Noble gas After the risks caused by the flammability of hydrogen became apparent, it was replaced with helium in blimps and balloons. "Noble gas" is translated from the German noun , first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity. The name makes an analogy to the term "noble metals", which also have low reactivity. The noble gases have also been referred to as "inert gases", but this label is deprecated as many noble gas compounds are now known. "Rare gases" is another term that was used, but this is also inaccurate because argon forms a
Greenhouse gas biodiversity and human livelihoods. At current emission rates temperatures could increase by 2 °C, which the United Nations' IPCC designated as the upper limit to avoid "dangerous" levels, by 2036. Greenhouse gases are those that absorb and emit infrared radiation in the wavelength range emitted by Earth. In order, the most abundant greenhouse gases in Earth's atmosphere are: Atmospheric concentrations are determined by the balance between sources (emissions of the gas from human activities and natural systems) and sinks (the removal of the gas from the atmosphere by conversion to a different chemical compound or absorption by bodies of water).