Friday, April 5, 2013

This is the Way the World Ends

From T.S. Elliot's The Hollow Men:
This is the way the world ends
This is the way the world ends
This is the way the world ends
Not with a bang but a whimper.

Actually, it will probably be a slow bang. 


Catastrophes and Mass Extinctions – Are they periodic?

Q: At the Ask-a-Geologist desk, we have received quite a number of end-of-the-world queries. These could be consolidated into a single sentence with two parts: 

Are mass extinctions real, and will another one happen soon?

A: There has been accumulating evidence over the past century that animal life on Earth has been decimated repeatedly. The biggest extinction events:
  • ~440 million years ago (the demise of the Bryozoa, among other fossil species, marking the end of the Ordovician period),
  • 251 million years ago (the “Great Permian Extinction” that saw the disappearance of over 95% of all genera living at the time including the Trilobites),
  • 219 million years ago (the end of the Carnian stage in the late Triassic period, coincident with the appearance of the huge, ~85-km Manicougan craters in Quebec, Canada),
  • 65 million years ago (the end of the Cretaceous period and with it most of the dinosaurs), sometimes called the Chicxulub event for a village in northern Yucatan, Mexico.
  • 33 million years ago (The demise of the Cassidaria family of mollusks near the end of the Eocene, after horse ancestors first appeared),
  • 2.6 million years ago (the boundary between the Pliocene and the Pleistocene epochs)…
  • …and 40,000 and 12,000 years ago.
What could possibly cause all these extinctions?

In the past century geologists have come to realize that the Earth’s crust doesn’t change gradually, either, but instead it apparently evolves episodically. This takes two general forms: asteroid or comet impacts, and episodic convulsions of the Earth’s deep interior. 

The first possible reason for extinctions: asteroids or comets.

For some time astronomers have known about a 26-30 million year cycle of the Solar System, oscillating in and out of the plane of the galaxy as it revolves around a supermassive black hole at its core (Sagittarius-A* in the center of the Milky Way). There is a very rough (in other words, very arguable) periodicity in asteroid impacts mapped in the Earth’s crust. 

The thinking goes something like this: as the Solar System passes through the plane of the Galaxy, there are close approaches by other stars, which disturb the previously-stable orbits of Oort belt objects. These are icy planetesimals orbiting far beyond Kuiper Belt objects such as Pluto and Sedna, reaching out to 50,000 astronomical units from the Sun (up to a light year). The Oort belt is where most of the comets come from. Thus, a disturbance out at this distance could send one or more into the inner Solar System. These may directly impact the Earth, or may disturb or deflect one or more asteroids orbiting between Mars and Jupiter. Asteroids are far more common in the mid-to-inner Solar System, but comets generally have a much high relative velocity with respect to Earth. Since kinetic energy goes the mass times the velocity squared, a comet could potentially do quite a bit more damage for the same size if it impacted the Earth.

For more than a century scientists have been aware of these extinctions in the paleontological record. The cause of the great Permian Extinction of 250 million years ago is still not fully understood, but may be related to huge seafloor craters now known to exist off the northwest coast of Australia (Bedoubt) or the Falkland Islands east of Argentina. The extinction of the dinosaurs 65 million years ago actually has a 'smoking gun': a huge, 150-to-180-km crater now lying beneath the northern edge of the modern Yucatan Peninsula of Mexico. There is other evidence: ginormous tsunami deposits elsewhere in the Caribbean including Haiti, a tektite strewn field throughout the American southeast, and distinctive fragments found in Montana and eastern Pacific ocean deep-sea drill cores.

Keep in mind that the Earth’s crust is a very dynamic place; while we see thousands of craters on the Moon, we see few on the Earth. Careful mapping has identified only 170+ asteroid-impact craters on the Earth, even counting the tiny ones like Wabar in Saudi Arabia, and Henbury in Australia. The Earth’s crust is evolving constantly because of plate tectonics and weathering, so evidence of impacts is steadily being erased.

The second possible reason for mass extinctions: gargantuan volcanic eruptions

A recent article in EOS, the Transactions of the American Geophysical Union (Rampino and Prokoph, EOS 94, No 12, 19 March 2013, p. 113-114), points out that there have been roughly cyclic episodes of large igneous provinces (LIP’s). The Deccan Traps, making up much of western India, is one of these provinces: kilometers-thick, continent-sized basalt flows all erupted over a fairly short window of time. A vast basalt province in Siberia called the Siberian Traps, and the huge Columbia River basalts are among the others. These are thought to be the result of large upwelling mantle plumes; for scale imagine the eastern US being covered by miles-thick flows of basaltic lava.

The geologic record shows these LIP’s to have occurred around
  • 390 million years ago
  • 295 million years ago
  • 250 million years ago (the Siberian Traps)
  • 200 million years ago
  • 185 million years ago
  • 135 million years ago
  • 100 million years ago
  • 65 million years ago (the Deccan Traps occurred close to the Chicxulub impact, causing some confusion about the relative effects of the two events)
  • 30 million years ago
  • 17-14 million years ago (the Columbia River Basalt province).
From these ages frequency-domain filtering (and your eye if you plotted them out) suggests an apparent rough cyclicity of 28-to-35 million years, especially prominent starting 135 million years ago.

When volcanic centers this size erupt, there is a huge degassing process associated with it: sulfur dioxide and vast amounts of carbon dioxide are released. When Mount Pinatubo erupted in 1992, it sent a proportionally smaller cloud of SO2 into the stratosphere – and the Earth’s average temperature cooled for two years afterwards. And that's just from what happens in the stratosphere.

Could there be a third reason for mass extinctions? 

Around 40,000 years ago, most of the large animals of Australia abruptly disappeared. These include the rhino-sized, wombat-like marsupials called Diprotodons, giant 200-kg kangaroos, a goanna bigger than the modern Komodo dragon, a giant goose-like bird twice the size of the emu, and many others. These animals had survived at least two episodes of climate change prior to 40,000 years ago. In North America about 12,000 years ago, most of the large “charismatic megafauna” of North America (mammoths, giant sloths, camels, cave bears, saber-tooth tigers, etc.) suddenly disappeared. In both cases, these mass extinction events (and a more recent event on Madagascar that is still very much on-going) correlate closely with the arrival of the human species in these regions. The implication of overhunting is hard to miss here. As the human population surges past 7 billion today, the largest mass extinction in the past 65 million years is fully underway, and the Passenger Pigeon is just the first and most obvious victim. Habitat loss, overhunting, and accelerating climate change are the proximate mechanisms for this current and stunningly rapid mass extinction event. 

The End of Things As We Know It

There are Near Earth Objects (NEO’s) out there that NASA and the US Air Force are monitoring (the number keeps growing, but at least the search process is now automated). Based on their known sizes (we can generally only see the big ones) and what happened at Chicxulub 65 million years ago, most of these could wipe out human civilization as we currently know it... not if but, when one hits us. 

If Yellowstone (just one of several known supervolcanoes) unzipped tomorrow, it would cover the eastern two thirds of the United States with a vast blanket of ash, suffocating all living things. The gas and peripheral consequences would devastate the entire planet. To put things in perspective, the last eruption 640,000 years ago left an off-white layer 20 meters (65’) thick called the Pearlette Ash Formation near Colorado Springs… 800 miles away. I have personally pulled a camel’s tooth from the bottom of this formation.

However, the problem may be more imminent. 

As Pogo said, “We has met the enemy, and it is us.”

Monday, April 1, 2013

Home Invasions and Practical Statistics

I was awakened a few days ago around 4am by a thump downstairs. This is about the time that the newspaper is delivered to our front porch, so I rolled over and went back to sleep.

But a thunk sound below my bedroom at 1:30am a few days later was a different thing, and I got up and did a systematic search of my 3-level house. In truth, I was pretty sure the sound was a book falling off an unbalanced stack downstairs, or perhaps even a weird dream. How I did that search speaks more to my “weaponized” (NOT firearms) house and my background: I'm a Taiho-Jutsu sensei. Of the Japanese martial arts, this one is sometimes called “Jujitsu on steroids.”

Oh BOY! There may be a 1% chance I can USE this!

But first, back to home invasions. The expression alone conjures terrible images from lurid newspaper reports. If you are only robbed and beaten up, you are fortunate. Home invasion differs from a burglary in its violent intent, and this distinction appears to be largely American.

Home invasions are real, if very rare. Statistics on these are notoriously hard to find, in part because of different crime classifications in different jurisdictions (in many places these are classified separately as homicide, rape, kidnaping, etc.). However, the impact on the human psyche is not unlike the impact of shark attacks. As in most of these “news” events, the real killers are rarely mentioned:
  • fishermen wantonly kill millions of sharks every year just for their fins; 
  • handguns in the United States kill 1,130 times more people per year than lightning does, and 
  • 31,672 more people are killed by handguns in the United States each year than are killed by sharks.
To put things in perspective:

In 2011, there were 8,583 murders in the United States committed with handguns. However, there were 31,672 TOTAL handgun deaths - all the rest (73%) were suicides, with the occasional handgun accident lumped in. This is comparable to motor vehicle deaths in the US.

There is a message here: having a handgun ready to blast someone in your home is statistically a far greater threat to you than the statistical chance of any possible safety it may offer. Read on.

There were 118 reported shark attacks world-wide in 2011, with 17 fatalities. There were 47 “unprovoked” shark attacks in the United States in 2012, with just 1 fatality. You have to wonder about the “unprovoked” caveat: do a lot of people “mess” with sharks? The vast majority of shark attacks occur in Florida. One human death to several million shark deaths is a very unsportsmanlike ratio, IMHO.

There were 28 Lightning fatalities in the United States in 2012, and some 24,000 lightning deaths worldwide. Again, you have to wonder at the disparity in the statistics, as the US represents 6% of the world population. There are many possible reasons, including regions like the Pacific Northwest where lightning is a very rare thing, or perhaps people live in flimsier houses elsewhere.

Back again to home invasions. Are you at risk of one? A pattern of dealing in illegal and “recreational” drugs will dramatically increase your potential likelihood for being targeted. Living in Anacostia, Maryland, or south Chicago will also dramatically increase your risk, but this is probably no surprise to anyone in the US.

What can you do about it?

The reality here is dramatically different than what the National Rifle Association would have you believe. If a woman carries a handgun, there is an 80% statistical likelihood that it will be used against HER: in other words, she will be either shot with her own weapon, or pistol-whipped with it. That’s a pretty large statistical number - basically it is a high probability.

Another take-away: don't carry a pistol in your handbag.

If you’ve ever been to a gun-range, the following observation will be obvious:
It takes slow, calm focus and concentration to hit a human target at 5 meters (16 feet) distance. Imagine trying to do that in the dark, when charged with adrenaline, and both the shooter and the target are moving.

There is a video on YouTube where a traffic stop ends with a perp jumping out of a stolen car and firing several shots at the police officer. The dashboard cam shows that the officer then proceeds to fire at least 12 rounds at the perp, who is running in a straight line towards the nearby forest. NOT ONE BULLET ON EITHER SIDE HIT ITS TARGET.

In a home invasion situation, a handgun is an excellent means to poke holes in your house - and probably several neighboring houses at the same time. It will likely NOT protect you.

  1. Actually, there are several. There are two excellent and inexpensive tools for this, in fact, and used together they are pretty effective:  The first is a cell-phone that has been charging near your bed. USE IT. Call 911 and the entire conversation will be recorded. 
  2. The second tool is a Mag-Light. This has a steel shaft, and a six-C-cell version is the sine qua non, if hard to find. Held on your shoulder, it can be used to both momentarily blind an attacker in the dark and strike a devastating blow. It works like an ASP baton, but it is significantly heavier.
  3. There is also a Taser, if you can afford one (and the necessary training that goes with it). A Taser has been shown to be nearly 100% effective in disabling a targeted human being for up to several minutes after a single zap. There is at least one case, however, where a very angry man fired weapons at police and nearby civilians continuously after taking 42 separate bullet "hits" to his body. Only the 43rd bullet, which severed his upper spine, stopped his murderous rampage.

So...should you then search for the invader and pound him? 

NO! Searching for the invader in your home, no matter HOW many stripes you have on your black belt, is statistically stupid - tactically, medically, and legally*.

Instead, with the cell phone in one hand, you can provide your address to the 911 Operator, and then maintain a running recording of what you see - perhaps including the only court-defensible and relevant description of any intruder that you might encounter. Your objective, however, is to GET SAFELY TO YOUR FRONT DOOR, UNLOCK IT FOR THE POLICE, AND THEN GET OUT.

Leave it to the professionals to deal with the intruder. They can use a Taser (far more disabling than a handgun), pepper spray (which you would only inflict yourself with if you tried to use it without some training and experience), and a handgun if absolutely necessary.

Then stand back and watch. Use your phone to video the "perp walk" for your family, friends, and local TV station.

* Stupid Tactically, Medically, and Legally:
  1. First, compare yourself against a trained pair of completely awake and alert police officers. You lose majorly in this comparison.
  2. Second, a significant number of people, inexperienced in using a handgun in complex circumstances, end up injuring themselves with their own weapon (3rd degree burns, lacerated hands, even self-inflicted gunshot wounds). 
  3. Third, unless you have an unlimited bank account, you should expect that ANY use of a firearm on another human being - for whatever reason - will require hiring an attorney, and then months of court appearances and thinking about them.