The root is human nature. Beyond that are things like greed, need for safety and simplicity. In addition, psychopaths contribute. Wikipedia says, "Psychopathy has a much higher prevalence in the convicted and incarcerated population, where it is thought that an estimated 15–25% of prisoners qualify for the diagnosis. A study on a sample of inmates in the UK found that 7.7% of the inmates interviewed met the PCL-R cut-off of 30 for a diagnosis of psychopathy. A study on a sample of inmates in Iran using the PCLV found a prevalence of 23% scoring 18 or more. A study by Nathan Brooks from Bond University found that around one in five corporate bosses display clinically significant psychopathic traits - a proportion similar to that among prisoners." .....Etc.

Corruption and greed.

Stupidity?

Every comment so far, has humans in the center. I live on an island and there are no predators. Here the rabbit and deer populations have exploded. The deer often starve in the winter and the rabbits get to a certain size and then develop a disease which cuts down their numbers. This is a problem for those species but is not human caused. Our porblems are the same as the rabbits and deer - too many of us subsisting on limited natural resources. Nature keeps trying to establish a balance and we keep thwarting her.

Yes is our drive for survival and breeding but every form of life has that same drive. We think we are smart to beat Mother Nature but we aren't really that smart and this is one woman who will win in the end. One of the emphasises of this site was to promote overpopulation (along with the Humanist and Freedom From Religion Foundation).

Religion, power, greed, and the compulsion to control others.

Schools not being secular of course! Sad thing is it would take 25yrs or so before those kids were policy makers....

I would say it is due to our base animal nature. We are basically no different from our caveman ancestors, and therefore not far removed from apes.

If we look at chimps we see many parallels with ourselves. They are social and political, they can use primitive technology, they possess a language of sorts, they are capable of great compassion to members of their troop, but are also capable of great cruelty to members of other neighbouring troops. They also ‘play favourites’ with some members of their own troop whilst shunning, ostracising or outright bullying others.

Humans simply add greater IQ to the equation, which allows for planning and technology. We can then use this for the greatest acts of kindness, such as charities, disaster relief etc., but can also use it for the greatest acts of cruelty, such as war and genocide.

A lot of this boils down to scarcity - i.e. competition for resources, territory, mates etc. If everyone had everything they needed / wanted then a lot of the conflict should fade away, in theory at least. Prosperous nations, communities etc. where resources are in abundance tend to have less conflict than those where resources are scarce. Wealth inequality is therefore a big problem.

The other main cause is the human tendency to follow leaders, which again stems from our animal ancestry. A chimpanzee troop will follow who they perceive to be the strongest leader, and humans do likewise, only now with our IQ, nations, technology etc. those troop leaders may now be the heads of state. Being perceived as a strong leader does not always equate to being a just and decent human being, often it is the opposite, which is how we get the Hitlers, Stalins and Pol Pots of the world.

How we go about solving these problems is anybodie's guess. Anyone got any ideas?

A lack of empathy.

I think it was a pesky talking snake that encouraged a naked lady to add more fruit to her diet.

The Ego. If people weren't ego maniacs we could stop wars, feed, cloth, and house everone, and solve all the world's problems.

Religion.

Seeing a starving child as a problem someone else will take care of.

Greed!
If there were only 2 men left on the planet, they would still fight over what the other one has! Maybe it's nature's way of controlling the population, although I doubt it could have predicted how fast we would develope ways of destroying ourselves!

Quite obviously the root of all evil is square. Quick, the square root of 37? Evil, that.

Inequality.

Be it income, race, religion, colour, creed... If we were all to be equal, a lot of the world's problems would fade away.

I can be wrong, but I believe that ignorance is the main troublemaker. At least in my country.

The root of all problems... Reality. Important to remember when they think you take too much for granted. No reality, no problems. More reality, more problems. Increase the number of variables and the possibility of complications leading to failure increase. Most success stories are tales of reducing expectations, compartmentalizing, and managed time and resources. Not gifts from above, and not extreme suffering.

Human greed without a doubt. The buybull said "money" as a root of all evil, but I'm sure greed covers that nicely.

The human condition. Our thought processes are far less aware / conscious and far sloppier than most people realize, and our emotions rule us. Even the minority of folks who understand logic, logical fallacies, and critical thinking, under-utilize it (and no, I'm not satisfied with my utilization, either).

Whatever hope I have for humanity is based on the slowly (hopefully, not TOO slowly)-improving respect for rational thought and discourse and the erosion of negative systemic influences like religion.

unrealistic expectations,lack of compassion/apathy.

There is no single root of all problems in the world. Greed =, "true belief" in total ystem ideologies, egocentrism, ethnocentrism are all among the major causes.

Failure to communicate

Religion.

Active ignorance masked at morality wrapped in selfishness...