Carbon footprint through time

Map using proportional not choropleth symbology

Choropleth map

Recently in the news were choropleth* maps of Canadian election results, this one posted by Gletham on Facebook. The vast territory skewed however the impression one gets on vote proportions per party:

Dot-density map

Contrast this dot-distribution* map of same made by Kenneth Field and posted on twitter:

Not only is it far more realistic in terms of actual vote distribution, it’s also enlightening in terms of population density on this vastly empty geography.

*: choropleth, dot-distribution and proportional symbols are all part of of thematic maps.

Let’s see now how effective a third method, proportional symbology* can be to map vast amounts of data.

I was asked to create CO2 emissions maps for a forthcoming book by @lsklair on the effects of the Anthropocene, having written how story maps help data journalism in Climate Change. While the forthcoming book uses static monochrome figures like the graphs below, why not show the same as animations of bubble maps or proportional symbols?

Web app snapshot

The CDIAC offers CO2 emissions data from 1751 to 2014 and BP Statistical Review until 2018. While TotalCO2 exist for the entire span, per Capita exist only after 1950. I posted these on UN country outlines centred on CIA World Factbook centroids. To see CO2 Emissions time animation, go to CO2 emissions 1751 2018.

perCapita stats explained under “Non geographic posting” here

The point of the book, however, will be the effects of increased carbon footprints over time and space... So why not turn the map on its head, and animate it by country instead of time? Let’s show the growth of per Capita (cyan) and Total CO2 (magenta) by country, from smallest to largest carbon not geographic footprint.

Note that it may look as increasing emissions over time, since our brain is trained to see time sequences. But for that, consult the historic animation referred to above.

You can see that animation, posted as a static colour map above, as a web app (webGL error? try the browser version): watch the increased emissions animation, or scroll back and forth across countries to increase or decrease them... Is it not an arresting way to show the disproportionate emissions at a global scale?

That scale shows great variations in area per country… ranging from tiny island nations to sprawling sub-continents! More the reason we used proportional symbols on points representing each country… A choropleth map that lays swatches of colour over each country area would invariably skew that impression, as in the opening electoral maps.

Like on my blog, I try and show how easy it is to grasp and portray various data on simple maps accessible on desktop or the web. I posted the data here under CC BY-SA 4.0, so you can have a go. Contact me @azolnai if you’re interested in exploring this.

Thanks Raluca Nicola for the inspiration from here methods here, and ArcGIS Open Data .