A map showing legislation for balcony solar in each US state, with around half moving forward with it. Plug-in solar should be available in the UK by the end of the summer if all goes to plan, and will bring solar power within reach for millions of renters and low income households.

The culture warriors hate it, but London’s commitment to reducing air pollution under mayor Sadiq Khan has yielded a 40% drop in pollution related deaths.

Swedish railway operators have been painting the rails white to make them more reflective and reduce the risk of buckling during heatwaves.

Scientists and meteorologists, fired by the tens of thousands by the Trump administration, have rebuilt the Climate.gov website that their government deleted. They’re carrying on their work at Climate.us.

It’s been a very busy end of term round here. Lots of school visits to fit in, and I’m finishing the next draft of a children’s book, so not much time for the blog of late. It will likely remain fairly quiet over the summer, but I’m still here…

Recent highlights

• Inequality and the planetary boundaries
• Book review: We need to tax billionaires, by Gabriel Zucman
• The changing colours of the energy transition

A study in Nature offers this useful visual summary of the planetary boundaries, divided into deciles. In the case of climate change, the red segment below, we see that the richest 10% are responsible for 43% of carbon emissions.

The pattern repeats with the richest responsible of 23% of damage from land use change, 24% of nitrogen and phosphorus pollution. For biodiversity loss the share is 37%, and water use at 18%. All of these, you will notice, breach the safe limit, which is marked by the red line near the centre of the graph. It’s even worse if you split the top 1%.

At the other end of the economic ladder, the poorest decile are responsible for relatively and are within the safe thresholds on all six measures here.

“Our analysis reveals extreme inequality in environmental footprints,” write the researchers, “highlighting the disproportionate responsibility of affluent groups in both developed and developing countries.” A reminder then, that while environmental action needs everyone, the need to reduce consumption applies first and foremost to the richest.

This was the year that we saw the world’s first trillionaire, a state of imbalance so absurd that it really ought to rewrite how we talk about inequality. I don’t see any sign of that yet, but this book might have one practical and popular answer: tax billionaires.

An important thing to note here: first, this is a call to tax billionaires, not the rich more generally. Those who would be affected are a tiny fraction of one percent of citizens, and there is nothing to fear for the rest of us mere mortals. If governments don’t do it, we will all know why and it will only reinforce the case for the next government to do it.

Neither is it an argument to take more from billionaires than from everyone else. As the book points out, most people pay somewhere near the average level of tax, until we get to the very top. Then the rules go out the window, and billionaires pay less than everyone else. In France, the average tax level is around 50% of income. Billionaires pay half that, despite fair and proportional taxation being written into the constitution.

The book explains some of the reasons why billionaires are so hard to tax. One of the main reasons is that billionaires pay very little income tax, and corporation taxes don’t make up the shortfall. Where most of us get our money through earnings, billionaires accrue wealth through ownership. They can easily funnel assets and dividends through holding companies, often offshore, allowing very rich people to claim that they actually earned very little. The Bezos, while remaining a billionaire throughout, has been known to file so little taxable income that he has received child tax credits. To stop that kind of nonsense, we need wealth taxes instead of income taxes.

Taxing billionaires fairly isn’t a punishment. Nor is it the politics of envy, though no doubt the think-tanks will dutifully say it is. To Zucman, it’s a matter of completing the “unfinished revolution” of income taxation. It would take away an unfair advantage that drives the gap between rich and poor – the less tax you pay, the easier it is to accumulate wealth. And it would help to reduce the deficit, because billionaires’ contribution to government revenues is currently miniscule.

Wealth taxes haven’t always been successful in the past, and the last sections of the book look at examples that we can learn from. Tax rules in some countries are better than others, and we can identify best practice that would make it harder for people to squirrel their fortunes away. There are loopholes that have scuppered previous efforts to tax billionaires, and we know to avoid them this time. Zucman’s favoured solution is a global minimum tax on billionaire wealth, and he sets out how it might work.

Gabriel Zucman is a professor at the Paris School of Economics, and so the main arguments in the book are made from a French context, with comparisons to other countries along the way. Unfortunately the UK doesn’t feature at all, as it hasn’t been possible to replicate the research into billionaire taxation that underpins Zucman’s work. That is telling in itself, of course.

We Need to Tax Billionaires is short and to the point, making its case in 96 pages and we’re done. (This is a mercy – I can think of notable books by French economists that weigh in at ten times that.) It’s got one central idea, and the prospect of having to tax trillionaires now should sharpen political resolve to get it done.

• We Need to Tax Billionaires is available from Earthbound Books

Belgium is the first country to appoint a Chief Planetary Officer, a role “designed to bring Planetary Boundaries science directly into national decision-making, helping governments assess planetary risk across policy, budgets, infrastructure, finance, and national security planning.”

Following last week’s story about climate and dentistry, here’s a nicely presented Grist article on the various ways that climate change affects human health.

With heatwaves getting drawn into the culture wars this summer, a World Weather Attribution study found that “a similar heatwave in June would have been about 3.5°C cooler during the day in 1976 and about 2°C cooler in 2003”, because of the effect of climate change. They also remind us that “heatwaves cause more deaths in Europe than all other natural hazards combined”.

Polestar, almost certainly the world’s most sustainable car manufacturer, has been banned from selling cars in the US. It will close its factories in the US and focus on sales in Europe.

Recent highlights

• What happened to Britain’s window shades?
• Book review: Heatwave, by John L William
• How Frontier Markets empowers women traders

Frontier Markets is a social commerce platform designed to connect businesses with customers in rural India, through a network of women entrepreneurs that they call Sahelis. These women run shops or small businesses, and are equipped with a phone and sales system to connect farming families with a wide range of goods and services that they didn’t have access to before – from small scale solar to farming supplies, household appliances to insurance.

As the founder says, it’s “the first ever AI-enabled technology platform which was designed with, for and by rural women.” It’s a nice example of technology in service to those at the margins, and that understands the human role in the system. It doesn’t matter how good the tech is, it’s useless without the women in the villages and the relationship of trust that they have with their neighbours.

Ashden’s video puts them at the centre of the story too, and the award should help to boost their profile as Frontier Markets seeks to reach more of India’s 800 million citizens in rural villages.

It’s fifty years since the famous 1976 heatwave which broke records as the driest and hottest British summer of the 20th century. From a weather perspective it was a true freak occurrence, and it’s left a lasting legacy. Some of that is benign – lots of people have very happy memories of an ‘endless summer’. Less positively, it’s also a touchstone of climate denial in the UK. “I was there in 1976” has served as convenient shorthand to dismiss the idea of global warming, and a way of talking down to younger climate activists.

Both of those aspects have been on display in recent weeks as the anniversary coincides with another heatwave. The right wing press have trotted out a series of articles about how everyone had a wonderful time in 1976 and we should all calm down. Not bothering to check the facts, some have insisted that schools stayed open throughout. Nobody panicked, everyone was fine, and hydration hadn’t even been invented then.

Some of this is climate denial by implication. Some of it is starkly explicit, such as an editorial in the Daily Mail that somehow uses the heatwave as an excuse to go after the “climate cultists” and their “suicidal rush to net zero.”

Since I wasn’t there in 1976, I picked up a copy of Heatwave by historian John Williams (not my Dad), to get a bit more perspective on what really happened. It’s fair to say that not everyone was having a lovely time. There was water rationing, farming was devastated and the government had to appoint a Minister for Drought. There was a simmering threat of violence in some cities, and that summer saw race riots and murderous gang warfare. Racial minorities and the LGBTQ community are likely to remember the summer differently. Police call-outs for domestic violence spiked by 600 extra calls a day in London alone. A teenager with special needs was murdered at an overcrowded outdoor swimming pool and somehow no suspect was ever identified. The NHS struggled to cope with the heat itself and the rise in demand from heatstroke, heart attacks and other heat-related conditions.

So no, not everything was fine.

It is also true that a lot of people were experiencing a uniquely wonderful summer. Those most likely to be enjoying themselves were children and young people, who had more freedom at the time. The book has plenty of their stories too, as they’re out swimming or riding their bikes and meeting their friends. My favourite anecdote is an interviewee remembering how the sun melted the yellow lines on the roads, and children peeled it off and competed to see who could scrape up the most. “My ball of paint was the size of a football”, she claims.

That raises an interesting question about the age and background of newspaper columnists, and whose stories get told fifty years on. The prevailing story today is from those who were children in 1976. We hear far less from the adults who were dealing with pupils fainting in their classrooms, or nurses trying to keep vulnerable patients cool in overheated hospital wards. For those of us who weren’t there, I think it’s important to recognise that different stories can be told about the same event.

Standing back from individual perspectives of the heatwave, Williams’ book conveys a powerful sense of a changing culture. 1976 was a turning point for the UK. It was the year that Britain had to be bailed out by the IMF, leading to emergency austerity measures and paving the way for Margaret Thatcher and her economic reforms. It was a breakthrough year for a number of social movements, including the Trico strike for equal pay for women, and the Southall Youth Movement of young asians. In the counterculture, 1976 was also the year that punk emerged.

The book is actually more about these cultural shifts than anything else, with the heatwave serving as a backdrop to explorations of culture and politics. It’s written almost like a scrapbook or a collage, with short sections on items in the news or songs in the charts, interspersed with longer chapters on specific events or trends. There’s a chapter on sleaze cinema and the ‘confessions’ series, which sounds like the worst of 70s trash but usefully illustrates how norms have changed. Another chapter looks at Joan Armatrading and how she bucked the trend as a popular black singer-songwriter – someone I didn’t know much about and am listening to as I write. Williams, who was 15 at the time, writes about his fascination with Soul Boy fashion, the Entebbe raid, or the West Indies cricket tour. As a child of the Francophonie with very near zero interest in cricket, it’s a testament to his writing that I found this chapter rivetting.

As a book, Heatwave is an engaging piece of social history, a mosaic of stories from a specific and memorable summer. As an event, the summer of 1976 is a complicated story that we should neither romanticise nor catastrophise. And given how much has changed in that fifty years, I’m not sure glib comparisons between today’s heatwaves and that one are remotely useful. What matters is today is what we do and how we treat each other in our hotter world, where such events are going to be more frequent.

• Heatwave is available from Earthbound Books

I have no particular problem with air conditioning where it is really needed, especially if it’s paired with solar. But other solutions are available, and there’s a really obvious one that we have forgotten about in the UK.

Over half term we were in France, and it was hot. Most homes had ways of dealing with this, and I bored the family by pointing out shutters, roller blinds and awnings. Keeping the sun off your windows is entirely normal in France. I’ve seen similar things in the Netherlands and Belgium, which have a similar climate to us, but they are much rarer in the UK.

It was not always like this. Historic photos of city streets often feature awnings on the buildings. At the top of the post is a picture of Luton’s high street in the 1950s, with awnings outside all the shops. Not a single one of these remains. Shades were widely used on upper windows and on homes as well. Below is a picture taken in the garden of Buckingham Palace in 1897, with external window blinds pulled down on the lower floors. For American readers, check out the nifty awnings that used to be on the White House.

Awnings and blinds were particularly popular in the Victorian era, and adverts from the time offer a broad range of styles. They were a common feature, and there were catalogues and showrooms to browse.

Where did they go? They apparently fell out of fashion in the 20th century, and I haven’t found an entirely satisfactory explanation yet. I’ve read that it’s because of air conditioning, but that’s an American answer for the similar disappearance of their own awnings and blinds.

AC isn’t common in homes in the UK, and so it can’t explain the absence of blinds on domestic buildings, though it might be true of offices and shops. I wonder if it’s more to do with changing design preferences, and a modernist aesthetic that favoured straight lines and avoided decorative elements.

Another factor could be double glazing, which offers some protection against heat as well as cold. Awnings also protect wooden sash windows from the rain, which is less important when windows are mainly made from PVC.

Whatever the reason or combination of reasons, people didn’t just stop building homes with shade structures, they also removed existing ones. Architectural historians working for Historic England point out that the fittings for awnings and canopies and rain hoods can often be seen on heritage buildings even though the shades themselves have gone.

We used to know how to stop our homes from overheating, by keeping direct sun off the glass. Then we forgot, and have become dependent on machines to remove the heat from the buildings when we could have prevented it from entering in the first place. Before we reach for the more expensive technofix of air conditioning, maybe it’s time we rediscovered window shades.

For a nice example, see the Shellhusen building in Copenhagen. It was designed with shade canopies in 1951. They went out of fashion and were removed, and then they were restored in 2022 and look fantastic. More of this sort of thing, yes?

That has risks of its own of course. It can tip towards coercion or get derailed by perverse incentives. And it has the opposite problem to western environmentalism: where we might rely too much on individual actions that don’t add up to systemic change, a top-down approach can focus on infrastructure and systems and forget to involve ordinary citizens. So it’s interesting to see a raft of new measures from the Chinese government this year that aim to influence consumer choices.

China’s Ministry of Commerce, in concert with eight other government departments, has set out a nationwide strategy to encourage greener consumption. It aims to support more sustainable businesses, build the circular economy, and raise environmental standards across the board.

I won’t detail all of the measures, but there are some interesting points to note across the strategy. One is a boost to organic food and more sustainable farming practices, using new certification programmes and consumer-facing logos. There’s also a provision for certifying geographical origins, like France pioneered with its ‘appellation d’origine contrôlée’. (France declared its first protected origin in 1411, a full 582 years before the UK, which tells you a lot about national food cultures). China is also looking at carbon labelling and energy efficiency stickers, empowering consumers to make educated purchasing decisions.

The strategy also looks at waste, recycling and single use plastics. There will be new rules on plastic bags, and investment in a wider set of materials for recycling, such as e-waste and textiles. This is an opportunity to create circular economy businesses, and new forms of ‘reverse logistics’ that take things back for reuse.

Something I’ve not seen elsewhere is a focus on secondhand goods as part of a sustainable consumer culture. Detail is scant at the moment, certainly in English, but there is talk of support for online and in-person secondhand markets, formally recognising it as a key plank in a circular economy. A healthy secondhand market for electric cars is also mentioned, ensuring that there’s a full ecosystem for EVs and that those on lower incomes are able to participate.

There are sections of the strategy that target specific sectors too, such as hospitality. Caterers will have to get to grips with new rules on food waste and biodegradeable packaging. Hotels are encouraged to use environmentally friendly cleaning products, eliminate single use plastics and install water saving technologies. Procurement guidelines – an under-appreciated aspect of environmental action – are pressed into service to bring transparency to supply chains and encourage carbon footprint evaluations.

I can’t find much on this yet either, but it looks like some of this will be ‘gamified’ through a credit system rather than a set of bans or taxes. People will earn credits when making greener choices, and then cash those in for discounts. That’s an interesting approach, and introducing a scheme like that with government backing could be a powerful incentive.

We’ll have to wait for more information about the specifics of all of this, but it’s an impressively broad and comprehensive agenda. If it goes to plan, it could take China a big step closer to the ecological civilisation that they aspire to be.

In a striking example of how climate harm spins out in unexpected directions, a dentist in Pakistan writes about prolonged outdoor working in extreme heat destroys people’s teeth. He describes it as “environmental collapse writing itself directly into human biological systems”. One of his patients puts it more directly, saying that climate change is “here, right now, in my mouth.”

Social media has become the biggest source of news for the first time, according to the Reuters Institute’s annual report. I thought that had happened already, but TV news and news websites had been ahead until 2025.

Are hot schools putting pupils and teachers at risk? My wife Louise, the proper journalist in the house, writes about school overheating for the BBC.

Let’s Go Zero, the schools campaign I work on with Ashden, has released its impact report for 2026. With over 9,000 schools signed up, it’s now the biggest schools climate campaign in the UK.

Recent highlights

• The changing colours of the energy transition
• Price parity for EVs has arrived
• Why buildings overheat

The big story is of course the global transition to clean electricity. If we were able to fast-forward, we’d be able to watch the colours change. Brown and red would blink out as countries move away from burning coal and oil for electricity. Some of them will switch to gas instead, so the orange areas of the map will shift and then erode. More and more yellow and teal will appear as renewable energy accelerates. The UK is likely to be wind-powered teal the next time this image is compliled. Large parts of the map, especially in the global south, will turn yellow.

We have forerunners already, and this is where we get the smaller individual stories. Take Lithuania, which had historically run on nuclear power. When it closed its aging Soviet plant in 2009, it switched almost wholesale to gas. That’s proven to be a major liability, and Lithuania has led the way in reducing Europe’s damaging dependence on Russian gas. It built wind turbines and solar power, and in 2022 became the first EU country to stop buying gas from Russia.

Uruguay is another country to flip colours recently. Like much of South America it has been largely hydro-powered, but is experiencing more frequent periods of drought due to climate change. When this happens they have to turn to more expensive energy imports, and so wind power is a form of climate adaptation in Uruguay. It’s an unusual example of a country transitioning from one form of low carbon energy to another.

Chile is also diversifying its energy mix to make it more resilient to droughts, and in their case it is solar that dominates, with hydropower providing the baseload.

Another country in yellow on the map is Spain, although it has very nearly equal amounts of wind, nuclear and gas. True solar states will emerge, with Pakistan moving fastest towards it. From less than 1% a decade ago, solar power has grown to 19% in record time. It’s overtaken coal as a power source and hydropower and gas are next.

Pakistan has been hailed as the fastest solar transition in the world and I’ve written about that myself. There’s another country with a less noted but similarly steep upward trajectory. That’s Hungary. It had ticked along with Russian gas, oil and nuclear fuel during the Orban rule. It is now building solar at a formidable rate, with solar power rising from almost nothing to 27% of energy generation in ten years. Not everyone will match that pace, but it shows how fast things can change when a solar boom takes off. Looking at the trend curves, it’s likely that even big coal users like Australia or Turkey will be yellow on this map in ten years’ time.

There are many more such stories. There will also be stories of laggards and obstruction, places where cheap fossil fuels delay the rise of renewable energy or where grid infrastructure fails. Other energy stories are in play as well as renewable energy, such as gas in Africa. Overall however, a huge shift is underway, another industrial revolution in how we generate energy.

With so many to be getting on with, does the world need another ‘ism’ to fret about? It’s a question I asked myself on first encountering Paul Dolan‘s book, but the definition won me over. Beliefism is prejudice against people you disagree with, and if you live in the same world that I do, that might sound very familar.

In fact, some of the people who are most passionately against other ‘isms’ are most likely to be beliefist, ready to judge, avoid or act with hostility towards others based on their beliefs. There is a tendency in certain circles to write a person off on one aspect of their views. If they think the ‘wrong’ thing on one hot-button topic we care about, that can spill over into the assumption that nothing else they have to say could possibly be relevant.

This is a form of prejudice and should be resisted, argues Dolan, a professor of behavioural science at the London School of Economics. Unlike some other forms of prejudice, a certain amount of beliefism is useful – there are views that we should not tolerate or entertain. But we should be wary of reducing people to simple binaries and refusing to engage with them if they’re on a different side.

Unfortunately there is a natural human tendency to do exactly that. We like mental categories we can place people and ideas into to avoid thinking about them any more than necessary. We flock together like those proverbial birds, forming in-groups and out-groups. That much is normal, but the internet and its algorithms have accelerated this effect, pushing people into bubbles and exaggerating difference. The anonymity of the internet makes it easier to push back in ways that we wouldn’t do in person, making us less likely to listen or to challenge our own opinions.

Dolan draws on his own research and that of others to explore which topics have the biggest divides and are most likely to trigger beliefist responses. You probably don’t need me to name any, but in the UK Brexit is a relatively new entry alongside political pot-boilers such as immigration or illegal drugs. There is evidence of increasing “partisan sorting” in friendship groups, dating, and where people choose to live, all reducing the sorts of interactions that erode prejudice. The world ends up divided between people who see a duck in the image on the book’s cover, and people who see a rabbit, and nobody can even begin to understand anyone who sees it differently.

Healthy societies need this kind of interaction however, and need a diversity of views. The lifeblood of democracy is debate, a back and forth exchange of ideas and a negotiation between them. And we’re also missing out on more diverse friendships, Dolan argues. Surely we ought to choose our friends on attributes like kindness, generosity or sense of humour, rather than which way they voted in a referendum or where they stand on veganism, gay marriage or Coldplay.

Dolan is open about his own views, and uses himself as an example throughout the book – as an academic from a working class background, he’s not easily pigeon-holed. Refreshingly, he insists that he’s not out to police opinion or change anyone’s mind about anything. Rather, his focus is on how we disagree without disdain.

This is an important distinction. Political polarisation is rooted in disagreement over policy. The hatred and hostility that seems so prevalent at the moment is separate: not about the disagreement per se, but an emotional reaction to it. This matters because it suggests that we can lower the temperature without forcing everyone to agree, and the book offers a variety of techniques for doing that, including humour, seeking common ground, and the simple practice of spending time with people with opposing views.

Beliefism doesn’t get into some of the other forces at work in our polarised world, and there’s no analysis of the media landscape or the way that rage is provoked for profit by the tech giants. It’s a short book to present a straightforward idea, and it’s very readable and at times very funny. Whether or not the word beliefism catches on, we’d all be better people if we were more alert to the way that we treat people with different opinions.

• Beliefism is available from Earthbound Books

I will admit to a moment of hesitation. I was already stressed by the delays, and I didn’t want to let my colleague down by turning up late. I didn’t need the extra hassle of dealing with someone’s net zero cynicism, or having to defend the value of my job. I also knew I shouldn’t be judging the driver or assuming anything about his views, and that his honest curiosity deserved an straight answer.

I told him I worked for a climate campaign and was there to do a sustainability audit, and there was no roll of the eyes in the rear view mirror. Instead he told me enthusiastically about the solar panels he had installed on his house, how his daughter had come back from university and convinced him he should do it. As we pulled up to the school, he wished me well and discounted the fare.

It was a good reminder to me that stereotypes are lazy, and while we can’t prevent our brains from presenting us with cognitive shortcuts, we can and should resist them and treat people as individuals. Even West Ham fans.

It was also a good example of how important it is that people see the benefits of the clean energy transition for themselves. My driver had got his solar panels for free through an energy company scheme, and had saved thousands of pounds over the last decade. He didn’t need any convincing that renewable energy was a good idea, because he could see it working for him every day.

Unsurprisingly, people are more supportive of climate action when they will benefit from it, as polling from YouGov shows:

41% of people still support climate action even if it makes them worse off, which is higher than one might expect. But ideally we’d want to show as many people as possible that a sustainable future will be better for them, and it deserves their wholehearted support.

Environmentalism is too often framed around bans and taking away things that people like. Indeed, this same YouGov poll makes that mistake and goes on to ask people if they support banning meat, petrol cars and flying on holiday. Thanks YouGov. In reality the cheapest form of energy generation in the UK is onshore wind, with solar right behind it. Research from Auto Trader shows that the average electric car driver saves £980 a year. Done well, environmental policy can address the cost of living crisis, helping to reduce poverty and inequality.

Conversely, the climate crisis is a major driver of rising prices – particularly of food, but also in more indirect ways such as rising insurance premiums

This should be an easy sell, but we find ourselves in a strange place in the UK. People are struggling with higher energy bills, and yet the party doing best in political polling at the moment wants to ban the cheapest forms of energy generation. Likewise in Trump’s America, where hundreds of millions of dollars of taxpayer funding is going to suppressing cheap renewable energy and keeping the fossil fuel fires burning.

The Climate and Community Institute (CCI) is a US think-tank that argues for a ‘working class climate agenda‘ as the best reponse to this problem. Past climate initiatives in the US didn’t deliver tangible benefits fast enough to outlast the electoral cycle, and now they have been scrapped before they had a chance to prove their effectiveness. There’s a very real risk of the same thing happening in the UK. If the Reform party get into government, they have pledged to scrap the country’s climate policies and renewable energy strategy. So there’s an urgent need to demonstrate the worth of climate policy, and end the idea that it’s a middle class concern.

What sort of thing might that involve?

The CCI suggest that it would need measures that are delivered fast, that prioritise the public sector, and that shape flows of investment towards things that matter to ordinary people.

Practically, that could mean focusing on social housing, ensuring that those households are first in line for energy saving retrofits, solar and batteries. Bus travel is another natural priority, improving services and making them more affordable – or even free where possible. For those who can’t use buses or live in rural areas, charging infrastructure and help to buy electric cars can bring cleaner mobility there too.

To direct more funding towards the green economy, governments can use their procurement power and work with their supply chains to raise environmental standards. They can use government owned land and property to create green jobs in retrofit or in land restoration. Publicly owned banks and companies are a useful vehicle for raising investment too, as the UK is doing with Great British Energy.

These aren’t new ideas of course, but it’s useful to see them articulated really clearly for an American context. There’s no lack of real world examples in CCI’s paper either, with Zohran Mamdani’s priorities as mayor of New York perhaps the most high profile.

In the UK, I think the government is well aware of the need to demonstrate the value of climate policy for ordinary citizens, and this agenda is well understood. The question now is whether it can deliver on the first of CCI’s points, and act fast enough to beat the electoral cycle.