Ocean Health Index

By | 2018-01-15T08:59:58+00:00 August 17th, 2012|Biodiversity, Knowledge Base, Oceans|0 Comments

Anyone who has read the Hitchhiker’s Guide to the Galaxy will know what the answer to the Ultimate Question of Life, The Universe, and Everything is: 42. It took the fictional supercomputer Deep Thought 7.5 million years to come up with that answer.

A group of marine scientists and conservationists have taken rather less time to come up with the answer to the (Less Ultimate but Still Important) Question: ‘How healthy are the oceans?’

Their answer? 60.

In a paper published this week in Nature, Benjamin Halpern and colleagues collected data for 10 ‘public goals’ across the territorial waters of 171 countries. The goals include food provision, carbon storage, livelihoods, and biodiversity, as well as harder-to-quantify measures such as ‘sense of place’ and recreation.

Goals were scored 0 to 100 by country, with scores aggregated to give global and national ‘ocean health’ numbers. Although the global score was 60, there is huge variation between countries, from 36 (Sierra Leone) to 86 (Jarvis Island, an uninhabited atoll in the South Pacific). In general, developed countries scored higher than developing nations, and a third of countries got less than half marks. There was also enormous variation in the performance of each goal, with food provision, natural products and tourism consistently low and carbon storage, biodiversity and clean water scoring highly.

These results may seem counterintuitive (as the paper’s authors concede). Marine biodiversity has been enormously reduced in recent human history, as scientists like Jeremy Jackson, Boris Worm, and others have established. The loss of mangroves, seagrasses and other ‘carbon-rich’ habitats has also been accelerating in recent decades.

Why the high scores? Part of the reason is methodology. The index sets a baseline of 1980 against which to measure changes; data coverage before then is patchy. Thus, even though there is ample evidence that species and habitats have declined enormously from their pre-human state – to the extent that coral reefs were recently declared ‘zombie ecosystems’ – the index only tells us that things are slightly worse than 30 years ago. Conversely, others have criticised the methods used to score fisheries, saying they have overestimated the potential for expansion.

Quibbles over methods aside, some will no doubt take issue with the paper’s philosophy of assessing ocean health through the lens of human wellbeing. The authors are clear about wanting to avoid a “purely protectionist” approach that acts as if humans are somehow external to nature. Here they echo a gathering movement, perhaps best encapsulated by Emma Marris’ book ‘Rambunctious Garden’, away from the increasingly distant dream of preserving ‘pristine’ nature and towards the concept of “a global, half-wild rambunctious garden planet, tended by us”.

The Index was launched explicitly to help with such management, by providing a cross-sectoral approach that departs from previous indicators (such as the Living Planet Index, which only looks at marine populations). This can help policy makers to evaluate tradeoffs between different uses—although whether they use it is another matter—and over time the index will be updated to monitor progress. A nifty website was also launched to coincide with the paper – www.oceanhealthindex.org – which lets you explore the index in more detail, find out how the authors decided upon benchmarks for each of the goals, and download the data for yourself.