Climate change is caused by an increase of carbon dioxide in the Earth' s atmosphere. Carbon dioxide traps heat and remains in the atmosphere longer than other heat-trapping gases. Between 2000 and 2012, 890, 000 square miles of trees around the world were cut down -- more than one-eighth of the original forest covering Earth. Overall, deforestation has led to the loss of half the world' s trees. Unless the rapid pace of deforestation is halted, the Earth' s climate will change drastically in the near future. The argument relies on which one of the following assumptions being true? ['Deforestation is a manmade phenomenon.', 'Trees produce carbon dioxide, releasing the gas into the atmosphere.', 'Climate change negatively impacts the Earth.', 'Trees lower the amount of carbon dioxide in the atmosphere.']