Human suffering is, in many ways, tied to the suffering of the Earth.
When farms dry out from drought, people move to the cities to look for jobs that, often, cannot sustain their large families (sometimes, none at all). Dwindling harvests and catches from the sea lead to lower food production levels, which lead to starvation, malnutrition, and poverty. Waste disposal techniques have not caught up with the conveniences of modern living, so much so that plastic bags and all sorts of rubbish have clogged up storm drains, causing floods and wreaking havoc on cities. Carbon emissions have contributed greatly to the greenhouse effect. The list goes on; most of our problems in the environment seem to be caused by our collective arrogance, apathy, and disrespect towards the environment.
