The charred remains of David Buckel, 60, were discovered shortly after sunrise when firefighters responded to a report of a fire in the southwest corner of the sprawling Brooklyn park, police sources said.
Buckel also reportedly attached a typed note explaining his actions, as well as his business card.
'My early death by fossil fuel reflects what we are doing to ourselves'.
Some of his other more prolific cases include arguing against the Boys Scouts of America's ban on homosexual members, fighting for the creation of an LGBTQ club at a high school in Utah and helping a Pennsylvania woman win a lawsuit over being allowed to put "beloved life partner" as an epitaph over her deceased partner.
Buckel had long fought for gay rights through the courts and was the marriage project director at Lambda Legal, which was at the forefront of the battle for gay marriage in the US.
Buckel said he wanted his death to lead to increased action, writing: "Honorable objective in life invites honorable goal in death". "We will honor his life by continuing his fight for a better world", Taylor wrote.
Buckel acted as lead counsel on behalf of the family of Brandon Teena, a transgender Nebraska man raped and murdered in 1993.
"Honorable objective in life invites honorable goal in death", Buckel wrote.
The 1999 movie earned actress, Hilary Swank an Oscar for her portrayal of Teena.
In his suicide note, Buckel recalled the Tibetan monk protesters who have set themselves on fire in protest of the Chinese occupation in Tibet, according to the New York Daily News.
"Here is a hope that giving a life might bring some attention to the need for expanded actions, and help others give a voice to our home, and Earth is heard".
He was also a nationally renown pioneer in #CommunityComposting and one of my mentors. 'But it is incredibly satisfying work'.
"He was all about justice, but he was also all about what it means to be human", recalls Susan Sommer, a former Lambda Legal attorney.
Adding, 'He was a very smart and methodical lawyer.
The statement continued: "Our hearts go out to all who knew David".
"David was a brilliant legal visionary".