Environmental advocates warn oil leaks or spills could cause irreparable damage to the unique and understudied ecosystem.They are suing the Brazilian government and its largest state-owned oil producer, Petrobras, to stop the project.By Teresa TomassoniAs world leaders conclude the United Nationsâ annual climate talks in BelĂŠm, Brazilâ a summit meant to accelerate global action on phasing out fossil fuelsâthe Brazilian government is facing mounting criticism over its recent decision to authorize offshore drilling for oil near the Great Amazon Reef System.