When the sun is out, many of us reach for sunscreen, but myths and misinformation have left some people confused about when and how to use it, and how to ensure we still get enough vitamin D. , a skin cancer expert at QIMR Berghofer Medical Research Institute in Australia, has led clinical trials looking at the link between sun exposure and skin cancer, and sunscreen use and vitamin D. She also recently led the development of a new that considers how to balance the risks and benefits of sun exposure. Here, she lists five things that everyone should know about sunscreen.

Sunscreen should be used as a last line of defence

Many people think it’s OK to lie on the beach all day in a tiny bikini as long as they rub sunscreen all over their exposed skin and reapply it every 2 hours. They think sunscreen makes them bulletproof. But even if you apply the best sunscreen perfectly, it still lets some ultraviolet (UV) radiation through. If you’re out in the sun for hours, that gradually adds up to a dose that is big enough to cause skin damage. At that point, it doesn’t matter if you apply more sunscreen; the damage is already done.

People often assume that if they reapply sunscreen every 2 hours, they’re sort of starting the protection again, but that’s not how it works. You also need to protect yourself with a hat, sunglasses, rash shirt or other protective clothing, and stay in the shade in the middle of the day. Sunscreen should be considered a last line of defence for the parts of your skin that you can’t easily cover while you’re outdoors, like your hands and neck.

There is good evidence that sunscreen protects against skin cancer and wrinkles

The largest, longest-running study of sunscreen was conducted in the Australian town of Nambour. In 1992, 1600 people in the town were randomised to apply daily sunscreen or continue with their normal sunscreen use, which tended to be minimal. It found that those who applied the daily sunscreen were years down the track.

The researchers also created moulds of the backs of the study participants’ hands to look at damage to the surface of the skin. Those in the daily sunscreen group had compared with those who didn’t. When they were followed up on in 2014, they also had .

The sunscreen to choose is the one you like wearing

It’s no good having sunscreen that sits in your cupboard and doesn’t end up on your skin because you don’t like the feel of it. If you’re going on a hike and you’re going to be out all day, it’s better to wear sunscreen with a high sun protection factor (SPF) of 50+. But it’s harder to get a high-SPF sunscreen that feels really nice, so if you’ll be popping out for only short periods throughout the day, you can choose an SPF 15 or 30 sunscreen. Tinted sunscreens can offer the same protection as normal sunscreens, but only if you apply them thickly. But because these often make the skin look overly tinted, people tend to apply them too thinly. One option is to first put on a thick layer of normal sunscreen, then apply the tinted sunscreen on top of it.

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Chemical sunscreens, meaning those that contain organic ingredients such as octocrylene and avobenzone, work by absorbing UV radiation from the sun and converting it to harmless heat. Inorganic sunscreens, also known as mineral or physical sunscreens, contain zinc oxide or titanium dioxide particles. They are often reported to work by reflecting or scattering UV radiation, but they actually , like chemical sunscreens.

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Wearing two layers of sunscreen helps to achieve adequate coverage

You get the SPF listed on the bottle only if you apply 2 milligrams of sunscreen per square centimetre of skin, which is around in an average adult. But it’s really hard to apply this amount of sunscreen in one go. One day, I decided to measure it out exactly, and I couldn’t rub it all on; it was too much. So now, I apply one layer, let it sink in while I brush my teeth and do other things, and then a second layer, so I can apply the full recommended amount.

I was born in Armidale, Australia, in the late 1960s and didn’t wear sunscreen as a child, despite my pale skin. I’ve since had three skin cancers removed, the first of which appeared when I was just 29. So now, I am careful to protect my skin.

If you’re diligent with sunscreen, you might need to take a vitamin D supplement

We recently conducted a trial called the Sun-D Study to see whether applying SPF 50+ sunscreen every day affects people’s vitamin D levels. We randomly assigned 639 people to apply SPF 50+ sunscreen as part of their daily morning routine on days when the UV index was forecast to reach 3 or higher, or to use it at their own discretion. After about a year, a – about 46 per cent compared with 37 per cent in the control group. If you wear sunscreen every day, I would advise taking a vitamin D supplement so that you don’t become deficient, especially in winter. I take one myself – they are cheap, safe and effective.

People with dark-coloured skin are at greater risk of developing a vitamin D deficiency. I recently led the development of a new that looked at how to balance the various risks and benefits of sun exposure. It brought together experts from many Australian universities and medical organisations, and it concluded that people with dark-coloured skin need to put on sunscreen only if they plan to spend more than 2 hours outdoors on days with high UV radiation levels. This is in recognition of the fact that melanoma incidence is 30 times lower in people with dark-coloured skin than in those with light-coloured skin, and that vitamin D deficiency poses a greater risk.

Europe suffered unprecedented wildfires and heatwaves in 2025, impacts that are expected to worsen on the world’s fastest-warming continent.

Last year was the hottest year on record in the UK, Iceland and Norway and one of the three hottest years in Europe as a whole, according to an annual report by the European Centre for Medium-Range Weather Forecasts (ECMWF). More than 95 per cent of the continent experienced above-average annual temperatures. Scandinavia, Finland and north-western Russia saw their worst-ever heatwave, 21 days of simmering temperatures that reached 30°C (86°F) even at the Arctic circle.

This extreme heat probably stunted animal and plant growth while encouraging the spread of invasive species and pests, showing how the climate crisis is contributing to a crash in biodiversity, at the World Meteorological Organization said at a press conference.

“This region would [typically] see zero to two days of strong heat stress, and we are speaking about 21, so this had a major impact on ecosystem health,” she said. “Since 1980, Europe has been warming twice as fast as the global average, [and] heatwaves are becoming more frequent and severe.”

Climate warming set the stage for record wildfires in Portugal and Spain in August, the extremely hot, dry, windy conditions there at least 40 times more likely. More than 10,000 square kilometres burned, and at least three people were killed. Fires approached Madrid, and authorities had to shut down parts of the Camino de Santiago pilgrimage route. Smoke drifted as far as the UK.

Across Europe, wildfires emitted 47 million tonnes of carbon, a record amount. Spain, the UK, the Netherlands, Germany and Cyprus all topped their previous fire-emissions records.

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Soil conditions were the driest in 33 years of observations, with more than a third of Europe suffering extreme agricultural drought, especially the UK, Turkey and Ukraine. While parched soils probably encouraged wildfires in many countries, it was increasing fluctuations in the weather that supercharged the blazes in Portugal and Spain, according to at ECMWF. An extremely wet spring that boosted vegetation growth was followed by record summer heat, which dried out those plants and shrubs, creating a tinderbox.

“If you have a very high fuel load in addition to the wildfire weather, so hot, dry winds in particular, that’s when we get these catastrophic conditions where wildfires spread very quickly,” Burgess said at the briefing. “National parks need… firebreaks around them to make sure if there is a fire, it doesn’t spread.”

The ocean around Europe was also abnormally hot, breaking the record for annual sea surface temperature for the fourth year in a row. A record 86 per cent of these seas suffered strong, severe or extreme marine heatwaves. The most extreme hotspots occurred west of Ireland, south of Iceland and south-east of Spain.

For the past three years, heatwaves have struck 100 per cent of the Mediterranean Sea, which is warming up faster than the global average. Waters in Italy and Spain reached 30°C, warmer than a typical swimming pool, raising the risk of fish death, as well as the spread of bacteria and algae. Past marine heatwaves in the Mediterranean have killed off huge amounts of coral, seagrass beds and shellfish.

To limit future damage, Europe needs to lead the way on slowing climate change, of the European Commission said at the briefing. In 2025, solar power generated a record 12.5 per cent of the continent’s electricity, with a total 46 per cent coming from renewables.

European countries are also among those taking part in the first in Colombia this week, which was organised after the COP30 climate summit in Brazil failed to agree on a roadmap to end oil, gas and coal emissions.

At the same time, Europe should adapt to future climate risks, such as multi-year megadroughts similar to the one already gripping the western US, according to officials.

“We need to address these risks,” Chrenek said. “The cost of inaction is significantly higher than the cost of tackling negative impacts.”

The UK should urgently prepare for summer temperatures in excess of 40°C (104°F), according to the Met Office, the country’s national weather service, which warns the likelihood of extremely high summer temperatures is increasing rapidly as the climate warms.

Temperatures in Lincolnshire, in the east of the UK, hit a record 40.3°C (104.5°F) in July 2022, the highest level ever recorded in the country. The heatwave was made at least 10 times more likely by climate change, scientists said at the time.

Now researchers are warning such extremes won’t be an isolated event. The team, led by at the Met Office, used a climate model to simulate more than 2500 UK summers to assess the kinds of extremes possible under 2023 climate conditions.

The results show there is a 50 per cent likelihood of temperatures above 40°C occurring in the next 12 years, with the south and east of England most vulnerable to heat extremes. The chance of such extreme heat has risen rapidly in recent decades, increasing sixfold from the 1980s and almost tripling since 2000, the research shows.

Meanwhile, temperatures over 42°C (107.6°F) have a 1 per cent likelihood of occurring in any given year, and the maximum possible temperature the UK could see under current climate conditions is 46.6°C (115.9°F) – although this peak would be “exceedingly rare”, says Kay.

The simulations also give meteorologists a sense of the weather conditions needed to produce extreme heat in the UK. The most likely scenario is a persistent heatwave settling over Europe, with the hot air then moving across the UK’s south and east coasts. This week the Met Office warned a fresh heatwave loomed for the UK, triggered by intense warmth across the European continent.

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Heatwaves have become more persistent as the climate has warmed. The hot summer of 1976 saw daytime temperatures remain above 28°C (82.4°F) for a fortnight – under today’s climate, such conditions could persist for well over a month, the new research shows. Simulations show three or four consecutive days of temperatures above 40°C are also possible under current conditions.

“Temperatures several degrees above the 40°C that we saw in July 2022 are possible, and we should be preparing for those,” says Kay, pointing out that as the climate warms, such temperatures become increasingly likely. During the July 2022 heatwave, the UK struggled to cope with even a brief burst of heat above 40°C. More than , rail transport was disrupted, schools were closed and wildfires swept through the countryside.

Kay urged public authorities – particularly those responsible for public health – to “stress-test” their systems to ensure they can adequately cope with such extreme temperatures. “The Met Office and other similar organisations have said for a long time now that with climate change, we should be expecting more intense and more frequent heatwaves,” she says. “This is exactly what we’re seeing in the study.”

Prolonged heatwaves are dangerous. Not only do they strain environmental ecosystems – drying out soils, wilting plants, stressing animal life – but they also pile stress on the human body, especially if both daytime and nighttime temperatures remain high for a long period. Longer-lasting heatwaves significantly . The risk is highest in regions where persistent hot weather is unusual, such as in the UK, as homes rarely have air conditioning.