, and Atlanta. More (and worse) disasters of this type are likely hardwired into our future.]
Today’s globalized connectedness has helped once-localized disasters morph into worldwide problems. Start with Katrina. In earlier flooding events, the damages and losses were relatively localized. By 2005, however, New Orleans hosted major oil refineries, and a gasoline prices spiked not just locally but regionally and nationally following the floods. The Port of New Orleans was the distribution point for much of the U.S. grain exported overseas. Foreign governments worried for weeks about whether these grain supplies would be disrupted. Think about Eyjafjallajokul. Air freight has allowed African farmers to grow and sell flowers for European markets. But this market, and African economies, were hit by the volcanic eruption. Just as mosquitoes are a vector for the spread of malaria, globalized commerce has become a vector by which localized disasters have worldwide effects.
Here’s another one. Prior to the mid-1800’s, solar flares and associated space weather manifested themselves only through beautiful displays of aurora borealis at high latitudes: awesome and mysterious, but benign. But the invention of the telegraph changed all that. When we started stringing long wires across the country, space weather began to cause real damage. At first, the problems were confined to the high voltage surges that would tear through the telegraph lines, knocking telegraph operators out of their chairs. But in the century since then we have added regional power grids, satellite communication systems, GPS, trans-Arctic flights, and many other activities which have increased our vulnerability to space weather.
A final example. The rise and spread of internet communications has been accompanied by a series of small and disquieting events associated with accidental failures and malicious hacking. Experts agree that major disruptions are likely a matter of time, even as they struggle to postpone that day of reckoning.
Read enough? In countless ways we can already discern, disasters are changing not just by degree in response to social change; they’re changing in fundamental nature and character. But our imaginations are limited. Further surprises are in store.
by William Hooke, AMS Policy Program Director,