A look at landmark environmental decisions by past presidents.

1832: President Jackson sets aside for preservation the land in and around Hot Springs in Arkansas, initiating what would become a national movement by Commanders-in-Chief to preserve public space for the common good.

1864: President Lincoln signs an act of Congress to protect the land surrounding Yosemite Park.

1903: President Theodore Roosevelt creates the first National Bird Preserve in Florida. By 1909, his administration has preserved 42 million acres of national forest.

1933: FDR tackles mass unemployment by creating the Civilian Conservation Corp, which puts to work thousands of young men in preventing soil erosion, creating park trails, and beekeeping.

1970: Richard Nixon establishes the Environmental Protection Agency.

2001: Bill Clinton leaves office having protected 58 million acres of national forest from development and establishing 8 million acres of land for new national monuments.

2012: What will be Barack Obama's legacy?

Top Five Priorities for the Obama Administration's Environmental Agenda

1. Send global warming legislative framework to Congress
2. Ensure that climate legislation creates jobs
3. Regain U.S. leadership in international climate negotiations
4. Free California to cut global warming emissions from cars
5. Restore healthy oceans by making catch shares the standard for managing fisheries

Source: Environmental Defense Fund