Brown pelican Feb. 4, 1970: Ground is broken for the Chernobyl nuclear station complex north of Kiev in the Ukraine. The plant’s first reactor starts operation in 1977. Its fourth reactor explodes and burns in 1986 in the worst nuclear power accident in history.

Feb. 4, 1976: A 7.5-magnitude earthquake strikes Guatemala and Honduras , killing an estimated 23,000 people.

Feb. 4, 1985: The brown pelican (at right) is removed from the U.S. Endangered Species list after 15 years of protection. The birds had made a strong recovery following the 1972 ban on DDT.

Feb. 4, 1997: U.S. President Bill Clinton sets goals for declaring 10 American Heritage Rivers, and in a first for any president, he mentions global warming in a State of the Union speech.

Photo: kevincole /Flickr

This feature is compiled by Peter Dykstra, an MNN contributor and publisher of Environmental Health News and The Daily Climate .