1. The risk of widespread chemical warfare: Both sides developed and used chemical weapons such as chlorine, phosgene, and mustard gas. These weapons caused horrific injuries and deaths, and there was concern that their use could escalate to catastrophic levels.
2. The threat to civilian populations: The war saw a significant increase in the deliberate bombing of civilian targets. This was particularly the case in the later stages of the war when air power became more sophisticated. The bombing of cities like London and Paris caused widespread devastation and loss of life.
3. The potential for a prolonged and stalemated conflict: The war quickly settled into a stalemate on the Western Front, with both sides unable to make significant gains. This led to fears that the war could drag on for years, leading to even greater loss of life and destruction.
4. The fear of a global conflict: The war began as a regional conflict in Europe but soon spread to involve other parts of the world, including the Middle East, Africa, and Asia. This raised concerns that the conflict could escalate into a global war, involving even more countries and further increasing the scale of destruction.
5. The political and economic consequences of the war: The war had a profound impact on the political and economic landscape of Europe and the world. It led to the collapse of several empires, the redrawing of national borders, and significant economic disruption. There were concerns about the long-term consequences of these changes and how they would shape the future of global politics and economics.
6. The psychological toll on soldiers and civilians: The war took a heavy psychological toll on both soldiers and civilians. The experience of trench warfare, the constant threat of death, and the loss of loved ones led to widespread mental health issues, including post-traumatic stress disorder (PTSD).