All animals breathe oxygen and exhale CO₂. Plants and micro-organisms like plankton in the ocean do exactly the opposite - they convert CO₂ into oxygen through photosynthesis. It's estimated that photosynthesis converts around 60bn tonnes of carbon dioxide every year - in fact, it's the most effect way to reduce carbon levels.

This is almost perfectly balanced with the amount of animals exhaling CO₂. and that is why the destruction of the Earth’s rainforests is so critical in upsetting the Earth’s ecosystem.

More than 50% of the forests that existed after the last Ice Age have disappeared. Rainforests in South America, Asia, and Africa are being cut down 10 times faster than First World nations are re-planting them. It doesn't take a genius to figure out that this current situation is unsustainable.