The ocean is an important component of the global environment and must not
be ignored in the assessment of environmental risks, even when attention is
focused on land surface issues. This paper addresses the use of space tech
niques for remote sensing of the ocean, in the context of how marine enviro
nmental risks may be monitored. Since there are several significant differe
nces between remote sensing over land and over sea, the techniques specific
to ocean observation are first reviewed, identifying what can be measured
from space and what are the sampling capabilities and inherent limitations.
Ocean environmental risks are then identified at global, regional and loca
l scales, and serve as examples of how space techniques can be used to addr
ess them. Finally operational environmental monitoring and risk management
is shown to require an integrated approach using models and measurements fr
om space and at sea.