There are a few reasons I think the end of the world is near. Many are logical-
Global Warming-> accelarated by deforestation, growing number of vehicles, increased use of fossil fuels (2 thermal power plants are commissioned every 2 weeks in China alone)
Population Explosion-> religious leaders are calling for having more kids to increase their strengths. More pressure on resources like land, water, food, jobs etc. This will definitely lead to more conflicts. The next world war could well be fought for water
Diseases-> new diseases are appearing regularly, some cause more panic attacks than infections, but some could well be the next bubonic plague or flu epidemic of WW1. Viruses are evolving and bacteria becoming resistant to antibiotics. Add to it viruses and bio-weapons being created for a new type of war.
Our lifestyle is simply not sustainable. We will run out of resources eventually, air and land and water will become too polluted for us and there will be NOTHING left.
Some other reasons are moral. I think human beings as a species have outlived their utility to this planet and it is time someone else took over. We have been blinded by consumerism and materialism and this is exploited by those in power to keep us docile while they satisfy their greed.
Selfishness and greed-> large corporations, in their effort to make huge profits turn a blind eye to the human cost. All they want to do is protect and serve their investors while they destroy the lives of entire communities or even countries. Nigeria is a case in point where the abundance of oil has destroyed the country. Almost all of Africa has a similar story of looting and plunder by foreigners while the indigenous people have suffered.
We have lost our sense of what is right and what is wrong. We are not able to make up our minds about what is good and what is bad.
lack of conscience-> we have become accustomed to violence and crime. We do not think twice about things that we should not be doing. We are no longer hurt by the suffering of others, we have lost our heart. We have achieved a machine like detachment from nature and hurting others does not seem a bad thing to do these days.
Support for mediocrity-> although excellence cannot be achieved always, glorifying mediocrity and dubbing those who do succeed as 'nerds' or 'uncool' or 'sad' fellows is something that must be avoided.
It does not have to be a killer asteroid or disease or war, but there is definitely going to be something that will cause the end of the world as we know it, end of a world dominated by humans.