Answer: Please see expalanation column for answer
Explanation: Beginning with with most recent, we have
The explosion of the Deep water Horizon---April 20,2010
 The drafting of the Kyoto Protocol---  December 11  1997
 The oil spill of the Exxon Valdez---       March 24, 1989
The ratification of the  Montreal Protocol, 16 Septemnber, 1987
 The meltdown of the reactor at Chernobyl---April 26,1986
The leak of methyl isocyanate in Bhopal--- 2 December, 1984
The discovery of contamination at  Love Canal,---      June 19 1978
 The passage of the US Endangered Species Act. -  Dec 28 1973
The first Earth Day----- April 22, 1970