@@callumhill8522 Because each year humans extract 50 billion tonnes of carbon from the ground and gasify it into the air. Trees store about 1 tonne of carbon on average. Humans otherwise plant 2 billion trees per year. If humans tripled their annual planting, still only 4 billion tonnes extra would be stored each year. Additionally, that storage must be considered temporary. Thunderf00t has made some good videos on the matter and i like his numbers: kzbin.info/www/bejne/kGbYpnyZiJmep6c Trees could work, if they were grown on masse to be used as carbon sponges and then physically returned deep enough into the ground, that the carbon couldn't get back out.