Month: March 2024

A new climate intervention strategy aims to decrease the amount of water vapor in the stratosphere by injecting it with ice-forming nuclei. The idea is that, by reducing the water content, more heat in the form of infrared radiation would leak out into space.

Scientists described the strategy a study published Wednesday in Science Advances. “It’s not a very complicated idea,” Joshua Schwarz, a researcher at National Oceanic and Atmospheric Administration’s Earth System Research Laboratory and lead study author, told Gizmodo. “But this idea… it’s not a silver bullet, it’s not the magic solution that nobody knows about. It’s just one alternative that will do a little something in the right direction.”

Water vapor acts as a greenhouse gas in Earth’s atmosphere, absorbing radiation from the Sun and then emitting it to the surface of our planet. The scientists behind the new study want to target a small amount of the water vapor found in the stratosphere, the second layer of Earth’s atmosphere, by adding ice-nucleating particles. With water vapor condensing to ice, there would be less trapped heat. Removing around 3% of the water vapor would have a global effect, according to the study.

Using observations from NASA’s Airborne Tropical TRopopause EXperiment (ATTREX), a research aircraft that tracked the transport of water vapor into the upper atmosphere, the team created a model to examine the amount of particles needed to pull off stratospheric dehydration and their predicted trajectories. The models suggested that the idea can work to help mitigate the effects of global warming, but a lot of technical challenges still lie ahead in terms of implementing the strategy.

“We have confidence that it would be a win… that it wouldn’t do anything bad and we know exactly how to do it,” Schwarz said. “We didn’t find anything that said, this is impossible, give up. Instead, we only learned that there’s still more to know.”

The stratosphere extends from 4 to 12 miles (6 to 20 km) above Earth’s surface to around 31 miles (50 km) up. There are aircraft capable of reaching those heights, but the idea still needs the development of an engineering capability to inject the nuclei into the stratosphere. And much more work would need to be done to identify the potential risks and unintended effects.

“If we had one magic way to [address climate change] I wouldn’t say, oh we shouldn’t use it,” Schwarz said. “At this point, my feeling is we need more ideas and to explore the implications of the approaches we decided to take…it might be easier to get a mixture of options that’s better for the planet and humanity than just one approach.”

A lifetime of snacking and frozen food dinners may affect your body in lots of surprising ways, new research suggests. The study, a large-scale review of the existing evidence, found an association between regularly eating ultra-processed foods and a higher risk of many health problems. It also found that these foods were associated with an early death.

Many studies have indicated that ultra-processed foods are uniquely bad for our health. But the authors of this latest research, published Wednesday in the BMJ, say there hasn’t yet been a comprehensive, bird’s-eye view of the scientific literature surrounding these foods. To remedy that, they decided to conduct an “umbrella review”—a review of other reviews and meta-analyses on a particular topic.

All told, the team looked at data from 14 reviews that collectively involved nearly 10 million people, none of which were funded by manufacturers of ultra-processed foods. Across the board, they found that a higher exposure to these foods was associated with a higher risk of 32 health outcomes, from heart disease to trouble sleeping to depression. Greater intake of ultra-processed foods was also tied to a greater risk of dying from any cause (21% higher), as well as a greater risk of heart-related death specifically (66% higher).

“This umbrella review found consistent evidence of a higher risk of adverse health outcomes associated with greater ultra-processed food exposure,” the authors wrote.

It can be very difficult to tease out just how unhealthy any one group of foods can be, and the authors note that the evidence for some of these links is much stronger than others. With conditions like Crohn’s disease, obesity, and colon cancer, for instance, the authors found weak to no evidence for a potential association. Conversely, the strongest evidence for a higher risk was seen with heart-related deaths, common mental health disorders, and type 2 diabetes.

Another limitation of this research is that not everyone might agree on what exactly is an ultra-processed food. The criteria used by the authors and many other researchers is known as the NOVA Food Classification system, which defines these foods as anything “made entirely or mostly from substances extracted from foods, derived from food constituents, or synthesized in laboratories from food substrates or other organic sources.” Common examples of ultra-processed foods include soft drinks, candy, and ready-to-eat meals. But there has been some debate over how useful this system really is and whether even food experts can reliably identify an ultra-processed food based on this criteria.

That said, small randomized and controlled experiments have found that ultra-processed foods might be especially bad for us. And given all of the data collected, it would be very strange if there wasn’t some genuine health risk from eating too many of these foods. For their part, the authors say that more rigorous research is needed to understand exactly how these foods can negatively affect our health, but they also argue that policymakers should already be doing more to reduce our dependence on them. Other research has suggested that everyone’s diets—including the diets of kids and teens—are far too full of these foods.

“These findings support urgent mechanistic research and public health actions that seek to target and minimize ultra-processed food consumption for improved population health,” the study authors wrote.