Increasing greenhouse gaseous concentration in the atmosphere is perturbing the environment to cause grievous global warming and associated consequences. Following the rule that only measurable is manageable, mensuration of greenhouse gas intensiveness of different products, bodies, and processes is going on worldwide, expressed as their carbon footprints. The methodologies for carbon footprint calculations are still evolving and it is emerging as an important tool for greenhouse gas management. The concept of carbon footprinting has permeated and is being commercialized in all the areas of life and economy, but there is little coherence in definitions and calculations of carbon footprints among the studies. There are disagreements in the selection of gases, and the order of emissions to be covered in footprint calculations. Standards of greenhouse gas accounting are the common resources used in footprint calculations, although there is no mandatory provision of footprint verification. Carbon footprinting is intended to be a tool to guide the relevant emission cuts and verifications, its standardization at international level are therefore necessary. Present review describes the prevailing carbon footprinting methods and raises the related issues.

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/ Models available in the literature on nutrient uptake, lightavailability, and chlorophyll growth have been suitably modified andintegrated through the computer program CHLORF (written in "C"language), which has the advantage of being amenable to simulation undervarious combinations of input variables. The model has been used forsensitivity analysis in order to identify the most sensitive set ofparameters whose control can form an appropriate basis for evolving pragmaticmanagement strategies. In addition, greenhouse mitigation potential has beencomputed in terms of assimilation of carbon dioxide for a case study ofIndian wetlands.KEY WORDS: Wetland; Nutrient cycling; Modeling; Greenhouse effect

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Dioxins like various gaseous pollutants and aerosols can be scavenged by appropriate vegetative greenbelts. Based on their stomatal properties and the models for contaminant uptake, uptake of dioxin (2,3,7,8-TCDD) by three important Indian plant species, viz. Eugenia jambolana (Jamun), Azadirachta indica (Neem) and Ficus religiosa (Peepal), has been estimated. 2,3,7,8-TCDD is a contaminant with severe harmful ecological ramifications. Computations show that Ficus religiosa has highest uptake capacity. The present exercise has its utility in designing appropriate green-belts for mitigating adverse environmental and human health impacts due to dioxins. This can be an effective management option for mitigating the damages caused by dioxins.

In view of their sensitivity and importance, an ecological-economic analysis of wetlands has been carried out for various Indian states. Subsequently, the ecological wealths of different zones (north, south, east and west) have been computed and compared. Amongst states, Karnataka (7896.5 million US dollars yr(-1)), Gujarat (7689.4 million US dollars yr(-1)) and Andhra Pradesh (7670.9 million US dollars yr(-1)) are found to be the richest, whereas Nagaland (3.1 million US dollars yr(-1)), Meghalaya (5.9 million US dollars yr(-1)) and Sikkim (15.9 million US dollars yr(-1)) turn out to be the poorest. Amongst different zones, Southern Zone turns out to be the richest and the Northern Zone poorest. A ratio called ANR [Artificial (A) Wetland Wealth to Natural (N) Wetland Wealth Ratio (R)] has also been devised, which is the ratio of the ecological-economic values of artificial and natural wetlands. In other words, this ratio indicates the level of environmental concern of a given region. ANR ratio is found to be the highest for Madhya Pradesh (564.1) and Karnataka (159.8) states.

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Sulfate aerosols have been found to be the major contributors to precipitation acidity. Thus, in view of the long-term ecological repercussions they have on aquatic ecosystems and their acidity-potential, the present analysis focuses on a case study application of the layer-averaged aerosol-scavenging model (Okita et al., 1996) for predicting values of the wet scavenging coefficient and sulfate concentrations in precipitation samples on the basis of the information available for some selected Indian cities. Through sensitivity analysis (Pandey et al., 1997) the scavenging coefficient has been found to be very strongly dependent on precipitation intensity. Comparison of model predictions has been done with the measured values for Delhi, Mumbai, Calcutta and Chennai in India.