connection between words in a sentence

[Klpno]

Hi, everyone.
Sometimes I find it somewhat difficult to figure out the connection between words in a sentence. Here is an example.

The security of states was also affected by other developments in world history. The rapid rise in population since the eighteenth century, together with the gigantic increases in energy consumption and industrial output were creating new problems. Deforestation, desertification, pollution spreading beyond national boundaries and, worst of all, the destruction of the ozone layer and global warming, were all world dilemmas which affected the security of every state and which none could counter on its own.

As far as I understand the word 'spreading' relates only to the word 'pollution'.
Am I right? And are there any rules for such cases?

[Conor]

[quote]...Deforestation, desertification, pollution spreading beyond national boundaries and, worst of all, the destruction of the ozone layer and global warming, were all world dilemmas which affected the security of every state and which none could counter on its own...[/quote]

You are correct in that "spreading" only relates to "pollution" in this example, I'll try and show you why:

The sentence, "Deforestation...counter on its own" is a list of problems:

1) Deforestation
2) Desertification
3) pollution spreading beyond national boundaries
4) the destruction of the ozone layer and global warming

You'll notice that every item in that list is separated by a comma. The confusion here probably arises from the extra information "worst of all" which applies to the 4th item and is used to qualify it as the worst in the list.

simply put, the general idea of the sentence is: "deforestation, desertification, spreading pollution, and the destruction of the ozone layer were all world dilemmas which no state could counter on its own"

I hope that helps.

[Klpno]

Thank you very much, Conor.