What is humans problem of today, some believe God exists and others believe not?

Only in the sense that some of the humans who believe that God exists are expecting that God to perform a miracle to solve all our Earthly problems.

Humanity's problem of today is thinking up new technologies to produce more food (e.g., vertical gardens, irrigation systems, GMOs) on what arable land remains, while thinking up new technologies to reduce pollution (e.g., finding alternatives for fossil fuels) so as not to lose too much more arable land to rising sea levels (e.g., as is evident in Bangladesh now), and while educating people in parts of Africa, China and India, where birth rates are highest, on how and why they need to use birth control to save humanity.

Although it might seem as though these problems are not particularly urgent today, and that we still have plenty of arable land, and more than enough food to feed everyone, it is an appreciation for the exponential growth of the overall birth rate that brings these problems into sharp focus.

There are already almost 8 billion people on Earth. If the birth rate in those parts of Africa and Asia where the birth rates are highest continues to be high, then best estimates are that there will be 11.3 billion people on Earth within the next 80 years, or so. If that happens, the upshot will be massive famines and outbreaks of illness such as cholera. This will be a global problem as food will be diverted to those countries in an attempt to quell the famines, and/or people from those countries will become refugees in search of food.

The human problem is not belief or disbelief but the intolerance of those who refuse to understand that others do not "need" theirs.

I agree with Shadowfire. People put themselves above others and look down upon those who don't share their beliefs. The God which many speak of tends to be created in the image of the speaker.

THE UNsaved will fail Judgment if they do not get saved before that happens...the SAVED will rapture ahead.

The problem of humans today, regardless of what they believe, is that some humans treat other humans like subhuman scum.