The eastern Siberian landscape is not normally like hell. In winter it is blanketed in snow:in summer, its forests are lush(苍翠繁茂的). This year, however, the region is on fire, as one large parts of the Arctic Circle.

The fires began in June, caused by an extremely hot and dry early summer. It was the hottest June on record globally. In the regions that are burning, temperatures peaked at 8-10℃ warmer than the average from 1981 to 2010. This has dried out the landscape, producing tinder(易燃物)for natural forest fires.

So far, hundreds of above-ground fires have been recorded by satellites in the Arctic and sub-Arctic. It is estimated that fires within the Arctic Circle have produced more than 100m tonnes of carbon dioxide in a year. That is a lot. But burnt vegetation can regrow within a decade, and in doing so reabsorbs much of the released carbon dioxide. It is what is happening below ground that most worries ecologists and climate scientists.

Global warming will melt Arctic permafrost(永久冻土), releasing large amounts of stored greenhouse gases. But if fires in the region become more common, that could have even bigger consequences. Wildfires will release much faster and bigger amounts of carbon, rather than melting permafrost. The fires also produce black carbon which, if dropped on the Arctic sea ice by favourable winds, will darken its surface, making it more likely to absorb sunlight and melt. This decreases the reflectivity of the region and further increases Arctic warming.

Smog from the fires is blanketing much of Siberia. "What is scary about the Arctic fires is that they are driven by climate change, and there's very little you can do," says Thomas Smith. Few natural fires this big have ever been successfully managed. The only way to deal with the spread of these fires is to slow the rate of global warming. Don't hold your breath.

Connie Monroe clicks a button, turns her wrist and watches as her neighborhood floods. The reed-covered shorelines are first to go. Then, the baseball fields at Fleming Park. By the time seawater reaches the senior center, it has covered streets, flooding more than a dozen complexes that she can see.

Monroe moves her head up and down, side to side, taking in the simulated (模拟的) view. This is what could happen to Turner Station, a historic African American community, as sea levels rise.

“Everything’s underwater. The school is underwater. Our house is underwater,” Monroe says. A frown (皱眉) forms below the virtual reality headset. “Is the water really supposed to get that high?”

Climate change presents many challenges to coastal communities, but one of the most worrisome problems is: how do you show people — and convince them — of a possible future?

“It’s one thing to hear or read the news that sea levels could rise as high as 7 feet in Maryland by the end of the century under worst-case situations, but it’s another to imagine what that will look like in your own backyard,” says Jackie Specht, the coastal science program manager. “And if it’s hard to imagine, it’s hard to face and prioritize.”

Communicating the realness and immediacy of the climate threat is important to climate researchers and those aiming to prevent its causes. But it’s also paramount to communities faced with coming changes that are already unavoidable.

Climate projects need public support and input. That’s why Monroe and other residents at this recent community meeting are being directed to sit in metal chairs, put on virtual reality headsets and watch their homes flood.

Virtual reality is an immersive (沉浸式的) experience that can trick the human brain into thinking it’s real. But tricking people is not the goal of the sea level rise simulation being used at Turner Station, says Juliano Calil, one of the program’s developers.

The goal, he says, “is to help folks visualize the impacts of climate change and the solutions, and also discuss the trade-off between them.”

The human body can't handle overheating. The processes that keep us alive work best within a certain temperature between about 36° C and 37° C, depending on the person.

If someone's body temperature goes higher, the body's primary response to heat is to try and get rid of it. To get rid of the overheat, blood vessels(血管) expand. At the same time, the heart begins beating faster. That pushes blood flow to the skin. There, the blood can release heat to cool down. Meanwhile, sweating kicks in to cool the skin.

But there is a limit to how much the body can adjust. That limit depends on an individual's health, as well as the temperature and humidity(湿度) outside. If the outside temps are hotter than the body, blood at the skin won't release heat. And where humidity is high, sweating won't cool the skin. That's because the sweat can't evaporate(蒸发). In 2008, two scientists suggested that humans can't cool off if they spend extended time at a temperature over 35° C.

No one is resistant to heat. But it hits some groups harder than others. The elderly are considered the weakest. One reason: They have fewer sweat glands(汗腺). But their bodies also respond more slowly to rising temperatures. Children, too, are at risk because they haven't fully developed the ability to regulate heat. People with certain diseases such as diabetes and heart disease also can have trouble cooling their bodies. And people living in poverty often lack air conditioning and other resources to help them beat the heat.

Many people see heat as more of an annoyance than a threat. But climate change, extreme heat and human health are all connected. As Earth's temperatures climb, extreme heat waves will probably become more common, endangering more people.