In recent years, we've seen an increase in the intensity of tropical storms and hurricanes due to global warming. But how and why do hurricanes form? Sigrid provides a basic explanation of this phenomenon.

The Great Barrier Reef is the world's largest coral reef system and one of the most diverse and rich ecosystems on the planet. It is now in great danger, as the Australian and Queensland governments are giving coal companies permission to dig up coal and ship it out through the Great Barrier Reef.