Assuming that the bowl judgments will last about three-and one-half years, we may conclude that each plague will last about six months. Thus, we may figure that this fourth bowl will begin about one-and one-half years from the midpoint of the Tribulation (or from the beginning of the bowl judgments). We also should keep in perspective the fact that, as we said from the beginning, the judgments, all of them are ongoing. Therefore, we need to keep in mind that at this point (the beginning of the fourth bowl) people are still suffering from malignant sores, from bloody seas that are causing people to be sick, and from having to drink bloody water. And this is just from the bowl-plagues. The seal and the trumpet plagues are also still causing trouble.
So, with this in mind, we will look now at the fourth bowl. It is a judgment that is poured out upon the sun in order to scorch people with fire and to inflict them with fierce heart. Direct rays of the sun will be only two-thirds of the day, because, as we recall, a third of the sun will be darkened (at the fourth trumpet). Nonetheless, even the dark hours will still be as hot as an oven—no relief in sight! Even the bloody oceans and rivers will probably be warm.
Now what will be the consequences of this plague? As we can see from the text, men (people) will be scorched with fire of the sun and will suffer from the sun’s fierce heat. The word “scorch” seems to imply the burning of the skin—so much that there will be significant damage; a severe sunburn. When I think of scorching I usually think of black marks to a white shirt by a hot iron that was held too long on the shirt. Anyway, the days will certainly be a scorcher! And very hot! Probably over 150 degrees every day. And it will last many months, for the rest of the Tribulation.
But we can also surmise that there will be disastrous changes to the earth, caused by the melting of the polar ice caps, which will result in catastrophic loss of life. Some estimate that the sea level will rise as much as 200 feet. Scientist are also saying that the melting ice will cause the shifting of the earth’s crust horizontally.6
And since we may regard that this fourth plague will continue for some time, it is highly likely that the events of the seventh bowl (verse 20) will have something to do with this melting of the ice caps—besides, of course the great earthquake (verse 18).
I think the most shocking thing about this plague is how the people will react to it. They will not be humbled and repent; instead, they will curse God. And this reaction tells us that they definitely will know that God exists and that He is the One that brought this plague on them.
Hence, even though they may declare themselves as atheists, in their blasphemy they will reveal that they all along knew God in their heart, but refused to honor Him. Thus, in their foolishness they, without knowing it, will be declaring Romans 1:21 to be true: “For even though they knew God, they did not honor Him as God or give [Him] thanks…”
6 Clea Simon, “Melting of polar ice shifting Earth itself, not just sea levels,” at https://news.harvard.edu/gazette/story/2021/09/melting-of-polar-ice-shifting-earth-itself-not-just-sea-levels/