ONS develops algorithm to tell how green Britain's gardens to help tackle flooding and CO2 levels

Charles Hymas
The ONS has developed an algorithmic technology that can measure how green our gardens are - PA

Britain’s official statisticians have developed an algorithmic technology that can measure how green are all our gardens in a bid to help combat flooding and reduce pollution and CO2.

Within any town or city, the Office for National Statistics (ONS) will be able to pinpoint the proportion of vegetation in each and every garden versus the amount of paving, patios, decking or rockery.

It is critical with the onset of climate change because it will enable planners to establish how well each town and city’s vegetation can soak up carbon dioxide and withstand flooding. Town planners can then adapt public policies to encourage residents to make their gardens greener.

The more vegetation gardens have, then the more cities and towns are able to clean up the air that their residents breathe and the better they can soak up run-off water to combat floods. Vegetation also cools cities, particularly as heat climbs.

The “machine learning” technology analyses aerial images through both the normal light spectrum and infrared and has been taught to distinguish between paving, decking and even artificial grass and natural vegetation.

It has established the average British garden is 62 per cent greenery, with 38 per cent inert. There are, however, significant differences between cities.

Bristol and Cardiff, where the technology was tested by the ONS and Ordnance Survey, respectively recorded an average of 45 per cent and 54 per cent of vegetation in their gardens.

There are also huge variations within the cities between paved stone obsessives who have no interest in mowing a lawn and the jungle types who want to return to nature.

“Some gardens were almost entirely paved so the figure is close to 0, whilst other gardens are almost fully turfed and near to 100 per cent,” said the ONS.

The research is important because the United Nations predicts the proportion of the population worldwide living in cities will rise from 54 per cent to almost 70 per cent by 2050.

“We are trying to strengthen and  improve our understanding of natural capital [the ecosystem that makes human life possible] and statistics on green space in the UK,” said Tom Smith, director of the ONS’s data science campus.