New study suggests climate is very sensitive to greenhouse gases
Although the rate of global warming has increased dramatically in the last few decades, a new study suggests that human activities have been driving climate change for the past 180 years. The findings suggest that global warming is not just a 20th century phenomenon, and that the climate system is, indeed, quite sensitive to the buildup of heat-trapping pollution.
The study was led by Nerilie Abram, of The Australian National University, who warming began during the early stages of the Industrial Revolution and started leaving a fingerprint in the Arctic and tropical oceans around the 1830s, much earlier than scientists had expected. Continue reading “Global warming started earlier than you think”→
Court settlement includes mitigation and buy-back program
Volkswagen isn’t the only company to try and circumvent clean air rules. This week, Harley-Davidson agreed to pay a $12 million civil penalty for installing illegal devices that increase air pollution from their motorcycles.
Under the court-approved settlement, the company also agreed to spend $3 million to mitigate air pollution by replacing older wood stoves with cleaner heating units, and to stop selling and to buy back and destroy the so-called super-tuners.
According to court documents, Harley-Davidson manufactured and sold about 340,000 of the devices, that, once installed, caused motorcycles to emit higher amounts of certain air pollutants than what the company certified to EPA. Aftermarket defeat devices like these super tuners alter a motor vehicle’s emissions controls and are prohibited under the Clean Air Act for use on vehicles that have been certified to meet EPA emissions standards.Continue reading “Harley-Davidson to pay $15 million for cheating on clean air rules”→
Study says disastrous tipping points could be reached by 2050
Forests of the future may not be able to remove heat-trapping CO2 from the atmosphere as effectively as previously thought, scientists said in a new study that’s based on an extensive analysis of tree ring data from the past.
“We utilized a network of more than two million tree-ring observations spanning North America. Tree-rings provide a record into how trees that grow in different climates respond to changes in temperature and rainfall,” said Brian Enquist, a professor in the UA’s Department of Ecology and Evolutionary Biology and a fellow of the Aspen Center for Environmental Studies in Aspen, Colorado.
The research challenges assumptions about how forests will respond to warmer average temperatures, increased greenhouse gas emissions, and shifting rainfall patterns. It also suggests that the warming climate already is rapidly pushing many forests towards an ecological tipping point, which may be reached as early as 2050, Exposure to unprecedented temperatures hampers tree growth and makes them susceptible to other stress factors. Continue reading “Forests may not benefit from rising CO2 levels”→
New growth in delta could offset CO2 released from riverbed
Human management of natural ecosystems always has unintended consequences, and the Colorado River is no example. After decades of intense dam building and diversions, the mighty river is a mere shadow of it former self, reduced to a trickle in some places and polluted by return flows in others. Along its entire length, ecosystems, including riparian zones and native fish, have suffered, with some of the biggest impacts in the Colorado River delta.
In an effort to restore at least some key reaches of the river, scientists and water managers have teamed up to try mimic some of the Colorado’s natural functions, with controlled releases of water to build up beaches. Those efforts culminated in early 2014 during an eight-week experiment that unleashed a mighty torrent of water from Morelos dam (on the border with Mexico and the USA).
The huge surge (130 million cubic metres) of water raised river levels down to the delta, which has been starved of water for decades. Scientists closely monitored how the release — and potential future releases — affect agricultural crops and natural plant and animal life of the lower delta.
New study measures permafrost changes with impacts to carbon cycle
Global warming is limiting the growth of seasonal ice on Arctic lakes, which could have implications for the global carbon cycle. new study accepted for publication in Geophysical Research Letters, permafrost beneath shallow Arctic lakes is starting to thaw — another sign of the widespread Arctic meltdown due to climate change.
The changes stem from warmer winter temperatures and increased snowfall during the past 30 years. Lakebed temperatures of Arctic lakes less than 1 meter (3 feet) deep have warmed by 2.4 degrees Celsius (4.3 degrees Fahrenheit) during the past three decades, and during five of the last seven years, the mean annual lakebed temperature has been above freezing, the study found. Continue reading “Climate: Thawing Arctic lakes could boost greenhouse gases”→
New study shows soil moisture is a big factor in global warming equation
Methane won’t be the only problem as Arctic permafrost thaws in the coming decades. A new study shows that, as frozen permafrost areas warm and dry out, they will also release more CO2. The study was led by Northern Arizona University assistant research professor Christina Schädel and published in the journal Nature Climate Change.
Pole to pole and across the world’s oceans and mountains, climate change impacts are adding up
By Bob Berwyn
For any Summit Voice readers not following my Twitter or Facebook feeds, here’s a list of links to my recent stories for InsideClimate News.
Of greatest interest here in the West is a new University of Utah study that projects a dramatic upward shift of the snowline in the Rockies and coastal ranges in California, Oregon and Washington. Less spring snowpack at lower elevations has huge effects on we manage our water, and could also result in more early season wildfires: Unabated Global Warming Threatens West’s Snowpack, Water Supply.