There are consequences of the successful efforts worldwide to save beavers from extinction. Along with the strong increase in their population over the past 100 years, these furry aquatic rodents have built many more ponds, establishing vital aquatic habitat. In doing so, however, they have created conditions for climate changing methane gas to be generated in this shallow standing water, and the gas is subsequently released into the atmosphere. In fact, 200 times more of this greenhouse gas is released from beaver ponds today than was the case around the year 1900, estimates Colin J. Whitfield of the University of Saskatchewan in Canada. He led a study in Springer's journal AMBIO² about the effect that the growth in beaver numbers in Eurasia and the Americas could be having on methane emissions.

The fur trade of the sixteenth to nineteenth centuries nearly led to the extinction of beaver populations worldwide. After trapping was limited and conservation efforts led to the re-introduction of these animals into their natural ranges, the number of North American (Castor canadensis) and Eurasian (Castor fiber) beavers grew. The North American beaver has also been introduced to Eurasia and South America (specifically the archipelago of Tierra del Fuego); establishment of these populations has, in effect, created an anthropogenic greenhouse gas source in these landscapes.

Average chloride concentrations often exceed toxic levels in many northern United States streams due to the use of salt to deice winter pavement, and the frequency of these occurrences nearly doubled in two decades. Chloride levels increased substantially in 84 percent of urban streams analyzed, according to a U.S. Geological Survey study that began as early as 1960 at some sites and ended as late as 2011. Levels were highest during the winter, but increased during all seasons over time at the northern sites, including near Milwaukee, Wisconsin; Chicago, Illinois; Denver, Colorado; and other metropolitan areas. The report was published today in the journal Science of the Total Environment.

Princeton University researchers have uncovered a previously unknown, and possibly substantial, source of the greenhouse gas methane to the Earth's atmosphere. After testing a sample of abandoned oil and natural gas wells in northwestern Pennsylvania, the researchers found that many of the old wells leaked substantial quantities of methane. 

Natural gas power plants produce substantial amounts of gases that lead to global warming. Replacing old coal-fired power plants with new natural gas plants could cause climate damage to increase over the next decades, unless their methane leakage rates are very low and the new power plants are very efficient.

These are the principal findings of new research from Carnegie’s Ken Caldeira and Xiaochun Zhang, and Nathan Myhrvold of Intellectual Ventures that compares the temperature increases caused by different kinds of coal and natural gas power plants. Their work is published in Environmental Research Letters.

The climate warming caused by a single carbon emission takes only about 10 years to reach its maximum effect. This is important because it refutes the common misconception that today’s emissions won’t be felt for decades and that they are a problem for future generations. For the first time, a study conducted by Carnegie's Katharine Ricke and Ken Caldeira has evaluated how long it takes to feel the maximum warming effect caused by a single carbon emission. Their work is published in Environmental Research Letters.

Scientists have presented the most comprehensive evidence to date that climate extremes such as droughts and record temperatures are failing to change people’s minds about global warming. Instead, political orientation is the most influential factor in shaping perceptions about climate change, both in the short-term and long-term, said Sandra Marquart-Pyatt, a Michigan State University sociologist and lead investigator on the study.

The deliberate, large-scale intervention in the Earth’s climate system is not a “quick fix” for global warming, according to the findings of the UK’s first publicly funded studies on geoengineering.

The results of three projects – IAGP, led by the University of Leeds; SPICE, led by the University of Bristol; and CGG, led by the University of Oxford – are announced at an event held at The Royal Society, London, on 26 November.

Researchers from North Carolina State University have created a model that mimics how differently adapted populations may respond to rapid climate change. Their findings demonstrate that depending on a population's adaptive strategy, even tiny changes in climate variability can create a "tipping point" that sends the population into extinction.

Carlos Botero, postdoctoral fellow with the Initiative on Biological Complexity and the Southeast Climate Science Center at NC State and assistant professor of biology at Washington State University, wanted to find out how diverse populations of organisms might cope with quickly changing, less predictable climate variations. 

Small volcanic eruptions might eject more of an atmosphere-cooling gas into Earth’s upper atmosphere than previously thought, potentially contributing to the recent slowdown in global warming, according to a new study.

One of the most abrupt rises in the carbon dioxide concentration in the atmosphere at the end of the last ice age took place about 14,600 years ago. Ice core data show that the CO2 concentration at that time increased by more than 10 ppm (parts per million, unit of measure for the composition of gases) within 200 years. This CO2 increase, i.e. approx. 0.05 ppm per year, was significantly less than the current rise in atmospheric CO2 of 2-3 ppm in the last decade caused by fossil fuels.