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
Life on Venus Life on Venus The speculation of life currently existing on Venus decreased significantly since the early 1960s, when spacecraft began studying Venus and it became clear that the conditions on Venus are extreme compared to those on Earth. Venus's location closer to the Sun than Earth and the extreme greenhouse effect raising temperatures on the surface to nearly , and the atmospheric pressure 90 times that of Earth, make water-based life as we know it unlikely on the surface of the planet. However, a few scientists have speculated that thermoacidophilic extremophile microorganisms might exist in the lower-temperature, acidic upper layers