People have also started to consider the impact of their diets, leading to a boom in plant-based meat and dairy companies. "That's not coming from an edict or a government policy requirement," says Peter Newell, a professor of international relations at the University of Sussex. "That's just businesses seeing that's where the market is shifting."
But these changes are too gradual for the emergency we are in, says Kenner: "We're going past climate tipping points and species are going extinct." The issue is about speed, and for that government action is necessary, he says.
Targeted taxes on unsustainable behaviours, such as frequent flying and the overconsumption of meat, could help shift people to low carbon behaviours more quickly, says Newell, especially if there is a direct link between punishing polluting behaviour and investments that benefit many.
For example, proceeds from a frequent flyer tax could be invested into a cheaper or even free public transport system, and money from a "mansion tax" could be put towards insulating houses, bringing down levels of fuel poverty. The problem, though, is if the richest can simply absorb these costs and continue as before.
A more radical idea is a personal carbon allowance (PCA), where individuals are allocated an equal, tradable carbon allowance. If people want to emit more, they must buy the unwanted allowances of others. Versions of a PCA have been explored in Ireland, France, and California. In 2018, the UK government analysed its feasibility but concluded that a PCA would be too expensive, difficult to administer and unlikely to be accepted socially.
But in the context of a climate emergency and a pandemic, which has forced people to accept individual restrictions in the name of collective gain, it may be a policy worth reconsidering, according to a recent analysis.
A PCA is appealing on one level, says Newell, "because it makes it really clear what our per capita entitlements are." But, he adds, "it's an extreme version of individualising responsibility." It could end up unjustly penalising people who, for example, live in areas with few public transport options.
Another policy idea that's gaining popularity is "choice editing", where governments restrict carbon-intensive products – like private jets or mega yachts – from coming to market in the first place. The idea is low-carbon options, many of which already exist, will fill the gap.
Choice editing may sound radical but it's not new, says Akenji. The UK government, for example, uses choice editing on public safety grounds to ban the sale of guns or cars with no seatbelts. "Undoing unsustainable behaviours is a whole lot harder than preventing unsustainable products from coming to market in the first place," concluded an April report on behaviour change co-authored by Newell.
But even as time runs out for tackling climate change, many governments baulk at behaviour-change policies fearing they will be politically toxic to voters and unpalatable to the rich. The control that the wealthiest have over governments through lobbying and hefty donations gives them huge influence to dilute climate action and shape the choices available for everyone, says Kenner. "There's this other future, this alternative future, which is being denied on a daily basis," he says.