The GROWTH rate is declining, but the population will still increase until the rate drops to zero (basically one child born for every one person that dies, which would maintain the population at the level it is at when that happens). What will the global population level off at? Nine billion? 12 billion? The only way we're sustaining the population we currently have (7 billion and growing) is by supercharging the soil with chemicals so it can grow more crops than it would naturally. Unfortunately, chemical fertilizers are not absorbed as well as natural fertilizers, so there's a lot of run off when it rains. When the rain washes the excess fertilizer into rivers and then into oceans, it causes algae blooms which use up the oxygen in the water which kills the fish. There are significant and growing "dead zones" in oceans around the world. Which is nature's way of saying there's already too many people.