Man-made natural disasters

tan Cox - Recently, Astronomy magazine asked, “Is this our final century?” In an article under the same title, astronomer Martin Rees raised the possibility that any one of several highly improbable hazards could cripple or even destroy civilisation on this planet: large-asteroid impact, mammoth solar flares, or maybe the explosion of a nearby star.
We have no control over such hazards. But, Rees pointed out, there are other extremely improbable world-wrecking catastrophes that could be set off by humans - if, say, an extra-powerful particle accelerator were to create a black hole that could consume the Earth. That sounds pretty bad, but Rees warned that we should not be too reluctant to use high-stakes technologies: “Innovation is always risky, but if we don’t take those risks, we may miss out on disproportionate benefits.”
But similar logic, unfortunately, is routinely applied not only to improbable mega-hazards but also to more common climatic and seismic hazards that, increasingly, are spinoffs of our everyday productive, profitable activities. There would clearly be risks in reining in economic growth; however, carrying on with business as usual will lead to increasingly frequent and destructive natural disasters.
Do-it-yourself disaster
Less than a year ago, Hurricane Sandy and Typhoon Bopha finally got us all talking about what had long been obvious: not only have we made a habit of turning hazards like tropical cyclones and earthquakes into human and economic disasters, but now, more and more, the seemingly natural hazards themselves are aggravated by the normal workings of the human economy.
For example, while the frequency of tropical cyclones in the North Atlantic is not (yet) thought to be affected by greenhouse emissions, it has been confirmed that those storms are growing in intensity, supercharged by warmer surface waters. And Sandy isn’t the only recent tropical cyclone to cause havoc in an unconventional setting.
Before 2011, monster typhoons hit the Philippine islands Palawan, Negros, Cebu, and Mindanao only very rarely. But that year, Typhoon Sendong dumped a month’s worth of rain in 12 hours on the big southern island of Mindanao, causing flash floods and laying waste to several towns and villages. That was followed just a year later by Bopha, the strongest storm ever to hit Mindanao, the second-deadliest storm to hit the Philippines since independence in 1946, and the world’s deadliest disaster of 2012.
Cyclones are historically rare in such regions, where winds in the upper atmosphere are much faster than those below. The wind shear rips storms apart before they can gain much strength. But if greenhouse-gas-induced warming of the ocean surface energises lower-altitude winds, decreasing the wind shear, then out-of-place hurricanes like Bopha will become more common.
The increasing frequency of calamitous droughts that has been observed globally over the past 60 years is well-predicted by climate models that take into account the human economy’s emissions of greenhouse gases and sulfate aerosols. When scientists extend those models into the future trends, they predict that the most extreme drought conditions, which currently affect one percent of the Earth’s land surface, will affect 30 percent of its land surface by 2100.
Humans also contribute to the development of droughts, of course, through inappropriate land use policies, and in some unexpected ways as well. Industrial “brown clouds” of particulate matter and chemical aerosols were largely responsible for the Sahel drought of the 1970s, and are expected to cause more droughts in North Africa and South Asia in coming years.
And increasingly, intense droughts and calamitous floods are pairing up like fever and chills. The catastrophic floods that struck Pakistan in 2010 were part of the same greenhouse-charged weather system that brought deadly drought to Russia.
Beyond climate change
Climate disruption isn’t the only force that’s contributing to destructive unnatural hazards. The phenomenon with the widest variety of anthropogenic causes may be the all-too-routine landslide. Between 2004 and 2010 alone, mostly small landslides (ones not associated with earthquakes) killed more than 32,000 people and caused untallied property damage.
As the atmosphere warms, more intense rainfall is expected to trigger even more landslides, from Seattle to Sumatra. But it is often other human activities - deforestation, growing crops on steep erodible land, building houses (often the homes of the very rich or the very poor) on vulnerable sites, construction of earth-destabilising roads or dams, irrigating in the wrong place - that prime hillsides for collapse.
The technologies that are opening up large new pools of fossil fuels could also trigger new rashes of catastrophic events even before we have a chance to burn the oil or gas that is being extracted. It is now confirmed that a mud volcano that erupted in Indonesia in 2006 (and is expected to continue covering a vast, formerly inhabited area with a hot mud-flood for the next 30 to 80 years) was set off by nearby natural-gas drilling.
The cause of a magnitude-5.7 quake that destroyed more than a dozen houses in the US state of Oklahoma in 2011 has been traced to a nearby oil field, where waste water had been disposed of by pumping it underground into porous rock for more than two decades. Indeed, recent studies have confirmed that a sharp increase in the number of small earthquakes across the world can be attributed to the injection of fluids into oil and gas formations. Furthermore, large “natural” earthquakes that are nowhere near an oil or gas field can set off smaller ones near fluid-injection sites thousands of kilometres away.
Sea-level rise and land subsidence combined with torrential rains have caused epic floods in Bangkok, Mumbai, and many other coastal cities in recent years. In the near future, flood vulnerability will be amplified, perhaps even doubled, in cities situated on the world’s great river deltas - because groundwater extraction and upstream damming are causing those deltas to sink.
And of course, one of history’s oldest, most common, and biggest mistakes has been to try to contain rivers - the Yangtze, the Mississippi, and others - within their banks, holding back many small floods only to guarantee an occasional mega-flood.
It has long been obvious that, whatever the cause of a particular hazard - natural or otherwise - economies have a distinct talent for turning danger into disaster. Developers of shrimp farms and beach resorts strip away mangroves and other biological defences against storm surges and tsunamis. Power utilities place nuclear reactors in the path of storm surges and tsunamis. For centuries, political and economic policies have been turning routine droughts into famines.
Through it all, it is generally low-income families who find themselves stuck, living in earthquake-vulnerable houses, apartment buildings, and schools near fault lines. It is big commodity agriculture that drives farm families off their land and onto small plots on vulnerable slopes, while urban development often pushes poor people onto the lowest-lying coastal lands.
In sum, the number of disasters is increasing thanks to forces stretching from one end of the world economy to the other: the technologies now used in mining hard-to-get fossil fuels; greenhouse emissions from burning those fuels; and many of the lucrative but ecologically suicidal and inhumane economic policies and practices that those potent energy sources make possible.
Preventing those perennial disasters, whose roots run so deep under the world economy, will be much more difficult than, say, knocking a big incoming asteroid off course. But while we don’t know if or when that asteroid is coming, we can foresee all too well our dismal prospects if we persist in our ecologically suicidal ways.–Aljazeera

on epaper page 11
natural disasters
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