Good pollution management is a matter of making the right choices

To make the right choices, science and society need each other to address questions such as which environmental problems to solve first, and which to leave until later, said Prof. Carolien Kroeze on 29 September in her inaugural address as Professor of Pollution Management (holding a personal chair) at Wageningen University, part of Wageningen UR.

Over the past few decades, research in pollution management has shifted from a single-pollutant approach to a focus on a multitude of substances and the connections between them, explained Prof. Kroeze in her inaugural lecture entitled Dilemmas in Pollution Management. Her own scientific discipline has uncovered a number of crucial dilemmas, showing that a lot of questions still remain unanswered. Many of these questions and dilemmas require consideration and choices, particularly on the part of society and policy-makers. Science can help. The process of consideration must be clear and straightforward. Kroeze cites the assessments of the UN climate panel IPCC as a good example. Despite criticism from climate sceptics, they contain summaries that are of great use to policy-makers.

Many environmental problems are highly complex and have a wide range of implications. This inevitably leads to the fundamental question of which source of contamination should be tackled first, and whether all forms of pollution must and can be combated. To illustrate her point, Kroeze cites the eutrophication of coastal waters; the abundance of fertilisers like nitrogen and phosphate, which are responsible for the proliferation of algae in these waters. The implications are serious and include deterioration of the ecosystem, biodiversity and fish stocks. Research has shown that the amount of fertiliser found in rivers varies greatly. Moreover, fertilisers can originate from natural sources or as the result of human intervention. The discharge of these substances into the sea is another crucial factor. Damming of rivers (which is often controversial for other reasons) can have a beneficial effect on the transport of nutrients by rivers to coastal waters, , as they increase nutrient retention in reservoirs.

Another dilemma that needs serious consideration is the question of which environmental problems actually need resolving. Take the choice between climate change and eutrophication, for example. Although the use of biofuels has a net advantage for CO2 emissions, producing raw materials for biodiesel (whether grains or algae) requires huge amounts of fertiliser, which in turn results in increased eutrophication in surface water.

The question of which dilemmas most urgently need resolving, cannot be answered by science alone, claims Prof. Kroeze. In her eyes, this is a subjective choice. Science can supply research findings and analytical methodology, but the ultimate responsibility for making a subjective assessment of the various problems lies with the interested parties and policy-makers