RIO DE JANEIRO — Calling Aldo Rebelo a climate-change skeptic would be putting it mildly. In his days as a fiery legislator in the Communist Party of Brazil, he railed against those who say human activity is warming the globe and called the international environmental movement “nothing less, in its geopolitical essence, than the bridgehead of imperialism.”
Though many Brazilians have grown used to such pronouncements from Mr. Rebelo, 58, his appointment this month as minister of science by President Dilma Rousseff is causing alarm among climate scientists and environmentalists here, a country that has been seeking to assert leadership in global climate talks.
“At first I thought this was some sort of mistake, that he was playing musical chairs and landed in the wrong chair,” said Márcio Santilli, a founder of Instituto Socioambiental, one of Brazil’s leading environmental groups. “Unfortunately, there he is, overseeing Brazilian science at a very delicate juncture when Brazil’s carbon emissions are on the rise again.”
Brazil won plaudits for lowering its annual emissions from 2004 to 2012, largely by slowing the rate of deforestation in the Amazon. But emissions jumped 7.8 percent in 2013, according to the Climate Observatory, a network of environmental organizations. Several factors were to blame, the observatory said: deforestation on the rise again, growing use of power plants that burn fossil fuels, and increased consumption of gasoline and diesel.
Ms. Rousseff, a leader of the leftist Workers Party, has been speaking strongly about the need to reduce carbon emissions around the world, raising hopes that Brazil will work harder to preserve much of its Amazon rain forest. The destruction of tropical forests is viewed as a major contributor to climate change.
But Mr. Rebelo’s appointment comes as some scientists are questioning Brazil’s commitment to reducing deforestation and emissions. Environmentalists have also expressed concern over Ms. Rousseff’s new minister of agriculture, Kátia Abreu, a combative supporter of industrial-scale farming who worked with Mr. Rebelo on a recent overhaul of Brazil’s forest protection laws.
“Old-line Communist Rebelo is on exactly the same page on climate science as the hardest of the hard-core Tea Partiers,” Stephan Schwartzman, director of tropical forest policy at the United States-based Environmental Defense Fund, said in a blog post.
Before the international climate talks that were held in Lima, Peru, in December, the Brazilian government said that the rate of deforestation in the Amazon had declined by 18 percent in the period from August 2013 to August 2014. But analysts said the government had tailored its announcement to exclude a recent resurgence in deforestation. Imazon, a Brazilian institute that uses satellite imagery to track the issue, saw a fourfold increase in November compared with the same month in 2013.
Mr. Rebelo, who was sports minister during Ms. Rousseff’s first term as president, has not distanced himself from his earlier statements about climate science, including his assertion that “there is no scientific proof of the projections of global warming, much less that it is occurring because of human action.”