Nicaragua's major environmental problems are soil erosion, caused in part by cultivation of annual crops on steep slopes, and depletion of upland pine forests for lumber, fuel, and human settlement. The nation lost an average of 2.5% of its forest and woodland each year between 1990 and 1995. One contributing factor is the use of wood for fuel. Excessive or ineffective use of pesticides to control malaria, along with widespread agricultural use, has resulted in some environmental contamination. Nicaragua's cities produce about 0.5 million tons of solid waste per year. Industrial pollutants have contaminated the lakes and rivers. The nation has 190 cu km of renewable water resource, with 84% used for farming and 2% in industrial activity. As of 2000, 91% of Nicaragua's city dwellers and 59% of its rural population have access to safe drinking water. Dumping of sewage and chemical wastes has made Lake Managua unsuitable for swimming, fishing, or drinking. Primary responsibility for resource conservation is vested in the Nicaraguan Institute of Natural Resources and Environment (Instituto Nicaragüense de Recursos Naturales y del Ambiente—IRENA), established in October 1979.
In 2001, four of the nation's mammal species were endangered, as were three bird species and 29 plant species. Endangered or extinct species in Nicaragua include the tundra peregrine falcon, four species of turtle (green sea, hawksbill, leatherback, and olive ridley), the spectacled caiman, and the American crocodile.