| Abstract from DBPedia | A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Without greenhouse gases, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F). The atmospheres of Venus, Mars and Titan also contain greenhouse gases. Human activities since the beginning of the Industrial Revolution (around 1750) have increased the atmospheric concentration of carbon dioxide by over 50%, from 280 ppm in 1750 to 421 ppm in 2022. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago. This increase has occurred despite the absorption of more than half of the emissions by various natural carbon sinks in the carbon cycle. At current greenhouse gas emission rates, temperatures could increase by 2 °C (3.6 °F), which the United Nations' Intergovernmental Panel on Climate Change (IPCC) says is the upper limit to avoid "dangerous" levels, by 2050. The vast majority of anthropogenic carbon dioxide emissions come from combustion of fossil fuels, principally coal, petroleum (including oil) and natural gas, with additional contributions from cement manufacturing, fertilizer production, deforestation and other changes in land use. In the current world, the United States Environmental Protection Agency estimates that 27% of all USA greenhouse gas emissions are related to transportation.温室効果ガス（おんしつこうかガス、英: greenhouse gas、GHG）とは、大気圏にあって、地表から放射された赤外線の一部を吸収することにより、温室効果をもたらす気体のことである。水蒸気、二酸化炭素、メタン、一酸化二窒素、フロンなどが温室効果ガスに該当する。近年、大気中の濃度を増しているものもあり、地球温暖化の主な原因とされている。 (Source: http://dbpedia.org/resource/Greenhouse_gas) |
