Cumulative human impacts: change in pressures and cumulative impact (2008 to 2013)

This is a portion of the data used to calculate 2008 and 2013 cumulative human impacts in: Halpern et al. 2015. Spatial and temporal changes in cumulative human impacts on the world's ocean. Seven data packages are available for this project: (1) supplementary data (habitat data and other files); (2) raw stressor data (2008 and 2013); (3) stressor data rescaled by one time period (2008 and 2013, scaled from 0-1); (4) stressor data rescaled by two time periods (2008 and 2013, scaled from 0-1); (5) pressure and cumulative impacts data (2013, all pressures); (6) pressure and cumulative impacts data (2008 and 2013, subset of pressures updated for both time periods); (7) change in pressures and cumulative impact (2008 to 2013). All raster files are .tif format and coordinate reference system is mollweide wgs84. Here is an overview of the calculations: Raw stressor data -> rescaled stressor data (values between 0-1) -> pressure data (stressor data after adjusting for habitat/pressure vulnerability) -> cumulative impact (sum of pressure data) -> difference between 2008 and 2013 pressure and cumulative impact data. This data package includes rasters of the difference between 2013 and 2008 for each pressure (N=12) and final cumulative impacts data (N=1). These are calculated using data from: pressure and cumulative impacts data (2008 and 2013, subset of pressures updated for both time periods), and consequently do not incorporate data from: sea level rise, ocean pollution, invasives, and shipping because these data were not available for 2008. Data for 2008 and 2013 did not differ for: artisanal fishing, inorganic pollution, and ocean acidification.