And I don't think it should be anything to do with Global Warming because
Just adding to what was already given as an answer....
Golding uses the word scar (scarring was mentioned in the other answer) for what the plane does to the island.
The island is a microcosm of society at large. The book is almost an allegory. The boys represent all of humanity. The island is earth in general. The island starts as something perfect--a modern Garden of Eden. When man is introduced into the environment, everything goes wrong. We "civilize" the environment by building shelters and introducing laws/rules; however, we have the capacity for evil (symbolized by the sow's head), so our endeavors go horribly wrong. We cannot live and truly appreciate our world--we must alter/change it...usually for the worse.
The sow's head is the Lord of the Flies--Beelzebub, another name for Satan. When we enter a paradise, our evil natures can't help but corrupt it.
On a larger scale, the book takes place during World War II--think about all the atrocities that came from that war.
The fires the boys start cause unnatural damage to the island. The plane they arrived in also damaged the island. Killing animals cause a decline in the animal population which could have environmental effects.
The Island is at first visit a pristine and uninhabited place. The boys have just left a civilization that has been destroyed by humanity. They are now at a place where there is a chance for a fresh start. However, with the arrival of their transport, their new place has begun to transform into the destructive place that they have left. The vehicle that they arrived on the island caused scarring to the island. This symbolized how the island had already begun to be altered by their presence. Ralph fusses about the boys letting the fire getting out of control and burning the area. He was scared that they might burn up the island. When the boys make shelters they have changed the natural environment in order to create some protection.
Ralph calls an assembly to discuss issues he is concerned about. He addresses with the littleuns that they have been using the bathroom too close to their sleeping area. He instructs them to go in the rocks and only in the rocks.
By placing the boar head on the stick the boys have changed the scene in the forest. The head symbolizes something menacing. We later learn that that the evil is within the boys.
it was made in the 195o's... i think