In order to guard the environment, the precautionary strategy shall be extensively utilized by States in accordance with their capabilities. Where there are threats of serious or irreversible harm, lack of full scientific certainty shall not be used as a motive for postponing value-efficient measures to forestall environmental degradation. When an exercise raises threats of hurt to human health or the atmosphere, precautionary measures needs to be taken even when some trigger and impact relationships usually are not totally established scientifically. In this context the proponent of an exercise, somewhat than the general public, ought to bear the burden of