Tag Archives: heat

Green walls can reduce heat lost by buildings by over 30% in temperate climates

Plants can help keep buildings warm in the winter, and cool in summer, according to new research. The trick is to plaster walls in them.

The Sustainability Hub at the University of Plymouth retrofitted with an exterior living wall facade. Image credits University of Plymouth.

Retrofitting cavity walls (double masonry walls with an air gap in between) with green or living walls goes a long way to reducing heating bills, according to new research. Such an improvement can slash the amount of heat a structure loses by over one-third (30%), the authors report.

The study was conducted at the University of Plymouth campus on its Sustainability Hub, a pre-1970 building. While the findings have practical applications for individual users, wide-scale adoption of such measures would also bring a significant and positive contribution to our efforts to combat the climate crisis.

Green for warmth

“Within England, approximately 57% of all buildings were built before 1964. While regulations have changed more recently to improve the thermal performance of new constructions, it is our existing buildings that require the most energy to heat and are a significant contributor to carbon emissions,” says Dr. Matthew Fox, a researcher in sustainable architecture and the study’s lead author.

“It is therefore essential that we begin to improve the thermal performance of these existing buildings, if the UK is to reach its target of net zero carbon emission by 2050, and help to reduce the likelihood of fuel poverty from rising energy prices.”

The study compared the insulating properties of two sections of the building’s walls with green walls providing extra insulation, using uncovered walls as a control. The green wall consisted of a flexible felt fabric sheet with a system of pockets to hold soil, in which various species of plants were planted. These included sedges, ferns, rushes, and flowering shrubs. The living wall was fitted to the exterior of the masonry wall. Due to the internal layout of the building, only one of the green-walled areas was monitored, as per the diagram below.

The performance of these two wall sections was monitored over a five-week period. By the end, the authors report, the one with the living wall facade showed a 31.4% reduction in lost heat compared to its bare counterpart.

Apart from better heat retention, the living wall also improved the thermal stability of the structure. Daytime temperatures in the two green-walled sections of the building fluctuated less than in the uninsulated ones — meaning it was easier for the buildings’ heating systems to maintain the desired temperature range.

The two monitoring locations in the building. Image credits Matthew Fox et al., (2021), Building and Environment.
A building’s U-value (thermal transmittance) showcases how much heat it transfers (loses) with its environment. Image credits Matthew Fox et al., (2021), Building and Environment.

They also discovered daytime temperatures within the newly-covered section remained more stable than the area with exposed masonry, meaning less energy was required to heat it.

Building energy use directly accounts for 17% of the greenhouse gas emissions in the UK, the authors explain. Heating alone makes up over 60% of all the energy usage in buildings, so green walls could put a significant dent in a country’s emissions if employed on a wide scale. They can also bring other benefits to the table, such as offering a way to increase biodiversity in city environments, which they sorely lack. They also provide a modest but important contribution to air filtration in cityscapes, help with our mental health, and keep temperatures in cities bearable.

On a personal note, I also find green walls to look quite cool.

This study is one of the first to look at the merits of living walls as insulation systems in temperate climates, the team adds, giving us reliable data on their effectiveness. Such data can serve both private and public actors such as homeowners, corporations, and policy-makers when deciding on what insulation systems to apply to buildings.

“With an expanding urban population, ‘green infrastructure’ is a potential nature-based solution which provides an opportunity to tackle climate change, air pollution and biodiversity loss, whilst facilitating low carbon economic growth,” adds Dr. Thomas Murphy, one of the study’s authors.

“Living walls can offer improved air quality, noise reduction and elevated health and well-being. Our research suggests living walls can also provide significant energy savings to help reduce the carbon footprint of existing buildings. Further optimizing these living wall systems, however, is now needed to help maximize the environmental benefits and reduce some of the sustainability costs.”

The paper “Living wall systems for improved thermal performance of existing buildings” has been published in the journal Building and Environment.

Worsening heatwaves could kill more than 8 million people by 2100

The amplifying effects climate change will have on heatwaves have already been detailed in past research. A new report, however, comes to quantify the cost in human lives if we decide not to take action — millions of people around the world could lose their lives, the team reports.

Image in public domain.

The findings pose a new warning to officials and the public regarding the price of inaction in climate issues.

Deadly greenhouse

The team from the National Bureau of Economic Research (NBER), a non-profit based in the USA, reports that if greenhouse emissions are not reduced, heatwaves in the future could kill millions of people in all areas of the globe.

Not only will these heatwaves directly kill people (through heat stress and stroke), but they will also indirectly increase mortality by making it harder for our bodies to regulate their temperature. Not only will this heavily impact older people and those with underlying conditions, but excessive heat will also make it harder for everyone to carry out their tasks.

The findings are based on an analysis of past heatwave patterns in eight countries around the globe and the European Union, the number of heat-related deaths caused by them, and projected changes in heatwave patterns and temperatures in the future. From this data, the authors estimated the number of casualties such events will cause in the future.

The authors note that excessive heat is among the deadliest types of extreme weather. Prolonged exposure to high temperatures can lead to heart conditions, heart attack, and a host of other conditions (caused by our bodies working extra hard to keep cool). Such an effect would be much larger in hotter areas of the globe such as those close to the equator.

Future heatwaves could kill 85 in every 100,000 (around 8.5 million) people by 2100 if greenhouse gas emissions continue undisturbed, the team writes. They also “estimate the mean increase in mortality risk is valued at roughly 3.2% of global GDP” by the same date. The poor and the elderly, especially those living in already hot areas, are particularly at risk. The findings are supported by previous research on the topic, which estimated how many Europeans will be at risk from weather-related phenomena in the future.

The availability of air conditioning can help mitigate the effects of heatwaves, the authors note, but it’s a relatively expensive good that these categories have limited access. Wide-scale use of air conditioning can make cities even hotter, however, and they drive an increase in CO2 emissions if their energy is sourced from fossil fuels.

The paper “Valuing the Global Mortality Consequences of Climate Change Accounting for Adaptation Costs and Benefits” is available here.

Heatwaves are getting hotter, longer, more frequent globally

Heatwaves are becoming more frequent around the world, a new paper reports.

Image via Pixabay.

A worldwide analysis of heatwave patterns on the regional level reveals that these have been increasing in length and frequency in the last 70 years. Cumulative heat — the total amount of heat in individual heatwaves and heatwave seasons — has also been increasing. This property signifies the intensity of the heatwave season and represents “the product of all seasonal heatwave days and average heatwave intensity.”

Catching some (heat) waves

“Not only have we seen more and longer heatwaves worldwide over the past 70 years, but this trend has markedly accelerated,” said lead author Dr. Sarah Perkins Kirkpatrick from the ARC Centre of Excellence for Climate Extremes in Australia.

For the study, the researchers looked at heatwave trends over multi-decade intervals between 1950-2017 and found some very telling signs.

The Mediterranean region, for example, saw an overall increase in heatwave duration of two days per decade. When looking at the 1980-2017 time frame specifically, the team found an increase in heatwave days of 6.4 days per decade. This suggests that most if not all of the increase is focused during these last decades.

Regions like the Amazon, north-east Brazil, and West Asia are also experiencing a rapid increase in heatwaves and their intensity while areas like South Australia and northern Asia are seeing a slower rate of increase.

Virtually all areas of the globe are seeing longer, hotter heatwaves more often, but every region is affected differently. For example, Australia experienced an additional 80°C of cumulative heat during its worst heatwave season, whereas western Russia logged a mighty 240 °C of extra heat during its worst season.

The longer a heatwave season is, and the more intense its temperatures, the higher this cumulative heat value will be. On a global level, cumulative heat is rising by roughly 1°C-4.5°C per decade, according to the authors. Some areas are experiencing rises of “up to 10°C a decade,” according to Kirkpatrick.

Such changes will impact the lives of all of us, but poorer countries with more fragile infrastructures are bound to be hit hardest, the team believes. Furthermore, they explain that longer, more intense, more frequent heatwaves have “long” been identified as “a clear sign of global warming“, according to Kirkpatrick.

“The dramatic region-by-region change in heatwaves we have witnessed over the past 70 years and the rapid increase in the number of these events, are unequivocal indicators that global warming is now with us and accelerating,” he adds.

“This research is just the latest piece of evidence that should act as a clarion call to policymakers that urgent action is needed now if we are to prevent the worst outcomes of global warming. The time for inaction is over.”

The paper “Increasing trends in regional heatwaves” has been published in the journal Nature.

Volcano-dwelling beetle inspires new ‘passive cooling’ material

Researchers at The University of Texas at Austin’s Cockrell School of Engineering, alongside scientists from China and Sweden, have created a new material that passively cools itself down.

A Longicorn Beetle.
Image credits Flickr / patrickkavanagh.

The material was inspired by the wing structure of a longicorn beetle species native to volcanic areas in Southeast Asia. The beetles rely on self-cooling tissues to allow them to live in such inhospitable places.

Cool new materials

“Anywhere that needs cooling, this can help,” said Yuebing Zheng, an associate professor in the Walker Department of Mechanical Engineering. “Refrigerators, air conditioners and other methods consume large amounts of energy, but this is cooling by itself.”

While the insect uses its body’s ability to regulate heat and gain access to an environment its competitors can’t live in, the researchers plan to use the new material it inspired to help cool everything from buildings to electronic devices in an environmentally friendly manner.

The researchers first had to determine what gave the beetle (Neocerambyx Gigas, one of 26,000 species of longhorn beetle) its cooling capability. They discovered that their wings are covered in triangular “fluffs” that disperse body heat while also reflecting sunlight.

The team then created a new “photonic film” based on these structures. This film is constructed from common, flexible material (PDMS polymer), and the team explains that it is mechanically strong enough for wide-spread use and easy to manufacture.

The film is applied as a coating on objects and can help decrease temperatures in spaces, buildings, appliances, or electronics without expending energy to do so. In lab tests, it was able to reduce the temperature of items in direct sunlight by up to a respectable 5.1 degrees Celsius (9 degrees Fahrenheit).

It could be put over windows in office spaces or apartment buildings to reflect incoming sunlight, and thus keep temperatures down. It can also be used to protect solar panels from sunlight-induced degradation, or to keep cars cool while parked. In the long run, it could even be used with clothing and personal electronics, the researchers hope.

The paper “Biologically inspired flexible photonic films for efficient passive radiative cooling” has been published in the journal Proceedings of the National Academy of Sciences.

Australia records its hottest day ever — while burning from a thousand bushfires

This week, Australia has experienced its hottest day on record. Authorities expect the current heatwave to worsen, however, and further feed the bushfire season — which is already unprecedented as well.

With a nationwide average temperature of 40.9 degrees Celsius (105.6 degrees Fahrenheit), this Tuesday set a new record for the land down under. The previous record of 40.3 degrees Celsius was recorded in January 2013.

The heat is on

This year, Australia’s summer bushfire season has experienced a very early and intense start. Hundreds of fires have been roaring across the nation for months now, including a “mega-blaze” north of Sydney, the country’s largest city. Smoke from this blaze has led to increased levels of air pollution in Sydney, prompting authorities to declare the event a public health emergency.

All in all, over three million hectares (7.4 million acres) of land has been burned across Australia so far. Six people have lost their lives to the blaze, and about 700 homes have been destroyed.

Global warming is likely fanning the flames higher and earlier than usual. Australia has also experienced a prolonged drought, leaving a lot of dry plant matter in the bush, and leaving several towns out of water. The fires have sparked climate protests targeting the conservative government, which has resisted calls to address the root causes of global warming — in favor of the country’s lucrative coal export industry.

The heatwave started in the country’s western reaches, where firefighters were engaging thousands of bushfires earlier this week. It has since crept across central Australia and is spreading to the heavily populated eastern states. Weather forecasts for parts of New South Wales, of which Sydney is the capital estimate temperatures in the mid-40s Celsius (around 110 Fahrenheit) for the end of the week. On Saturday parts of Sydney are expected to reach over 46 degrees celsius (115 Fahrenheit).

Most bushfires so far have been recorded in Australia’s eastern states. Turbulent winds of up to 100 kilometres (60 miles) an hour are expected in the area later this week, which may further stoke the fires. Embers from the fires can travel up to 30 kilometers (around 18.5 miles) by strong winds, authorities explained, which further increases the risks during this time.

“Over the next few days we are going to see firefighters, the emergency services and all those communities close to fires […] challenged with a new threat,” New South Wales fire commissioner Shane Fitzsimmons said on Wednesday.

On Wednesday, police officers evacuated residents from dozens of homes in the Peregian area (northeastern Queensland) as out-of-control bushfires threatened the properties.

“Fire crews and waterbombing aircraft are working to contain the fire but firefighters may not be able to protect every property,” Queensland Fire and Emergency services said. “You should not expect a firefighter at your door. Queensland Police Service are door knocking in the area. Power, water, and mobile phone service may be lost.”

While Prime Minister Scott Morrison is on holiday at an undisclosed, overseas location, climate protesters plan to march in Sydney this week to demand change and highlight his absence as vast stretches of Australia burn. Recently, Mr. Morrison has acknowledged climate change as one of “many other factors” driving the bushfires.

Melting ice cream.

The recent heatwave in Europe between 1.5 to 3.0 °C hotter due to man-made climate heating

An international team of researchers says that the heatwave which fell upon northern Europe last month was made worse by man-made climate heating.

Melting ice cream.

Image via Pixabay.

Last month’s heatwave was 1.5 to 3.0 degrees Celsius hotter due to human activity, according to researchers from the World Weather Attribution (WWA) initiative. The temperatures were estimated based on comparing climate modelling and historical heatwave trends with temperature data measured  across the continent.

Hotter with you

“In all locations an event like the observed would have been 1.5 to 3°C cooler in an unchanged climate,” the WWA said. This difference was “consistent with increased instances of morbidity and mortality.”

Last month, much of Europe was faced with a massive heatwave. The worst-affected area was northern Europe, with record-shattering temperatures measured in Belgium, the Netherlands, and Britain. Paris also saw its hottest day since record-keeping began on July 25, with the mercury topping out at 42.6°C (108.7 Fahrenheit).

The heatwave caused widespread disruption. Many cities took emergency measures and governments issued warnings for locals to avoid going outside if possible. Several heat-related deaths were reported, although a precise toll is not yet available.

Man-made climate warming likely increased temperatures during this heatwave, the team reports. Temperatures produced by the climate models were as much as 3C (5.5 degrees Fahrenheit) lower than those actually observed during the heatwave in Europe, they explain. Michael Byrne, lecturer in Earth and Environmental Sciences at the University of St Andrews, told Phys the analysis had “found the fingerprints of climate change all over (last month’s) extreme temperatures.”

Global heating also made the July heatwave 10-100 times more likely to occur in some countries compared with computer simulations. Overall, the heatwave itself was made at least five times more likely by climate change, and was around 4°C hotter than an equivalent heatwave a century ago.

“We know without doubt that climate change will bring increasingly severe heatwaves, but also heavier downpours and more flooding,” added Byrne, who was not involved in the research.

“July has re-written climate history, with dozens of new temperature records at local, national and global level,” said World Meteorological Organization (WMO) Secretary-General Petteri Taalas.

Europe has experienced intense heatwaves in 2003, 2010, 2015, 2017, 2018 and two this year. These temperature peaks are consistent with the general warming trend, the team explains, as the four hottest years on record globally were the last four years. Temperature readings provided by the European Union’s Copernicus monitoring service showed that the first 29 days of July 2019 were equal to or possibly warmer than the hottest month ever (currently July 2016), the team adds. The WMO seconded that result on Friday, saying that preliminary data showed July may have been the hottest month ever recorded.

While the data needs confirmation, the WMO said the figures were “particularly significant” as July 2016 occurred during a strong El Nino warming event. There was no such event to drive up temperatures in 2019.

“This is not science fiction. It is the reality of climate change. It is happening now and it will worsen in the future without urgent climate action,” said Taalas.

The report “Human contribution to the record-breaking July 2019 heatwave in Western Europe” is available here.

More green spaces can help some cities keep cool

Researchers looking into how to help keep our cities cool say that more green spaces can help, although not everywhere.

Image credits Khusen Rustamov.

The urban heat island effect is a phenomenon through which the temperature in a city is noticeably higher than in the surrounding rural area. Which is, obviously, very irritating.

In a bid to find out how to control the effect, an international team of researchers looked at the role of precipitation and population size have on city temperatures compared with the surrounding countryside. All in all, they report that more green spaces can help bring city temperatures down, but not everywhere.

Plant some plants

“We already know that plants create a more pleasant environment in a city, but we wanted to quantify how many green spaces are actually needed to produce a significant cooling effect,” says Gabriele Manoli, former postdoc with the Chair of Hydrology and Water Resources Management at ETH Zurich and lead author of the study.

When urban heat island effects compound with the sort of heatwaves that hit most of Europe this summer, it can pose a very real and deadly threat to the elderly, sick, and other vulnerable groups.

The team looked at urban heat islands across the globe and at the different heat-reduction strategies they employ. The effectiveness of these strategies depends heavily on regional climate, they explain.

Manoli and his team — with members from ETH Zurich, Princeton University and Duke University — studied data from around 30,000 cities worldwide and their surrounding environments. The factors they analyzed include average summer temperatures, population size, and average annual rainfall.

The larger the city, the more dramatic its urban heat island, the authors explain — but also more rainfall in the region. As a rule of thumb, more rain means more plant growth, meaning that areas surrounding large cities are much cooler than them. This effect is the strongest when annual rainfall averages around 1500 millimeters (as in Tokyo), but does not increase further with more rain.

Cities in very dry regions (like Phoenix, Arizona) can, through carefully-targeted planting efforts, bring their average temperatures below that of the surrounding countryside. Those surrounded by tropical forests on the other hand (such as Singapore) would need far more green spaces to reduce temperatures — but the authors warn that this would also increase humidity.

Therefore, cities located in tropical zones should look to other cooling methods, such as increased wind circulation, more use of shade, and new heat-dispersing materials.

One of the main takeaways from the study, Manoli explains, is a preliminary classification of cities to help guide planners on possible approaches to mitigate the urban heat island effect.

“There is no single solution,” Manoli says. “It all depends on the surrounding environment and regional climate characteristics.”

“Even so, searching for solutions to reduce temperatures in specific cities will require additional analysis and in-depth understanding of the microclimate. Such information, however, is based on data and models available to city planners and decision-makers only in a handful of cities, such as Zurich, Singapore or London.”

The team is now working to determine which types of plant are most useful for reducing the heat island effect.

The paper “Magnitude of urban heat islands largely explained by climate and population” has been published in the journal Nature.

Atom-thick heat shield could make smartphones even thinner

A model of graphene’s structure. Credit: Public Domain.

Smartphones, laptops, and other electronics naturally give off heat during their operation. To protect these devices from malfunction, engineers have to incorporate a thermally insulating material in their designs, which can be glass, plastic, or even an air gap.

In a new study, researchers at Stanford University have pushed the boundaries of thermal insulation by stacking atom-thick materials like sheets of paper atop hot spots. The resulting material is only 10 atoms thick but provides the same insulation as a sheet of glass 100 times thicker.

This achievement might have massive implications for the electronics industry. Thinner heat shields free up space so that electronics can get even more compact.

The atom heat shield

For their study, Eric Pop, who is a professor of electrical engineering at Stanford, and colleagues had to think outside of the box. This meant that they had to think of heat in a radically new way — as like it was sound.

Both heat and sound are actually waves of energy — it’s just that heat is a form of high-frequency sound. When viewed through this lens, you can treat heat insulation the same way a studio engineer dampens acoustic waves to achieve a clean sound. Pop, who used to be a radio DJ at Stanford’s KZSU 90.1 FM, was well aware of this dynamic.

But it was ultimately home construction that provided the missing puzzle piece. Modern homes employ multi-paned windows which are made of sheets of glass with varying thickness with layers of air trapped between them.

The researchers adapted this idea and used a layer of graphene and three other atom-thick materials. The resulting four-layered insulator is just 10 atoms deep.

Despite its ridiculous thinness, the insulator is effective because heat is dampened as it passes through each layer.

“As engineers, we know quite a lot about how to control electricity, and we’re getting better with light, but we’re just starting to understand how to manipulate the high-frequency sound that manifests itself as heat at the atomic scale,” Pop said.

The challenge now lies in finding a cheap manufacturing method that can incorporate such a thin insulator in electronics.

But beyond commercial applications, the researchers hope to reach an even more ambitious goal: to one-day control heat flowing through solid objects similarly to how we now control electricity and light passing through wires.

The findings appeared in the journal Science Advances.


Atom-thin insulators pave the way to new, thinner devices

The heat given off by devices can certainly be annoying when you’re home, in bed, laptop on your belly, watching Youtube videos of cats to get you sleepy. But, it can also be dangerous for the devices themselves. Excess heat contributes to malfunctions and, in extreme cases, can even cause lithium batteries to explode.

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Four atom-thin layers that form a heat-shield just two to three nanometers thick, or roughly 50,000 times thinner than a sheet of paper.
Image credits National Institute of Standards and Technology.

In order to keep this heat contained in heat-generating components like microprocessors, designers and engineers use sheets of glass, plastic, or pockets of air as insulation. All of them, however, take up quite a lot of space.

And space is a commodity

In an effort to make insulation — and thus the devices themselves — as compact as possible, researchers at Stanford University have shown that a few layers of atomically thin materials, stacked atop hot spots, can provide the same insulation as a sheet of glass 100 times thicker.  According to Eric Pop, Professor of Electrical Engineering and senior author of the paper, this line of research will help make our devices even more compact than today.

“We’re looking at the heat in electronic devices in an entirely new way,” Pop said.

This paper is built on a simple but powerful shift in approach: the team treated heat as sound.

When you get down to it, heat, really, is sound. Heat is actually the vibration or movement of particles in a body — the more they vibrate, the hotter the object gets.

The heat in our devices is generated by electricity. As electrons move through wires, they collide with the metal atoms of said wires. Each collision causes an atom to vibrate, and the more current flows through the material, the more collisions occur. In the end, you are left with a number of atoms, all enthusiastically vibrating. Moving atoms is also what generates sound, but the electricity-induced vibrations move through the solid material at frequencies far above what our ears can pick up, so we can’t hear it — but we do feel that energy as heat.

This line of thinking inspired the team to borrow a few principles from audio insulators. Music recording studios, for example, are quiet thanks to thick glass windows that block the exterior sound — this is pretty similar to how we design heat insulators today. However, the obvious problem with this is that it relies on the sheer mass of material — and thus, on volume — to block heat.

So, instead, the team borrowed a trick from homeowners and installed multi-paned insulators. Just as a multi-paned window uses layers of air to insulate your room, so too does the team’s insulator.

“We adapted that idea by creating an insulator that used several layers of atomically thin materials instead of a thick mass of glass,” said postdoctoral scholar Sam Vaziri, the lead author on the paper.

The team used a layer of graphene and three other sheet-like materials — each three atoms thick — to create a four-layered insulator just 10 atoms deep. Despite its thinness, the insulator is effective because the atomic heat vibrations are dampened and lose much of their energy as they pass through each layer.

So far the technology is solid, but the team needs to find an effective means of mass-producing the atomic insulator in order to bring it to market.

“As engineers, we know quite a lot about how to control electricity, and we’re getting better with light, but we’re just starting to understand how to manipulate the high-frequency sound that manifests itself as heat at the atomic scale,” Pop said.

The paper “Ultrahigh thermal isolation across heterogeneously layered two-dimensional materials” has been published in the journal Science Advances.

It’s so hot in Finland’s Lapland the reindeer have hit the beach

The heatwave in Finland is causing some unusual scenes: a pair of reindeer were spotted on the beach in northern Finland.

They bother no one and no one bothers them. Image credits: This is Finland.

It’s been a sizzling couple of days in Scandinavia. The heatwave that’s been ravaging central and western Europe has migrated northwards, making for some tropical days in Norway, Sweden, and Finland. Authorities have issued heat warnings, urging people to stay indoors if possible and stay hydrated. But humans aren’t the only ones affected by the scorching temperatures.

In Finland, authorities have warned motorists to be mindful of moose, who are crossing more roads than usual in their attempts to find water and quench their thirst. Elsewhere, the newspaper Helsingin Sanomat reported earlier this week of reindeer “queuing at the Kela office” — after a group of reindeer gathered outside a social benefits agency in a Lapland village of Inari to stand in the shade.

But without a doubt, the star of the show were the two reindeer that sought some respite from the heat on a beach in Lapland — Finland’s northernmost region known for its Christmas spirit and its reindeer. They didn’t seem to care about anything other than cooling down.

“Many people took photos and it didn’t seem to bother them in the slightest. Children were playing nearby and that didn’t disturb them either,” said Johanna Koivisto, who snapped a picture of the resting duo.

Koivisto said she wasn’t surprised too surprised to see reindeer at the beach — it’s become quite a common sight, as temperatures in Finland continues to rise. Temperatures at the beach were around 28 °C (82 F).

The annual Finnish mean temperature has risen 2.3 °C since preindustrial times. Warming has been greatest in early winter, nearly 5 °C, but summer temperatures are harder to bear for wildlife. The month of July 2018 in Finland had the highest-ever temperatures recorded by the Finnish Meteorological Institute since recordings started in 1838, although this month is very similar.

July temperatures in Finland average 13 to 17°C (55-63 F), but pass 30°C in some parts during heatwaves. The northernmost municipality of Utsjoki, north of the Arctic Circle, experienced a record-breaking temperature of 33.3 °C (92 °F) in July 2018.

As for reindeer, the pair that made it to the beach can consider themselves lucky. The climate crisis which our world is facing is devastating for reindeer populations,  and more than 50% of their population has collapsed  over the past few decades. Reindeer in Lapland, like those all over the Arctic, are finding it extremely difficult to cope with the high temperatures.

Paris registers all-time hottest day amid Europe’s heatwave

A historic heatwave caused record temperatures on Europe and shattered all-time highs in multiple countries and cities. Paris is one of the hardest-hit cities, registering 108.7 degrees Fahrenheit (42.6 Celsius), breaking the previous record of 104.7 (40.4) set in 1947.

Credit: Wikipedia Commons


The heatwave was caused by a massive area of high pressure air that extended into the upper atmosphere. The phenomenon — known as a heat dome — has temporarily rerouted the typical flow of the jet stream and allowed hot air from Africa to surge northward. It is expected to migrate farther north by the weekend.

French authorities issued a red alert in the Paris region and 19 other districts as temperatures were expected to reach 108-109 degrees (42-43C) in parts of the country. Locals were advised to avoid traveling to work from home if possible. Some nurseries were closed.

“No one is safe in such temperatures,” said Agnès Buzyn, France’s health minister. “This is the first time that this affects departments in the north of the country, populations that are not accustomed to such heat.”

France is particularly wary of high heat after a 2003 heatwave killed nearly 15,000 people, especially elderly people. Since then, the government has introduced a color-coded heat alert system to warn people when temperatures are expected to rise to dangerous levels in their area and trigger government assistance efforts.

The alert system went to its maximum level of red for the first time during last month’s heatwave, when France saw its highest-ever recorded temperature of 114.8 degrees (46C). On Thursday, about one-fifth of French territory was issued a red alert, stretching from the English Channel through the Paris region and down to Burgundy. Élisabeth Borne, France’s minister of sustainable development, urged citizens to cancel or postpone all unnecessary travel. The SNCF, France’s state-owned railway company, allowed customers to exchange or cancel free of charge any Thursday travel to the heaviest-affected 20 northern regions.

Climate experts at the UK’s Met Office said there’s “no doubt” climate change is playing a role in the heatwave, assuring it’s making summer heatwaves five times more likely and significantly more intense – making these temperatures the new normal in many parts of the world.

“What we have at the moment is this very warm stream of air, coming up from northern Africa, bringing with it unusually warm weather,” Peter Stott, from the Met Office, said. “But without climate change, we wouldn’t have hit the peaks that we’re hitting right now.”

The UK recorded a record temperature for July of 100.5 (38.1C), with trains running more slowly to stop rails from buckling. Meanwhile, Belgium, Germany, Luxembourg and the Netherlands also reached new record highs, of 107.2 (41.8C), 106.7 (41.5C), 105.4 (40.8C) and 105.2 (40.7C) respectively.

But temperate Europe – where air conditioning is rare – isn’t equipped for the temperatures sizzling the region this week. So, tourists frolicked in fountains to seek relief, while authorities and volunteers fanned out to help the elderly, sick, and homeless — those hit hardest by the heat.

Across Germany, Switzerland, and Austria, some communities painted rail tracks in white hoping the light color would help cool them down by a few degrees. In Cologne in western Germany, volunteers offered free water to passers-bys at the initiative of the city’s local transportation system.

University of Utah mechanical engineering associate professor Mathieu Francoeur. Credit: Dan Hixson/University of Utah College of Engineering.

New nanodevice converts wasted heat into more battery life

A mechanical engineer at the University of Utah has found a ‘loophole’ around a physical principle that allows a device to convert wasted heat into electricity. The nanotechnology harvests heat from an object by placing two surfaces until they’re almost contacting one another. In the future, this setup might not only be able to cool down mobile devices like laptops and smartphones but it may also be able to channel their heat into more battery life.

University of Utah mechanical engineering associate professor Mathieu Francoeur. Credit: Dan Hixson/University of Utah College of Engineering.

University of Utah mechanical engineering associate professor Mathieu Francoeur. Credit: Dan Hixson/University of Utah College of Engineering.

The device in question, called a “Near-Field Radiative Heat Transfer Device”, was elaborated by Mathieu Francoeur, a mechanical engineering associate professor at the University of Utah. In order to harvest heat, this device blows past the so-called blackbody limit.

A black body is an object that absorbs all the electromagnetic radiation (i.e. light) that strikes it. However, in order to stay in thermal equilibrium, the black body must also emit radiation at the same rate as it absorbs it. For this reason, a black body also radiates well — it’s why stoves must be black.

The theoretical blackbody limit tells us the maximum amount of heat that can be emitted from an object. However, this ceiling is known to be no limit at all when the spacing between objects is small enough.

Francoeur and colleagues devised a 5mm-by-5mm chip, which is no bigger than an eraser head, made of two silicon wafers spaced by a nanoscopic gap only 100 nanometers thick — that’s one thousandth the thickness of a human hair.

“Nobody can emit more radiation than the blackbody limit,” he said. “But when we go to the nanoscale, you can.”

The chip was placed in a vacuum. The researchers then heated one side of the chip and cooled the other side separated by a tiny gap, creating a heat flux that can be converted into electricity. Generating electricity in this manner is not novel, but where the new study shines is in its demonstration of fitting two silicon surfaces close enough to achieve this effect without them touching each other. The closer the two surfaces are to one another, the more electricity can be generated.

About two-thirds of the energy consumed in the U.S. each year is lost as heat. Francoeur envisions a version of his chip in the future which cools down laptops and smartphones and channels extra electricity to the battery. He estimates that battery life could potentially be improved by 50% using this technology. For instance, a laptop with a six-hour charge could last nine hours. The blackbody chip could also be used to up the efficiency of solar panels or in automobiles to convert heat from the engines to power the electrical systems.

“You put the heat back into the system as electricity,” he said. “Right now, we’re just dumping it into the atmosphere. It’s heating up your room, for example, and then you use your AC to cool your room, which wastes more energy.”

The findings were published in the journal Nature Nanotechnology.

NASA puts InSight experiment on hold because one stubborn rock is blocking their instruments

A key instrument on NASA’s Mars InSight rover has run into a problem — ground control suspects a stone.

Mars landing.

A rendering of a InSight Mission Candidate Landing Site made using topography data from the University of Arizona / NASA/.
Image credits Kevin Gill / Flickr.

The rover’s heat probe has struck an obstacle just below the red planet’s surface over the weekend and hasn’t been able to make progress since.

The Heat Flow and Physical Properties Package Problem

“The team has therefore decided to pause the hammering for about two weeks to allow the situation to be analyzed more closely and jointly come up with strategies for overcoming the obstacle,” Tilman Spohn, the principal investigator for the heat probe, wrote Tuesday in the mission logbook.

The instrument, known as the Heat Flow and Physical Properties Package, or HP³, was designed to hammer itself 16 feet (roughly 5 meters) into Mars’ underground and measure how much heat its interior leaks. This data would help researchers estimate the planet’s composition and history.

However, trouble is brewing underneath InSight — this probe (nicknamed the “mole”) encountered some kind of resistance underground over the weekend and hasn’t been able to make any progress since. Ground control (at the Jet Propulsion Laboratory in La Canada Flintridge, California) first tried to power it up last week. This first attempt failed to reach all the way to the Mars Odyssey orbiter, however, which was supposed to pass it on to InSight.

The mole was deployed last Thursday, after the team established a stable connection to the rover. It pushed its way in the red soil and made quick progress. For about five minutes. The next four hours of hammering failed to push the mole much deeper and eventually forced the device to one side — the mole is now lodged in the underground, leaning at about 15 degrees of vertical.


Artist’s concept of InSight and its instruments.
Image credits NASA / JPL-Caltech.

Current estimates place the mole at a depth of around one foot (0.3 meters). This means that the probe — measuring some 16 inches (0.4 meters) in height — is partially sticking out of the ground. Despite this, the probe likely still is burrowed “deeper than any other scoop, drill or probe on Mars before,” which was its intended purpose.

Spohn writes that the team is a bit worried but that they “tend to be optimistic.” They’re currently working on the assumption that the holdup is a buried boulder or some gravel.

This particular spot was picked for InSight to land on as it appeared to be mostly sandy and soft. However, the team was aware that such a holdup was possible. Tests carried out at JPL suggested that the probe should be able to dig its way around small rocks or layers of pebbles. Since the second attempt to hammer away at the probe didn’t do that, the team decided to put the mole on hold. They’re currently waiting to receive more data from InSight, including pictures, so they can “better assess the situation.”

But not all is lost. The probe is still intact — that’s a really good thing — so it can actually start collecting data. The team has already put it to the task. HP³ will measure how quickly a generated pulse of heat spreads through the soil. Later this week, as (Mars’ moon) Phobos passes overhead and eclipse the sun over InSight the probe will also track how the event changes surface temperatures. While not its intended role, these readings should help the team make better sense of heat flow values in Mars’ soil if and when the probe is deployed as planned.

Florida Harvester Ant.

Desert ants’ complex behavior is actually built from very simple interactions

Ant colonies don’t organize per se, but they still pull off complex behavior in harsh environments without any glitches. New research looks into how the insects manage this, offering inspiration for future robotic systems.

Florida Harvester Ant.

Florida Harvester Ant (P. badius).
Image credits Judy Gallagher / Flickr.

Researchers from Princeton have created a new mathematical model to explain how desert harvester ants coordinate efforts to gather seeds. This seemingly-simple process actually needs to be very finely-tuned: in the desert, the colony needs to carefully weigh the water expenditure of foraging against the benefit of bringing in seeds (which serve as both food and water). The model could help future research analyze how ant colonies respond to environmental changes, the team writes, and how behavioral differences among colonies affect their long-term survival and reproductive success.

Anting it

“[The study] was this beautiful marriage of the opportunity not just to collect data, but to define experiments — to use our models and our perspective to try to understand the connection between what individuals are doing and what happens at the level of the group,” said Naomi Ehrich Leonard, Princeton’s Edwin S. Wilsey Professor of Mechanical and Aerospace Engineering, and the paper’s corresponding author.

The study was borne of Professor Leonard’s expertise — she has previously analyzed the dynamics of bird flocks and fish schools to understand how large groups can operate efficiently without central control — and that of Stanford University biologist Deborah Gordon. Gordon and her team have spent the last three decades monitoring red harvester ants (Pogonomyrmex barbatus) at a field site in the New Mexico desert.

Leonard powered-up Gordon’s efforts with a computer model meant to describe how interactions between individual ants generate the complex and highly-tuned behavior seen on the colony-level. In turn, the research will help in the design of robot swarm teams for search and rescue missions or other tasks in environments we can’t reach.

All in all, the ants are an excellent example of how a group of individuals interacts and makes tradeoffs in uncertain conditions. In the dry deserts of the southwestern United States and northern Mexico, red harvester ants gather seeds for both food and water. However, unless they go about it properly, they risk losing more water than they recover from seeds — which would, eventually, lead to the colony dying of dehydration.

“The ants are able to regulate the rate at which they send out foragers with a very limited communication framework,” says Renato Pagliara Vasquez, the study’s lead author.

Vasquez explains that the ants communicate mainly via smell. When two ants tap their antennae together, “they can smell what are called cuticular hydrocarbons, and that smell changes when they’ve been outside the nest. One ant can also tell if the other is carrying a seed, and this information is enough to regulate the entire foraging behavior of the colony.”

The model Leonard developed crunches these interactions to estimate how likely each forager is to leave the nest in search of seeds. Put together, these estimates allow them to analyze how a colony’s foraging rates fluctuate in response to environmental conditions.

To gather data for the model, Gordon’s team used videos and computer-vision software, as well as manual counts, to record 13 colonies of ants. They monitored how many of the insects entered and exited the nests during the morning hours (before it got too hot for the ants to forage) and how these figures varied from colony to colony.

The team looked at foraging behavior as a “closed-loop system” in which the environment and ants that are already foraging outside influence interactions inside the colony. In turn, this affects foraging rates. Ants coming into the colony interact with those already there, influencing their likelihood of engaging in foraging. What they wanted to understand is how environmental conditions affect each ant’s sensitivity to these interactions — something they call “sensitivity level volatility”.

It’s actually very similar to how simple interactions between neurons form our thoughts and memories, the team writes.

“The ants don’t know what the current temperature or humidity is outside the nest, so they become informed the first time they leave the nest,” Vasquez explains. “So, we proposed [that once] they’ve been outside for the first time they change how sensitive they are to interactions with returning foragers. In essence, the colony can use the accumulated information from the incoming ants to regulate how sensitive the colony is to sending out new foragers.”

“This model puts together the interactions of ants inside the nest and the rate at which they forage outside into one system, so that we can understand the process that evolution is shaping,” said Gordon. “Natural selection is acting on how this all works dynamically, and now we have a way to describe that. It’s a very elegant way to think about a lot of noisy dynamics and put it together into a model that can be used to guide further work.”

The researchers plan to expand their research by looking at the behavior of single ants throughout the day. Gordon also plans to integrate the foraging model with genetic data on the ant colonies to explore whether foraging behavior that helps the ants conserve water is heritable, since it is known to affect a colony’s reproductive success.

The paper “Regulation of harvester ant foraging as a closed-loop excitable system” has been published in the journal PLOS Computational Biology.

Portugal and Spain brace for record-breaking temperatures

Amid a scorching-hot summer spanning almost all of the northern hemisphere, Portugal and Spain are preparing for temperatures that could break not only the national record — but a record for the entire continent.

Forecast via Euronews.

Spain’s current record high is 47.3°C (117.14°F) and Portugal can boast a slightly-higher highest temperature, at 47.4°C. But all that may soon change, as current weather models forecast significantly higher temperatures. It’s not out of the question for Portugal to reach a groundbreaking 50°C, surpassing not only the national record but also the European record, which is currently at 48°C (recorded in Athens, Greece, in July 1977).

The probable maximum is set for Saturday, in the southern parts of Portugal and south-western parts of Spain. Met Office forecaster Sophie Yeomans says that the heatwave is directly connected to “a plume of very dry, hot air from Africa.” Although it’s unlikely for temperatures to go over 50°C, records may very well be broken, Yeomans says.

“There’s an outside chance of hitting 50C,” said Yeomans. “If somewhere gets the right conditions, it could do [it] but that’s a very low likelihood.”

Other forecasters have echoed this prognosis.

“Friday and Saturday are likely to be the hottest days with a very real chance of breaking records,” the forecaster of Meteogroup said.

The Spanish meteorology agency, AEMET, has issued an official warning of extreme temperatures, and authorities are already making emergency preparations for the dramatic heatwave. Some 11,000 firefighters and 56 aircraft have already been deployed and are on standby to tackle forest fires — that are likely to emerge in the searing heat.

Iberia, the peninsula hosting the two countries, is not the only area suffering from extreme heat. Scandinavia, an area known for its frigid temperatures, is reporting record highs, Greece is ravaged by wildfires, and most parts of France and Germany have been scorching for months. Aside from some mountainous areas and northern latitudes, few areas have been spared.

Most of Europe is under a heatwave. It’s hard to say that it’s global warming — but it sure walks and quacks like global warming.

Although it’s very difficult to assign a global trend to individual events, there is already substantial evidence that climate change is connected to these record temperatures. Recent studies have shown that man-made climate change is making heatwaves much more likely and, as was the case in previous years, it’s becoming increasingly unlikely that current temperatures and global warming are not connected.

Although record-breaking temperatures are not the norm yet, it’s becoming increasingly plausible that this will be the case in the very near future. The evidence is indicating that climate change is increasingly affecting our lives, whether we care to admit it or not.

Unusual heat waves in Britain are revealing traces of ancient civilisations

While most people in Britain struggle to deal with the summer heat, aerial archaeologists are loving it: the hot weather is revealing archaeological features which are usually hidden.

These crop marks indicate the location of an ancient settlement. Image credits: Toby Driver/RCAHMW.

It’s not usually this hot in the UK. While no records were really broken, overall temperatures were unusually high, often with serious consequences for ecosystems. But the heat had another unexpected consequence: it is revealing archaeological features.

“I’ve not seen conditions like this since I took over the archaeological flying at the Royal Commission in 1997,” aerial investigator Toby Driver from the Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW) told Wales Online.

“So much new archaeology is showing it is incredible.”

Britain is riddled with archaeological features. Continuously inhabited since pre-Roman times, the country can boast a trove of archaeological remains, which are now being brought to light without any digging. The remains of former castles, forts, farms, mansions, and more are becoming visible — some of them dating back to the Iron Age, while others, like WWII air shelters, are much more recent structures.

A prehistoric or Roman farm. Image credits: Toby Driver/RCAHMW.

Many of these were previously known to researchers but some are entirely unknown.

The reason these structures are popping up has a lot to do with water in the soils. The difference is that archaeological soil (soil that contains archaeological remains) often has different physical characteristics than its surrounding areas. For instance, it can be more compact or contain iron particles, which make it a bit harder for plants to survive.

A similar thing can happen if the soil is rocky — due to foundations or walls being buried under it, for example. Under heat stress, plants above these areas are more likely to wither away. Conversely, ancient ditches or moats that later get filled in with fresher soil can make it easier for plants to survive. Either way, archaeological features often cause a contrast i soil properties which can have visible effects on vegetation.

Image credits: Buried ramparts (Toby Driver/RCAHMW).

This kind of event is not exactly rare, but it’s not very common either. If archaeologists want to make the most out of this opportunity, time is of the essence: the window might close soon, and there’s a good chance that the marks will only remain visible for a week or two (depending on the weather conditions).

What will likely happen after these new features have been noted down is a geophysical survey — a non-invasive measurement of the subsurface properties which produce an even clearer evidence of buried archaeological structures. After that, archaeologists may decide to start digging and bring them to light.

Chaotic cities are cooler than orderly ones, researchers report

A new paper reports that street and building layout plays a major role in a city’s urban heat island effect, which makes them hotter than their surroundings.


Cities with an orderly pattern have a much greater urban heat island effect than those with a more disorderly pattern.
Image credits Pellenq et al., 2018, Physical Rev. Letters.

If you’re an American living in a big city, you’re probably used to all the streets and buildings being laid out in an orderly grid. If you happen to be European, not so much — our cities still sport the chaotic, sprawling road networks set down ages ago. While it can make navigation a pain, the latter can also help keep cities cool, according to new research led by MIT and National Center for Scientific Research senior research scientist Roland Pellenq.

The findings suggest that cities laid out in precise grids, like New York or Chicago, experience a far greater buildup of heat relative to their surroundings than those arranged more chaotically, like London or Boston.

The Hot Grid

The heat island effect is a product of the fact that building materials, like concrete, absorb heat during the day and radiate it out at night. Natural areas also trap some heat, but it’s a tiny amount compared to cities — mostly because plants use up incoming sunlight during photosynthesis. Heat island effects can make cities over 5° Celsius (10° Fahrenheit) warmer than surroundings, in areas that get a lot of sunlight. It can cause health issues for city dwellers and causes energy use to spike during hot weather. So, a better understanding of the effect can improve quality of life for residents and presents (several) economic advantages to boot.

To explore the heat island effect, the team adapted mathematical models that were developed to analyze the atomic structures in materials, developing a new and straightforward method to study the relationship between a city’s design and its heat-island effect. Such systems describe how individual atoms in a material are influenced by other atoms, and the team reduced the simulation to much simpler, statistical descriptions of how far away buildings are from each other. Then, they applied them to patterns of buildings in 47 cities, from the U.S. and also from other countries.

Each city was thus ascribed a ‘local order parameter,’ ranging between 0 (total disorder) and 1 (perfectly ordered structure, which is generally a description of how orderly atoms in a material are — typically, this parameter is obtained by bombarding a sample with neutrons. For this paper, however, Pellenq and his team used Google maps to pinpoint the location of each building. The cities included in the paper varied from 0.5 to 0.9 on their local order parameter.

Temperature data was recorded for each city by two stations — one within the city proper, and another outside but still close — which were used to determine the heat island effect in each case.

The team reports that the heat island effect seems to result from the interactions between buildings that radiate and re-radiate heat. This heat can be trapped by other buildings that face them directly, the team reports, meaning the city has a very hard time cooling off. They estimated that in the state of Florida alone, urban heat island effects lead to some $400 million in excess costs for air conditioning per year.

So, understanding how it works and planning around the effect might have significant benefits, especially for countries such as China that are rapidly building new cities, or areas of rapid urban expansion. In hot locations, cities could be designed to minimize the extra heating, while colder places might benefit from amplifying the effect.

“This gives a strategy for urban planners,” says Pellenq.

“If you’re planning a new section of Phoenix, you don’t want to build on a grid, since it’s already a very hot place. But somewhere in Canada, a mayor may say no, we’ll choose to use the grid, to keep the city warmer.”

Other important findings of the study are that research on construction materials can offer a way forward in regards to heat management and heat interactions between buildings.

The paper “Role of city texture in urban heat islands at nighttime” has been published in the journal Physical Review Letters.


New eco-friendly AC uses only water to cool down air, saves on the energy bill to boot

A new type of air conditioning is waiting to make its cool debut on the market. Suitable for both indoor and outdoor use, the system is much more energy efficient than traditional units, uses plain water instead of chemicals refrigerants, and produces drinking water to boot.


The team and their novel AC system.
Image credits NUS.

With the winter holidays coming to a close, it’s time to plan for the future. The hot, sweaty, sticky near-future of summer. There is solid ground to assume that this year will be a scorching one, which should still feel like small fry compared to those in the future.

All this heat will not be doing anyone any favors. According to researchers from the Natural Resources Defense Council, future summers won’t be only about ice-cream and beach holidays — they will be very deadly seasons, claiming tens of thousands of lives all across the US. The EU is on the hook too, and there’s no reason to believe people in other areas of the world will fare much cooler than, essentially, the world’s technological and economic powerhouses.

Too hot for comfort

It’s not an overstatement, then, to say that proper temperature control, in the form of air conditioning, will become a matter of life or death in the future. However, our current approach to the issue leaves us in a spot of hot water.

For one, air conditioning isn’t so much about ‘destroying’ heat as it is about taking it somewhere else — specifically, out of the room. Comfy on the inside, but the reverse of the coin is that the ‘outside’, especially if you live in a big city, gets much warmer very fast. Le Chatelier’s principle on equilibrium tells us that this will make it progressively more difficult for air conditioning units to actually push all that heat outside: it’s more laborious to create a big imbalance (pumping heat from a cold room to a hot outside) than a small one (say, between two bodies at closer temperatures). It’s like pushing water uphill. Which segues us into issue Mk.2:

The harder our ACs have to work, the more energy they need. Ironically, this makes everything hotter, as that energy degrades into heat. It’ll also put a large dent in many a family’s finances, and many people will have to contend with an unenviable choice: go into overdraft, or gamble that nobody’s going to get heatstroke. Zooming back even further, it will put a huge strain on often aging and already-overtaxed power grids — and we definitely don’t want these to pop when everybody’s hugging the AC for dear life.

Lastly, our current systems employ chemical refrigerants such as chlorofluorocarbons and hydrochlorofluorocarbons for cooling, which are quite nasty for the environment. More directly important to you, however, is that these compounds are quite expensive to manufacture and very deadly if leaks occur indoors.

So we need a better alternative. Luckily for us, that’s exactly what one team of researchers from the National University of Singapore (NUS) has been working on, with support from the Building and Construction Authority and National Research Foundation Singapore. The device they came up with could potentially address the limitations of the century-old AC principle in use today.

The water-based AC system can cool air down to 18° Celsius (64.4° F) without using the energy-intensive compressors or the chemical refrigerants the most common ACs today use. Suitable both for indoor and outdoor use, the device is fully portable and can be customized to work in all weather conditions, says the team led by Associate Professor Ernest Chua from the university’s Faculty of Engineering.

Cooler cooling

Because it relies on water in lieu of chemical refrigerants, the device is also cheaper to manufacture than traditional AC systems, is more sustainable, more eco-friendly, and potential leaks will be a nuisance at their worst. Running costs should also be much lower, as the team reports their cooler uses roughly 40% less electricity than traditional systems — good for your bill and the planet, too.

A final feature you’ll enjoy on a scorching noon is that the system also generates potable water as it cools your room.

“For buildings located in the tropics, more than 40 per cent of the building’s energy consumption is attributed to air-conditioning,” Chua says. “We expect this rate to increase dramatically, adding an extra punch to global warming.”

“Our novel membrane and water-based cooling technology is very eco-friendly — it can provide cool and dry air without using a compressor and chemical refrigerants. This is a new starting point for the next generation of air-conditioners, and our technology has immense potential to disrupt how air-conditioning has traditionally been provided.”

Instead of dehumidifying and cooling the air at the same time, as conventional designs do, the team from NUS decided to handle them separately. Finer control over each process allowed the team to increase their energy efficiency.

The first step in the process is to pass air through a paper-like membrane which removes moisture. Then, the dry air is passed through a dew-point cooking system. In broad lines, this is a system that uses part of the dry air produced in the first step to force evaporation on metallic plates inside the AC. Since water needs energy to turn into a gas (and heat is energy), this process cools the plates which, in turn, cool the air flowing through them. Out the end comes a stream of cooled, drier air than compared to the environment, and about 12 to 15 liters (12.68 to 15.85 quarts) of potable water per day.

According to the team, the device can easily be adapted to work in all types of weather and climate, used for individual homes or scaled up to service clusters of buildings. The team says it’s particularly well-suited for confined areas that need reliable humidity control, such as bomb shelters, wine cellars, or hospitals. “Armoured personnel carriers, and operation decks of navy ships as well as aircrafts,” are also good candidates, Chua adds.

The team is currently refining its design to further improve user-friendliness. They plan to incorporate features including pre-programmed thermal settings, based on human occupancy, and real-time tracking of its energy efficiency. The team hopes to work with industry partners to commercialize the technology.


Why does hot water freezes faster than cold water? Enter the Mpemba effect

A Spanish team of researchers has developed a framework theory that could explain the Mpemba effect — the mysterious physical phenomenon that makes hot water freeze faster than cold water.


Image via Pixabay.

Preheated liquids freeze faster than cold ones. There’s some evidence that Aristotle first observed this effect in the 4th century AD, and it later piqued the curiosity of intellectual heavyweights such as Francis Bacon and René Descartes.

Hot ice cream

In 1960, the phenomenon took its first steps toward theory when Tanzanian student Erasto Mpemba observed that the hottest mixture of ice cream froze faster than the cold one during cookery class. Later, as a student at Mkwawa Secondary School in Iringa attending a physics lecture, he inquired about the causes of this phenomenon and was ridiculed by classmates and his teacher. However, the lecturer, Dr. Denis Osborne from the University College in Dar es Salaam, tested and confirmed Mpemba’s observations. The two published a paper in 1969 detailing the findings.

The strange effect later made it into both educational and science outlets, but its causes have been poorly understood until now. That’s why a team of Spanish researchers set out to determine why the seemingly counter-intuitive Mpemba effect exists.

“It is an effect that, historically, has not been addressed in a rigorous manner but merely as an anomaly and a didactic curiosity,” said Antonio Prados, paper co-author and researcher at the Universidad de Sevilla Department of Theoretical Physics. “From our perspective, it was important to study it in a system with the minimum ingredients to be able to control and understand its behavior.”

Certain “ingredients” have to come together for the effect to occur in a given system, the team reports. They studied the Mpemba effect in granular fluids, substances that contain hard inelastic spheres but behave as liquids. This environment was selected so that the team could simulate interactions between particles and “make analytical calculations to know how and when the Mpemba effect will occur,” said Antonio Lasanta, study co-author and a researcher at the UC3M, Universidad Carlos III de Madrid.

When these particles collide they shed energy. Since higher temperatures mean more motion at the molecular levels, the Mpemba effect will take place faster in warmer liquids. The study also confirmed the existence of a ‘reverse-Mpemba’ effect generated by the same interactions, where the coldest system will heat up faster than the hottest one. This reverse was first predicted about a year ago by Oren Raz, now at the Weizmann Institute in Israel, and Zhiyue Lu from the University of Chicago.

“The scenario that the effect will most easily occur in is when the velocities of the particles before heating or cooling have a specific disposition — for example, with a high dispersion around the mean value,” the athors add. This way, the evolution of the temperature of the fluid can be significantly affected if the state of the particles is prepared before the cooling, they explain.

A better understanding of the Mpemba effect won’t just advance our understanding of basic science but could have practical applications in the mid to long term. If the team’s theory is verified, it could lead the way to electronics that cool down faster, for example.

There’s still a ways to go until then, however. Like Raz and Lu’s paper before, the study garnered some criticism for the very simplified model used to study the effect, compared to water’s more complicated behavior. Taken together, however, the studies support each other and lend a great deal of confidence that such particular interactions fit in the wider mechanisms of the Mpemba effect.

At the same time, Mpemba himself first observed the effect in milk, which has many large particles suspended in water. The granular liquid models could also apply to water samples: large solute particles in impure water samples could contribute to the overall Mpemba effect.

The paper “When the Hotter Cools More Quickly: Mpemba Effect in Granular Fluids” has been published in the journal Physical Review Letters.

Climate-change-induced heat will kill tens of thousands of Americans every year by 2090

According to a new analysis performed by the Natural Resources Defense Council, failure to limit emissions might cost the lives of more than 13,000 Americans every year by the mid 2040s and more than double that number by 2090.


Image via Pixabay.

From agricultural breakdown to rising ocean levels, climate change will drastically change our world and our place in it. But its effects always feel like they’ll take place somewhere else, don’t they? The ocean’s far away, and farms are a pretty rare sight these days. One effect, however, will hit everywhere, cities in particular, and will enact a massive toll of human lives — scorching summer heat.

“If we continue to emit climate-changing pollution at our current rate, our largest urban areas like New York, Philadelphia, and St. Louis will see many more summertime deaths,” the Natural Resources Defense Council’s (NRDC) report reads.

Deadly hot

Heatwaves can lead to a number of dangerous, potentially fatal health conditions, such as heatstroke, cardiovascular, and respiratory disorders. Children and the elderly are particularly at risk, as are low-income families who can’t afford to cool their homes or (largely thanks to the Don’T Care Act) seek medical help from heat-associated symptoms.

The paper estimates that for 45 of the US’ largest urban centers alone, heat-related fatalities could total 13,860 every year by the mid-2040s — that’s roughly 150 deaths, every day, for the whole summer. By 2090, that figure could increase to a staggering 30,000 per year, or more than 300 deaths every day of summer.

The 2090 estimates show that heat waves could kill 7,370 people per year in New York on average, 5,040 in Philadelphia, 2,440 in Chicago and 1,340 in Boston. Juanita Constible, the NRDC’s special projects director and author of the report, said that the analysis shows “some of the most dire consequences” of where current US policy is leading the country.

“The Trump administration is doing everything it can right now to roll back climate and health protections,” she said.

“Instead of accelerating our nation’s transition to a cleaner, safer future, President Trump and his Cabinet are driving in reverse with their eyes closed.”

NRDC graph.

Image credits Natural Resources Defense Council.

The best way to put these figures into context is by looking at past statistics. Between 2006 and 2010, the Centers for Disease Control and Prevention reports, there were about 620 reported cases of heat-related deaths. In the entire US.

Constible also estimates that if countries around the world meet their Paris goals, some 12,820 lives could be saved each year in the largest 45 metropolitan areas, the NRDC estimates — more than 3,100 in New York alone, and around 1,600 in both Philadelphia and Chicago.

But again, that’s contingent on the goals agreed upon in Paris, which aim to keep global warming below 2 degrees Celsius, being met. With the US’ recently announced withdrawal from the agreement, one of the largest emitters in the world doesn’t seem interested in pursuing that goal any longer. At the same time, Americans will likely have to deal with both more frequent, and more intense heatwaves, as well as a more polluted and dangerous environment: President Trump has promised to save America’s dying coal industry, and increase oil and gas production, and is set to gut the Environmental Protection Agency’s funding for climate programs.

“To minimize needless and preventable American deaths from heat-related causes, the Trump administration must cease these rollbacks of vital health and environmental protections and immediately recommit to the Paris Agreement,” the report concludes.

You can read and download the full report here, via NRDC.