//Of course we will become extinct//

A fair point and well made. No need for the sermon, old man, but amen anyway.

I think nearly everybody understands that human life on earth is ultimately doomed due to natural causes, Ultimately our only hope would be to colonize other planets.

The critical question is will humans cause their own extinction, well we are certainly capable doing so. The most obvious problem is nuclear weapons of which there are at least 15,695 warheads. It is unlikely that humans would survive a major nuclear war. Even without starting a nuclear war chemical and biological war fare have the potential to wipe out huge numbers of people and other creatures possibly making humans extinct.

http://www.ploughshares.org/world-nuclear-stockpile-report

Human induced climate change is a very serious problem and has the potential to cause human extinction should we continue to refuse to do anything substantial about it. The good news on that front is that 2014 was the first year that CO2 emissions did not increase but yet global economic growth increased by 3%. previously growth has always been tied to increases in CO2 emissions.

http://www.abc.net.au/environment/articles/2015/03/16/4198541.htm

It would would seem that the worst case scenario as a result of human induced emissions of greenhouse gases is that global temperatures could increase by over 10 Deg C. This would be disastrous leading eventually to the loss of all Greenland and Antarctic ice and raising sea level by some 220 feet. This would have such a dramatic effect on climate and coastline that nearly everybody would have to move and war would become almost inevitable. Even today we have wars in the northern Africa which are exacerbated by climate change and encroaching desert.

Other problems include chemical pollution so severe that it damages the planets life support systems, for example if the use of fluorocarbons had not been radically reduced, eventually it would have destroyed the ozone layer and made most plant life impossible, and thus the extinction of humans.

http://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2012-2013/ozone-layer-our-global-sunscreen.html

We are more likely to die from stupidity after reading the warmist propaganda. Surely no one believes that rot.

It won't be climate change that will cause the demise of the human race, but rather the madly populating countries who are causing our world to be over crowded.

The rapidly growing secularism in the developed countries have allowed them to move on from the ancient religious call against contraception and abortion rights.

We need to assist the many poorer countries to access the same knowledge and rights in order to slow down their rapid population growth.

Runner
Yes people are very likely to die of stupidity, if they refuse to take action to solve a problem that is well understood and we know how to solve.

Suseonline
Overpopulation if not solved by us will be solved by nature, either by starvation or by an acute epidemic. I don't think it is likely to cause the extinction of humans or even the collapse of civilization.

Have you looked at robotics and artificial intelligence lately? The "Terminator" themed movies may be closer to reality than any other reasons so far raised on this forum.