Natural Sinks Of Co2

Most of the attention with respect to the increase in atmospheric greenhouse gas concentrations centers around three issues: human-generated sources of carbon, mostly from burning fossil fuels; tropical deforestation, which accelerates the production of atmospheric carbon while causting havoc with biodiversity and the economic development of tropical countries; and the temperature increase that may accompany increased atmospheric greenhouse gas concentrations. This is the first book to focus extensively on the reverse to emissions of carbon dioxide (CO2), i.e. the sequestering of atmospheric carbon by aquatic and terrestrial ecosystems. Natural ecosystems are currently sequestering carbon and it is economically feasible to manage existing and additional terrestrial (forest, soil, saline land) and aquatic (coastal, wetland and ocean) ecosystems to substantially increase the level of carbon storage. The prospect of managing natural systems to absorb additional carbon should begin to change the mindset under which scientists, policy makers and society deal with the issue of further greenhouse gas increases.

In this first comprehensive handbook of the earth's sinks for greenhouse gases, leading researchers from around the world provide an expert synthesis of current understanding and uncertainties. It will be a valuable resource for students, researchers and practitioners in conservation, ecology and environmental studies.

While a number of gases are implicated in global warming, carbon dioxide is the most important contributor, and in one sense the entire phenomena can be seen as a human-induced perturbation of the carbon cycle. The Global Carbon Cycle offers a scientific assessment of the state of current knowledge of the carbon cycle by the world's leading scientists sponsored by SCOPE and the Global Carbon Project, and other international partners. It gives an introductory over-view of the carbon cycle, with multidisciplinary contributions covering biological, physical, and social science aspects. Included are 29 chapters covering topics including: an assessment of carbon-climate-human interactions; a portfolio of carbon management options; spatial and temporal distribution of sources and sinks of carbon dioxide; socio-economic driving forces of emissions scenarios. Throughout, contributors emphasize that all parts of the carbon cycle are interrelated, and only by developing a framework that considers the full set of feedbacks will we be able to achieve a thorough understanding and develop effective management strategies. The Global Carbon Cycle edited by Christopher B. Field and Michael R. Raupach is part of the Rapid Assessment Publication series produced by the Scientific Committee on Problems of the Environment (SCOPE), in an effort to quickly disseminate the collective knowledge of the world's leading experts on topics of pressing environmental concern.

The lntergovernmental Panel on Climate Change (IPCC) has recently summarized the state ofthe art in research on climate change (Climate Change 1995). The most up to date research findings have been divided into three volumes: • the Science ofClimate Change (working group I), • the Impacts, Adaption and Mitigation of Climate Change (working group II), and • the Economic and Social Dimensions ofClimate Change (working group III) There is a general consensus that a serious change in climate can only be avoided if the future emissions of greenhouse gases are reduced considerably from the business as usual projection and if at the same time the natural sinks for greenhouse gases, in particular that of CO , are maintained at the present level or 2 preferrably increased. Forests, forestry and forestry industry are important parts of the global carbon cycle and therefore they are also part of the mitigation potentials in at least a threefold way: 1. During the time period between 1980 and 1989 there was a net emission of CO from changes in tropical land use (mostly tropical deforestation) of 2 1. 6 +/- 1 GtC/a, but at the same time it was estimated that the forests in the northem hemisphere have taken up 0. 5 +/- 0. 5 GtC/a and additionally other terrestrial sinks (including tropical forests where no clearing took place) have been a carbon sink ofthe order of l. 3 +/- l.

Towards the Balance and Management of the Carbon Budget of the Biosphere The current state of misunderstanding of the global C cycle and our failure to resolve an issue that has been debated for 100 years (Jones and Henderson-Sellers, 1990) speaks loudly about the limitations of modem science when faced with the complexity of the biosphere. Efforts to understand and balance the global C budget have gone through several phases. First was a holistic view of the C budget as part of efforts to understand the geochemistry of the Earth (e. g. , Clarke, 1908). Next, came a period of data collection and sythesis which focused on the diversity of sectors of the biosphere. This phase culminated in the early 1970's with the realization that humans were greatly impacting the global C cycle as measured at the Mauna Loa Observatory (Keeling et al. , 1973). New syntheses of the global C budget emerged at this time (Woodwell and Pacan, 1973; Bolin et al. , 1979). The next phase was one of controversy and intense focus on particular sectors of the biosphere. The controversy rested on discrepancies about the role of the terrestrial biota in the global C cycle and the failure to account for sufficient C sinks to absorb all the C emitted by land-use change in the tropics (Woodwell et al. , 1978, 1983; Houghton et al. , 1983).