Climate change activists in Latin America rallied for action on global warming Friday, heeding a call by Swedish teenager Greta Thunberg to hold demonstrations across the world.

In Rio de Janeiro, a small group of students gathered outside the state legislature to deliver a letter dated from the future in which they lamented Brazil's loss of coastline, rainforests and species.

"We, the Brazilians of the future, are also asking you: is there anything more important than protecting life and ensuring a quality future for the next generations? No, there is not," they wrote.

In more than a dozen other cities throughout the country, youth also staged strikes and took to the streets, using the issue to challenge the environmental policies of the far-right government of President Jair Bolsonaro.

Bolsonaro says excessive regulation has hindered economic development and has moved to strip the environment ministry's authority over water and forestry services.

Last week, his environment minister questioned the effectiveness of the Amazon Fund created to contain deforestation. The minister has also called climate change a "secondary issue" and said that agribusiness in Brazil is "under threat."

Meanwhile, in the Venezuelan capital of Caracas, a few dozen protesters explicitly abstained from commenting on politics amid a monthslong standoff between President Nicolás Maduro and opposition leader Juan Guaidó.

Andreina Duffy said protesters were careful not to voice opinions about the conflict between the Venezuelan government and the opposition but were prepared to criticize "whatever government exists" on environmental issues. She said economic hardship had compelled many Venezuelans to consume and waste less, making them more aware of the need to conserve.

"Of course, there's still a lot to do," she said.

Her daughter, 7-year-old Victoria Duffy, showed up with a picture of Earth.

"You can make a difference," the poster read.

Venezuelan demonstrators are concerned about the degradation of the El Ávila national park that borders Caracas and whose mountain springs were a key source of water for desperate residents during recent nationwide blackouts.

Dannalice Anza, a 19-year-old student who went to the protest with her twin sister Dayalice, said the key to conservation was to think globally "beyond the problems in Venezuela."

Demonstrations were also planned in Mexico.