April 17 - April 22 marks the 38th anniversary of Earth Day, a day of celebration and activism intended to raise awareness of environmental issues. In 1970 a nationwide "Environmental Teach-In," led by U.S. Senator Gaylord Nelson and Denis Hayes, helped organize around 20 million demonstrators to show support for a policy agenda focused on these concerns.

Many laws to protect the environment, including the Clean Air Act, were enacted by Congress after the first Earth Day. And the U.S. Environmental Protection Agency was created to protect the environment and public health.

Over the past year, several National Academies projects have looked at how science and technology can be harnessed to protect the Earth and sustain the diversity and well-being of the life it supports.

In September 2007, the National Academy of Sciences unveiled Safe Drinking Water Is Essential, a Web site that examines the state of the world’s water supply and what can be done to improve it. Currently more than one is six people lack reliable access to safe drinking water, and the problem is especially acute in the developing world.

On the issue of global warming and climate change, the National Research Council recently released the 2008 edition of "Understanding and Responding to Climate Change," an easy-to-read booklet with information extracted from the Academies' expert reports on climate change. The booklet offers what is currently known and understood about climate change and provides helpful analysis and direction to policymakers and stakeholders.

And last February, the National Academy of Engineering announced the grand challenges for engineering in the 21st century. A diverse committee of experts from around the world, convened at the request of the U.S. National Science Foundation, revealed 14 technological challenges that, if met, would improve quality of life worldwide in the near future. The challenges include a number of environmental issues -- developing methods for carbon sequestration, managing the planet's nitrogen cycle, providing access to clean water, and making energy economically available through fusion and solar power.

• Safe Drinking Water is Essential
• Understanding and Responding to Climate Change
• Grand Challenges for Engineering in the 21st century

• Earth Day 2008