Global Problems Demand Good Maps

By Henry Woodbury

The study of climate change is a global endeavor which means that data is often plotted to continental or world maps. As such, many of the challenges of good map making reappear as problems in presenting climate change data. Two researchers at the University of Idaho, Jean McKendry and Gary Machlis, point out that a key map from the 2007 Intergovernmental Panel on Climate Change (IPCC) Summary for Policymakers (PDF, p. 10), fails in both intelligibility and accuracy:

One of the most common ways in which climate maps can be misleading is to fail to take account of the map’s projection. “All map projections have distortions (distance, area, direction, and/or shape). For example, if temperature is displayed using coloured squares of equal size across the map, but the map projection does not minimize areal distortion, the squares appear to but do not represent equal areas on the Earth,” McKendry told environmentalresearchweb.

Other problems include overlapping data points, a multi-colored data scale, and unclear labels.

The map is reproduced below in all of its orange glory: