These are 3rd/4th graders who have to go to school during vacation. And they gave you those options?

Jeeze, doesn't seem age appropriate to me. Global awareness is important but still surprises me.

Ok, to be helpful: You could try doing a simulation to prove a point. For example, in the US I taught a 5th grade class on the Colorado River damming issue. I gave out fruit punch but gave too much for the kids inthe beginning and ran out. We then tried to discuss what happened, if it was fair, and then I gave everyone fruit punch.

You could think of relevant activities like that for famine or lack of fresh water.

Save the Earth.

Recycling.  Conserving water.  etc.

I made two toys from water bottles I had the kids bring in.  First is a kind of arcade game.    Here's a video:

I found the bottle label didn't work well, so I just had them cut a paper strip two inches wide and roll it up.  I used a hot glue gun to secure the "post" into the neck of the bottle.

Second, we used their other water bottle to play this game:
But instead of attempting to hurt each other, whoever got the bottle to stand up three times first, won/earned points/whatever.