席爾瓦於5月15日首次針對她的辭職發表言論，她的離開是源自於停滯不前的狀況，同時表示政府需要有新共識的政治家來維持環境保護的長期工作，席爾瓦說她還沒有和總統盧拉（Luiz Inácio Lula da Silva）討論過她的辭職，雖然總統只負責簽署送到他辦公室的辭職公文。
She rose from a rubber tapper's family to become Brazil's Secretary of the Environment for the past five years, but Amazon rainforest defender Marina Silva resigned on Tuesday, citing "the difficulties I have been facing to pursue the federal environmental agenda."
Silva said she would go back to her seat in the Brazilian Senate to strengthen political support for environmental causes, according to the state news agency Agencia Brasil.
Speaking about her resignation for the first time today, Silva said her exit was motivated by "stagnation" and said the government needs "a new agreement politician" to maintain a continuity of environmental protection. Silva said she has not spoken about her resignation to President Luiz Inácio Lula da Silva , who is no relation, but simply had her letter of resignation delivered to his office.
Silva praised the president's choice of the new environment minister, Carlos Minc, Rio de Janeiro state's environment secretary.
Silva says her successor, “characterizes the process” and will be able to give continuity to the country's environmental management.
Silva said today that she had difficulties with other ministers, such as the Minister of National Integration Ciro Gomes with whom she had “very heated quarrels” as she sought changes in the proposal to divert part of Brazil's San Francisco River to the vast drought-prone Northeast part of the country.
Opponents of the diversion say only four percent of the diverted water will go to benefit the rural population in the receiving areas. Instead, they say the diversion will benefit big business such as agro-industries, construction companies and sugar cane for ethanol. In her letter of resignation, Silva stressed that Brazil could not back down on the battle against illegal logging.
Silva said that after years of quarreling over the issue, the government finally had obtained approval of the Law of Management of Public Forests and said, “we cannot come back behind.”
She said Brazil must move ahead on the certification of sustainable wood products "so that they have more environmental quality."
Born in the Brazilian Amazon, Silva spent her childhood making rubber, hunting and fishing to help her father support their large family. At 16 illness brought her to the city. Although she had been illiterate, she soon earned a university degree. She went on to found the independent trade union movement with rubber tapper leader Chico Mendes in the state of Acre.
This movement led to the idea of establishing sustainable extractive reserves in the rainforest.
Undaunted by Mendes' assassination in 1988, Silva continued to push for their creation. Today Acre's sustainable extractive reserves encompass two million hectares of forest managed by the traditional communities that inhabit them.
Health problems, including contamination with heavy metals, have caused Silva to be hospitalized for long periods of time. Fragile health has not stopped her. In 1994 she was the first rubber tapper ever elected to Brazil's federal senate.
In 1996, she was awarded a prestigious Goldman Environmental Prize.
In 2002 when President Lula took office, Silva was chosen as environment secretary.