Sir

Your Editorial “Circulation challenge” (Nature 439, 244; 200610.1038/439244b) calls for ocean observations to be “sustained for much longer periods than foreseen in the six-year RAPID programme” and “augmented globally”. But you do not mention the Global Ocean Observing System (GOOS; see ioc.unesco.org/goos), which already exists specifically to take up this challenge.

GOOS provides an operational structure for sustained global observations comprising the oceanographic component of the Global Earth Observing System of Systems. The open-ocean module of GOOS is designed to describe and forecast the state of the physical ocean in order to help understand and predict weather and climate. Its implementation is achieved by pooling the commitments of individual nations, made through their government agencies, navies and oceanographic research institutions, together with sponsorship from international agencies.

Not long ago, Nature called for enhanced support for GOOS (“Making sense of the world” Nature 433, 785; 200510.1038/433785a). Heeding this call requires first and foremost that nations support the development of a robust commitments mechanism that can efficiently take stock of national efforts and at the same time increase the resources available for coordination. GOOS will also need to increase its efforts to reach, and cater for, a wider range of contributors and users of the system. GOOS welcomes the circulation challenge.