I've already mentioned Fukushima as a subject students revisit. Another one is ocean acidification. ACE Science Short: Ocean Acidification was the video from last August's talk on this topic.
Learn about how climate change is impacting our oceans. Alliance for Climate Education educates young people on the science of climate change and empowers them to take action.To repeat what I wrote in August, this video "is a scary reminder that climate change isn't the only outcome of too much carbon dioxide in the atmosphere."