The biggest problem this generation will have to overcome is the slow but steady diminishment of our planet's natural resources. The expeditious growth of the human population is simply too much for this planet to sustain. I'm not sure of the exact statistic, but it's been calculated that hundreds of acres of farmland is required to meet the dietary needs of one American for one year. Stephen Hawking recently stated that in order for the human race to survive we would have to colonize the moon and Mars because of this impending resource crisis. The Carrying Capacity Theory in biology states that the earth can only sustain a human population of 10 billion. We are currently at 7 billion. The theory states that once we reach 10 billion, the natural resources of the planet will not be enough to sustain a comfortable life style for all the world's people. The theory also goes on to predict that in that scenario, many nations would go to war to preserve what resources it can. An interesting theory floating around suggests that in fact what the United States has been doing in the Middle East, invading and occupying Afghanistan and Iraq, is in fact a military attempt to acquire their natural resources under the facade of national security, in anticipation of the resource crisis. The Carrying Capacity Theory also predicts rampant famine and disease, especially in the impoverished parts of the world. With nuclear-armed nations at war, with a pandemic of disease and famine, a resource crisis is the accelerator and agitator of many other problems that could cause strife powerful enough to end human civilization.
This certainly appears to present a bleak future for the planet and our civilization. However, we have the opportunity now to prevent this potential crisis and create an alternative future for our planet. The word is being spread, especially in regards to global warming, a problem inexorably linked to the thinning of natural resources. We need to take complete advantage of that opportunity.