Most U.S. rooftops in good repair can take the weight of solar photovoltaic (PV) systems. That’s the conclusion of a three-year study by a research team led by Sandia National Laboratories.

“There is a misperception in the building industry that existing residential rooftops lack the strength to carry the weight load of rooftop solar photovoltaic installations,” said Sandia structural engineer Steve Dwyer. “Most existing well-built wooden rooftops can support PV system loads.”

Sandia took on the job of analyzing rooftop structural strength to address concerns raised in the U.S. Department of Energy’s (DOE) Solar America Cities program. The agency named 25 cities to promote adoption of solar technology at a comprehensive, local level through photovoltaics.

The climate talks that concluded last December were a great success, but it will be decades before we can judge whether the Paris Agreement itself is ultimately successful. What can be said is that the accord provides a good foundation for meaningful progress on climate change, and represents a dramatic departure from the past 20 years of climate negotiations.

I have long viewed the dichotomous distinction between Annex I and non–Annex I countries in the Kyoto Protocol as the major stumbling block to progress. The protocol included mandatory emissions-reduction obligations for developed countries, but none for developing countries. That made progress impossible, because significant growth in emissions since the protocol came into force in 2005 has been entirely in the large developing countries — China, India, Brazil, South Korea, South Africa, Mexico, and Indonesia.

About a tenth of overall global greenhouse-gas emissions from agriculture could be traced back to food waste by mid-century, a new study shows. A team from the Potsdam Institute for Climate Impact Research for the first time provides comprehensive food loss projections for countries around the world while also calculating the associated emissions. Currently, one third of global food production never finds its way onto our plates. This share will increase drastically, if emerging countries like China and India adopt Western nutrition lifestyles, the analyses shows. Reducing food waste would offer the chance to ensure food security, which is well known. Yet at the same time it could help mitigate dangerous climate change.

Of all the impacts of climate change, one stands out for its inexorable menace, writes Pete Dolack: rising oceans. And it's not just for distant future generations to deal with: new scientific studies show that people alive today may face 6-9 metres of sea level rise flooding well over a million sq.km including many of the world's biggest cities. So where's the emergency response?

There is a possibility, a real danger, that we will hand young people and future generations a climate system that is practically out of their control. We have a global emergency.

When it comes to global warming, what else don't we know?

An international team of scientists led by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) have managed to open a new window into the climate history of the Arctic Ocean. Using unique sediment samples from the Lomonosov Ridge, the researchers found that six to ten million years ago the central Arctic was completely ice-free during summer and sea-surface temperature reached values of 4 to 9 degrees Celsius. In spring, autumn and winter, however, the ocean was covered by sea ice of variable extent, the scientists explain in the current issue of the journal Nature Communications. These new findings from the Arctic region provide new benchmarks for groundtruthing global climate reconstructions and modelling.

The researchers had recovered these unique sediment samples during an expedition with Germany's research icebreaker RV Polarstern in summer of 2014. "The Arctic sea ice is a very critical and sensitive component in the global climate system. It is therefore important to better understand the processes controlling present and past changes in sea ice. In this context, one of our expedition's aims was to recover long sediment cores from the central Arctic, that can be used to reconstruct the history of the ocean's sea ice cover throughout the past 50 million years. Until recently, only a very few cores representing such old sediments were available, and, thus, our knowledge of the Arctic climate and sea ice cover several millions of year ago is still very limited," Prof. Dr. Ruediger Stein, AWI geologist, expedition leader and lead author of the study, explains.

The world's soils could store an extra 8 billion tonnes of greenhouse gases, helping to limit the impacts of climate change, research suggests.

Adopting the latest technologies and sustainable land use practices on a global scale could allow more emissions to be stored in farmland and natural wild spaces, the study shows. 

El Niño years can have a big impact on the littlest plants in the ocean, and NASA scientists are studying the relationship between the two. In El Niño years, huge masses of warm water – equivalent to about half of the volume of the Mediterranean Sea – slosh east across the Pacific Ocean towards South America. While this warm water changes storm systems in the atmosphere, it also has an impact below the ocean’s surface. These impacts, which researchers can visualize with satellite data, can ripple up the food chain to fisheries and the livelihoods of fishermen.

Elderly adults are bigger around the middle when they turn up the heat inside their homes during the cold season and have smaller waistlines when their homes stay cool, new research finds. Investigators from Japan will present their study results Friday at the Endocrine Society's 98th annual meeting in Boston.

"Although cold exposure may be a trigger of cardiovascular disease, our data suggest that safe and appropriate cold exposure may be an effective preventive measure against obesity," said the study's lead investigator, Keigo Saeki, MD, PhD, of Nara Medical University School of Medicine Department of Community Health and Epidemiology, Nara, Japan.

Cold exposure activates thermogenesis, to generate body heat, in brown fat. This type of fat is the good calorie-burning fat that prior research found most humans have. However, Saeki said the association between the amount of cold exposure and obesity in real life remains unclear.

If there is an animal emblematic of the northern winter, it is the snowshoe hare.

A forest dweller, the snowshoe hare is named for its big feet, which allow it to skitter over deep snow to escape lynx, coyotes and other predators. It changes color with the seasons, assuming a snow-white fur coat for winter camouflage.

But a changing climate and reduced snow cover across the north is squeezing the animal out of its historic range, according to a new study by researchers at the University of Wisconsin-Madison. Writing in the current (March 30, 2016) Proceedings of the Royal Society B, the Wisconsin researchers report that the range of the hare in Wisconsin is creeping north by about five and a half miles per decade, closely tracking the diminishing snow cover the animal requires to be successful.

Economic and population growth on top of climate change could lead to serious water shortages across a broad swath of Asia by the year 2050, a newly published study by MIT scientists has found.

The study deploys detailed modeling to produce what the researchers believe is a full range of scenarios involving water availability and use in the future. In the paper, the scientists conclude there is a “high risk of severe water stress” in much of an area that is home to roughly half the world’s population.