BBC: To tackle climate change, many of us need to cut our carbon footprints. But what do truly low-carbon lifestyles look like?

According to the Intergovernmental Panel on Climate Change (IPCC), with the right policies, infrastructure and technology in place to enable changes to our lifestyles and behaviour, we can reduce overall greenhouse gas emissions substantially by 2050. The IPCC also says the world needs to reach net zero emissions with limited overshoot by 2050 to keep global warming below 1.5C.

In richer countries, this means moving towards a far lower carbon lifestyle for most people. But the changes to get there aren’t necessarily painful or even negative. For example, research has shown that good public services enable higher wellbeing at lower energy use.

One major change would be to change how we move around. Akenji envisions a combination of public transport alongside micro-mobility systems (such as electric scooters and drones) which make it efficient and effective for people to reach it. Private cars, with their huge emissions and often empty seats, would largely be a thing of the past, he says, and car parks converted to green public spaces where people go to play, relax or do exercise.

This high-quality public transport would be electrified and powered by renewable sources, says Gore. It would be complemented by cycling and walking and other forms of mobility that get people active – benefiting wellbeing and health too.

This would entail huge changes to urban planning in many places around the world which are designed for private cars, notes Gore. It could also mean a comeback for local high streets and markets where people could shop on foot or by bicycle. There would also be a substantial reduction in flying, he adds, with longer distance travel provided instead by the expansion of high-speed rail and night train services. (Read more about what a flying-free world would look like.)

Housing, meanwhile, is among the lowest hanging fruit for cutting carbon, says Gore, so huge changes would be quickly seen in a drive towards a two-tonne-per-person world, starting with a huge scale-up of energy efficiency renovations in homes. “We’d save every household money while lowering our emissions, and probably create a lot of jobs for people doing that renovation in the process, and add to the value of people’s housing assets,” says Gore. “It’s a no brainer.”

The International Energy Agency (IEA) has argued that well targeted public spending to support insulation and other kinds of energy efficiency could go a long way to cutting carbon. In her effort to live on one tonne of carbon a year, Readhead realised that turning on her gas boiler for just 45 minutes ate up her entire daily budget of carbon. When she later installed secondary glazing on her windows, however, she found she hardly had to put the heating on at all.

Thinking of hot weather, meanwhile, all new homes would be also redesigned allow good level of comfort in warm places and minimise their air conditioning requirements, says Lucas Chancel, an economist at the Paris School of Economics.

Another large-scale change in a two-tonne world would be to our diets – especially moving to plant-based diets, says Julia Steinberger, professor of ecological economics at the University of Lausanne in Switzerland. “These are often cheaper as well. They require a bit of experimentation and a learning curve – cooking based on lentils, beans, tofu and other forms of plant protein, rather than meat or dairy – but are achievable by all.” (Read more about the lowest carbon sources of protein).

Meat and dairy products would be seen more as a luxury or a special occasion treat rather than something you would eat two or three times a day, says Gore.

A major 2019 report looking at the “planetary health diet” aimed to set out the optimal diet for balancing both healthy people and the planet. It recommended meals should consist of around half a plate of fruit vegetables and plenty of legumes and nuts. Vegan and vegetarian diets can help meet these requirements, it said, but some meat and dairy can still be incorporated.

Diet is also a particularly personal thing for people. In her two-tonne experiment, Mainprize, already a vegetarian, found cutting out milk and cheese fairly doable. In contrast, Readhead found herself struggling to completely abolish meat from her diet, especially through the colder winter months when she did eat the odd meal with lower carbon meats, such as chicken and venison.

And then there are our other types of consumption. “[A low-carbon world] is a world where overall we consume less of ‘stuff’,” says Chancel. We might consume more cultural experiences (think festivals, theatre trips or dance classes), but “in terms of stuff, whatever has a weight, whatever is produced with matter and with energy, we consume less of that”, he says.

This is not some plan to get rid of all our electronics and clothes, but it is a world where their production is based on renewable electricity not fossil fuels, where better quality, longer lasting products rule and where we simply buy fewer of them. It also means a far higher focus on repairability and recycling, says Gore – rather than buying a new phone every year or so.