Global development in the twenty-first century

The global nitrogen cycle in the twenty-first century: introduction.

The global nitrogen cycle in the twenty-first century.

Global nitrogen fixation contributes 413 Tg of reactive nitrogen (Nr) to terrestrial and marine ecosystems annually of which anthropogenic activities are responsible for half, 210 Tg N. The majority of the transformations of anthropogenic Nr are on land (240 Tg N yr(-1)) within soils and vegetation where reduced Nr contributes most of the input through the use of fertilizer nitrogen in agricult...

Global warming in the twenty-first century: an alternative scenario.

A common view is that the current global warming rate will continue or accelerate. But we argue that rapid warming in recent decades has been driven mainly by non-CO(2) greenhouse gases (GHGs), such as chlorofluorocarbons, CH(4), and N(2)O, not by the products of fossil fuel burning, CO(2) and aerosols, the positive and negative climate forcings of which are partially offsetting. The growth rat...

Urban Development in India in the Twenty First Century:

Blindness: a global priority for the twenty-first century.

Vision is one of our most cherished senses. Yet, most of us can hardly imagine what it would be like to lose it— to be unable to drive, to need assistance with daily activities, or to have difficulty recognizing friends and family members. This is the reality, however, for the nearly 45 million people worldwide who are blind (1). A further 135 million people are visually disabled, and are depen...