The document discusses how deforestation contributes significantly to climate change by releasing large amounts of stored carbon into the atmosphere. Mature forests store enormous quantities of carbon both in trees and soil, but logging and burning releases this carbon. Deforestation accounts for up to one-fifth of global emissions, more than the transport sector. As a result, Indonesia and Brazil are now the third and fourth largest emitters due to deforestation, which is responsible for up to 75% of Brazil's emissions mainly from clearing the Amazon rainforest. Preserving remaining ancient forests is important to tackle climate change.