Coal the heat and pressure of deep burial causes the loss of water, methane and carbon dioxide and an increase in the proportion of carbon. Thus first lignite (also called "brown coal"), then sub-bituminous coal, bituminous coal, and lastly anthracite (also called "hard coal" or "black coal") may be formed. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, although coal is known from most geological periods. The exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants—this coal is presumed to
What the Health funded via an Indiegogo campaign in March 2016, raising more than $235,000. The film was released globally on Vimeo on March 16, 2017, and screenings licensed through Tugg Inc. The following doctors were featured in the film: A number of non-physicians were also interviewed: The documentary has drawn criticism from many, including scientific skeptics, who contend that it misrepresents facts: A companion book of the same name was released February 2017. It was authored by Eunice Wong, who is married to journalist Chris Hedges. What the Health What the Health is a 2017 documentary film which critiques the health impact