climate_science_study   1485

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Reversal of global atmospheric ethane and propane trends largely due to US oil and natural gas production | Nature Geoscience
Helmig et al, 2016: Non-methane hydrocarbons such as ethane are important precursors to tropospheric ozone and aerosols. Using data from a global surface network and atmospheric column observations we show that the steady decline in the ethane mole fraction that began in the 1970s1,2,3 halted between 2005 and 2010 in most of the Northern Hemisphere and has since reversed. We calculate a yearly increase in ethane emissions in the Northern Hemisphere of 0.42 (±0.19) Tg yr−1 between mid-2009 and mid-2014. The largest increases in ethane and the shorter-lived propane are seen over the central and eastern USA, with a spatial distribution that suggests North American oil and natural gas development as the primary source of increasing emissions. By including other co-emitted oil and natural gas non-methane hydrocarbons, we estimate a Northern Hemisphere total non-methane hydrocarbon yearly emission increase of 1.2 (±0.8) Tg yr−1. Atmospheric chemical transport modelling suggests that these emissions could augment summertime mean surface ozone by several nanomoles per mole near oil and natural gas production regions. Methane/ethane oil and natural gas emission ratios could suggest a significant increase in associated methane emissions; however, this increase is inconsistent with observed leak rates in production regions and changes in methane’s global isotopic ratio.
ethane  methane  Climate_Science_study 
3 days ago by huntercutting
Scientists link climate change to melting in West Antarctica
2019: A new study has for the first time presented solid evidence that human-caused global warming is linked to melting of the West Antarctic Ice Sheet. Scientists already knew that periodically changing winds in the region have caused an increase in warm ocean conditions around key glaciers in West Antarctica, and that this is causing them to lose ice. But they did not know whether changes in the winds could be linked to global warming. The new study shows that changes in the winds have indeed been influenced in part by warming climate, along with shorter-term natural variations in climate. The findings are published today in the journal Nature Geoscience.
Antarctica  icesheet  Climate_Science_study  attribution 
3 days ago by huntercutting
Discrepancy between simulated and observed ethane and propane levels explained by underestimated fossil emissions | Nature Geoscience
Dalsoren et al, 2108: Ethane and propane are the most abundant non-methane hydrocarbons in the atmosphere. However, their emissions, atmospheric distribution, and trends in their atmospheric concentrations are insufficiently understood. Atmospheric model simulations using standard community emission inventories do not reproduce available measurements in the Northern Hemisphere. Here, we show that observations of pre-industrial and present-day ethane and propane can be reproduced in simulations with a detailed atmospheric chemistry transport model, provided that natural geologic emissions are taken into account and anthropogenic fossil fuel emissions are assumed to be two to three times higher than is indicated in current inventories. Accounting for these enhanced ethane and propane emissions results in simulated surface ozone concentrations that are 5–13% higher than previously assumed in some polluted regions in Asia. The improved correspondence with observed ethane and propane in model simulations with greater emissions suggests that the level of fossil (geologic + fossil fuel) methane emissions in current inventories may need re-evaluation.
methane  ethane  Climate_Science_study 
3 days ago by huntercutting
Global ethane concentrations rising again, study says
Helmig et al, 2016 - Global ethane concentrations rising again
Climate_Science_study  ethane 
3 days ago by huntercutting
Natural-gas leaks are important source of greenhouse gas emissions in Los Angeles | EurekAlert! Science News
He et al. 2019: New research by Caltech scientists shows that, at least in the Los Angeles Basin, leaks of natural gas used for heating homes and businesses are major contributors to methane in the atmosphere.
methane  Climate_Science_study 
5 days ago by huntercutting
Atmospheric Methane Emissions Correlate With Natural Gas Consumption From Residential and Commercial Sectors in Los Angeles - He - 2019 - Geophysical Research Letters - Wiley Online Library
He et al. 2019

Legislation in the State of California mandates reductions in emissions of short‐lived climate pollutants of 40% from 2013 levels by 2030 for CH4. Identification of the sector(s) responsible for these emissions and their temporal and spatial variability is a key step in achieving these goals. Here, we determine the emissions of CH4 in Los Angeles from 2011–2017 using a mountaintop remote sensing mapping spectrometer. We show that the pattern of CH4 emissions contains both seasonal and nonseasonal contributions. We find that the seasonal component peaks in the winter and is correlated (R2 = 0.58) with utility natural gas consumption from the residential and commercial sectors and not from the industrial and gas‐fired power plant sectors. The nonseasonal component is (22.9 ± 1.4) Gg CH4/month. If the seasonal correlation is causal, about (1.4 ± 0.1)% of the commercial and residential natural gas consumption in Los Angeles is released into the atmosphere.
Plain Language Summary

CH4 is a desirable target for greenhouse gas emission reductions because emission controls will have a rapid impact on radiative forcing. However, its emission budget is highly uncertain and poorly quantified. This paper reports new results from a novel mountaintop remote sensing spectrometer overlooking the Los Angeles basin. The study shows that the megacity's methane emissions are strongly correlated with the consumption of natural gas by residential and commercial consumers, with a leakage rate of (1.4 ± 0.1)%, while the nonseasonal component is (22.9 ± 1.4) Gg CH4/month. By identifying a clear relationship between CH4 emissions and natural gas consumption, our results provide strong constraints on the pathways for fugitive CH4 emissions from the natural gas distribution system in Los Angeles.
methane  Climate_Science_study 
5 days ago by huntercutting
'No doubt left' about scientific consensus on global warming, say experts | Science | The Guardian
The Little Ice Age, for example, reached its extreme point in the 15th century in the Pacific Ocean, the 17th century in Europe and the 19th century elsewhere, says one of the studies. This localisation is markedly different from the trend since the late 20th century when records are being broken year after year over almost the entire globe, including this summer’s European heatwave.

Major temperature shifts in the distant past are also likely to have been primarily caused by volcanic eruptions, according to another of the studies, which helps to explain the strong global fluctuations in the first half of the 18th century as the world started to move from a volcanically cooled era to a climate warmed by human emissions. This has become particularly pronounced since the late 20th century, when temperature rises over two decades or longer have been the most rapid in the past two millennia, notes the third."

[Cook]said that at the end of his 20-year study period there was more agreement than at the beginning: “There was 99% scientific consensus in 2011 that humans are causing global warming.”
climatecomms  Climate_Science_study  temperatures  detection 
24 days ago by huntercutting
Recent increase in catastrophic tropical cyclone flooding in coastal North Carolina, USA: Long-term observations suggest a regime shift | Scientific Reports
Overall, our analysis indicates that; 1) we are experiencing a regime shift in the intensity and quantity of rainfall associated with these events, and 2) this shift has led to unprecedented large loads of nutrients and orgenic matter with major implications for biogeochemical cycling, primary production and overall water quality conditions in the receiving APS and adjacent coastal waters. Furthermore, our observations are consistent with similar observations elsewhere and with predicted hydrologic, nutrient and carbon flux changes taking place in a warming climate
extremePrecipitation  hurricanes  Climate_Science_study  attribution  detection  flooding  fisheries  carbonSinks 
25 days ago by huntercutting
Rise of Candida auris blamed on global warming | EurekAlert! Science News
\Global warming may have played a pivotal role in the emergence of Candida auris, according to a new study published in mBio, an open-access journal of the American Society for Microbiology. C. auris, which is often multi-drug resistant and is a serious public health threat, may be the first example of a new fungal disease emerging from climate change.

"The argument that we are making based on comparison to other close relative fungi is that as the climate has gotten warmer, some of these organisms, including Candida auris, have adapted to the higher temperature, and as they adapt, they break through human's protective temperatures," said Arturo Casadevall, MD, PhD, Chair, Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland. "Global warming may lead to new fungal diseases that we don't even know about right now."

C. auris emerged independently on three continents simultaneously, with each clade being genetically distinct. "What is unusual about Candida auris is that it appeared in three different continents at the same time, and the isolates from India, South Africa, and South America are not related. Something happened to allow this organism to bubble up and cause disease. We began to look into the possibility that it could be climate change," said Dr. Casadevall. "The reasons that fungal infections are so rare in humans is that most of the fungi in the environment cannot grow at the temperatures or our body." Mammalian resistance to invasive fungal diseases results from a combination of high basal temperatures that create a thermal restriction zone and advanced host defense mechanisms in the form of adaptive and innate immunity.

In the new study, the researchers compared the thermal susceptibility of C. auris to some of its close phylogenetic relatives. The researchers found that C. auris is capable of growing at higher temperatures than most of its closely related species, and the majority of the relatives were not tolerant for mammalian temperatures. Adaption to higher temperatures is one contributing cause for the emergence of C. auris, say the researchers.

"What this study suggests is this is the beginning of fungi adapting to higher temperatures, and we are going to have more and more problems as the century goes on," said Dr. Casadevall. "Global warming will lead to selection of fungal lineages that are more thermally tolerant, such that they can breach the mammalian thermal restriction zone."

Dr. Casadevall said that if better surveillance systems were in place, the rise of C. auris would have been detected earlier. "We need to make investments in better surveillance of fungal diseases. We are pretty good at surveilling influenza and diseases that cause diarrhea or are contagious, but fungal diseases are not usually contagious and therefore nobody has really bothered to document them well," said Dr. Casadevall. "If more fungi were to cross over, you really wouldn't know until somebody started reporting them in the literature."
Climate_Science_study  detection  attribution  health 
25 days ago by huntercutting
New Climate Economy 2018 report
We are significantly under-estimating the benefits of cleaner, climate-smart growth. Bold climate action could deliver at least US$26 trillion in economic benefits through to 2030, compared with business-as-usual. There are real benefits to be seen in terms of new jobs, economic savings, competitiveness and market opportunities, and improved well-being for people worldwide.
climate_economics  transformation  Climate_Science_study 
5 weeks ago by huntercutting
Climate Change and Drought: From Past to Future | SpringerLink
Cook et al. 2018 Drought is a complex and multivariate phenomenon influenced by diverse physical and biological processes. Such complexity precludes simplistic explanations of cause and effect, making investigations of climate change and drought a challenging task. Here, we review important recent advances in our understanding of drought dynamics, drawing from studies of paleoclimate, the historical record, and model simulations of the past and future. Paleoclimate studies of drought variability over the last two millennia have progressed considerably through the development of new reconstructions and analyses combining reconstructions with process-based models. This work has generated new evidence for tropical Pacific forcing of megadroughts in Southwest North America, provided additional constraints for interpreting climate change projections in poorly characterized regions like East Africa, and demonstrated the exceptional magnitude of many modern era droughts. Development of high resolution proxy networks has lagged in many regions (e.g., South America, Africa), however, and quantitative comparisons between the paleoclimate record, models, and observations remain challenging. Fingerprints of anthropogenic climate change consistent with long-term warming projections have been identified for droughts in California, the Pacific Northwest, Western North America, and the Mediterranean. In other regions (e.g., Southwest North America, Australia, Africa), however, the degree to which climate change has affected recent droughts is more uncertain. While climate change-forced declines in precipitation have been detected for the Mediterranean, in most regions, the climate change signal has manifested through warmer temperatures that have increased evaporative losses and reduced snowfall and snowpack levels, amplifying deficits in soil moisture and runoff despite uncertain precipitation changes. Over the next century, projections indicate that warming will increase drought risk and severity across much of the subtropics and mid-latitudes in both hemispheres, a consequence of regional precipitation declines and widespread warming. For many regions, however, the magnitude, robustness, and even direction of climate change-forced trends in drought depends on how drought is defined, with often large differences across indicators of precipitation, soil moisture, runoff, and vegetation health. Increasing confidence in climate change projections of drought and the associated impacts will likely depend on resolving uncertainties in processes that are currently poorly constrained (e.g., land-atmosphere interactions, terrestrial vegetation) and improved consideration of the role for human policies and management in ameliorating and adapting to changes in drought risk.
Drought  Climate_Science_study  attribution 
5 weeks ago by huntercutting
Downpours of torrential rain more frequent with global warming -- ScienceDaily
Papalexiou and Montanari, 2109: The frequency of downpours of heavy rain -- which can lead to flash floods, devastation, and outbreaks of waterborne disease -- has increased across the globe in the past 50 years, research led by the Global Institute for Water Security at the University of Saskatchewan (USask) has found.

The number of extreme downpours increased steadily between 1964 and 2013 -- a period when global warming also intensified, according to research published in the journal Water Resources Research.

The frequency of 'extreme precipitation events' increased in parts of Canada, most of Europe, the Midwest and northeast region of the U.S., northern Australia, western Russia and parts of China, (see maps and graphics).

"By introducing a new approach to analyzing extremes, using thousands of rain records, we reveal a clear increase in the frequency extreme rain events over the recent 50 years when global warming accelerated," said Simon Papalexiou, a hydro-climatologist in USask's College of Engineering, and an expert in hydroclimatic extremes and random processes.

Papalexiou, who led the research, added: "This upward trend is highly unlikely to be explained by natural climatic variability. The probability of this happening is less than 0.3 per cent under the model assumptions used."

The USask study of over 8,700 daily rain records from 100,000 stations monitoring rain worldwide found the frequency of torrential rain between 1964 and 2013 increased as the decades progressed.

Between 2004 and 2013, there were seven per cent more extreme bouts of heavy rain overall than expected globally. In Europe and Asia, there were 8.6 per cent more 'extreme rain events' overall, during this decade.

Global warming can lead to increased precipitation because more heat in the atmosphere leads to more atmospheric water which, in turn, leads to rain.

Torrents of rain not only lead to flooding, but can threaten public health, overwhelming sewage treatment plants and increasing microbial contaminants of water. More than half a million deaths were caused by rain-induced floods between 1980 and 2009.

Heavy rain can also cause landslides, damage crops, collapse buildings and bridges, wreck homes, and lead to chaos on roads and to transport, with huge financial losses.

Co-author Alberto Montanari, professor of hydraulic works and hydrology at the University of Bologna and president of the European Geoscience Union, said:

"Our results are in line with the assumption that the atmosphere retains more water under global warming. The fact that the frequency, rather the magnitude, of extreme precipitation is significantly increasing has relevant implications for climate adaptation. Human systems need to increase their capability to react to frequent shocks."
Climate_Science_study  attribution  detection  extremePrecipitation 
5 weeks ago by huntercutting

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