Saturday, 15 February 2020

Visualising ecological footprints

A very short post today on something slightly different. I was discussing the issue of how to visualise a city's ecological footprint with Dan Raven-Ellison last year and I made a very simple interactive map of it. The ecological footprint of an area can be expressed in relation to amount of land required to sustain an area's use of natural resources. It's usually expressed in a hectares per capita way, so for London I took the Greater London population (about 8.8 million) and multiplied it by a conservative value of 4.4ha per capita to get an area of about 38,720,000 hectares or 387,200 sq km (about the size of Japan). Since the shape of Greater London is quite well known, I used this to visualise it, as you can see below.

Black = actual boundary | Pink = ecological footprint equivalent

I did put this on an interactive map, although it doesn't actually do much apart from show you the size in relative terms and the wide area it covers. Click the map for a little bit of info on the area, as in the image below. The land area of the UK is about 242,000 sq km. That's about 94,000 sq miles. Or about the size of Oregon, or half the size of Sweden, or just a bit bigger than Uganda, or twice the size of North Korea.

Note that the figure above is in sq km 

Notes: I have seen a number of different figures per hectare for London, the UK and different places online but I used the number I did so that I could be sure I wasn't over-estimating it. This report on London puts the per capita figure for the city at 6.63ha per head (see p. 11). That would give an area of 488,680 sq km for London's ecological footprint - almost exactly twice the land area of the UK (yep, the size of Turkmenistan, 80,000 sq km larger than California, and a little bit smaller than Spain).