Solar is "offensively cheap"

 From The BBC

The world's solar power is crossing a threshold. A decade ago, it barely registered on a global scale, providing just 1% of the world's power. In 2026, it will almost certainly increase to 10% of power, and overtake nuclear, a mainstay of electricity since the late 1970s. [That's a compound growth rate of +-25% per annum.  At this growth rate, it will reach 12.5% in 2027 (assuming no growth this year because of the Chinese slowdown), 15.6% in 2028, 19.5% in 2029, 24% by 2030.]

Globally, solar electricity generation quietly overtook nuclear power (just) in 2025, according to statistics from UK-based energy think tank Ember. And BBC analysis of Ember data over the past 12 months up to September 2026 shows it clearly outstripping nuclear, producing 13% more power.

"[Solar] generating more electricity than all the world's nuclear power plants is a pretty insane stat, for sure," says Dave Jones, co-founder of Ember.

From China's vast arrays to a recent solar upsurge driven by escalating oil prices, the incredible rise of solar power has defied all projections. Here are seven ways it has become an apparently "unstoppable force" – and what the future looks like from here.

1. An underestimated force

"Solar is now the engine of the power transition," says Jan Rosenow, a professor of energy and climate policy at the University of Oxford in the UK.

Solar has become the fastest-growing source of new electricity in history, and by far the largest source of new electricity globally. In 2025, it [i.e., excluding growth in wind and nuclear] met three-quarters of the growth in the world's demand for electricity, overtaking wind power generation (wind power is also growing, just a little more slowly).
That's where solar's going, to not just be king of electricity, but king of energy – Dave Jones

"It wasn't expected," says Rosenow. Mainstream projections, he says, have underestimated solar year after year. Outlooks such as those from the International Energy Agency (IEA), an influential intergovernmental organisation based in Paris, "assumed linear growth and slowly falling costs, and got both wrong".

Over 2026, multiple sources indicate solar electricity generation will almost certainly far exceed nuclear globally. Nuclear's electricity generation has remained more or less constant since 2000, while solar's has increased some 2,700-fold.

2. 'Offensively cheap'

Solar, a mature technology for some 15 years now, became the cheapest electricity in history in 2020. Since then, solar has scaled, efficiency has risen, and the amount of silicon and silver used in panels has gone down, leading prices to fall yet further, says Jones.

"Massive Chinese manufacturing scale and current overcapacity have pushed module prices to record lows," says Rosenow.

In particular, a large fall in the price of panels in 2023-24 pushed us into the current era of what Jones calls "offensively cheap" solar. "A panel in itself is just so unbelievably cheap," he says. "It's well under $100 (£75)… and that's going to keep you generating electricity for 30, 40 years without any input at all."

Of course, it's not just in purely economic terms that solar is bringing down costs. Researchers have calculated the US's rising wind and solar generation brought it $249bn (£186bn) in climate and health benefits between 2019 and 2022.

3. Global uptake

China is still the world's biggest solar power by far but is by no means the only player.

Despite the US imposing a variety of tariffs on solar, it remains the second country when it comes to installations, which are still skyrocketing – especially in states won by President Trump in 2024. In fact, the US now has enough solar to power more than one-third of its households.

"Tariffs and other federal policies that constrain renewable energy growth are certainly expected to raise costs and slow expansion relative to what we otherwise would have seen," says Alicia Zhao, an expert in US mitigation pathways at the University of Maryland.

"However, economics are a key part of why solar has been able to grow so quickly. Even with rising costs, solar is still one of the cheapest sources of new power in the US. And it is getting built regardless of political lines."

India, meanwhile, is moving away from fossil fuels far faster than China did, and new solar has met 60% of its rise in power demand in the past two years.

In Australia, over four million homes now have rooftop solar: well over a third of all households.

4. Unreliable fossil fuels

Countries like Pakistan and Lebanon have also begun installing solar at breakneck speeds, while across Africa countries are installing some 100,000 solar panels per day.

In many places, escalating diesel prices, driven by the Russia-Ukraine conflict and US-Israel war with Iran, has swung the cost needle yet further in solar's favour. This is especially the case in many African countries where home diesel generators are a mainstay due to unreliable grids. Rooftop solar panels, nearly all of them imported from China, have now taken off as an alternative.

Ethiopia has even banned the import of petrol and diesel cars in a bid to tackle oil dependency and pollution, says Jones.

Solar is also rapidly providing new electricity where fossil-based grids can't keep up with demand. Pakistan, for example, has become a surprising poster child for the solar revolution due to its extraordinarily rapid rise in installations. In 2019, solar provided less than 2% of its electricity; now it's 24%, driven by costly, unreliable grid electricity combined and cheap solar imports from China.

"What's really incredible in Pakistan is… generally most of the solar boom has been out of people's pockets," says Jones. "People can afford it, without needing to take out loans."

A similar story has been seen in several other "sun belt" countries, from Lebanon to Nigeria. "[Solar] lets households act without waiting for governments or utilities," says Rosenow. "In uncertain times, that speed and independence is extremely valuable."

5. Battery revolution

Solar power, of course, can only be produced during the day when the sun is shining. To turn it into electricity that can be dispatched at any time, it needs to be paired with batteries.

Fortunately, batteries have been having their own cost revolution, transforming their ability to support the solar rollout. "Solar plus storage is now routinely cheaper than new fossil plants in sunny regions," says Rosenow. "Batteries have largely solved the daily problem of shifting midday sun into the evening."

In California, for example, solar and batteries met on average over a quarter of electricity demand from 19:00-21:00 (the evening peak) over the first half of 2026. US states such as Vermont are now rolling out grid-integrated systems of home batteries, often paired with solar.

Barriers still remain for longer-term storage of solar across seasons, cloudy periods and monsoon seasons, though, both Rosenow and Jones say. It means the integration of solar into the wider electricity system still matters, says Rosenow.

6. Electrify everything

Solar is seen as a key part of the push towards electrification, reducing fossil fuel use in areas that previously didn't use electricity, such as via electric cars. Electrification has been chosen as a major theme at this year's UN climate talks in Turkey.

"That's where solar's going, to not just be king of electricity, but king of energy," says Jones.

 

7. Expanding tech

In the past few years, plug-in panels (or "balcony solar"), have started spreading rapidly in Germany. These generate less electricity than rooftop panels [because they're smaller, not because they're a different kind of panel] but feed it directly into homes via a standard socket.

They have now been approved in several other countries and US states including California. [Still under review by governments in Australia, where officialdom is so s-l-o-w.]

Meanwhile, agrivoltaics, which combines food production and solar panels, is being touted as a solution to concerns in some areas about the land use of solar.

Other technologies from floating and "mirror" solar plants to perovskite panels and solar windows could all see growth in coming years.

 

What's next for solar

In 2026, the world's solar capacity will go on rising, but the rate of expansion may slow down for the first time ever, says Jones.

This is down to China: last summer, it changed its regime for managing and supporting new solar installations, leading to a burst of installations in 2025 to fall under the old price regime. Elsewhere, it's a different picture. "If you exclude China, there's more panels being installed this year than last year," says Jones.

By 2030, the IEA thinks solar power generation will have reached double that of 2025's levels, [my forecast is 25%, see above] with solar overtaking hydro to become the world's third-largest electricity source.

"Wherever grid power is costly and unreliable, the economics keep pulling people towards solar," says Rosenow. "There is one caveat: if Chinese solar panels are difficult to import this will not happen at speed."

There has been a lot of bad news about the climate recently. It's now incredibly likely the 1.5C global limit set in Paris in 2015 will be breached, the world is seeing rising climate impacts and is edging towards several climate tipping points this century.

But the solar success story shows we are also making progress in ways that were never anticipated. A decade ago, "no one was getting close to expecting that to happen", says Jones, noting that the growth in clean electricity has directly translated to fewer coal plants being built.

"Now, worst cases [of climate change] are somewhere between 2-3C of warming, rather than 4C of warming."  [Still not good enough.  But the acceleration of solar and EV takeup is likely to reduce that forecast.]

The Earth is heating up faster

 From the BBC

The fossil fuels that we've been burning for more than a century produce two very different kinds of pollution. As is well known, carbon dioxide warms the Earth. But less well-known is sulphur pollution, which forms vast numbers of tiny particles in the air and reflects sunlight back into space, partly counteracting the warming effect of carbon.

Thanks to clean-air policies around the world - like the US's Acid Rain Program in the early 1990s, that reduced gas pollution from power plants - sulphur emissions are falling sharply while carbon dioxide emissions remain near record highs. 

Scientists increasingly believe the loss of that cooling effect is slightly  [more than slightly — increasing it by 50%!] speeding up global warming. 

The past three years were the three warmest ever recorded, and the Met Office says 2027 is "very likely" to replace 2024 as the warmest year on record.

Is it possible that our planet is actually more sensitive to greenhouse gases than we imagined?

And if so, might the climate be changing more rapidly than we feared? 

Global temperatures jump around naturally from year to year. El Niño, for example, a natural warming of the Pacific Ocean, can temporarily push them higher. So a run of record hot years does not necessarily mean the underlying rate of global warming has increased.

Reto Knutti and his team at ETH Zurich have tried to strip out the effects of El Niño and other natural fluctuations to reveal the underlying trend. 

"It's pretty clear that the rate of warming has accelerated," says Knutti, a professor of climate physics at the Swiss university and a former co-ordinating lead author for the IPCC - the UN-backed body that produces the world's most authoritative assessments of climate science. 

A separate study published this year reached a similar conclusion after accounting for several major natural influences. 

And it seems aerosols are playing a role. 

Burning coal and oil releases sulphur dioxide, which forms tiny particles known as sulphate aerosols. These particles are bright and reflect some sunlight before it can reach and warm the planet's surface.

Pollution from ships can create bright trails through clouds, visible from space
Source:NASA

You've probably heard the greenhouse analogy used to explain global warming. Gases like carbon dioxide make it harder for heat to escape from the Earth, rather like the glass windows of a greenhouse.

Well, sulphur pollution acts a bit like dust on the greenhouse windows. The more dust that gathers on those windows, the less sunlight gets inside, and the slower the greenhouse heats up in the first place.

Dr Øivind Hodnebrog, a principal researcher at Cicero, the Norwegian climate research institute, has studied how falling aerosol pollution affects the climate. "Sulphate aerosols, they are really small particles, but they are bright particles," he says.

As well as reflecting sunlight, aerosols also cool the planet by changing the formation of clouds. Aerosols act like tiny seeds around which water vapour can condense, making some clouds brighter or longer-lived. Pollution from ships can even create bright trails through marine clouds visible from space. So more aerosols mean brighter clouds and more reflection, and so less warming.

But sulphur pollution also damages human health (it can get into our lungs and make it harder to breathe), and causes acid rain, which can destroy forests and kill fish - and so countries have spent decades cutting it. Emissions have fallen sharply in Europe, North America and China, while new rules have also reduced sulphur pollution from shipping.

In our greenhouse analogy, it's as if we've wiped some of the dust away from the windows of the greenhouse, allowing in more sunlight.

And while carbon dioxide remains in the climate system for centuries, sulphate aerosols survive in the atmosphere for just days or weeks. So when sulphur emissions fall, their cooling effect disappears almost immediately.

The effect is strongest where sulphur pollution has fallen fastest. One study estimates it has added around half a degree to summer warming in western-central Europe since 1980.

Prof Piers Forster, a climate scientist at the University of Leeds and another senior author of the IPCC's most recent assessment, estimates that declining aerosol pollution may now be adding around 0.05C to 0.1C of warming per decade [to the existing 0.2C per decade].

But aerosols can only explain part of the recent acceleration in warming. Greenhouse gases remain much more important.

Forster estimates they are currently adding around 0.2C of warming globally per decade. "It is a very significant contribution," he says of the aerosol effect, "but it is not as important as the greenhouse gas contribution by quite a long way."

"The aerosols have masked some of the greenhouse gas warming from earlier," is how Hodnebrog explains it.

"Masked" - that's an interesting word he uses. What he means is cleaner air is not causing the underlying warming; it is removing some of the cooling that had been holding that warming back.

So if cleaner air is only responsible for part of the recent acceleration in global warming, what else is at work?

To see what else might be going on, scientists zoom out and look at the Earth as a whole: how much energy it absorbs from the Sun, and how much heat it loses back into space. Scientists call the difference Earth's energy imbalance.

Cleaner air is part of that picture. Fewer sulphate particles mean less sunlight is reflected away - in our greenhouse analogy, the windows are cleaner.

For a long time, the Earth has been absorbing more energy than it loses. That surplus is what warms the planet. And Knutti says that imbalance has roughly tripled over the past two decades - although the precise increase depends on which years are compared.

Greenhouse gases principally work by making it harder for heat to escape out into space. That's what we're all familiar with. But when you look at Earth's energy imbalance, you find that there's also more sunlight getting in (and therefore more heat that can be absorbed).

So what else might be letting more sunlight in?

Much of that change appears to involve something we have already encountered in this story: clouds. We saw how sulphur pollution can make some clouds brighter and longer-lived, reflecting more sunlight away. But global warming itself can also change clouds. As some parts of the ocean warm, low cloud cover can diminish. That matters because clouds are bright, while the ocean beneath them is dark. Remove some cloud and more sunlight reaches the sea, where much of it is absorbed as heat.

That can create a feedback: warming reduces some cloud cover, which allows more sunlight in, which produces still more warming.

And the oceans are certainly heating up. The World Meteorological Organization says the oceans have warmed more than twice as fast over the past two decades than they did between 1960 and 2005.

Dr Paulo Ceppi, a climate physicist at Imperial College London, says his research suggests this feedback loop between climate change and clouds is more important than sulphur pollution in explaining the recent decline in low clouds.

But there's still lots of uncertainty. Scientists say the impacts of cleaner air, natural variations and the effects of warming itself are all tangled together. And, when I asked Knutti how much of the cloud change came from each, his answer was simple: "We don't know."

And this is where the story takes an even more worrying turn.

That uncertainty matters because clouds are one of the hardest things to represent in the computer simulations scientists use to project future warming. Some models show more warming than others for the same amount of greenhouse gas emissions.

Scientists call this variability "climate sensitivity": how much the climate responds to gases like carbon dioxide.

And the recent observations give Knutti and his colleagues a new way to test those models. They found that models which best predicted the recent warming, as well as the rise in the Earth's energy imbalance, are also the ones with a more sensitive climate.

In other words, the models that predict more warming are looking like the most accurate.  His team's analysis suggests that the same emissions could produce about 25% more warming than we previously thought.

And a study published in the journal Science last year points in a similar direction. Models which projected relatively little warming struggled most to reproduce the observed rise in Earth's energy imbalance.

Under policies governments currently have in place, the world is estimated to be heading for around 2.8C of warming by the end of the century. Forster says that if this new evidence proves correct, the same broad emissions path could instead produce warming closer to 3.5C. 

It sounds serious - but there are important reasons for caution. [For climate scientists, yes.  For governments and the general population, no.  Because prudence suggests we assume the worst.  If that is wrong, we've reduced emissions faster than we were going to do anyway.  If it's right, we instead face climate and civilisational catastrophe.]  

Warming appears to have accelerated, but Forster says that does not mean it will keep doing so.

He points out that the recent observations that underpin these estimates cover a relatively short period.

"We have to be very cautious of how we go about interpreting observations that last for one or two decades," he says.

The satellite record is short, natural variations are large, and these new studies do not overturn previous estimates.

But still, some scientists are alarmed.

So - is cleaning up the air making global warming worse?

In one narrow sense, yes. Removing sulphate pollution takes away some of the cooling that had been counteracting greenhouse warming. That really has contributed to the recent acceleration. But cleaner air has not caused climate change.

The aerosol story may help explain part of that acceleration. But the wider evidence raises a more worrying possibility: that the climate responds more strongly to greenhouse gases than central estimates have assumed.

If that's correct, the same emissions could produce more warming than we expected. Climate risks increase with every fraction of a degree of warming, with the potential for more severe heatwaves, floods, droughts, and wildfires as temperatures rise.

Some of the science we have explored here is complex and important questions remain unresolved. But on the central point, the science is clear: the more greenhouse gases we emit, the warmer the planet will become.

And, if the climate really is more sensitive than previously thought, cutting emissions quickly becomes even more important.

See also: 

Significant acceleration of global heating since 2015

Global warming *has* accelerated

Sulphur dioxide decline adds to global heating

100s of climate scientists expect 2.5 degrees