If these things will serve as signs of Christ's coming, how will this prediction be fulfilled if not by an increase in the frequency and/or intensity of the phenomena mentioned here? Or hasn't yet arrived the time for this prediction to be fulfilled?

Luke 21:32"I tell you the truth, this generation will certainly not pass away until all these things have happened.

Matt 24:6You will hear of wars and rumors of wars, but see to it that you are not alarmed. Such things must happen, but the end is still to come. 7Nation will rise against nation, and kingdom against kingdom. There will be famines and earthquakes in various places. 8All these are the beginning of birth pains.

Matt 24:9"Then you will be handed over to be persecuted and put to death, and you will be hated by all nations because of me. 10At that time many will turn away from the faith and will betray and hate each other, 11and many false prophets will appear and deceive many people. 12Because of the increase of wickedness, the love of most will grow cold, 13but he who stands firm to the end will be saved. 14And this gospel of the kingdom will be preached in the whole world as a testimony to all nations, and then the end will come.

There are signs that are the beginning of the birth pains, and there are signs that identify the compleated birth. Earthquakes clearly belong to the first group.

Ok, but birth pains increase gradually in frequency and intensity until the child is born. Do you think the birth pains have started yet or not?

". . . there will be fearful sights and great signs from heaven." Perhaps it is when these things, whatever it means, happen in addition to earthquakes, faminies, and pestilences then we can start thinking Jesus' second advent is drawing nigh.

Notice Luke 21:32, the birth pains have been around since the time of the apostles.

Thomas, I don't believe the meaning of Luke 21:32 is that which you are attributing to it, otherwise the following words of Christ would make no sense at all:

"Now learn this parable from the fig tree: When its branch has already become tender and puts forth leaves, you know that summer is near. So you also, when you see all these things, know that it is near——at the doors!" (Matt. 24:32, 33).

So what part of famines, earthquakes, wars, rumors of wars, is new to our generation and was unheard of with the apostles?

Even if earthquakes are increasing, statistics say famines and wars decreasing. What conclusion could be drawn from one of the signs increasing in intencity if all other signs are decreasing in intencity?

". . . there will be fearful sights and great signs from heaven." What is this referring to?

I'm not sure about that. There is a disagreement between the data of the Human Security Report Project (HSRP) and those of the International Rescue Committee (IRC).

http://congosiasa.blogspot.com/2010/01/how-many-people-really-died-in-congo.html

Not to mention the number of deaths in the Iraq war and Afghan War which had been concealed.