Healthy foods are green foods.
A analysis of 57,000 foods reveals which ones have the best and worst environmental impacts. A team of researchers used an algorithm to estimate the amount of each ingredient in thousands of products sold in major UK supermarket chains. The scientists then gave the foods an environmental impact score of 100, with 100 being the worst, by combining the impacts of the ingredients in 100 grams of each product. They considered various factors, including greenhouse gas emissions and land use.
The healthiest foods tended to have a low environmental impact, the team found. Products containing lamb and beef, such as prepared meat pies, had the most serious environmental impact. The lowest-impact foods tended to be made from plants and included bread products, fruits, vegetables, grains, and high-sugar beverages. There were some notable exceptions: both nuts and shellfish had good nutritional scores but relatively high environmental impacts.
Source: M.Clark et al. proc. National Academy. science usa 119e2120584119 (2022).
covid-19 rebound
After the COVID-19 antiviral Paxlovid came into use in late 2021, researchers noted that some people experience a rebound in virus and symptoms after taking the drug. Two recent studies suggest that it is surprisingly common for SARS-CoV-2 to come back in untreated cases of COVID-19 as well. To determine the frequency of rebound, Jonathan Li, a physician-scientist at Brigham and Women’s Hospital in Boston, Massachusetts, and his team analyzed data from hundreds of people who were randomized to receive a placebo in a large-scale trial of COVID-19 drugs. antibodies More than a quarter of participants infected with SARS-CoV-2 reported a rebound in their symptoms, according to the study, which has not yet been peer-reviewed. “The main take-home message is that recovery from COVID-19 will not be a linear process,” says Li.
Source: Deo, R. et al. Preprint on medRxiv https://doi.org/10.1101/2022.08.01.22278278 (2022).
How trees grow in a warmer world
This graph shows how the early arrival of spring, due to climate change, affects tree growth and the amount of carbon they sequester. in a role in Nature, the researchers investigated the consequences of an early start to the growing season in deciduous forests. The emergence of leaves is followed by the absorption of carbon through the process of photosynthesis. Over time, carbon can be captured for long-term sequestration if it contributes to radial growth of stems or wood formation. The areas under the curves represent annual growth in terms of: the amount of carbon captured by leaves (upper curves, brown); annual radial growth (lower left curve, blue); and increase in woody biomass (lower right curve, red).
The authors report that the early arrival of spring, which shifts the margins of the growing season (lighter curves), had little impact on the width of the final annual rings or the amount of woody biomass produced, while high temperatures in summer had a negative effect. effect on radial growth (dotted curve). Other studies (plotted here as dotted curves) indicate that high temperatures and associated drought can suppress carbon sequestration and woody biomass production.
The study provides evidence that warmer springs have advanced the appearance of leaves in temperate deciduous forests, but have not substantially increased their wood production. This suggests that additional carbon dioxide uptake does not contribute to sustainable carbon sequestration in the trunks of long-lived trees, such as ours. News and views article explains.
