From The Idea of Justice, by Amartya Sen:
The environment is sometimes seen as the ‘state of nature’ , including such measures as the extent of forest cover, the depth of the groundwater table, the number of living species and so on. To the extent that it is assumed that this pre-existing nature will stay intact unless we add impurities and pollutants to it, it might, therefore, appear superficially plausible that the environment is best protected if we interfere with it as little as possible.
..the value of the environment cannot be just a matter of what there is, but must also consist of the opportunities it offers to people. The impact of the environment on human lives must be among the principal considerations in assessing the value of the environment. To take an extreme example, in understanding why the eradication of smallpox is not viewed as an impoverishment of nature (we do not tend to lament: ‘the environment is poorer since the smallpox virus has disappeared’), in the way, say, the destruction of ecologically important forests would seem to be, the connection with lives in general and human lives in particular has to be taken into consideration.
…the environment is not only a matter of passive preservation, but also one of active pursuit. Even though many human activities that accompany the process of development may have destructive consequences, it is also within human power to enhance and improve the environment in which we live. In thinking about the steps that may be taken to halt environmental destruction, we have to include constructive human intervention.
Development is fundamentally an empowering process, and this power can be used to preserve and enrich the environment, and not only to decimate it. We must not, therefore, think of the environment exclusively in terms of conserving pre-existing natural conditions, since the environment can also include the results of human creation.