Global warming-fuelled heat and drought is already hitting yields of maize, wheat and soybeans to the tune of $20 billion a year, a study has estimated. This could rise eightfold, to more than $160 billion by 2100, unless we slash emissions.

While the financial losses will be greatest for big producers such as the US, the impacts will be felt most in the lowest-income countries, where ,��������� at the International Institute for Applied Systems Analysis (IIASA) in Austria. “If you look at the least-developed countries in Africa, the impact is much bigger.” This could lead to social unrest and increased migration, she warns.

There is great uncertainty about these kinds of projections, not least because so much depends on how farmers respond and adapt to a continually changing climate, for instance, by switching to different crops or adopting irrigation where it is possible. In fact, the whole point of this study is to raise awareness and encourage adaptation, to help ensure these projections turn out to be overestimates, says team member , also at IIASA. “This is the entire mission of climate scientists: we make these cases for people to react, so our projections turn out to be wrong.”

The researchers started by gathering data on the yields per country of maize, wheat and soya from the UN Food and Agriculture Organization (FAO). Next, they took past climate data and calculated the drought level, using a standard approach that estimates soil moisture levels from rainfall and evaporation levels.

Past heat extremes and drought levels were then compared with the yields from 1974 to 2004 to estimate the impact of heat and drought. They then used these statistical correlations to estimate crop losses from 2007 to 2019. Their results suggest that increases in heat extremes and drought have caused a 3.5 per cent decline in yields relative to the 1974 to 2004 baseline. “Three per cent or so might not sound like much, but this is a major impact [on] the global food market, which regionally can trigger a severe crisis,” says Kornhuber.

The researchers then calculated the economic losses, based on FAO data showing how much farmers would have been paid for their produce at the time. Finally, they used the same approach to project future losses in several different emissions scenarios, assuming that some adaptation takes place.

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In a high-emissions scenario, known as SSP3-7.0, global yields will fall by around 35 per cent by 2100, with annual losses rising to more than $161 billion. “The production losses caused by heat and drought are around 855 million tonnes a year,” says Hwong, who presented the results at a meeting of the European Geosciences Union in Vienna in May. “I think that is equivalent to what around 2 billion people consume over a year.”

This could be an underestimate of the full impact of climate change for a number of reasons: it’s just three crops, and it doesn’t include flood, storm or rain damage, or the possibility that shortages could lead to big price increases, as is already happening with some other crops such as coffee and cacao.

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at Columbia University in New York says the study’s reliance on the statistical relationships between yield losses and extreme heat and drought could result in it overestimating the impacts by 2100. “Statistical yield models are great for explaining what’s happening now, and in the near past [or] future, but they are inherently unreliable when pushed into vastly different environmental regimes, such as high-emission climate scenarios by the end of the century.” Computer models of how plants are affected by rising CO2 and temperatures are better for projecting what will happen by the end of the century, he says.

at the University of Queensland, Australia, makes the same point. “Although models are not perfect, they are better suited for this type of extrapolation.” However, her team recently released a , which hasn’t been peer-reviewed, showing that two widely used models for wheat make large errors and are especially poor at forecasting the combined effects of extreme heat and drought.

But Kornhuber has defended his team’s use of statistical methods. “The models are remarkable tools, but some of the validation papers have suggested that they might not be super responsive to extremes,” he says. “In our project, extremes were the main focus, so we decided to establish these relationships directly through statistics.”

���ܰ��DZ��’s most extreme heatwave so far may have killed between 17,000 and 25,000 people, according to an early estimate based on past deaths from heat in the region.

“These numbers are preliminary,” says at Indiana University. “But they highlight the need for rapid adaptation investments to avoid these impacts in the future.”

Callahan’s estimate is based on . “We’re taking data on temperature and mortality across Europe, and we are correlating how high temperatures relate to excess mortality rates,” says Callahan. “We then use that relationship to infer how a given heatwave affects mortality over a region like Europe.”

Callahan’s conclusion is that the heatwave in Europe from 22 to 28 June 2026 killed approximately 20,390 people, including 5210 in France, 4543 in Germany, 3163 in Spain, 2709 in Italy and 862 in the UK. These numbers are much higher than the direct counts announced so far, but this isn’t surprising because it takes time for data on deaths to be collected and analysed.

“This figure is a modelled estimate rather than a final count, and it will be some months before the true toll is confirmed, in part because heat rarely appears on a death certificate,” says at the University of Warwick in the UK.

For instance, on 28 June, the head of the World ��ҹ����1000���� Organization, Tedros Adhanom Ghebreyesus, said so far. This number is largely based on reporting around 1000 more deaths in the country than expected from 24 to 26 June.

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However, that statement made it clear that this number is based on a computerised death certificate system that is far from complete. It records 80 per cent of hospital deaths, 45 per cent of deaths in long-term care facilities and 25 per cent of deaths at home. “Mortality will consequently be higher than these initial figures suggest,” the statement said.

Even so, other experts think Callahan may have overestimated the numbers. “Twenty-thousand for a single week seems very large,” says at the University of Bristol in the UK. “We’d have to look into details of the modelling to be more sure.”

While Callahan’s method is sound, the main issue is that he used data from 2015 to 2019 to calculate the relationship between heat and deaths, says at Poznań University of Medical Sciences in Poland. People may now be less vulnerable due to ongoing adaptations, such as increased access to air conditioning, . Walkowiak’s back-of-the-envelope calculation is that if this is taken into account, the actual number of deaths would be around 15,000.

Callahan is sticking to his guns. “We don’t have very strong evidence that the relationship between temperature and mortality dramatically changed over time,” he says. “So it’s not obvious it’s different now than it was 10 years ago.”

“In general, we find that our sort of broader statistical estimates give higher numbers than direct reporting on the ground, because that direct reporting can often miss people who die from heat where it’s not obvious that heat was the cause,” he says.

On the flip side, Walkowiak says that Callahan hasn’t taken into account the fact that heatwaves of the same temperature are more deadly in early summer than in late summer. “In late summer, part of the especially vulnerable population is already long gone,” he says.

Mitchell also says the kind of approach used by Callahan also counts only the immediate deaths. There can be longer-term impacts, such as more deaths from domestic violence, suicides and kidney failure. “The impacts of heat on health vary a lot across timescales,” he says.

What matters most is avoiding further deaths as the planet warms further and heat becomes more extreme, says Nunes. “The signal is clear: heat is now the deadliest weather hazard we face, and the majority of these deaths are preventable,” she says. “We can now forecast these events with considerable accuracy; what we have not done is build the systems, across health, housing, social care and transport, for example, that translate an accurate forecast into actual protection. Adaptation is not keeping pace with the risk.”

What is the SpudCell?

So, is it alive?

Can we really call it a synthetic cell, then?

How was it assembled?

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How do the cells divide?

Why not just put all the genes on one piece of DNA?

Why do the cells stop doing anything after about five rounds of division?

This is all very impressive, but why create SpudCell in the first place?

Could it ever be dangerous?

We now know the master gene that controls embryonic development in people. Called NANOG, its role has been identified by making precise changes to the DNA of fertilised eggs using a technique called CRISPR base editing.

The discovery might lead to ways to boost the success rate of IVF and help treat non-fertility-related conditions. “The other reason we study these early stages of human development is that it has really profound importance for stem cell biology,” says at the University of Cambridge. “A better understanding will help stem cell research and regenerative medicine, and that could have a transformative impact that can affect all of our lives.”

It’s long been known from animal studies that NANOG plays a role in embryonic development. The gene was named after the Celtic world of the ever-young, Tír na nÓg, because its activation is what makes stem cells immortal. Crucially, though, the team’s work shows that NANOG has a different role in people than in other animals, such as mice.

When a fertilised egg starts developing, the cells take on one of three different roles – forming the placenta, the yolk sac, which is also in mammalian embryos, or the embryo itself. When the team used base editing to disable NANOG in fertilised mouse eggs, none of the resulting cells developed into yolk sac progenitors. Base editing is a modified form of CRISPR that changes a single DNA letter at a time. By contrast, the original form of CRISPR slices through DNA strands, resulting in various kinds of mutations. “The precision of the technique reduces the likelihood of unintended chromosomal abnormalities, which can occur with the original version,” says Niakan.

But when the team disabled NANOG in human eggs donated by women undergoing IVF treatments, none of the cells developed into those that form the embryo. In other words, the activation of NANOG is what initiates the developmental programme that results in cells forming a human body.

These embryos still appeared normal under a microscope, however, and the selection of IVF for implantation is based largely on shape, Niakan says. “One out of two times, even though from the shape it looks like the embryo is developing well, it doesn’t have the potential to implant,” she says. “So perhaps by identifying key markers or genes like NANOG, that knowledge could help improve on these rates.”

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Niakan’s team isn’t the first to base-edit human embryos. It was , but using embryos discarded because of abnormalities, so the results might not reflect what happens in healthy embryos. Then last month, at Columbia University in New York and his colleagues released , describing base editing of two-cell embryos.

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“What we were trying to achieve was fundamentally different. Our study is about understanding key genes – this is the first time that the technique has been used to study gene function in human embryos,” says Niakan. “Dieter’s study was evaluating the use of the technology in disease-associated mutation correction.”

Egli says Niakan’s study shows that NANOG has an important role in human development that is different to its role in mice.

All three studies suggest that CRISPR base editing of human embryos is much safer than editing them with the original form of CRISPR, as was done with three children. However,  at Monash University in Melbourne, Australia, who was part of Niakan’s team, stresses that we are still far from the point where CRISPR base editing could be used to create gene-edited children, for example, to prevent inherited conditions. “The technology is not ready for that,” says Herbert. “I think there is unanimous agreement on that.”

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A major obstacle to this is that, often, only some of the cells in an embryo are successfully gene-edited, known as mosaicism. This means if gene editing was used to correct disease-causing mutations in an embryo, the resulting child might still develop that condition.

For instance, with one edit that Egli’s team tried to make, 80 per cent of embryos were mosaics. Niakan’s team did its editing at a much earlier stage, injecting the gene-editing machinery into eggs along with the sperm used to fertilise them. This reduced mosaicism, but not by much: half of the eggs were still mosaics. “[This] would still be too high a rate of mosaicism in many circumstances if the methods were being used to correct a DNA variant that causes a genetic disorder,” says at the Francis Crick Institute in London.

Niakan says it would be really unethical to try to base-edit children at the moment, but she’s not ruling it out in the future: “I would also hugely advocate for much more basic research that’s publicly available and publicly discussed.”

I’m finding the heatwave hitting Europe really scary. It’s bad enough in itself, with many records being broken, especially for the higher nighttime temperatures that make it so much harder to cope. But I just keep thinking, “If it’s like this now, what’s it going to be like in 10, 20 or 30 years’ time?”

The answer, of course, is hotter and hotter and hotter. In the UK, national weather service the Met Office has just warned that, by 2056, there could be , with some places hitting 45°�� (113°F). In just 30 years! I’ve seen at least one piece asking “is this the new normal?” about the current heatwave, but we’re never going to have normal in our lifetimes again – just ever more extreme heat.

It’s possible to get through even worse heatwaves than this if all your infrastructure and systems are geared up to cope. But the UK is very much not prepared. The air conditioning in New Scientist’s office, for instance, is failing to keep up with the heat as I write – and lots of people have to endure this hot weather without any air conditioning at all. In a sign of the times, a meeting on adapting to extreme heat – part of London Climate Action Week – got .

Climate scientists are continually warning of the need to prepare for hotter heatwaves, worse droughts, more flooding and rising seas. During heatwaves like this one, they might even get a little media coverage. But then the weather cools, the news agenda moves on and nothing is ever done.

That’s not just my view – it’s the official verdict of the UK’s Climate Change Committee, which advises the UK government. “Adaptation progress is either too slow, has stalled, or is heading in the wrong direction,” it said in last year. Everyone seems to assume this green and pleasant land is going to remain green and pleasant, but it won’t. We’re heading towards catastrophe, but never looking up.

There are many aspects of this that frighten me. Firstly, emissions are still rising, so the fundamental cause of the problem is getting worse. True, it’s not getting worse as fast as it was, but we are currently , and possibly even more.

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Even these alarming numbers are a little misleading because the oceans that cover most of the planet don’t warm as fast as the land. Average land temperatures are therefore going to go up by a lot more than the above numbers imply.

And what really matters to us is extreme weather, not the average. The projections for future extremes are already dire, and there are reasons to think that we’re in for extremes even greater than those currently projected for a given level of warming. For starters, heatwaves are already more extreme than projected in some parts of the world. One reason for this is that climate models may not be capturing how the dynamics of the jet streams change in a warmer world. Another is that regional models haven’t accounted for reductions in sunlight-blocking air pollution.

The next level beyond is how bad the knock-on effects of this extreme weather will be. These kinds of things are very difficult to project because so many complex systems are involved, but here, too, there is reason to think we are underestimating the impacts.

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For starters, we could see mass deaths even among young people as heatwaves get more extreme. Then there’s our ability to feed people, the basis of civilisation. There’s growing evidence that global warming is already hitting food production, pushing up prices and causing yet more deforestation as farmers try to compensate.

As ever more weather extremes hit the world at the same time, the economic impacts are going to get ever more serious, too. One 2024 study warned that the result could be the worst global financial crisis ever.

And I haven’t even mentioned the wild cards, such as the Amazon drying up or the Atlantic Meridional Overturning Circulation shutting down. One researcher I chatted with at a recent conference thinks a slowdown of this crucial current system around 12,000 years ago triggered extreme seasonality in places like Britain, with sweltering summers, but temperatures plummeting tens of degrees below freezing in winter.

The fact is, the world is changing fast and we need to change just about every aspect of our lives to adapt – our homes and offices, factories and schools, cars and trains, farms and gardens, and so on. But it’s not happening.  That’s why if you’re not scared witless by this heatwave, you should be.