There are other reasons that breaks down the ecosystem of the ocean. For examplelike ocean acidification. Ocean acidification happens because the tree and the ocean shares carbon dioxide and absorbs it, but nowadays, many people cuts down trees. So the oceans have to absorb more carbon dioxide which makes it much more acidic. So the sea- creatures die out and even many corals die as a result. People greed makes the world polluted.  

Finally, the ice melting happens. Ice melting happens when the sun light comes through the ozone layer, it passes through and bounces out. But these days, there are many factories which make green house gases effect. The green house gas effect blocks the sun light from going out the ozone layer and causes the temperature to increase which is called global climate change. 

But because of the global climate change, the ice melts in artic 

 and makes some animals to lose their habitat. In conclusion, although we need some  resources to build house or do other things, I think it would be far more significant if we could keep environment as clean as possible for our next generation.