Workshop "Blue Planet, Green Planet"

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The General Assembly of the United Nations has decided, in his Resolution 52/56 of December 10th 1997, to hold the third United Nations Conference on the exploration and peaceful uses of outer space. This conference took place in Vienna from July 19th to 30th, 1999. A technical forum, part of this Conference, included workshops and round tables. CNES organised a special presentation, a round table and two workshops. The issues addressed by one of them, entitled "blue planet, green planet", are more specifically in line with the research activities of the MEDIAS network. This workshop was organised in close co-operation between CNES, Gérard BEGNI (MEDIAS-France) and Ichtiaque RASOOL (international consultant), who chaired the two sessions of the workshop.

The programme of the "blue planet" session was :

• Presentation of the session
  G. Begni - MEDIAS-FRANCE, France
• Global ocean circulation from TOPEX-POSEIDON
  J.F. Minster - Centre National de la Recherche Scientifique, France
• Ocean biogechimical cycles and carbon budget
  P. Liss - University of South Anglia, School of Environnment Sciences, UK
• Ocean color and Temperature Scanner data utilization
  M. Shimada, Earth Observation Research Center, Japon
• Coastal region studies from satellite
  O. Kopelevitch - Russian Academy of Scineces, Russia
• Contribution of space observations to improve the understanding of marine phenomena in Morocco
  H. Arid, Centre Royal de Télédétection Spatiale, Maroc
• Use of Polder/Adeos
  P.Y. Deschamps - Laboratoire d'Optique Atmosphérique, France

The programme of the "green planet" session was :

• Presentation of the session
  I. Rasool - Use of SPOT4/Vegetation for global biospheric from space
  J.L. Fellous - Centre National d'Etudes Spatiales, France
• Observing the dynamics of the biospher from space
  M. Leroy - Cesbio, France
• Tropical deforestation and regrowth assessments
  D. Skole -Michigan State University, USA
• Land use and land cover changes from satellites
  E. Lambin - Université Catholique de Louvain, Belgique
• Studies of desertification in Southern Mediterranean Region
  H.Khatelli, Institut des Régions Arides, Tunisie.

The results of the workshop was reported to the Conference, CommitteeI, Point 7 of the Agenda.

1. The study of the environment is the study of the Earth system. It requires co-ordinated multidisciplinary action at every level. Global climate change is largely the result of the growth of greenhouse gases, stemming from anthropogenic activity taking place on a regional or local scale. Global phenomena have a local and regional impact, however. Examples are the impact of El Niño on the living conditions of Peruvian fisherfolk and the impact of drought on nomads in the Sahel. The Workshop "Blue Planet, Green Planet" concentrated on those important scientific problems with a major short-, middle- or long-term social impact, especially on the poorest sections of the population. The regional impact of climate change can best be studied after more is known about their mechanisms and characteristics.
2. The Workshop examined the two major systems on the Earth�s surface: oceans and dry land. It examined some local concerns, but concentrated more on regional and global phenomena, the means of observing them and model-building that make it possible to understand and predict their behaviour and their interactions.
3. The most crucial scientific issue in this field is learning more about the carbon cycle, in particular the role of carbon dioxide (and that of methane), and about the water cycle, together with their interactions. For example, it would be useful to know more about the impact of a change in the water cycle on the carbon cycle, from one year to another and in the long term.
4. There is a need to know more about the carbon flux: how much the land emits; how much it absorbs; what the role is of the anthropogenic factor; how the balance between oceans and dry land evolves; and what interaction there it between major oceanic phenomena such as El Niño and the carbon flux. Research has been done on some 2 billion tons, out of a total of about 100 billion tons, the anthropogenic contribution being around 6 billion tons.
5. Growth in modelling and data assimilation, together with progress in space techniques and orbital systems, has made important contributions to the knowledge and understanding of those mechanisms. Systems such as the advanced very high resolution radiometer (AVARR) of the National Oceanic and Atmospheric Administration (NOAA) of the United States of America, the "Satellite pour l'observation de la Terre" (SPOT 4) VEGETATION system, the Polarisation and Directionality of the Earth's Reflectances (POLDER) system, Topex-Poseidon and ENVISAT, among others, have helped to increase not only the knowledge and understanding of the evolution of those phenomena, but also the possibility of predicting them.
6. It is important to set standards for space system products. In addition, there is a need to organise a coherent database and to ensure the continuity of space systems.
7. The Workshop made the following recommendations:
   �Homogeneous, calibrated and validated databases of surface parameters (both land and ocean) of the last two decades should be established, with a view to providing a documented historical perspective of the Earth's evolution;
   �The above-mentioned databases should be used to support improved global change models;
   �The continuous acquisition of high-quality remote sensing surface data should be ensured;�Data availability should favour the largest user community;
   �The needs of the users, including developing countries, should be taken into account when designing new systems;
   �New methods and associated databases that include socio-economic data should be developed that will make it possible to use new systems together with historical data records.

I. RASOOL
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