State of the Planet

News from the Columbia Climate School


Seeking the Signal in the Noise of Environmental Performance Metrics

This week CIESIN released, with its colleagues at Yale University, the 2012 Environmental Performance Index (EPI).  Wherever possible we collected and processed data in time series, to permit not merely comparisons across countries but also consistent comparisons over time.  This has made the EPI a much more powerful diagnostic tool, because trends are often much more revealing than static patterns.

To take one illustration, consider overfishing.  Globally, the picture is not pretty.  On our 0-100 scale, the world average went from 34 in 2000 to 29 in 2010—twice as many countries got worse than got better.

One of the real pleasures of producing the EPI is the chance to work with fellow data geeks who help guide us to the most suitable information and help us structure it into meaningful indicators.  For overfishing we turn to the Sea Around Us group at the University of British Columbia, led by Daniel Pauly and backed by a talented, hard-working team.  They have done incredible work collecting all the available fishery statistics, uncovering and correcting major errors, making the numbers as comparable as possible, and putting together compelling, informative time series that reveal where overfishing is running rampant and where it is under control.

Map of waters of Namibia. The top two panels show landings by species; the bottom two panels show stock status (click to enlarge). Source: Sea Around Us Project

I asked the people at Sea Around Us where these numbers show meaningful success brought about by deliberate policy efforts.  They pointed to Namibia as a clear example.  In our 2000-2010 trend analysis, Namibia’s score rises 34%.  The policy success is even more dramatic when looking at the full time series assembled by Sea Around Us, which reveals that things were extremely bad in the early 1990s, with about 80% of the stocks in a collapsed state.  By 2000 they had already improved considerably, and that improvement has continued to the present.  A major driver of this change has been the elimination of foreign fishing fleets from the Namibian EEZ. Until Namibia established its EEZ in 1990, South African, Russian, Spanish, and Ukrainian vessels took the bulk of the catch (see figure, top).  After 1990, Namibia restricted the access to its EEZ (NMFS, 2009), and was able to enforce restrictions.  Consequently the catches of horse mackerel, chub mackerel, hake, anchovy, and monkfish declined briefly and can be attributed to the dramatic decrease in fishing effort expended in the Namibian EEZ by foreign fleets, rather than an actual decrease in the biomass of these species (see figure, second from top).

Being able to see such trends and link them to policy efforts makes possible the identification of leaders and laggards and holds open the promise of accountability and progress.

Marc Levy is deputy director of the Center for International Earth Science Information (CIESIN). He is one of the authors of the just-released 2012 Environmental Performance Index (EPI); an EPI has been produced every two years since 2006.

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12 years ago

Thanks so much for the info, overfishing is a real issue that should be a bigger concern to more people. The data and trends are the only quantitative way to show the decision makers what is really happening, and prove the naysayers wrong.