[I've been relaxing a bit since the end of the semester (and enjoying the Malibu High Sharks great baseball season), so I haven't posted much lately. That will change soon, but meanwhile I'm moving Dr. Kevin Iga's great comment on this post onto the "front page," as it were. Consider him a guest blogger. Welcome, and thanks, Dr. Iga!]
I don't know if I agree with all of that [in "Ten Disasters"]. Some threats are real, like nuclear war or pandemics. But I disagree with a few estimates.
First, the telomere thing. It's telling that they have to cite a single individual, and this is a physician, not a biologist. It is true that our DNA has telomeres as ends, and with each cell division, our telomeres shrink. But the idea that telomeres degrade with each generation is not accepted.
Consider the repercussions if they did shrink. Of all the thousands of species we know about going extinct, not a single one was attributed to telomere depletion. People are not showing signs of aging earlier, and neither are animals or plants or fungi or protozoans.
Given this, what are the chances that this would happen to humans, and that, in the next 100 years?
Asteroid impact: This is a real danger, but the probability of it happening "in the next 70 years" is extremely miniscule, not "medium." Consider that the last time an asteroid impact caused worldwide extinctions was 65 million years ago. At that rate, we should expect the probability of this happening in the next 70 years as about 1 in a million (that's not a figure of speech; I just calculated it).
Robots taking over: This runs the risk of predicting technology. I've heard it said that if you ask someone to predict the future 5 years out, they underestimate change; if you ask them to predict 50 years out, they overestimate it. In 5 years there will likely be occurences that no one could possibly imagine that have drastic consequences. But for 50 years, people predict flying cars.
We have no idea what constitutes intelligence, really. What makes us think we will create artificial ones anytime soon? It is true that the field of artificial intelligence has made dramatic advances since the idea was posed 70 years ago. We have controls that guess at what you want, computers that can play chess, speech recognition, and systems that learn from their mistakes. But every time we reach another milestone of this sort, we discover that intelligence is still far in the distance, like a mirage that keeps moving away as we approach it.
More likely is that computers will allow us to automate our bureaucracies so well that we will be trapped in our own policies--there is no one who can have compassion and tell us, "okay, I feel sorry for you, just this once I'll make an exception, but don't tell the boss." Instead, it will only be, "application for credit denied," "parole denied," "no entry permitted."
Supervolcanoes: They are not both "very high chance" and "danger 7" at the same time. We may very well see another Pinatubo or Krakatoa. That's likely. But catastrophic though it was for the local population, it hardly ranks with the Black Death or such. A sufficiently large volcano could spell trouble, but they are much less likely. It erupting in the Amazon could also wreak havoc with climate but again, that would be very unlikely. We know where most of these hot spots are. They are on edges of tectonic plates, especially in the "ring of fire" in the Pacific.
While we're talking about speculative calamities, I'm surprised they don't list the more prosaic forms.
1. Civil war. Just because Africa has a bunch, and we don't doesn't mean it can't happen to us. Right now the conditions aren't there, but if you think we're immune because we're "more civilized," you should talk to someone from Argentina who lived through the 1980s or from Lebanon who saw their "Jewel of the Mediterranean" go up in flames.
2. Famine. It is possible that our population will outgrow our food supply.
3. Results of overcrowding. This is besides all that is listed with "pandemic" in that site. Of course overcrowding can lead to pandemics. But it can also simply increase the rate of spread of disease. One of the fastest growing diseases in the U.S. is tuberculosis, which depends on overcrowding and stressful conditions. Besides this, there will be higher incidences of murder, pollution-related illnesses, and automobile accidents.
4. Nuclear accident. You don't need a global nuclear war or a terrorist attack to get one of these. There are aging nuclear power plants and an essential moratorium on building new ones; we are dependent on their energy, so when one is on its very last legs, there will be a temptation to try to squeeze a little bit more out of it. Besides this, there could be failures in nuclear weapons.
5. Side effects of genetic engineering. One might argue that we've been doing genetic engineering ever since farmers started breeding plants thousands of years ago. But we're doing this more quickly than ever before, and in an environment where the new genes might spread quickly. A small mistake could make one of our food crops (for instance) susceptible to something that occurs only after the gene has spread.
6. Homogeocene: The species diversity on this earth is depleting rapidly. Species from one part of the world are spreading over the entire world, displacing other species. Not to mention farming practices that choose a single variety of a single species to cover acres, where once many types flourished. This will increase the instability of our biosphere, just as the fact that only the Lumper potato was grown in Ireland made the entire population susceptible when a blight that attacked only the Lumper potato crossed to Ireland. To solve the problem they had to go back to the Andes where the diversity existed. Today, growers of the Russett potato are similarly indebted to the Aymara of Peru as an insurance policy in case the same thing happens to the Russett. But what if those varieties go extinct because of deforestation?
7. Judgment day comes. Like a thief in the night. Sun goes dark, moon turns to blood. God separates the sheep from the goats. All that ....
Anyway, it's not clear where these would rank with respect to the ones listed, but I'd place some of these as better than the ones I criticized them about.
And while we're at it, take a look at this for other reasons the earth might be destroyed. My favorite is "total existence failure."