‘The Great Protein Fiasco’, from the title of a 1974 paper in The Lancet by Donald Mclaren, is the name given to the period in international development policy from the late 1950s until the early 1970s. Throughout this time, UN agencies including the WHO and FAO, national aid programmes and famine relief charities pursued policies which put a particular focus on protein, overseeing the development of novel, high-protein foods, and prioritising access to protein sources in delivering food aid. This policy consensus was motivated by three generally accepted beliefs: that kwashiorkor was the leading cause of child mortality around the world and was caused by specific protein malnutrition (see kwashiorkor); and that the world faced a ‘protein gap’, or was bound to do so as population increased (see the Protein Gap). All three of these assumptions were moderated or completely undermined as better evidence came to light, but even so it took some time for the policy consensus to change. In using the word ‘fiasco’ to describe his era, Mclaren was levelling the charge that a huge amount of time, energy and money had been wasted on narrowly protein-focused, technocratic solutions to world hunger that in the end had made little to no impact. His paper played a significant role in finally changing the focus of international development policy from the mid-1970s onwards.

Discounting refers to the practice of putting a present value on costs and benefits that will occur in the future. Economists generally value costs and benefits that are predicted to occur in the future less than those incurred in the present because it is assumed that economic growth will make people richer, on the whole, in the future than they are today. As such the value of a pound or dollar in the future will be worth relatively less. The lesser value economists assign to a future dollar also stems from the observation that because people are impatient and so they prefer income today over income tomorrow. There is much disagreement about how to set the discount rate and this disagreement has relevance for measures to address, for example, climate change. If the discount rate is set very high (i.e. the cost of a dollar tomorrow is much lower than it is today) then the upfront costs of tackling climate change will be judged to outweigh the future economic benefits of having avoided it. Some argue that discounting undermines the rights of future generations; turning fundamentally ethical issues into technical ones whilst wrongly assuming ecological crises will only marginally affect economic growth.

A tipping point, in ecological or geological terms, is a threshold at which a small “push” (such as additional greenhouse gas emissions) can lead to a runaway feedback loop, resulting in the sudden shift of a local ecosystem or the entire planet to a new state (say, a much hotter climate). These shifts may follow a pattern known as hysteresis, where is it much harder to reverse the shift than it is to cause it. For example, an ice sheet that melts rapidly due to climate change might take a long time to regrow even if climate change were to be reversed. Hence, tipping points could potentially result in environmental changes that are irreversible on human timescales.

Trophic interactions refer to the feeding and nutrient exchange relationships between organisms. Examples of trophic interactions include predation, grazing and parasitism.

Trophic rewilding is defined by the principle of restoring trophic interactions. These include predator-prey relationships in the food chain but also other processes such as scavenging or decaying that constitute nutrient flows in the ecosystem. Trophic rewilding aims for the diversification and increasing complexity of the web of such interactions. As such trophic rewilding is a broad concept that encompasses other rewilding strategies such as Pleistocene and Holocene rewilding. However, unlike these more specific strategies trophic rewilding does not seek to restore nature to a particular historical baseline and is silent on questions about scale.

Turbidity refers to the amount of light that can pass through water (i.e. its cloudiness), as a result of particles that are suspended within the fluid. It can vary naturally depending on location, but can have detrimental impacts on ecosystems if caused by human activity. For this reason, it is often used as an indicator of water quality.