megacities

Physorg | Charles Kolb, Ph.D., reports that the concept of urban metabolism has existed for decades. It views large cities as living entities that consume energy, food, water, and other raw materials, and release wastes. The releases include carbon dioxide, the main greenhouse gas; air pollutants, sewage and other water pollutants; and even excess heat that collects in vast expanses of concrete pavement and stone buildings. Humans directly produce a significant share of this waste, but emissions from industrial, power generation and transportation systems respire the largest quantities of greenhouse gases and other air pollutants. Other urban metabolizers include sewage systems, landfills, domestic pets and pests like rats, which in some cities outnumber people.

During the last five years, this body of knowledge has drawn into sharper focus the hazards of poor air quality in megacities, not just on the large local populations but also on population centers, agricultural activities and natural ecosystems located downwind from these sprawling areas, Kolb said. He is with the Center for Atmospheric and Environmental Chemistry and the Center for Aerosol and Cloud Chemistry of Aerodyne Research Inc. in Billerica, Mass.

"Carbon dioxide and other pollutants in megacities make them immense drivers of climate change," he said. "They impact climate on both a regional and global level because these long-lived greenhouse gases are dispersed around the world."

More than half the world's population today lives in cities, and the world's largest urban areas are growing rapidly. The number of megacities — metropolitan areas with populations exceeding 10 million — has grown from just three in 1975 to about 20 today.

Kolb said that the most highly polluted megacities are in developing countries. They include Dhaka, Bangladesh; Cairo, Egypt; and Karachi, Pakistan. Some megacities in less developed regions have recently mounted air quality management campaigns that have resulted in lower levels of pollution; they include Mexico City, Mexico; Beijing, China; Sao Paulo, Brazil; and Buenos Aires, Argentina. Even the cleanest megacities like Tokyo/Osaka in Japan and New York City and Los Angeles in the United States — all in the developed world — still have serious problems, Kolb said.

Everything Makes Sense If You Center Megacities As The Focus Of Global Governance

technologyreview |  In 2050, 2.5 billion more people will live in cities than do today. As the world grows more urbanized, many cities are becoming more populous while also trying to reduce carbon emissions and blunt the impacts of climate change.

In the coming decades, cities will be engines of economic growth. But they must also play a key role in confronting climate change; the world’s 100 most populous cities are responsible for roughly one-fifth of global carbon emissions. 

Some of the world’s biggest cities—called megacities—are rising to this challenge. However, these urban areas vary greatly in how efficient they are and how much they will grow. Seeing how they stack up can help us identify where our greatest opportunities are to reduce emissions.

consequences of regional scale nuclear conflict

Abstract. We assess the potential damage and smoke production associated with the detonation of small nuclear weapons in modern megacities. While the number of nuclear warheads in the world has fallen by about a factor of three since its peak in 1986, the number of nuclear weapons states is increasing and the potential exists for numerous regional nuclear arms races. Eight countries are known to have nuclear weapons, 2 are constructing them, and an additional 32 nations already have the fissile material needed to build substantial arsenals of low-yield (Hiroshima-sized) explosives.

Population and economic activity worldwide are congregated to an increasing extent in megacities, which might be targeted in a nuclear conflict. We find that low yield weapons, which new nuclear powers are likely to construct, can produce 100 times as many fatalities and 100 times as much smoke from fires per kt yield as previously estimated in analyses for full scale nuclear wars using high-yield weapons, if the small weapons are targeted at city centers. A single “small” nuclear detonation in an urban center could lead to more fatalities, in some cases by orders of magnitude, than have occurred in the major historical conflicts of many countries.

We analyze the likely outcome of a regional nuclear exchange involving 100 15-kt explosions (less than 0.1% of the explosive yield of the current global nuclear arsenal). We find that such an exchange could produce direct fatalities comparable to all of those worldwide in World War II, or to those once estimated for a “counterforce” nuclear war between the superpowers.

the century of disasters

Slate | All of these things have the common feature of low probability and high consequence. They're "black swan" events. They're unpredictable in any practical sense. They're also things that ordinary people probably should not worry about on a daily basis. You can't fear the sun. You can't worry that a rock will fall out of the sky and smash the earth, or that the ground will open up and swallow you like a vitamin. A key element of maintaining one's sanity is knowing how to ignore risks that are highly improbable at any given point in time.

And yet in the coming century, these or other black swans will seem to occur with surprising frequency. There are several reasons for this. We have chosen to engineer the planet. We have built vast networks of technology. We have created systems that, in general, work very well, but are still vulnerable to catastrophic failures. It is harder and harder for any one person, institution, or agency to perceive all the interconnected elements of the technological society. Failures can cascade. There are unseen weak points in the network. Small failures can have broad consequences.
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Most importantly: We have more people, and more stuff, standing in the way of calamity. We're not suddenly having more earthquakes, but there are now 7 billion of us, a majority living in cities. In 1800, only Beijing could count a million inhabitants, but at last count there were 381 cities with at least 1 million people. Many are "megacities" in seismically hazardous places—Mexico City, Caracas, Tehran, and Kathmandu being among those with a lethal combination of weak infrastructure (unreinforced masonry buildings) and a shaky foundation.

Natural disasters will increasingly be accompanied by technological crises—and the other way around. In March, the Japan earthquake triggered the Fukushima Daiichi nuclear power plant meltdown. Last year, a technological failure on the Deepwater Horizon drilling rig in the Gulf of Mexico led to the environmental crisis of the oil spill. (I chronicle the Deepwater Horizon blowout and the ensuing crisis management in a new book: A Hole at the Bottom of the Sea: The Race to Kill the BP Oil Gusher.)

In both the Deepwater Horizon and Fukushima disasters, the safety systems weren't nearly as robust as the industries believed. In these technological accidents, there are hidden pathways for the gremlins to infiltrate the operation. In the case of Deepwater Horizon, a series of decisions by BP and its contractors led to a loss of well control—the initial blowout. The massive blowout preventer on the sea floor was equipped with a pair of pinchers known as blind shear rams. They were supposed to cut the drillpipe and shear the well. The forensic investigation indicated that the initial eruption of gas buckled the pipe and prevented the blind shear rams from getting a clean bite on it. So the "backup" plan—cut the pipe—was effectively eliminated in the initial event, the loss of well control.

Fukushima also had a backup plan that wasn't far enough back. The nuclear power plant had backup generators in case the grid went down. But the generators were on low ground, and were blasted by the tsunami. Without electricity, the power company had no way to cool the nuclear fuel rods. In a sense, it was a very simple problem: a power outage. Some modern reactors coming online have passive cooling systems for backups—they rely on gravity and evaporation to circulate the cooling water. Fist tap Nana.

dry taps in mexico city

Time | The reek of unwashed toilets spilled into the street in the neighborhood of unpainted cinder block houses. Out on the main road, hundreds of residents banged plastic buckets and blocked the path of irate drivers while children scoured the surrounding area for government trucks. Finally, the impatient crowd launched into a high-pitched chant, repeating one word at fever pitch: "Water, Water, Water!"

About five million people, or a quarter of the population of Mexico City's urban sprawl, woke up Thursday with dry taps. The drought was caused by the biggest stoppage in the city's main reservoir system in recent years to ration its depleting supplies. Government officials hope this and four other stoppages will keep water flowing until the summer rainy season fills the basins back up. But they warn that the Mexican capital needs to seriously overhaul its water system to stop an unfathomable disaster in the future. (See pictures of the world water crisis.)

It is perhaps unsurprising that the biggest metropolis in the Western hemisphere is confronting problems with its water supply — and becoming an alarming cautionary tale for other megacities. Scientists have been talking for years about how humans are pumping up too much water while ripping apart too many forests, and warning that the vital liquid could become the next commodity nations are fighting over with tanks and bombers. But it is hard for most people to appreciate quite how valuable a simple thing like water is — until the taps turn off.

the establishment put out its cover story weeks ago...,

NYTimes |  There are two possible future chapters to this story that should keep us up at night.

The first possibility is that the Ebola virus spreads from West Africa to megacities in other regions of the developing world. This outbreak is very different from the 19 that have occurred in Africa over the past 40 years. It is much easier to control Ebola infections in isolated villages. But there has been a 300 percent increase in Africa’s population over the last four decades, much of it in large city slums. What happens when an infected person yet to become ill travels by plane to Lagos, Nairobi, Kinshasa or Mogadishu — or even Karachi, Jakarta, Mexico City or Dhaka?

The second possibility is one that virologists are loath to discuss openly but are definitely considering in private: that an Ebola virus could mutate to become transmissible through the air. You can now get Ebola only through direct contact with bodily fluids. But viruses like Ebola are notoriously sloppy in replicating, meaning the virus entering one person may be genetically different from the virus entering the next. The current Ebola virus’s hyper-evolution is unprecedented; there has been more human-to-human transmission in the past four months than most likely occurred in the last 500 to 1,000 years. Each new infection represents trillions of throws of the genetic dice.

If certain mutations occurred, it would mean that just breathing would put one at risk of contracting Ebola. Infections could spread quickly to every part of the globe, as the H1N1 influenza virus did in 2009, after its birth in Mexico.

Why are public officials afraid to discuss this? They don’t want to be accused of screaming “Fire!” in a crowded theater — as I’m sure some will accuse me of doing. But the risk is real, and until we consider it, the world will not be prepared to do what is necessary to end the epidemic.

In 2012, a team of Canadian researchers proved that Ebola Zaire, the same virus that is causing the West Africa outbreak, could be transmitted by the respiratory route from pigs to monkeys, both of whose lungs are very similar to those of humans. Richard Preston’s 1994 best seller “The Hot Zone” chronicled a 1989 outbreak of a different strain, Ebola Reston virus, among monkeys at a quarantine station near Washington. The virus was transmitted through breathing, and the outbreak ended only when all the monkeys were euthanized. We must consider that such transmissions could happen between humans, if the virus mutates.

add that goo-gol aggregate intelligence isht and big-A hives appear to trump little dog packs...,

There are 28 urban areas worldwide with at least 10 million people. By 2030, 12 more are expected to enter the ranks of the planet's megacities.