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Disastrous floods in the Balkans two years ago are likely linked to the temporary slowdown of giant airstreams, scientists found. These wind patterns, circling the globe in the form of huge waves between the Equator and the North Pole, normally move eastwards, but practically stopped for several days then -- at the same time, a weather system got stuck over Bosnia and Herzegovina, Serbia and Croatia that poured out record amounts of rain. The study adds evidence that so-called planetary wave resonance is a key mechanism for causing extreme weather events in summer. Further, the scientists showed that extreme rainfall events are strongly increasing in the Balkans, even more than the globally observed rise.

"We were surprised to see how long the weather system that led to the flooding stayed over the region -- it's like the Vb cyclone 'Yvette' was trapped there," says Lisa Stadtherr from the Potsdam Institute for Climate Impact Research (PIK), lead-author of the study to be published in Science Advances. "Day after day the rain was soaking the soil until it was saturated, which lead to the flooding that reportedly caused several dozen casualties and 3.5 billion Euro of damages."

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.

lear-cutting loosens up carbon stored in forest soils, increasing the chances it will return to the atmosphere as carbon dioxide and contribute to climate change, a Dartmouth College study shows.

The findings appear in the journal Soil Science.

Soil is the world's largest terrestrial carbon pool. In northern hardwood forests in the United States, mineral soil pools store up to 50 percent of total ecosystem carbon. Logging and other land-use changes are a major cause of soil carbon release, but there has been recent interest to further understand soil carbon dynamics in forested ecosystems after logging. This is of particular importance in the northeastern U.S. because of the great potential for the use of biomass as part of a diversified renewable energy portfolio.

The Dartmouth researchers explored whether clear-cutting changes the strength of the chemical bonds of carbon stored in mineral soils in hardwood forests in the northeastern United States. Clear-cutting involves harvesting all timber from a site at once rather than selectively culling mature trees. Carbon is stored in soil by binding only to certain soil structures.

The researchers collected soils from recently clear-cut forests and from older forests, and pulled carbon from the soil in a sequence of gentle to stronger extractions. The results showed that mature forest stands stored significantly more soil organic carbon in strongly mineral-bound and stable carbon pools than did soils from cut stands.

The globally increasing light pollution has negative effects on organisms and entire ecosystems. The consequences are especially hard on nocturnal insects, since their attraction to artificial light sources generally ends fatal. A new study by Swiss zoologists from the Universities of Basel and Zurich now shows that urban moths have learned to avoid light. The journal Biology Letters has published their results.

Some insects are attracted by light while others shy away from it. Proverbial is the attraction light has on moths. Street lamps and other artificial light sources often become death traps for nocturnal insects such as moths. Either they die through direct burning or through increased exposure to predators. Mortality of urban insects can thus be 40- to 100- fold higher than in rural populations.

Las conversaciones sobre el clima que concluyeron en diciembre pasado fueron un gran éxito, pero pasarán décadas antes de que podamos juzgar si el Acuerdo de París es en última instancia exitoso. Se puede decir que el acuerdo proporciona una buena base para un progreso significativo en el cambio climático y representa una dramática salida de los últimos 20 años de negociaciones sobre el clima.