The article discusses a recent study led by University College London researchers that suggests using existing large planes, like the Boeing 777F, to inject particles into the atmosphere to reflect sunlight and cool the planet. This approach, known as stratospheric aerosol injection, is a geoengineering technique that has been previously researched but assumed to require specially designed aircraft flying at high altitudes.

The study found that injecting sulphur dioxide particles at an altitude of 13 km above the polar regions could meaningfully cool the planet, albeit less effectively than at higher altitudes closer to the equator. This approach would require using three times the amount of aerosol and would have increased side effects like acid rain.

However, climate change is a serious problem, and it’s essential to understand all options for policy-makers to make informed decisions. The researchers used simulations in the UK’s Earth System Model 1 (UKESM1) to estimate the impact of stratospheric aerosol injection at different altitudes, latitudes, and seasons.

Injecting 12 million tonnes of sulphur dioxide a year at 13 km would cool the planet by around 0.6°C, which is roughly the same amount added to the atmosphere by the eruption of Mount Pinatubo in 1991. This strategy is not as effective as injecting particles at higher altitudes but could begin sooner.

The study’s lead author noted that any stratospheric aerosol injection would need to be introduced gradually and reduced gradually to avoid catastrophic impacts from sudden warming or cooling, and would not eliminate the need for emissions reductions. The researchers emphasized that long-term climate stability can only be achieved with net-zero greenhouse gas emission reductions.

As the world warms due to climate change, holiday flights in Europe may be forced to carry fewer passengers in the coming decades. Scientists at the University of Reading have studied how hotter air affects aircraft performance during take-off, with alarming results.

The researchers focused on the Airbus A320, a common aircraft used for short and medium-haul flights across Europe. By the 2060s, some airports with shorter runways may need to reduce their maximum take-off weight by the equivalent of approximately 10 passengers per flight during summer months.

Dr Jonny Williams, lead author of the study at the University of Reading, explained: “A warming world has an impact on people and businesses worldwide, and we are now showing one way it could increase the price of your summer holiday. Flying to Spain, Italy or Greece could get more expensive as flights carry fewer people due to climate change.”

The study found that hot summer days when smaller airports have to reduce their weight will become more common. Conditions which used to happen about 1 day in a summer may happen 3 or 4 days a week by the 2060s.

Four popular tourist destinations – Chios, Greece; Pantelleria, Italy; Rome Ciampino, Italy; and San Sebastian, Spain – will be most affected. These airports have shorter runways, meaning airlines can’t operate them at the maximum weight set by the manufacturer. Future increases in heatwaves will only make this worse, forcing operators to reduce aircraft weights and profit margins even further.

While larger airports like London Heathrow and Gatwick have runways long enough to handle the A320 even in extreme heat, they may face challenges with larger aircraft like the Airbus A380, which needs more runway space. Airlines might need to reschedule flights to cooler parts of the day, and runway maintenance needs could increase as surfaces degrade faster in extreme heat.

The researchers note that following a more sustainable climate path would stabilise these effects, whereas continued high emissions would make the problem significantly worse. Future studies will examine how other factors like humidity and changing wind patterns may further impact take-off performance.

The study, led by Professor Sunny Jung of the College of Agriculture and Life Sciences, aimed to explore how hand clapping generates sound depending on various factors such as hand shape, size, and technique. The researchers used high-speed cameras to track the motion, air flow, and sound produced by 10 volunteers clapping their hands in different ways.

The results showed that the larger the cavity between the palms, the lower the frequency of the clap. This is because the air column pushed by the jet flow of air coming out of the hand cavity causes the disturbance in the air, producing the sound we hear. The researchers also found that the softness of the hands plays a role in dampening the sound.

The study compared human data to theoretical projections using a traditional resonator called a Helmholtz resonator and confirmed that it can predict the frequency of the human handclap. This finding has potential implications for bioacoustics, as it may help explain various phenomena involving soft material collision and jet flow.

Moreover, the researchers discovered that claps are so short compared to sound made through a traditional resonator due to the softness of the hands vibrating after impact and absorbing energy. This knowledge can be used to design handclapping shapes that make the hand more rigid, resulting in a longer-lasting sound.

The study opens the door to using a handclap as a personal identifier or signature, with another researcher testing its potential for taking attendance in a class. The connection between the physics of hand clapping and its applications is new, and this research provides a comprehensive understanding of the phenomenon.

This study was supported in part by funding from the National Science Foundation and involved co-authors from Cornell University and the University of Mississippi’s National Center for Physics and Astronomy.