Three ways to deliver a net positive impact with biodiversity offsets

Abstract

Biodiversity offsetting is the practice of using conservation actions such as habitat restoration, management or protection to compensate for ecological losses caused by development activity, including construction projects. The typical goal of offsetting is no net loss (NNL), which means that all ecological losses are compensated for by commensurate offset gains. The focus of this work is a conceptual and methodological exploration of net positive impact (NPI), an ambitious goal that implies commitment to beyond NNL, and which has recently received increasing attention from both big business and environmental NGOs. We build upon three ways to deliver NPI: (i) use of an additional NPI multiplier, (ii) using permanent offsets to deliver additional gains after NNL has first been reached during a shorter offset evaluation time interval, and a (iii) novel modification of the mitigation hierarchy so that gains from its traditional third step, onsite rehabilitation, can no longer be counted towards reduced offset requirements. The outcome from these three factors is that for the same ecological damage, larger offsets will be required than before, and earlier, thereby necessarily improving the success expected from offsets. As a corollary, we show how offsets really are NNL only at one ephemeral point in time, before which they are net negative and after which they turn into either net positive impact or net negative impact, depending on whether permanent offsets are combined with partially temporary losses or if temporary offset gains are combined with partially permanent losses. While we provide operational guidance on how to achieve NPI, it should be understood that achieving it is fully conditional on prior achievement of NNL, and offsets have indeed been frequently observed to fail due to inadequate policy requirements, incompetent planning or incomplete implementation. Nevertheless, achieving NPI becomes straightforward if NNL can be credibly reached first.