Clean Air Linked to Fewer Deaths

In the past few decades, air quality in the United States has been slowly increasing thanks to new acts and standards that have been adopted. North Carolina took an additional step in improving air quality by joining the Southern Appalachian Mountains Initiative, which helped lead to the Clean Smokestacks Act that reduces coal-plant emissions. As the air quality slowly improves in this area, it provides scientists with the unique opportunity to see how changes in air quality affects mortality rates of diseases related to respiratory problems.

In the study published by The International Journal of COPD, scientists looked at how the concentrations of ozone, CO, NO_x, SO₂, PM_2.5, and PM₁₀ were related to changes in mortality rates of emphysema, asthma, and pneumonia. The air quality data was collected from EPA public data files for 1993-2010 and the mortality rates for emphysema, asthma, and pneumonia for North Carolina were collected from the Vital Statistics National Center for Health Statistics Multiple Cause of Death dataset from 1983-2010. Adjustments were made in the study for smoking prevalence and seasonal fluctuations in respiratory deaths. The relationships were all studied using a log-linear model. The statistical Bonferroni correction was used when looking at multiple comparisons.

Air quality measurements of North Carolina from 1993 to 2010 using arbitrary units to show the general decreasing trend in air pollutants. 

The study found that the air quality in North Carolina is slowly increasing, mainly due to decreases in CO, NO₂, and PM₁₀ levels. They also found that since 1983 the mortality rates of the three studied diseases also have decreased, although dramatic decreases started at different times for each of the diseases. Pneumonia death rates have been decreasing more dramatically since 1990, while asthma decreased more since 1995 and emphysema since 1998. These decreases in mortality rates for each disease were related to changes in different atmospheric pollution levels. The decrease in the mortality rate of emphysema was related to decreases in ozone, SO₂, NO₂, CO, and PM_2.5, but only SO₂ and CO were still significant after the Bonferroni correction. NO₂, SO₂, CO, and PM₁₀ decreases were shown to correlate with decreases in asthma mortality, with only NO₂ not significant under the Bonferroni correction. Decrease in pneumonia deaths was only found to be correlated with decreasing SO₂ levels. 

The article in the New York Times that discussed this study was very short. Although the article did mention that the study corrected for smoking and seasonal variations, it also got some points wrong. The article says that SO₂, PM, NO₂, and CO “decreased markedly from month to month” while graphs in the study show that there were some times that each of these compounds increased in concentration. It mentions that both emphysema and pneumonia death rate decreases were related to SO₂ and CO, which is correct but it didn’t mention that asthma mortality decreased with PM₁₀ also. Even though there was little mention of the methods of this study, a detailed description would have seemed out of place in this short of an article. I also thought that ending the article with a quote from lead author was a great way of showing that air quality studies on health effects is still being investigated.

Overall, I would have to give this article a 7/10. It gave some wrong information and mentioned almost no methods, but it did get the general idea of the study across in a very small amount of space. 

New York Times article: http://well.blogs.nytimes.com/2014/06/23/cleaner-air-linked-to-fewer-deaths/?_r=0

International Journal of COPD (through MLibrary): http://dl2af5jf3e.scholar.serialssolutions.com.proxy.lib.umich.edu/?sid=google&auinit=J&aulast=Kravchenko&atitle=Long-term+dynamics+of+death+rates+of+emphysema,+asthma,+and+pneumonia+and+improving+air+quality&id=doi:10.2147/COPD.S59995&title=International+journal+of+chronic+obstructive+pulmonary+disease&volume=9&date=2014&spage=613&issn=1176-9106

Committed Emissions Growing Dispite Lower Emission Commitments

Annual carbon emissions are often the main focus of scientists and policymakers when thinking about reducing greenhouse gases. However, unlike annual emission tracking, "committed emissions" track the expected carbon emissions if existing energy-infrastructure runs for its forecasted lifetime. Commitment Accounting therefore provides an alternative way to estimate carbon emissions and account for new capital investment as time progresses.

Credit: Davis/Socolow

A recent article in Science Daily shares research findings from a study in the journal, Scientific Research Letters, revealing how commitment accounting of CO2 emissions in the power sector further illuminates the global climate challenge.

Credit: Davis/Socolow

The article begins by claiming, "existing power plants around the world will pump out more than 300 billion tons of carbon dioxide over their expected lifetimes, significantly adding to atmospheric levels of the climate-warming gas..." Feeding into this carbon tally whenever we decide to build a new fossil fuel-burning plant, we "commit" at least 40 year's worth of emissions (Assuming an average lifetime of 40 years per power plant). Because more power plants are being built than are being removed, the rate of committed emissions is increasing "by a rate of 4% per year". One of the main points, however, is that as committed emissions have recently leveled off in Europe and the U.S., the worldwide commitment increase is reflective of China and developing world's rapid growth in the power sector. The article also makes mention that over 2/3 of these committed emissions come from coal-burning stations and that the emissions from natural gas-fire generators has increased from 15 to 27% from 1980 to 2012.

The Scientific Research Letters study further outlines the principles of emissions commitment accounting well, adding, "'committed' does not mean inevitable", in that if a power plant were to shut down, it's remaining emissions commitment would go to zero while the realized emissions would remain. The study also illustrates how the commitment accounting model can be incorporated alongside annual emissions measurements into various energy and economic outlook scenarios.

Overall, I think the news article does well in drawing attention to the model of commitment accounting, but falls short in conveying the potential for further utility. In addition to relying heavily on quotes from the researchers and including no figures from the paper, there is no mention of the sources on which the study retrieved power plant emission data. Doing so would have allowed interested readers the opportunity to further investigate committed vs. annual comparisons. Conversely, I felt the original journal article gives a much better introduction to the modeling concept, adding context with explanations for why researchers chose to use a 40 yr lifespan assumption for power plants. Furthermore, a weakness that is not identified by the Science Daily article is that commitment accounting concepts are still in infancy and must be further implemented by a diverse research base before being implemented in public policy debates.

As such,  I would give this Science Daily article a rating of 6/10 at best on the "Dan-Bator-Thinks-You-Rock" scale.

References
Science Daily Article 
http://www.sciencedaily.com/releases/2014/08/140826142443.htm

Scientific Research Letters journal article
http://iopscience.iop.org/1748-9326/9/8/084018/article

Air Pollution Causes Increasing River Flows

Particulate air pollution, such as aerosols (defined as a suspension of fine solid or liquid particles in gas), from industries reduces the amount of sunlight that can reach the earth’s surface. The lack of appropriate sunlight on the earth’s surface will lead to lower temperature; consequently, there will be lower river water evaporation and increasing water yield. Therefore, an elevated river flow will be observed.

The ScienceDaily article Air Pollution Increases River Flows summarizes a recently published Nature Geoscience journal article, Detection of Solar Dimming and Brightening Effects on Northern Hemisphere River Flow, which shows that serious air pollution has led to increased river flows.

                                          Credit: Fyle/Fotolia

The ScienceDaily article claims “air pollution has had a significant impact on the amount of water flowing through many rivers in the northern hemisphere”. Because of the increasing amount of air pollution, more and more sunlight is reflective so that they cannot reach the earth surface, which can refer to a new term “solar dimming”. As a result, an increasing in river flows is observed. Not only did they notice increasing air pollution leading to increasing river flows, but also the reverse way. “When the dimming began to reverse, reductions in river-flows were observed”. The key point in this article is discussing the relationship between the air pollution and flow rate. The ScienceDaily author states that the research group did take temperature and other aspects into consideration.

The Nature Geoscience article provides more detailed information regarding the model (a global land surface model: JULES) and methods they used to do the comparison. In addition, carbon dioxide and landuse were also considered to compare and contrast their effects on river flows.

Overall, I think the ScienceDaily article did a good job summering the main points of the Nature Geoscience article in an easy understanding way. It requires a lot of background knowledge to read the Nature Geoscience article since probably many audiences do not know the methods they used. Additionally, the ScienceDaily article gives explanations to professional terms, like “solar dimming”. As for the shortcomings of the article, I think it would be better if a little more detailed information were provided. From my point of view, I would give this article 8.5/10.

ScienceDaily article

http://www.sciencedaily.com/releases/2014/10/141005134913.htm

Nature Geoscience article (you will need to log into MLibrary)

http://www.nature.com.proxy.lib.umich.edu/ngeo/journal/vaop/ncurrent/full/ngeo2263.html

Temperature hiatus periods to become a 'thing of the past' as emissions soar

A global warming hiatus is a period of a slower rate of increase of the global mean surface temperature and/or the average land and sea temperature at the bottom of the troposphere. This occurs during continued global warming of the Earth's climate system when the overall energy uptake of subsurface–ocean heat increases. Hiatus periods are around ten - fifteen years long and are common in the surface temperature record.

The Sydney Morning Herald Climate Change editor further explained how volcanic activity has acted to stall warming of the planet’s surface. This is due to sulfur emissions from volcanic eruptions.  Other interesting mechanisms for hiatuses are/have been the emission of pine-smelling vapors from pine forests, which turn into aerosols, and the ban on chlorofluorocarbons as a result of the Montreal Protocol, since they were potent greenhouse gases in addition to their ozone-depleting properties. However, these hiatuses are becoming increasingly unlikely due to significant build-up of greenhouse gases overwhelming these natural cooling processes.

The article is engaging and includes many quotes from the lead author of the paper such as the point that by 2100, assuming greenhouse emissions continue to build at the present rate, "even a big volcano like Krakatau is very unlikely to cause a hiatus.” The article continues to explain how oceans have absorbed much of the extra heat trapped over the past decade, but that the process can also go in reverse, quickening warming.

The article does a very good job of introducing the topic. For its purpose, it explained in brevity what hiatus periods were and why they won’t be as likely to happen in the future. However, it derails completely at the end into what World Bank interests and how this problem is related to urban populations.

Despite this, the Geophysical Letters paper is primarily discussing their models for predictions of hiatus periods. I’ll give the article a 7.5/10 for presenting the information (albeit rudimentarily) about hiatus periods. As for actually discussing the Geophysical papers, I’d give it a 6.5/10. It doesn’t present any of the models in the paper, but does briefly explain what the models were used for.

That averages to a 7/10.

Sydney Morning Herald
http://www.smh.com.au/environment/climate-change/temperature-hiatus-periods-to-become-a-thing-of-the-past-as-emissions-soar-20140827-1091p3.html

Original Article
http://onlinelibrary.wiley.com/doi/10.1002/2014GL060527/abstract