Despite `92 hopes, emission levels grow as world leaders meet.(Chicago Tribune)

JOHANNESBURG _ In 1992, with a tremendous sense of optimism, world leaders gathered at the Rio de Janeiro Earth Summit and for the first time cobbled together agreements to begin jointly attacking emerging global environmental problems: overfishing, loss of biodiversity, global warming, forest destruction.

Nations agreed to hold fossil fuel emissions at 1990 levels to slow global warming and to set limits on catches of threatened fish. They promised to stem the loss of forests, promote sustainable energy use and protect vanishing species. Just as important, they agreed that cutting poverty and promoting sustainable development around the world were critical to protecting the Earth's environment.

As leaders meet again this week at the UN World Summit on Sustainable Development in Johannesburg, fossil fuel emissions have grown about 10 percent worldwide and a whopping 18 percent in the United States. Three-quarters of the world's fisheries are overfished, forests have shrunk by an area the size of Texas and Louisiana combined, extreme weather is increasingly blamed on global warming, and rare habitats are disappearing so quickly some scientists believe the planet is entering it first major extinction since the …