Instead of only looking at human rights that are missing, I think what is more important are the human obligations that are missing, and one of them, for me, is the environment, because the environment can't look after itself it's us who have to take care of nature. If you don't agree to that, then I would say that that is a very egoistical point of view because we live of the nature, and if nature doesn't exist in the future, then neither will we, so of what use are human rights if there aren't any humans anymore?
I don't want to defend any extreme sides, the ones which put nature above everything, and neither the ones which destroy nature unconsciously. However, I think what we should be aiming for is a healthy balance to prevent nature, and thus us, from disappearing.
My idea would be to publish some declarations, amongst others about protecting the rainforest about stopping overfishing the seas, about controlling the pollution of the atmosphere because of a lot of reasons: the climate change, the extension of different animals, our own intake of oxygen... about being less consumers of water, electricity...
All that leads to the conclusion that we have to take care of our enviroment because we don't want the world to disappears, we want to enjoy the human rights for many more years to come, that's why I think that amongst the human rights should be a list of human obligations as well.