Les incendies de forêt dévastateurs dans le nord du Canada ces dernières années ont des conséquences climatiques qui vont bien au-delà de la fumée et du dioxyde de carbone rejetés dans l'atmosphère, selon une nouvelle étude co-écrite par deux chercheurs de la NAU. L'étude, qui a examiné les divers effets des incendies dans le nord du Canada et en Alaska, n'était pas que de mauvaises nouvelles : les chercheurs ont découvert que les incendies au Canada, lorsqu'ils sont associés au manteau neigeux, ont un effet de refroidissement net. Ce refroidissement, cependant, n'est pas suffisant pour compenser les effets de réchauffement du carbone du pergélisol libéré dans l'atmosphère par les incendies en Alaska.
in Écologie
![Janette Kerr PPRWA Hon. RSA, Twenty Solargraphs from the Solargraphic Project 2020-24 Formless 2024-25 (exposure time 18 months) Solargraph on paper Kerr collaborated with communities in Iceland, Greenland, Shetland and Somerset, to record the slow passage of time in different landscapes. The solargraphic process is a form of long-exposure photography. Kerr captures the arc of the Sun, as it moves across the sky from dawn to dusk, on photographic paper sealed in DIY pinhole cameras made from drinks cans. Her approach combines science and art, chemistry and the digital processing of the final image. Slow Time. The Sun rises and falls each day, its gradual trek discreetly recorded by small tin cans whose uninterrupted gaze captures every photon of sunlight travelling across the sky. Solargraphy (from the Latin solar, of the sun, and graphia, writing) is a form of long-exposure photography that captures the Sun moving across the sky. It combines science and art, chemistry and [today] digital elements. Being able to capture an extended period of time in a single frame, far beyond the capacity of the human eye, is incredible enough, but even more amazing is how simple it is. A low-tech process, solargraphy typically uses pinhole cameras made from used drinks cans. Sheets of black-and-white photographic paper can be sealed inside the cans, and then the cameras are fixed outdoors, facing south [in the Northern Hemisphere]. We usually think of photography as an instant process, images captured digitally in a fraction of a second. Solargraphs by Kerr have been recorded over a period of 1?18 months, mapping landscape in slow time. Light waves are captured as they travel through the air, passing through a pinhole in the side of the can and slowly etching an image on photographic paper curved around the inside. The resulting images are shaped by landscape and the Sun?s daily elevation. Actions of the environment ? rain and other elemental detritus, or the can?s unexpected movement ? also leave traces on the final pictures, yet moving objects leave no trace. Solargraphy is a ?printing-out? process: this is where an image forms on photographic paper solely through the action of light, without using chemicals to develop the image. Light provides the energy required for silver halides (salts) in the photographic paper to change to a visible state. When silver halides are exposed to light, free metallic silver atoms are ?liberated?, forming a latent image. Over a prolonged exposure of several months the silver halide particles clump together, increasing in size. The photographic paper slowly becomes coloured, transitioning from yellow to sepia and then pink, even slate grey. (In traditional photography, the latent image would be chemically developed in a darkroom.) For contemporary solargraphy, the image captured on the paper can be scanned and manipulated, using a photo-editing program on a laptop, to form a digital record. A solargraphic project was initiated by Kerr during various residencies, and in collaboration with communities in Iceland, Greenland, Shetland and Somerset. The final images that she produces show the Sun?s progress as an accumulation of arcing and streaking lines, leaving ghostly exposures of landscape seen in slow time, out of phase with human activity. w3w: ///reporters.survived.formless (Coleford, Somerset) 2024?5 Solargraph on paper (exposure time: 18 months) 21 x 30cm COURTESY OF THE ARTIST](https://issues.fr/wp-content/uploads/2026/03/Des-artistes-regardent-l39espace-dans-une-nouvelle-exposition-epoustouflante-150x150.jpg "Des artistes regardent l'espace dans une nouvelle exposition époustouflante")