Can we list the primary threats to survival of the human race for the next 100 years?

Question

This is a sub-question to Hawking's question on human survival and is posted in response to:

http://answers.yahoo.com/question/index;_ylt=AhaRK._T3Ioz25Bb0m2cGC_sy6IX?qid=20060708184051AAqubF9

Answers might address factors such religious differences, cultural changes, envinronmental changes such as global warming and pathogens, competition for resources, and population growth.

Answer 1

There are 2 major categories of threats:
1) threats caused by humans;
2) threats caused by non-human factors;

The threats from non-human factors either have very low probabilities of occurring in the next few hundred years
(e.g. a huge meteor striking the earth) or are almost
impossible to stop (e.g. volcanoes the size of Wyoming).

Threats that are caused by, or severely exacerbated by,
humans have much higher probabilities and are within our
ability to stop, so I'll focus on those.

Note that human self-extinction probably will not be
caused by a single "event", such as a nuclear war.
Instead, some human-caused catastrophe (e.g. global
warming) will wipe out a percentage of the population
and will damage or destroy an even larger percentage
of our resources (farmland, energy, etc.), and the
humans who survive the first event will break up
into groups fighting over the remaining resources.

Each "round" of fighting and resource extraction will
destroy still more resources. (Think of the civil wars
where soldiers put mines in their enemies' farmland and
blow up their enemies' oil and gold and diamond mining
equipment -- destroying exactly the land and resources
that the fighters are trying to get by winning the war.)

A downward spiral of destruction and death could easily continue
until there are essentially no usable resources left, and the remaining people die or comprise too small a breeding
population to be viable.

Thus, as you read the following list of possible causes
of self-extinction, remember that few of these are likely
to kill 100% of humanity, but each could create conditions
in which we finish each other off. And even if they don't
lead to complete extinction, the potential suffering and
death of hundreds of millions or billions of people is
more than enough reason to figure out how to prevent these
scenarios.

1) Nuclear war.

2) Biological warfare. This is one of
the few threats that could kill 100%
of the population. Since disease organisms
are self-reproducing, it's almost impossible
to stop them once you've started them. Since
they mutate, they can kill even the people
who created them (and who presumably tried
to give themselves immunity).

3) Mass epidemics of "natural" disease.
Although a "natural" disease epidemic has never before
killed 100% of humans, and it seems moderately
unlikely to do so now, there are diseases that have a
virtually 100% kill rate (e.g. Ebola) that with
modern transportation can be spread internationally
in a very short time. Our large and relatively
densely packed population provides opportunities
for such diseases not only to spread rapidly,
but also to mutate rapidly, so that if one strain
doesn't have a 100% kill rate, a combination of
strains might.

Our over-use and mis-use of
anti-biotics has erased much of medical progress
during the last century, and diseases that were
once fatal and then became trivial to cure are
now almost impossible to cure. (Some strains of
Tuberculosis, for example, are resistent to
every single drug we have.)

4) Environmental catastrophe.
No single ecological "event" is likely to
kill 100% of humans. Instead, worsening problems
may kill a large percentage of the population and
cause the survivors to battle over the remaining
resources. Possible threats include:

A) Global warming (e.g. drying out food producing areas);

B) Population increase to the point where it exceeds
available resources, such as water, farmland, etc.
(We may already have reached this point without
realizing it because we are still drawing down
accumulated capital in the form of natural resources.)

C) Running out of key resources (energy, metals) or
reaching a point where they are impractical
to extract.

D) Unrecognized threats -- think about how long it took
before we knew there was a "hole" in the ozone layer.
We can't test every new chemical against every part of
every ecosystem; sooner or later there will be another
chemical that we won't initially realize could cause a
global catastrophe.

5) Social catastrophes.
When people become poorer, they look for someone
(besides themselves) to blame. Since just about
everybody on the planet is at least partly to blame
for our situation, it's easy to build a plausible
case against almost any group. There are many
possible social catastrophes, including

A) Religious warfare.

Street thugs (Al Qaeda, Christian Crusaders, etc.)
proclaim themselves God's right-hand men and proceed
to slaughter anyone whose land they want to take.

There is no natural endpoint to such religious conflicts.
The conflicts will not even end when one religion has
killed all its enemies. Even within religions, there
are many factions, some of which hate each other
(think Sunni vs. Shiite vs. Wahhabi). As long as
people need a scapegoat, they will find (or invent)
differences among groups as a justification for killing
other people and stealing their resources.

I'm sure there are other threats, too, but there's no reason
to wait for a "complete" list before we start working on these.

It seems to me that the human-caused threats fall into
2 major categories:
1) "Resource shortages", such as starvation,
2) "Behavior" threats, such as war.

Most or all of the "resource shortages" problems themselves are caused by human behavior (e.g. using up resources faster than we replace them), so ultimately the solution is going to boil down to changing human behavior. I'll try to post more details about that in answer to one of the other of these 6 questions.

Answer 2

War is the most feasible way the human species could be destroyed. We are very good at killing large numbers of people very quickly. We also have the capability to poison the air with radioactivity, so the people who don't die from an actual atomic blast will be killed by the radioactive fallout. Depending on the kind of radioactivity used, the fallout could persist long enough to kill all the other life forms we eat, for a long enough period, that any survivors would simply starve to death.

The triggers to such a war are harder to predict. They could include competition for scarce resources, ideological differences (religious or political), or simply the drive to dominate the rest of the planet. Which one will be the trigger will be determined by political events which are impossible to predict.

Answer 3

We must find some way to ELIMINATE religions! I have long considered religion to be the worst invention humans could have come up with. It is the basis of all human conflict and the mechanism of all control efforts: economic, cultural, gender, political, etc. Just look at the current mid-east, islam/christian mess. Get rid of religion and most of the world's problems would go away! Now, don't tell me to call upon "god".

Answer 4

Global warming
Polution of the environment's water resources
Run out of natural resources.
Disease
Nuclear wars
Natural disasters.

Answer 5

Global Warming is pretty big.
Terrorism/War
Nuclear Weapons
Super-Volcanos (There is one under Yellowstone National Park that can kill us all, it's eruption is overdue according to the Discovery Channel)
Meteors

Answer 6

Pollution, war, un-democratic government(s), guns (firearms), nuclear activity, social issues handled and viewed incorrectly (I won't say which)...

In other words, liberalism, the view of science as superior to religion when it comes to guidance, will be our downfall.

Answer 7

that is easy humans are the down fall the man kind plain and simple. humans destroy the planet and other human beings.

Answer 8

Go to http://www.livescience.com and you can find the top 10 ways to annihilate Earth.

Answer 9

viruses. imagine a mutated meningococcemia virus or worse airborne hiv

Answer 10

The biggest threats are: drunk, and stupid.