(This interview has been lightly edited)

Extreme urban heat impacts everything from sleep and mental health to daily wage-earning, especially in the Global South. From a development perspective, how should governments measure these invisible human costs, and how can we frame liveable, cooler cities as a basic health right rather than a luxury?

In many groups of countries, people consider that not working when it’s very hot is a luxury; it is not something that you should do. I think it is high time that we take heat into account. The first step would be to measure it properly. In India, for example, heat waves are not considered one of the major climatic disasters. Recognising that and organising what happens when it is hot would be good.

The problem is that [measuring its impact] is difficult because you want to compare unusually hot days to others, and that is hard to do properly [isolating heat from other causes of death requires complex statistical baselines]. That is why in my work I went backwards and looked at digits of data, comparing all of the different places in India to see how bad it is for people’s health when it is hot. You do notice that there is a huge increase in mortality during episodes of hot weather. For the more regular effect that you mentioned, long measurements of temperature—including inside people’s houses and in people’s bodies [proving how unventilated homes trap heat overnight and strain human health]—will help make the point that a lot of people live in extremely unhealthy environments.

Even the very visible costs, like excess mortality, are hard to measure. I am not even sure if we need to measure the invisible costs on a daily basis; we just need to acknowledge that they are there. It might be sufficient to have retrospective studies on the number of hospitalisations for mental health crises, violence or suicide in hot moments versus not, and make a list of the types of things that happen. I don’t think we need to measure them on a day-to-day basis to address them once we know they are there.

Look at the catastrophic Himalayan flash floods that happened in late August this year along the Nepal, China and India border regions. This is an example of vulnerable mountain communities bearing the immediate, deadly cost of global climate disruption. In your FAIR framework, which calls for wealthy, high-emitting nations to pay an automatic global climate tax directly to affected populations, how quickly would automated compensation reach families and local governments in a crisis like this, where the effects of climate change crosses borders faster than humanitarian aid?

The FAIR framework has three pillars. Two of them are not really appropriate for a sudden catastrophe like the Tibet-Nepal disaster, but:

• Direct cash transfers when it is hot: Giving people more money when it is hot helps them cope with dealing with heat, but not with dealing with a disaster [example small, automatic mobile money payments during heatwaves so workers can afford to stop working during extreme temperatures, pay for cooling or buy hydration].
• Helping communities directly: Giving money to communities, not just when it is hot, but always, every year, as block grants [guaranteed annual funding sent directly to local towns based on their historical climate exposure or average climate risk] proportional to the damages they get on average so they can undertake protective measures. That would be helpful for many things such as [preemptively] building levees so the water does not take away their houses [during floods] or making sure water infrastructure functions, but it would not help the Tibet-Nepal catastrophe directly.
• Insurance at the government level: This is the pillar that is relevant here. Part of the money collected under the grand bargain [global agreement where rich nations pay into a climate fund to cover the damages caused by their emissions] would go into a pool to serve as insurance against weather disasters.

Why this would be helpful is because today, when there is a disaster like that in Nepal, Nepal has to start by taking their begging bowl and going to every other country to say, ‘Please give us money, we cannot deal with this.’ Depending on the country and the disaster, it can take a long time, and that is a delayed time. Having an automatic insurance mechanism means the government in question would immediately unlock damages as a function of how bad the event is. All of this would be paid for by rich countries paying for damages. Now, wealthy nations must establish a mechanism to generate the funds to pay their share. We (economists Adrien Bilal and Abhijit Banerjee) explore different avenues, and we think the most likely to actually work out is to have a tax system that is more fair, where the richest people in the world and the largest corporations get taxed fairly. We are proposing to enact what Brazil proposed, which is a 2% tax on global billionaires [during its G20 presidency in 2024], which would be enough to pay for most of this.

It is the only way that capitalism can work. What you have to realise is that today, everybody contributes to taxes except the rich. Today, the poor are subsidising the rich. It is not fair, and it is also not healthy.

You’ve spoken about climate change as a fundamental issue of global unfairness, where those who contributed the least bear the heaviest health burden. How can international climate finance move past top-down promises and actually deliver direct, verifiable relief to anybody affected?

So I think we need to move past the current framework, which is project-based. For example, India walked away from the Just Energy Transition Partnership [a global deal where wealthy nations fund a developing country’s shift from coal to clean energy]. They walked away from it because the long list of things that they had to do to get this money at some point in the future was not worth it.

We need to move away from that to a system where we put the [recipient] country in charge. Once they institute carbon pricing [a policy that charges polluters a fee for every ton of carbon they emit], the right incentives would be in place [businesses would naturally cut pollution to save money] and the financing would be automatic and unrelated to the effort [international aid would arrive automatically as fair compensation for climate damage, rather than as a conditional reward for meeting donor demands]. On the one hand, there is an effort [a developing nation’s own internal policy, like setting a carbon price]; on the other hand, the financing is for compensating for climate damages [international funds owed as fair repayment for harm caused by historical global pollution, rather than a conditional prize for good behaviour].

Everything would move fast. The entitlement would move fast because that is just calculated formally; there are no administrative hold-ups [payout amounts are set automatically by a mathematical formula rather than donor negotiations]. The use of funds would also move fast because it involves direct cash transfers to people, cash transfers to communities and payments to the insurance fund, which are all automatic and quick [money flows immediately through pre-set channels like mobile cash payments and town grants, bypassing government red tape].

It wouldn’t be that difficult to put together. The situation now is that every aspect of climate financing is so complex that it just doesn’t happen. The funds stay there for years and are not spent—and we don’t have that kind of time.

For journalists trying to tell compelling stories about planetary health without causing audience fatigue, what data points or human and human angles do you think are most overlooked?

It is a great question, but a difficult question because of what you said about avoiding audience fatigue while touching on overlooked angles. It depends a bit on where people are as well.

I think for people in Europe, two things could be new:

• The regular, day-to-day impacts: In Europe, the only way we engage with climate is either through what affects us directly (like the heatwave this summer) or major catastrophes. Once these things are gone, when it’s not hot anymore or a week after the catastrophe, we stop thinking about it. It would be useful to show the regular, day-to-day impacts and invisible costs that people experience every single day in the Global South.
• Showing that large-scale progress is feasible: People in Europe can feel jaded because they think nothing can be done. Showing that a lot can be done would help. For example, one could do a story about a coal-powered thermal plant in India and how it would be cheaper and cleaner to convert or replace it. You could recycle plastic bottles all your life—which is a good thing to do—but you’re not going to have the same impact as replacing that coal plant. If a business person had the right incentives, that is feasible, but right now the incentives are so screwy that they can’t do it. Stories like that show huge opportunities to make a drastic difference without people feeling like they have to change a life where they feel they’ve already done everything they could.

In Europe, there are two kinds of people and reaching both types is important:

• The engaged and anxious: People who are really engaged, very anxious and feel there is nothing more they can do. Individually, they already do everything feasible—they take the train, cycle and compost—but they feel it isn’t making a visible difference.
• The disengaged: People who say, ‘I don’t care, it’s not me anyways, and I just want to continue eating my barbecue and putting air conditioning in my house.’ But even those people probably know that if clean alternatives could be implemented elsewhere, it would be better.

Both kinds of people could be reached by stories about what can be done elsewhere, which is completely ignored because we have a very narrow-minded, navel-gazing tunnel vision.

The perspective of the Global South:

It is so much harder for people in the Global South who are just trying to survive day-to-day. They don’t have the bandwidth, the means or the time to think about climate change because they are so poor. And they contribute nothing to climate change, so they don’t need to change their behaviour. They need to live! In fact, if anything, they need to consume more energy because a lot of these people don’t even have electricity. There is absolutely no way the burden should be on them. That is why the FAIR framework puts a lot of emphasis on giving money to them—giving money to the poor (which costs a little, but makes no negative difference to emissions) and taking that money from the rich.