Contributed Paper Dynamics in the global protected-area estate since 2004 Edward Lewis , 1 ∗ Brian MacSharry, 1 Diego Juffe-Bignoli, 1 Nyeema Harris, 2 Georgina Burrows, 3 Naomi Kingston, 1 and Neil D. Burgess 1,4 1 UN Environment – World Conservation Monitoring Centre, 219 Huntingdon Road, Cambridge CB3 ODL, U.K. 2 Luc Hoffmann Institute, Rue Mauverney 28, 1196, Gland, Switzerland 3 Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, U.K. 4 Centre for Macroecology, Evolution and Climate, Building 3, 2nd Floor, Natural History Museum, University of Copenhagen, Copenhagen 2100, Denmark Abstract: Nations of the world have committed to a number of goals and targets to address global envi- ronmental challenges. Protected areas have for centuries been a key strategy in conservation and play a major role in addressing current challenges. The most important tool used to track progress on protected-area commitments is the World Database on Protected Areas (WDPA). Periodic assessments of the world’s protected- area estate show steady growth over the last 2 decades. However, the current method, which uses the latest version of the WDPA, does not show the true dynamic nature of protected areas over time and does not provide information on sites removed from the WDPA. In reality, this method can only show growth or remain stable. We used GIS tools in an approach to assess protected-area change over time based on 12 temporally distinct versions of the WDPA that quantify area added and removed from the WDPA annually from 2004 to 2016. Both the narrative of continual growth of protected area and the counter-narrative of protected area removal were overly simplistic. The former because growth was almost entirely in the marine realm and the latter because some areas removed were reprotected in later years. On average 2.5 million km 2 was added to the WDPA annually and 1.1 million km 2 was removed. Reasons for the inclusion and removal of protected areas in the WDPA database were in part due to data-quality issues but also to on-the-ground changes. To meet the 17% protected-area component of Aichi Biodiversity Target 11 by 2020, which stood at 14.7% in 2016, either the rate of protected-area removal must decrease or the rate of protected-area designation and addition to the WDPA must increase. Keywords: Aichi target 11, coverage, protected area, protected area downgrading downsizing degazettement, World Database on Protected Areas Din´ amica de los Bienes de las ´ Areas Protegidas desde 2004 Resumen: Pa´ ıses alrededor del mundo se han comprometido con un n´ umero de metas y objetivos para tratar los retos ambientales mundiales. Las ´ areas protegidas han funcionado durante siglos como una estrategia clave en la conservaci´ on y juegan un papel importante en c´ omo se manejan los retos actuales. La herramienta m´ as importante que se usa para rastrear el progreso de los compromisos con las ´ areas protegidas es la Base de Datos Mundial de las ´ Areas Protegidas (WDPA, en ingl´es). Las evaluaciones peri´ odicas de los bienes de las ´ areas protegidas muestran un crecimiento constante durante las ´ ultimasdos d´ecadas.Sin embargo,elm´etodo actual, que usa la versi´ on m´ as reciente de la WDPA, no muestra la verdadera naturaleza din´ amica de las ´ areas protegidas a lo largo del tiempo y no proporciona informaci´ on sobre sitios que han sido removidos de la WDPA. En realidad este m´etodo s´ olo puede mostrar crecimiento o permanecer estable. Usamos herramientas de SIG en una estrategia para evaluar el cambio de las ´ areas protegidas a lo largo del tiempo con base en doce versiones temporalmente distintas de la WDPA que cuantifican las ´ areas a˜ nadidas o removidas de la WDPA ∗ email edward.lewis@unep-wcmc.org Article impact statement: To meet Aichi target 11, the world needs to reduce the rate of protected-area removal or increase the rate of protected-area designation. Paper submitted November 28, 2016; revised manuscript accepted November 17, 2017. 570 Conservation Biology, Volume 33, No. 3, 570–579 C  2017 Society for Conservation Biology DOI: 10.1111/cobi.13056