Satellites and the environment

The world conservation strategy stresses the need to maintain the earth's stock of natural capital. In this context, L. R. A. NARAYAN looks at how technology, such as remote sensing, plays a role in ensuring this.

AS a subject, the environment is not easy to define, as it encompasses everything connected with the earth - the atmosphere, land and water. People talk about it depending on the context in which it is referred to. In this regard, sustainability is referred to in terms of overcoming problems related to a deteriorating environment. People do want to improve their living standards. In the process there is an impact on the environment.

The World Conservation Strategy (1980), emphasises the interdependence of conservation and development, as contained in the second draft of the World Conservation Union (IUCN), the United Nations Environment Programme (UNEP), and the World Wide Fund for Nature (WWF-N). It emphasises "the need to maintain the earth's stock of natural capital, living only on income", which perhaps cannot be practically achieved. Therefore, if sustainability has to be maintained, there should be a strong and committed monitoring mechanism, so that remedial action can be taken to mitigate the effects of so-called development. While this is better said than practically implementable, it is clear that modern technology will have to play an important role in arresting the deterioration of certain resources.

The Government alone can do this through legislation and by trying to enforce it. It is the collective responsibility of the citizen, non-governmental organisations and government agencies, so that future generations are able to enjoy a high standard of living. It is in this context that technologies such as satellite remote sensing play a vital role.

Several aspects have been described in various fora, such as transforming attitudes and practices, conserving bio-diversity, the atmosphere, climate and energy, industry, urban land, farm and range land, forest land, fresh water bodies and the oceans as contained in the second draft (June 1990) of the IUCN, the UNEP and the WWF-N.

This report suggests certain strategies, but no further description of these is attempted here to keep this write-up short, except to examine a few examples in the use of remote sensing technology to monitor such activities. The aim is to emphasise the power of this technology and the need to harness it in order to apply it to every possible aspect of environmental monitoring, which, to some extent, will help in the concept of sustainability. The environmental impact becomes predominant if we do not realise the inter-relationships that exist between various natural resources. Many people generally do not take note of developmental activities that the government and other related agencies undertake or their environmental impact, till some of their adverse effects show up. Scientists and technologists may try to explain these activities and their effects, but seldom do they explain them when they show up much later. Very few agencies predict what is to come, especially when using an accurate and a continuously updated information system. To study these aspects on a regular basis, record them, and monitor them we have remote sensing technology, especially from satellites. This enables a large area and the surface of the earth to be monitored at regular intervals.

To map exact positions, we have the Global Positioning System (GPS). Further analysis is possible with an efficient Geographical Information System (GIS) which uses affordable computer systems as the type of data mentioned is obtainable in a digital domain - hard copy or in map form. In Indian conditions, a variety of environmentalists and non-government organisations concerned with environmental issues have not realised the full potential of these technologies, due to various reasons.

Remote sensing has come to stay and from using data of spatial resolution of about 80 m, in 1972 or so, it has now improved considerably. Data with a one metre spatial resolution has become available. A decision on what type of data is best suited for a particular activity, can be made keeping economy in mind. In fact as technology developers forge ahead, application orientation has still to catch up. If this is possible, the price of technology will come down and the benefits can be made available to a larger segment of the society.

Under paragraph 5.26 of the second draft of the publication titled A Strategy For Sustainability, it states that "a system for monitoring progress towards sustainability" is to be set up which will need the capacity to gather data, by various organisations such as NGOs, universities and research institutions. However, the primary exposure to the data has to be visual or descriptive. For this, remote sensing data is supreme.

It may not be possible to go into the details of how technology, the environment and society should be viewed together. This is because the environment is in state of flux with processes - human and natural - taking place. Some of these can be seen when observed from a satellite altitude. Many environmentalists acknowledge that only an aerial view or view from space platforms can point to changes that have taken place in the environment. The effective use of technologies for continuous monitoring though is still not well understood, both by space technologists who produce remotely sensed data, or by environmentalists who could benefit greatly from the application of such data. While developers and so called remote sensing specialists demonstrate some aspects of environmental applications in a specialised forum, the users or so called environmentalists are unable to appreciate the same. Therefore, there is a vacuum.

A paper on the theme of "Habitat diversity assessment using GIS techniques and remote sensed data" was presented recently by scientists at the National Environmental Engineering Research Institute (NEERI) by "using habitat diversity indices as a measure of the ecosystem's ability to provide habitat, prevent environmental degradation, and support other natural processes". The effectiveness of the method was demonstrated through a case study of four different ridge forest areas (northern, central, south central and southern) located in New Delhi (see maps) . This study used extensive data provided by satellite remote sensing and its analysis in a digital format and was supported by limited ground observation. It was said that landscape level indicators are best assessed by using remotely sensed data, than by any other method, and that satellite based assessment offered an opportunity for a more or less automatic periodic assessment of habitat diversity.

It has not been possible to go into the details of the methodology and an analysis of the results.

In conclusion it must be stated more can be obtained by using satellite remote sensed data than what is being done at present so that technology, the environment and society become inter- linked.

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