The years from 1900 to 2015 contain a series of events that it would have been impossible to predict in 1900. Predicting the next century will be equally difficult. Consider the past. WW1 from 1914-18 is followed by inflationary times in Europe and a worldwide depression in the 1930s. In the immediate postwar period an estimated 18 million people died worldwide from a flu strain, far more than had died during the war. In Western Europe and the Soviet Union in the 1930s, the political choice was seen to be between communism and fascism. The Soviet Union went one way and Germany, Italy and Spain the other. Somehow the UK steered a course between the two and like the US followed a liberal democratic path. The UK had coalition governments for most of the 20 interwar years which helped manage opposing left and right wing political views.
WW2 from 1939-45 represented a continuation of WW1 which had had a short respite while the players rearmed. Economic policies adopted to fight WW2 ended the depression years of the thirties, as men were conscripted and women employed to take their places in factories and on farms. Similar actions took place in the US once it decided to join the allies in fighting Germany and Japan. This time Italy joined the other side. It had actually adopted fascism before Germany. The Soviet Union started off allied to Germany and then changed sides when Hitler decided to invade Russia in order to expand his empire to the east.
The postwar years saw the west confronting the east, especially The Soviet Union and the occupied countries of Eastern Europe. A Cold War ensued under the shadow of nuclear weapons which remains today with a number of countries owning this weaponry. Some like North Korea and Pakistan are not too politically stable, as would be the case with Iran if it obtains them.
A brief synopsis of the recent past shows how difficult it is to forecast even the main events of the next 50 years.