SINGAPORE: No fans. No snack stands. No tour buses or hotel bookings. To many, this year's Tokyo 2020 Olympics may seem like no fun. But to environmentalists, the pared down approach is exactly what's needed in a world confronting climate change.

Initially, the Tokyo Organising Committee had estimated the mega-event would result in emissions of some 2.73 million tonnes of planet-warming carbon dioxide – more than what the cities of Vancouver or Melbourne reported emitting in all of 2019.

But without the travelling crowds to feed, house and entertain, that carbon footprint will be cut by 12%, to about 2.4 million tonnes of CO2, the organisers said in a sustainability report this month.

Combined with efforts to reduce, reuse, and recycle, the committee hopes the Games will be among the greenest in recent history.

"The carbon footprint in Tokyo would have risen enormously" had fans been allowed in the stands, said sociologist John Karamichas at Queen's University in Northern Ireland, who has studied sustainability practices at the Olympics.

Organisers will publish final emissions figures after the Games.

Scientists consider it essential for the world to halve global emissions from 1990 levels by 2030, and to reach net-zero emissions by 2050, to avoid catastrophic climate change. The Tokyo Games will be a reminder of those targets, with forecasters warning of summer temperatures that are set to climb above 30 degrees Celsius (86 degrees Fahrenheit) as the Games begin.

While Tokyo's decision to bar spectators was aimed at minimising coronavirus risks, Karamichas said he hopes the Games sets a minimalist precedent that future Olympics follow.

"From an environmental perspective, there is a concept that small is beautiful," he said. "This is the direction we are moving in."

Researchers in April found that sustainability measures generally declined over 16 summer and winter Games held between 1992 and 2020, according to an analysis published in the journal Nature Sustainability.

Salt Lake City in 2002 ranked the best, while the 2016 Rio de Janeiro Olympics and the 2014 winter Games in Sochi ranked at the bottom.

The authors suggested downsizing the Olympics and rotating it between the same cities could make the Games more sustainable.

Rio had estimated its 2016 event would result in 3.6 million tonnes of CO2 emissions. Four years earlier at the London Olympics, sold-out arenas meant spectators accounted for a third of the 3.3 million tonnes of CO2 emitted, organisers said at the time.

Paris in 2017 pledged that the Games it hosts in 2024 will have less than half the carbon footprint of London 2012.

Tokyo is on track to reverse the rising emissions trend, and not just by keeping sports fans at bay.

The athletes' village is being powered by renewable energy sources instead of fossil fuels. Electric vehicles are shuttling people between venues, and materials recycled from discarded electronics have been used to fashion the coveted medals.

In addition, the Tokyo Organising Committee acquired carbon credits worth 5.1 million tonnes of CO2 from the Tokyo Metropolitan Government's and Saitama Prefecture's cap-and-trade emissions schemes, which fund emissions-reduction efforts at factories and public buildings in the country.

"The Games must be a space for promoting decarbonisation and sustainability," said Masako Konishi, a conservationist at WWF Japan and a member of the Tokyo Games sustainability committee.

"Otherwise, we are just adding to the pressure on the planet."