I have a better interpretation of the accounts of Revelation 6:
The 1st seal represents the spread of Christianity from the first century after the Dispersion till the end of colonisation somewhere in 1950's when nations were all fighting for independence from their white colonial "Christian" masters i.e the white horse - 1st century to about 1950s and beyond. The spread of Christianity caused many deaths and sufferings
The second seal is about the rise of Communism which started in the 1900s from the fall of Tsarist Russia in 1912. Communism peaked after WW2... Eastern Europe 1945, China 1949, Vietnam 1952 etc. and ended with the fall of the Berlin wall in 1990's/ Although communism is still present in some countries but the fervor of communism is gone by the beggining of the 21st century. The red horse i.e. communism peaked after about the end of colonism (the white horse) from 1940's till about 1970's and then lost ite fervor by year 2000. Communism also caused lots of death and suffering...about 200 to 300 million casualties.
The third seal is about food crisis which started in the 2000's till now. There were food riots and panic in 2005 and 2008 and the price of food continues to go up since. The peak of the food crisis and food price inflation has yet to be reach but it will.... just watch for the price of wheat and barley. The cause of this inflation and famine is most probably due to a wheat fungal infestation and human hoarding and greed. However, the price of oil will continue to decline just as it has in 2009. This crisis will also cause lots of death and sufferings. The death and sufferings due to high food price and famine has already started since the beginning of 2000. The black horse relates to black stem rusts, the Black Sea, the black market, the black burnt forests, the black smog, Black Africa etc.
The fourth seal is about a great war which will occur after the third seal. What war or disaster will cause a fourth of the world to be destroyed? A most likely cause is World War 3 . Note also the sword of Seal 2 and the sword mentioned in seal 4, is it the same huge sword? A hugh missile? That war is definitely to cause lots of death and sufferings due to mass famine, and plagues (? nuclear radiation sicknesses) and diseases spread by wild animals :
7When the Lamb opened the fourth seal, I heard the voice of the fourth living creature say, "Come!" 8I looked, and there before me was a pale horse! Its rider was named Death, and Hades was following close behind him. They were given power over a fourth of the earth to kill by sword, famine and plague, and by the wild beasts of the earth ( perhaps emergence of a much virulent SARS and bird flu). Pale Horse is associated with death and Hades is following behind means that it will caused lots of death aftermath.
*Just to note: all the seven seals of Revelation caused lots of death and sufferings.