Greenhouse gas Greenhouse gas A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide and ozone. Without greenhouse gases, the average temperature of Earth's surface would be about , rather than the present average of . The atmospheres of Venus, Mars and Titan also contain greenhouse gases. Human activities since the beginning of the Industrial Revolution (around 1750) have produced a 40% increase in the atmospheric concentration of carbon dioxide (), from 280 ppm
Heaven and Earth (book) argues that "It's got nothing to do with the atmosphere, it's about what happens in the galaxy" and that climate is driven by the sun, the Earth's orbit and plate tectonics rather than the levels of atmospheric greenhouse gases such as carbon dioxide. Plimer says his book is for the "average punter in the street" who can "smell something is wrong in the climate debate but can't put a finger on what." Critics have regularly questioned Plimer about his commercial interests in the mining industry, but he defends the independence of his views, saying that these commercial interests do not