WWI and WWII brought an extreme destruction and devastation to the world, certainly the previous wars had also brought devastation, but in a totally different scale. These wars were the biggest in the history of men with unexpectedly huge causalities to every country participating. The technology of warfare had improved beyond the imagination of men, bringing weapons that could kill enormous masses of people within a short period of time.
WWI and WWII both had devastating results, far more than expected since each war took more than 10 million lives each and as written in the header, that was much more than any previous war. The cost of the war had gone along the size. Whole Europe fell in large debts from the wars, and there were inflation everywhere, more severe after the first war, and you can almost assume that the leaders of the countries had learnt something at least. Especially the inflation were high under the depression in Germany. The previous optimism from the 19th century was gone, now people had experienced the true horror of war, of the first world war, and after the second world war the horror that it could be repeated, a thought which didn’t occur to most people after the first war.
Partly due to that many countries changed their ideologies after both wars, countries drew back after the first war, trying to repair some of the devastation, along with the more republics that came, the ideologies became more turned inwards – the country above all, we are the better, nationalism is a possible definition, but in many cases, except Germany, who mostly under these years were driven by hatred and revenge against the unfair Versailles treaty, it was more a fear, a paranoia, especially for the French along the Maginot line, “walls” rose between countries and the whole area were pretty tense, not as tense as before the war, but still everything hadn’t faded away. The exception for this was the USA with their attempts to create the League of Nations, but it became very short lived and hadn’t the impact it needed for becoming strong.
However it planted the seed for the coming UN, which makes another similarity, both wars created these welfare organisations. But after the WWII the countries in Europe again started to look over their own borders, becoming a little more widely minded, countries became more involved in worldwide questions and started with these war-preventative organizations like NATO, trying to prepare for the next war, now that they knew that a repeat of the war weren’t impossible. These would show themselves useful sooner than expected. Since WWII as well as WWI led to a new conflict, for WWI obviously the WWII, and later for the second, the cold war, although it weren’t even close to the scale of the previous wars mostly due to the fact that it didn’t blossom to the war it were predicted to.
Both wars also had an enormous impact on the economy in Europe. Among others huge economic debts piled up for each country involved. Furthermore the countries lost labour, since they got killed in the war. This was a downfall for the economy but to make up for some of the scarcity of labour women got to work in the factories, something which earlier was unthinkable, especially in the first world war. A general opinion of men during the late 19th century and the early 20th century was that women should be at home, taking care of the family etc, while men should work, providing the family with money. Although women was accepted working in factories to a great extent in the second world war, compared to the first and especiallty the time before, it would take a lot of more years before a women, not during war time should work.
This also provided to the new liberal ideologies after the Second World War. Moreover things that had an impact on the economic change was the new technical improvements during the wars, since many products was invented as a consequence of the war and also the rate of mass production rose during the first world war. Also due to the enormous cost of the war there were inflation in many countries, one extreme example is Germany after the first world war, the Versailles treaty had put Germany under unimaginable debts. Debts that Germany had no opportunity paying back. That’s the major reason behind the inflation, when in just a few months in 1923 the worth of the mark compared to the dollar rose from 4.6 million to 4.3 trillion, about 1000000 times as much.
Also the geography of the world changed after the wars, the borders changed quite a lot, and for example the first world war was the final blow for the Ottoman Empire, the reason that it fell, although it were about to fall anyway this was the spark. Then during the war Austria Hungary fell and the borders changed a lot in the Balkans.
Finally, as pointed out the effects are quite similar, the atmospheres after the wars were rather similar, both were tense and allowed for new conflicts to start. The distrust of people for the government rose greatly. Furthermore there’s one effect I haven’t taken up yet, the destruction of the earth after the wars, great parts of Europe were affected, trenches were built, big land parts were bombed, and destructed even whole cities were bombed, then especially the Japanese cities Hiroshima and Nagasaki under the second world war.
Then there’s the social trauma, both of the soldiers and the families at home, losing their relatives. But as they are similar, there aren’t many significant differences, probably the biggest were however the fact that no country did demand any compensation for the war, then there were no opportunity of a scenario like the one of Germany after the First World War to occur another time. Even though there also were positive sides on the war like the great leap in technology the overall effects were greatly negative, both wars had devastating effects.