
-
Kenya's economy faces climate change risks: World Bank
-
Lessons and liquids: buried alive in Myanmar's earthquake
-
Nintendo Switch 2 sparks excitement despite high price
-
Sri Lanka's crackdown on dogs for India PM's visit sparks protest
-
China vows 'countermeasures' to sweeping new US tariffs
-
Trump jolts allies, foes and markets with tariff blitz
-
How Trump's 'liberation day' tariffs will impact China
-
Europe hits out at Trump tariffs, keeps door open for talks
-
Australia sweats through hottest 12 months on record: official data
-
South African artist champions hyenas in 'eco-queer' quest
-
Taiwan says US tariffs 'highly unreasonable'
-
Trump escalates trade war with sweeping global tariffs
-
China says opposes new US tariffs, vows 'countermeasures'
-
Quake-hit Myanmar's junta chief to head to Bangkok summit
-
New Spielberg, Nolan films teased at CinemaCon
-
Shiny and deadly, unexploded munitions a threat to Gaza children
-
Stocks tank, havens rally as Trump tariffs fan trade war
-
Financial markets tumble after Trump tariff announcement
-
Europe riled, but plans cool-headed response to Trump's tariffs
-
'Shenmue' voted most influential video game ever in UK poll
-
Revealed: Why monkeys are better at yodelling than humans
-
Key details on Trump's market-shaking tariffs
-
US business groups voice dismay at Trump's new tariffs
-
Trump sparks trade war with sweeping global tariffs
-
US stocks end up, but volatility ahead after latest Trump tariffs
-
Boeing chief reports progress to Senate panel after 'serious missteps'
-
Is Musk's political career descending to Earth?
-
On Mexico-US border, Trump's 'Liberation Day' brings fears for future
-
Tesla sales slump as pressure piles on Musk
-
Amazon makes last-minute bid for TikTok: report
-
Tesla first quarter sales sink amid anger over Musk politics
-
World's tiniest pacemaker is smaller than grain of rice
-
Nintendo says Switch 2 console to be launched on June 5
-
Certain foreign firms must 'self-certify' with Trump diversity rules: US embassies
-
Nigerian president sacks board of state oil company
-
Heathrow 'warned about power supply' days before shutdown
-
Epstein accuser Virginia Giuffre 'stable' after car crash
-
Swedish insurer drops $160 mn Tesla stake over labour rights
-
Stock markets mixed as uncertainty rules ahead of Trump tariffs
-
Warner showcases 'Superman' reboot, new DiCaprio film
-
Asian markets edge up but uncertainty rules ahead of Trump tariffs
-
UK imposes online entry permit on European visitors
-
How a Brazilian chief is staving off Amazon destruction
-
Brazil binman finds newborn baby on garbage route
-
Trump set to unleash 'Liberation Day' tariffs
-
GM leads first quarter US auto sales as tariffs loom
-
Trump 'perfecting' new tariffs as nervous world braces
-
Trump puts world on edge as 'Liberation Day' tariffs loom
-
UK vows £20 million to boost drone and 'flying taxi' services
-
Ford's US auto sales dip in first quarter as tariffs loom

Plane contrails: white fluffy contributors to global warming
The white, feathery lines behind airplanes that look like bits of harmless cloud are anything but, warn experts, who say they could have a greater environmental impact than the aviation sector's CO2 emissions.
The condensation trails -- contrails, for short -- are being increasingly studied as scientists work with the industry to find technological solutions to the problem.
Classified as non-CO2 emissions from aircraft, in September they were the subject of a symposium in Montreal organized by the International Civil Aviation Organization, a UN agency.
- What are contrails? -
Contrails are clouds that form at high altitudes in cold, humid areas called ice supersaturated regions (ISSRs).
When jet fuel is burned by engines, water vapor condenses on to soot particles to form ice crystals.
Enough ice crystals, and they begin to form cirrus clouds -- high-altitude, wispy white filaments that, when created this way, trail out behind planes as they cross the sky.
These trails trap some of the heat that rises from the Earth at night, preventing it from radiating back out of the atmosphere -- thus acting as a greenhouse gas, causing warming, explains Donald Wuebbles, a professor at the University of Illinois.
Contrails that stay in the sky for a few minutes are not very worrisome, he says.
"But if they form at night, they'll maybe last a little longer, and at night they can cause a warming effect," he adds.
- What is the impact? -
Non-CO2 emissions could account for up to two-thirds of aviation's impact on global warming, which "gives you an idea of how important they are to consider," Wuebbles said.
And contrails could form up to 57 percent of that impact -- far more than the C02 emissions from burning fuel, according to a 2021 study.
However, such emissions are short-lived compared to carbon dioxide and their impact on global warming could be quickly eroded if solutions were found to avoid them, experts say.
- So what can be done? -
Not all flights create contrails -- it can depend on weather conditions and the aircraft's trajectory.
For example, at Air France, just four percent of flights are responsible for some 80 percent of the airline's contrail impact on global warming, notes Irene Boyer-Souchet, who is leading up the company's efforts to mitigate the damage.
The long-term strategy is to modify the trajectory of a fraction of flights.
Air France pilots made more than 3,000 observations over 18 months with the aim of helping Meteo-France improve its forecasts for at-risk areas so that pilots could eventually avoid them.
"The main risk is that by thinking you're avoiding an area, you could end up flying there because it's slightly off the weather forecast," Boyer-Souchet points out, illustrating the importance of fine-tuning the research.
Pilots from American Airlines conducted 70 test flights above or below at-risk areas, guided by satellite images, weather data, software models and AI prediction tools.
A 54-percent reduction in contrails was observed, along with a two-percent increase in fuel consumption.
Accelerating the deployment of a global contrail avoidance system could reduce aviation's impact on the climate by 40 percent, according to a Cambridge University report published in September.
The more flights in the air, however, the more complicated the implementation of such a system would be, notes Boyer-Souchet, who hopes that it will be a reality by 2030.
S.F.Lacroix--CPN