Global warming and the Anthropocene

摘要

> By burning fossil fuels, humans have changed the carbon cycle, loading the atmosphere with extra carbon dioxide (CO ₂ ). Before the current Ice Age, high atmospheric CO ₂ levels generated warm climates. The Ice Age developed as the volcanic supply of CO ₂ lessened, and rock weathering increased. The CO ₂ lost from the atmosphere by chemical weathering was transferred to the ocean and trapped in carbonate sediments. Humans now replicate what volcanic activity did in the distant past, our CO ₂ emissions driving global warming. Earth's present climate should be cool, based on the present configuration of the Earth's orbit and the tilt of its axis, and on the decline in sunspot activity since 1990. Warming will grow further with rising emissions, further raising sea level. If business continues as usual we will end with an Eocene‐like ‘greenhouse climate’ and drowned coastal cities.