Issues
Letters
Is Boltzmann Entropy Time's Arrow's Archer?
Search and Discovery
Articles
Human Impacts on the Nitrogen Cycle
Fertilizer production ond other human activities have more than doubled the global rate of nitrogen fixation since preindustrial times. The resulting imbalance is contributing to ecosystem disruption, ozone depletion, greenhouse effects and other environmental problems.
Clouds and Their Effects on the Climate System
Covering the Earth on scales as large as millions of square kilometers, airborne water particles transport energy and affect the balance between incoming and outgoing radiation.
The Ocean's Overturning Circulation
Each second millions of cubic meters of water circulate between the ocean's surface and its depths. Despite the crucial role this ‘overturning’ may play in regulating Earth's climate, we still do not know how vulnerable it is to anthropogenic environmental changes.
Fuel Cells: Energy Conversion for the Next Century
What the world needs now is an environmentally benign way to generate electric power efficiently. The emerging technology of fuel cells is rising to meet the challenge.
Industrial Ecology: Minimizing the Impact of Industrial Waste
With the environment in jeopardy, we need to reconsider the design of products and the organization of industrial and consumer markets with recycling in mind.