A lot of activists these days are very fond of the precautionary principle, saying that we should not develop technology in the absence of absolute certainty in terms of the outcome. In general terms, I would argue that a better ethical or philosophical standard would be the creation of lesser problems than those that existed before.
There are seven billion of us right now on the planet. There will soon be nine or 10 billion of us. We will always have an impact. As long as we don't import food from outer space, we will have an impact on the planet, but I think the track record of the farming sector in Canada and in other advanced economies is fairly good. Again, there will be a few hiccups along the way, but creating lesser problems than those that existed before should be our main standard.