William Reilly and Bob GrahamMay 23, 1977: U.S. President Jimmy Carter commissions the Global 2000 Report, an attempt to envision what the world's environment would look like at the turn of the century. In a somewhat less-than-cheerful tone, the report predicts that "if present trends continue, the world in 2000 will be more crowded, more polluted, less stable ecologically, and more vulnerable to disruption than the world we live in now."

May 23, 2001: A U.N. Treaty on Persistent Organic Pollutants (POPs) is signed. POPs include highly toxic and long-lasting chemicals like DDT, PCBs, and dioxins that present a direct threat to human health. The treaty takes effect in 2004, and limits the manufacture, use and transport of numerous dangerous chemicals.

May 23, 2010:  U.S. President Barack Obama appoints two political heavyweights to head a commission investigating the Gulf Oil Spill:  Former Democratic Senator Bob Graham of Florida and William Reilly, a Republican and former head of the U.S. EPA and the US branch of the World Wildlife Fund. (Both men are pictured at right, with Reilly on the left.)

May 23, 2012:  Los Angeles becomes the largest U.S. city to ban plastic supermarket bags with a vote by its City Council.  A celebrity-studded campaign pushed for the bandue to concerns that plastic bags were clogging waterways, littering streets, and adding to the plastic mess in the Pacific Ocean.

Photo: ZUMA Press

This feature is compiled by Peter Dykstra, an MNN contributor and publisher of Environmental Health News and The Daily Climate.