Global Warming 2020

Global Warming News : Climate Change’s Impact On Invasive Plants In Western US May Create Restoration Opportunities

A new study by researchers at Princeton University’s Woodrow Wilson School of Public and International Affairs has found that global climate change may lead to the retreat of some invasive plant species in the western United States, which could create unprecedented ecological restoration opportunities across millions of acres throughout America. At the same time, global warming may enable other invasive plants to spread more widely.

The researchers assessed the relationship between climate change and the distribution of five prominent invasive plants in the western United States – known colloquially as the “kudzus of the West” – cheatgrass; spotted knapweed; yellow starthistle; tamarisk; and leafy spurge. Such plants are defined as invasive because they were brought into this country from other lands and now dominate and alter ecosystems in ways that threaten native wildlife, agriculture, and ranching. All have greatly expanded their ranges in recent decades in the western U.S., causing millions of dollars in damage to farmlands and rangelands. Invasive plants are increasingly expensive to control, and it is widely believed that global warming will make the problem worse.

But Bradley and her co-authors find that global warming may also reduce the competitiveness of some invasive plants if conditions become climatically unsuitable to the weeds, “creating opportunities for restoration in areas currently dominated by intractable invasive species,” according to the study.

The five species were selected in part because they represent the most problematic plants in the western U.S. The study authors created “bioclimatic envelope models,” wherein the authors identified where the invasive plant species occurred, and identified critical climate variables such as precipitation patterns and temperature patterns that are associated with the presence of the invasive plants under investigation. The authors then determined what combined set of climate variables best described the distribution of these weeds, and mapped all of the places in the U.S. where these climate conditions occur.

Developing such models is important because scientists can use them to assess how changing climate conditions might affect the distributions of invasive plants. Maps of how invasion risk is likely to change with global warming are also important for land managers designing long-term protocols for fighting invasive plants.

The researchers employed 10 atmosphere-ocean general circulation models (AOGCMs) that predict what climatic conditions in the West are likely to be in 2100 if emissions are not limited, and matched those predicted conditions to the climate conditions associated with each of the invasive plant species. The projected invasive species distributions for each of the models were added together to create a map of invasion risk under future climate conditions.

“Just as native species are expected to shift in range and relative competiveness with climate change,” the authors wrote, “the same should be expected of invasive species.”

Specifically, the researchers concluded that climate change is likely to expand invasion risk from yellow starthistle in California and Nevada – and lands currently occupied by invasive populations of the weed in California, Oregon and Washington are unlikely to become unsuitable for the species; hence, they have low potential for restoration. Tamarisk distribution, they found, is unlikely to be affected by climate change.

Cheatgrass, however, is likely to be affected by climate change, potentially moving northwards into parts of Idaho, Montana and Wyoming, but retreating in southern Nevada and Utah. And, according to Bradley and her co-authors, the impacts of climate change will likely shift spotted knapweed, currently distributed throughout the foothills of the Rocky Mountains and the Colorado Plateau, to higher elevations, leading to both expanded risk and restoration opportunities in part of Montana, Wyoming, Utah, and Colorado.

Leafy spurge, abundant in northern states west of the Mississippi River and some rangeland west of the Rockies, will likely retreat from some places in the face of climate change, creating restoration possibilities in Colorado, Nebraska, Iowa, and Minnesota – but potentially expanding into parts of Canada not included in the researchers’ study. In addition, the researchers found that leafy spurge is likely to retreat from Nebraska and parts of Oregon and Iowa, creating strong potential for restoration in these areas.

To better address the impacts of invasive species, the authors note, further modeling and experimental work is needed to determine which species will be able to occupy these sites if the invasive species are reduced or eliminated by climate change. Local native plants (the ones that were there prior to the arrival of the invasive species) may be unable to reoccupy these areas as a result of global warming. If local native plants cannot reoccupy the areas, then native plants from elsewhere in the West will need to be considered for restoration to prevent new invasive species from quickly invading these sites.

“The restoration opportunities associated with the retreat of currently intractable invasive species are vast in the western United States,” the authors wrote. “The uncertainties associated with these changes, as well as the unknown makeup of viable future vegetation… highlight a pressing need for integrated modeling, monitoring, and experimental work to better address the ecological consequences of climate change.”

“The question for policy makers and land managers is, ‘What do we want these lands to be?’” said Wilcove. “These lands will change, and we must decide now – before the window of opportunity closes – whether we do nothing or whether we intervene.”

“Governments need to reduce emissions quickly to avoid a variety of dangerous climate changes, Oppenheimer warned. “At the same time, it will be necessary to adapt to the inevitability of some warming. Proper management of ecosystems to minimize the damages is a key part of any effective adaptation strategy.”

Source: Global Warming News, Greenhouse Gas, Climate Chagne information sciencedaily.com

Global Warming News : Termite Insecticide Found To Be Potent Greenhouse Gas

An insecticide used to fumigate termite-infested buildings is a strong greenhouse gas that lives in the atmosphere nearly 10 times longer than previously thought, UC Irvine research has found.

Sulfuryl fluoride, UCI chemists discovered, stays in the atmosphere at least 30-40 years and perhaps as long as 100 years. Prior studies estimated its atmospheric lifetime at as low as five years, grossly underestimating the global warming potential.

The fact that sulfuryl fluoride exists for decades – coupled with evidence that levels have nearly doubled in the last six years – concerns study authors Mads Sulbaek Andersen, Donald Blake and Nobel Laureate F. Sherwood Rowland, who discovered that chlorofluorocarbons in aerosol cans and other products damage the ozone layer. That finding led to a worldwide ban on CFCs.

“Sulfuryl fluoride has a long enough lifetime in the atmosphere that we cannot just close our eyes,” said Sulbaek Andersen, a postdoctoral researcher in the Rowland-Blake laboratory and lead author of the study. “The level in the atmosphere is rising fast, and it doesn’t seem to disappear very quickly.”

This study appears online Jan. 21 in the journal Environmental Science and Technology.

Kilogram for kilogram, sulfuryl fluoride is about 4,000 times more efficient than carbon dioxide at trapping heat, though much less of it exists in the atmosphere.

Its climate impact in California each year equals that of carbon dioxide emitted from about 1 million vehicles. About 60 percent of the world’s sulfuryl fluoride use occurs in California.

Sulfuryl fluoride blocks a wavelength of heat that otherwise could easily escape the Earth, the scientists said. Carbon dioxide blocks a different wavelength, trapping heat near the surface.

“The only place where the planet is able to emit heat that escapes the atmosphere is in the region that sulfuryl fluoride blocks,” said Blake, chemistry professor. “If we put something with this blocking effect in that area, then we’re in trouble – and we are putting something in there.”

The chemists worry that emissions will increase as new uses are found for sulfuryl fluoride – especially given the ban of methyl bromide, an ozone-depleting pesticide regulated under the Montreal Protocol. Sulfuryl fluoride emissions are not regulated, though officials do consider it a toxic contaminant.

The insecticide is pumped into a tent that covers a termite-infested structure. When the tent is removed, the compound escapes into the atmosphere. Sulbaek Andersen, Blake and Rowland believe a suitable replacement should be found, one with less global warming potential.

To measure sulfuryl fluoride’s atmospheric lifetime, the chemists put it inside a Pyrex chamber with compounds that are well understood in the atmosphere, such as ethane. They shined lamps on the chamber to simulate sunlight, which caused chemical reactions that eliminated the compounds from the air.

By monitoring sulfuryl fluoride changes compared with changes to the well-known compounds, they were able to estimate its atmospheric lifetime.

“This is a cautionary paper,” said Rowland, Donald Bren Research Professor of Chemistry and Earth System Science. “It tells us that we need to be thinking globally – and acting locally.”

M.D. Hurley and T.J. Wallington of Ford Motor Co.’s Systems Analytics & Environmental Sciences Department also worked on this study, which was funded in part by the Comer Foundation.

Source: Global Warming News, Climate Change, Greenhouse Effect information at sciencedaily.com