Trees: London would need 1,330 more Hyde Parks 'full of trees' to combat its carbon emissions

The city of London, for all of its abundant parks, commons, and urban woods, would need 1,330 more areas the size of Hyde Park filled with trees to cancel out its annual carbon emissions, new mapping suggests.

How we eat, move about, and power and heat our homes is releasing more greenhouse gases like carbon dioxide (CO2) into the atmosphere than natural processes can remove. The world has just experienced its warmest year on record, but scientists already fear 2024 could be even hotter, and have been urging world government to clamp down on carbon emissions - particularly those created by burning fossil fuels - while there is still time to limit warming.

Swiss geospatial AI platform Picterra has analysed just how many extra trees 26 of the world's biggest and best known cities would need to neutralise their carbon footprint. The company used its technology to visualise each city's existing tree coverage, before analysing external data to estimate their CO2 emissions - and the number of trees and the amount of space it estimates would be required to offset them.

According to its calculations, London would need to make room for another 1,330 Hyde Parks (more than 465,000 acres) filled with trees planted to Woodland Trust tree density guidelines to neutralise its carbon footprint. That was a total of over 301 million trees - or an average of 30 per person.

However, of the 26 cities analysed, London was pretty far down the list when it came to who needed the most trees, at 17th. Meanwhile, New York, home to one of the most visited city parks worldwide, came fifth in the rankings, needing the equivalent of 1,304 Central Parks to counteract its emissions.

Tokyo came in first, emitting a whopping 320 million tonnes of CO2 every year. The Japanese capital would have to plant over 2 billion trees, which would require a total of 3.1 million acres of land. In second place was Beijing, followed by Moscow, Seoul, and New York, to round out the top five. On the opposite end of the scale, Rotterdam demanded the fewest trees to neutralise its approximate 7.9 million tonnes of emissions, with 49.5 million trees and 76,000 acres required.

Dubai, the United Arab Emirates' 'city of gold' famed for its modern skyscrapers surrounded by desert, came in tenth place overall. However, it fared the worst for the number of trees required per person to offset its CO2 levels, at an estimated 130.5 trees for every single resident. 

Picterra's chief operating officer, Frank de Morsier, said the company aimed to use its AI software to make a positive and meaningful impact on the planet. "That’s why we have used our geospatial AI tool to visualise the number of trees there currently are in each city’s centre, giving a realistic view of the state of forestation in the cityscapes we know so well."

Stark differences were clearly evident. "While the analysis of existing data alongside these visualisations is simply an estimate of how many trees and acres are needed to neutralise carbon emissions, it serves to illuminate how deep of an issue current CO2 levels are," he continued.

“Planting trees remains one of the most effective ways to temper carbon emissions - though, as this analysis shows, this would need to be on an extreme scale to make progress towards neutrality.”