dioxide, products deriving from methane photolysis can polymerize to form long-chain molecules that can aggregate into particles, forming the anti-greenhouse organic haze. The haze is formed when the ratio of methane to carbon dioxide exceeds roughly 0.1. It is posited that the organic haze allowed the creation of a negative feedback loop to stabilize the climate on Archean Earth. If temperatures increased in Archean Earth, methane production would increase due to methanogens' possible preference for warmer temperatures (see thermophiles). Increasing temperatures would also increase the carbon dioxide loss through weathering due to an assumed increase in precipitation, leading to decrease carbon dioxide concentrations. This would lead to a higher methane to carbon dioxide ratio and would stimulate the production of the organic haze. This increase in organic haze production would lead to increased opacity of the atmosphere to sunlight, decreased amounts of solar energy reaching the surface, and thus decreases in surface temperature, thus negating the initial increase in surface temperature. One estimation of the anti-greenhouse effect on Archean Earth calculated the impact to be up to about 20 K in surface cooling. In the modern state of Earth's atmosphere, there are a few sources of an anti-greenhouse effect. It has been suggested that stratospheric ozone and Earth's thermosphere create a partial anti-greenhouse effect due to their low thermal opacity and high temperatures. Additionally, ejected dust like that from volcanoes and nuclear fallout after a nuclear war has been suggested to typify an anti-greenhouse effect. Also, the formation of stratospheric sulfur aerosols from volcanic sulfur dioxide emissions has been seen to have a cooling effect on Earth that lasts approximately 1 to 2 years. All of these sources act to create a temperature structure where a hot upper layer lies above a cold surface, which typifies the anti-greenhouse effect. Earlier discussions in the scientific community pre-dating the current definition established by Dr. Christopher McKay in 1991 referred to the anti-greenhouse effect as a precursor to the Late Precambrian glaciation, describing it more as a carbon sequestration process. This is no longer the current usage of the term, which emphasizes surface cooling due to high-altitude absorption of solar radiation. On other planets There has been discussion about a weak anti-greenhouse effect on Mars, where storms carry dust into the upper atmosphere. Evidence for this effect came from Viking 1 measurements made in 1976-77 when in the aftermath of a global storm,