During the early 2000s, environmental scientists studying methane emissions noticed something unexpected: the global concentrations of atmospheric methane (CH4)—which had increased for decades, driven by methane emissions from fossil fuels and agriculture—inexplicably leveled off.

Sustainability leadership efforts at the University of New Hampshire have contributed to a groundbreaking initiative to measure and reduce the nitrogen footprint left behind by campus activities like food waste and energy consumption. The new research is highlighted in the April 2017 special issue of Sustainability: The Journal of Record. The publication outlines research being done at UNH, and seven other institutions, to reduce emissions of reactive nitrogen (all forms of nitrogen except unreactive N2 gas) and prevent negative impacts on such things as water quality, air pollution, and climate change.

In recent decades, scientists and land managers have realized the importance of controlled forest fires for reaching specific forest management objectives. However, questions remain about how often forests should be burned. Now, researchers at the University of Missouri have studied forests subjected to different frequencies of fires to determine what effects fire can have on oak forests over long periods of time. They found that the frequency of prescribed forest fires should be determined based on the long-term goals of land managers.

Diatoms are a group of unicellular algae particularly sensitive to changes that affect their aquatic environment. This is why they are used as bioindicators for the biological monitoring of water quality. However, their microscopic identification in river samples requires a lot of time and skills. Biologists from the University of Geneva (UNIGE), Switzerland, have succeeded in establishing a water quality index based solely on the DNA sequences of the diatoms present in the samples, without needing to identify each species visually. This study, published in the journal Molecular Ecology Resources, presents a revolutionary tool to process a very large number of samples in parallel, allowing wide coverage of the monitored sites in a reduced time and at a lower cost.

Photosynthesis requires a mechanism to produce large amounts of chemical energy without losing the oxidative power needed to break down water. A Japanese research team has clarified part of this mechanism, marking another step towards the potential development of artificial photosynthesis. The findings were published on February 27 in the online edition of The Journal of Physical Chemistry Letters.

Although human population studies have linked air pollution to chronic inflammation of nasal and sinus tissues, direct biological and molecular evidence for cause and effect has been scant. Now, Johns Hopkins researchers report that experiments in mice continually exposed to dirty air have revealed that direct biological effect.

Researchers have long known that smog, ash and other particulates from industrial smokestacks and other sources that pollute air quality exacerbate and raise rates of asthma symptoms, but had little evidence of similar damage from those pollutants to the upper respiratory system.

Birds sing differently in response to traffic noise, which potentially affects their ability to attract mates and defend their territory, according to research published in Bioacoustics. The study found that a species of North American flycatcher sings shorter songs at a lower range of frequencies in response to traffic noise levels. The researchers suggest traffic noise reduction, for example through road closures, is a viable option for mitigating this effect.

Since 2007, scientists have been searching to find the cause of a sudden and unexpected global rise in atmospheric methane, a potent greenhouse gas, following almost a decade in which concentrations had stayed relatively constant.

Recent studies have explored a range of possible causes. Suggestions have included a rise in oil and natural gas extraction, increased emissions from tropical wetlands or increases in emissions from growing East Asian economies.

How hot our planet will become for a given amount of greenhouse gases is a key number in climate change. As the calculation of how much warming is locked in by a given amount of emissions, it is crucial for global policies to curb global warming.

It is also one of the most hotly debated numbers in climate science. Observations in the past decade seem to suggest a value that is lower than predicted by models. But a University of Washington study shows that two leading methods for calculating how hot the planet will get are not as far apart as they have appeared.

Traffic-related air pollution may increase cardiovascular disease risk by lowering levels of high-density lipoprotein (HDL), commonly known as “good” cholesterol, according to new research in the American Heart Association’s journal Arteriosclerosis, Thrombosis, and Vascular Biology.