Smog-producing air pollution declining more slowly


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Catalytic converters have decreased the amount of carbon monoxide emitted by cars dramatically since they were first introduced in the 1970s. (Chris Keating/flickr)
Jenna Ladd | May 1, 2018

A new study found that levels of two primary pollutants in the U.S. atmosphere have not been declining as rapidly during recent years as they once were.

Researchers at the National Center for Atmospheric Research (NCAR) studied satellite data and ground level measurements of two smog-forming pollutants: nitrogen oxides and carbon monoxide. Levels of these air pollutants decreased dramatically following the implementation of the Clean Air Act in the 1970s. Requirements of that act pushed automakers and energy-producers to develop new technology which curbed the emissions of these two pollutants.

The study found that concentration of these two pollutants in the atmosphere decreased by seven percent each year between 2005 and 2009. However, from 2011 through 2015, the pollutants’ levels only shrunk by 1.7 percent annually.

Helen Worden is a scientist at NCAR and one of the study’s authors. She said to Phys Org, “Although our air is healthier than it used to be in the 80s and 90s, air quality in the U.S. is not progressing as quickly as we thought. The gains are starting to slow down.”

The study noted that the slower decrease in carbon monoxide and nitrogen oxides was especially severe in the eastern part of the U.S. This finding dispels notions that the slower pace can be attributed to traveling air pollution from countries like China. The positive news is that the slower decline in carbon monoxide, which is primarily emitted by vehicles, is likely due to the fact that major strides have already been made to reduce vehicle emissions. In short, clean air technology related to cars may have reached a kind of plateau.

This study was funded by NASA, the National Oceanic and Atmospheric Administration, the University of Colorado Boulder, and the National Science Foundation. The full journal article can be found in the Proceedings of the National Academy of Sciences.

Scientists question EPA’s rollback of hazardous pollution regulation


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It is estimated that 9 of the 12 major sources of pollution in Iowa’s third congressional district will be reclassified under the EPA’s latest rollback. (Bill Dickinson/flickr)

Jenna Ladd | April 26, 2018

Scientists are concerned about the human and environmental health impacts of the U.S. Environmental Protection Agency (EPA) recent decision to loosen regulations on toxic air pollutants.

The Clean Air Act Amendments of 1990 (CAAA) require major sources of hazardous air pollutants (HAP), or those pollutants suspected or known to cause cancer or other serious health effects, to use evidence-based pollution-control technologies to keep pollution below federal limits. These evidence-based pollution control technologies are also known as maximum achievable control technologies (MACT). Major sources are defined by the EPA as those facilities that emit more than 10 tons of any one HAP per year or more than 25 tons of a combination of HAP per year. Since then, the EPA has enforced the “once in, always in” policy, meaning that those sources that were regulated by the administration as “major sources,” would always be regulated by the administration under that classification. Until now.

In late January, Scott Pruitt’s EPA rolled back the “once in, always in” policy, thereby allowing major sources to become reclassified as “area source” polluters if they can show that they are emitting toxic air pollutants below the program’s threshold. If these sources are successfully reclassified, they will not be required to use MACT, which will likely make their emission reduction efforts less successful. To boot, hazardous air pollutants regulated by MACT measures include formaldehyde, chlorine and hydrochloric acid, none of which are safe for human inhalation, even in very small amounts.

The Union of Concerned Scientists, an independent research organization, created an interactive map to help U.S. citizens predict which parts of the country are most likely to be adversely impacted by the policy change. Scientists estimate that a minimum of 21 states will see more hazardous air pollution following the change. Low-income areas and communities of color are likely to suffer the most as a result. Their research predicts that 35 out of 41 facilities in Chicago could increase HAP emissions. Health effects associated with HAP emissions include cancer and respiratory illness, among others.

Gretchen Goldman is research director of the Center for Science and Democracy with the Union of Concerned Scientists. She made a statement on the organization’s webpage, “The EPA’s political leadership are ditching a successful policy and exposing more Americans to hazardous pollution.”

Users can view the likelihood that this policy change will affect air quality in their region using the interactive map provided here.

WorldCanvass event to focus on climate solutions


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Jenna Ladd | April 20, 2018

It’s obvious to anyone that follows climate news that climate change is longer a far-off possibility, it is happening now. Dr. Jerry Schnoor, professor of civil and environmental engineering and co-director of the Center for Global and Regional Environmental Research at the University of Iowa, illustrated this point in a recent guest opinion piece for the Press Citizen.

Dr. Schnoor pointed out several ways in which climate change has already taken hold in Iowa. More intense storms are eroding soil into waterways, humidity is on the rise, and floods are likely to be separated by periods of drought. If greenhouse gas emissions are not cut dramatically, all of these effects will become more severe. So, what can Iowans actually do to reverse course? Dr. Schnoor had several recommendations.

He urged individuals to consider limiting their own carbon emissions. At the state level, he stated that Iowa should join the sixteen other states in The Climate Alliance, which is a “proposition that climate and energy leadership promotes good jobs and economic growth.” Iowa is a national leader in wind energy and biofuel usage; the professor argued that joining the alliance obviously aligns with the state’s clean energy accomplishments.

Private sector and industry groups can be a part of the climate solution, too, he said. The World Business Council for Sustainable Development provides innovative ideas for companies looking to curb their emissions. Just recently, international martime shipping companies agreed to cut their greenhouse gas emissions by 50 percent before 2050.

Climate change policy recommendations must be based in research. Dr. Schnoor invited Iowans to attend a WorldCanvass program on April 25th to hear about the latest scientific research related to climate change and climate-smart policy from several CGRER members. Part of a series of nine recorded discussions focused on topics of international interest, the event is free and open to the public.

What: WorldCanvass Climate Science and the Environment—What’s Next?

When: Wednesday, April 25th from 5:30-7:00 pm

Where: MERGE, 136 South Dubuque Street, Iowa City, Iowa

A catered reception will take place from 5:00-5:30 pm. Dr. Schnoor’s full piece in the Press Citizen can be found here.

Mock climate change negotiation set for April 21st


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A mock climate negotiation is coming to Iowa City, challenging participants to keep climate change well below 2 degrees Celsius above preindustrial levels. (MIT technology review)
Jenna Ladd | April 12, 2018

Iowa City area residents have the opportunity to understand what it might be like to be a part of the United Nations climate change negotiations.

On Saturday, April 21,  the public is invited to participate in a World Climate Simulation. Created by Climate Interactive, nearly 900 of these simulations have taken place in 75 countries. The role-playing exercise assigns each participant a delegate position with a nation, interest group or negotiating bloc. During the mock international climate change negotiating meeting, participants are tasked with negotiating climate policy that would keep climate change below 2˚C over preindustrial temperatures. Meanwhile, the event facilitator, acting as a UN leader, uses the C-ROADS interactive computer model to demonstrate the climate implications of any number of climate policy proposals. The C-ROADS simulation is based on current climate change science.

Climate Interactive details the learning outcomes of the activity. They write, “During the event participants must face the climate science, engage in the drama and tensions of global politics, test their ambitions against a climate-modeling tool used by actual climate negotiators, and then reflect on how the experience challenges their assumptions about climate action.”

Iowa City’s simulation will take place from 1:00 pm to 4:00 pm at the Iowa City Public Library on April 21st. Interested parties are encouraged to sign up as soon as possible. More information about this event and the link to register can be found here.

“Frost-free” days increase, so does allergy season


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Climate Central’s graph illustrates how the number of frost-free days in Des Moines has increased over time. (Climate Central)
Jenna Ladd | April 11, 2018

Given that spring snow fell across Iowa this weekend, it may be hard to believe that the frost-free season across the U.S. is actually getting longer.

A recent report found that, on average, the last spring freeze is occurring earlier while the first fall freeze is happening later. Researchers define the frost-free season as the total number of days between the last day of 32 degree Fahrenheit or lower weather in the spring and the first day of 32 degree Fahrenheit weather in the fall.

The lengthening of this season means that pollen-producing plants have a longer growing period. One study in particular found that the growing season for ragweed, a common allergen in the U.S., lengthened by two to four weeks between 1995 and 2009. This data was collected from ten sites from the southern U.S. through Canada. Iowa has added nine days to the average length of its frost-free season from 1986-2015 when compared with the average from 1901-1960.

Not only are allergy-causing plants benefiting from longer growing seasons, but an uptick in atmospheric carbon dioxide also increases pollen counts. Last year was the worst allergy season in recent record and experts expect this year to be similar.

Dr. Joseph Shapiro, an allergist and immunologist from California told CBS news, “A recent study showed that pollen counts are likely to double by the year 2040, so in a little more than 20 years we’re going to see a significant increase [in seasonal allergies].”

Climate Central’s recent report provides an interactive graph that allows users to select a U.S. city and see how the frost-free season’s length there may have changed since 1970.

German court gives cities authority to ban diesel vehicles


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Munich is one of the German cities that routinely exceeds European Union NOx emission limits. (Vladimer Shioshvili/flickr)
Jenna Ladd | March 1, 2017

Germany’s federal court ruled on Tuesday that cities can ban diesel vehicles in order to lower air pollution.

Environmental Action Germany has been filing lawsuits against cities for years to encourage municipalities to implement policies that curb air pollution. German government statistics reveal that some 6,000 people die each year from nitrogen oxide pollution, 60 percent of which comes from vehicles on the road. Diesel engines in particular spew more NOx than gasoline engines and are more popular in Europe.

The ruling does not require communities to ban diesel driving, rather it grants them the legal authority to do so if air pollution in their city remains above the European Union limit for NOx in the air. Seventy German cities surpassed that threshold at least once last year.

Banning diesel vehicles would have negative implications for the country’s automotive industry. Since the ruling, the German government has proposed some measures to decrease pollution and avoid the ban, which include providing free public transportation and refitting existing diesel vehicles to meet clean air standards. However, it is unclear how the government would pay for such measures.

Germany is merely the latest country making a move away from diesel engines. Paris, Madrid, Mexico City and Athens have policies in place to ban diesel vehicles from city centers before 2025.

Climate change alters forest composition


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Sugar maples are seeing population decreases across the U.S. due to climate change, making fiery autumn leaves harder to find. (Mark K./flickr)
Jenna Ladd | February 28, 2017

Beech trees are crowding out other important tree species in northeastern United States woodlands because of climate change, according to a recent study.

Researchers from the University of Maine tracked beech, sugar and red maple tree data in the northeastern U.S. from 1983 to 2014. The U.S. Forest Service data showed that beech tree populations have increased significantly over the thirty years while the other tree species decreased. The study found that hotter temperatures and increased precipitation, both caused my climate change, allowed for beech trees’ population boom.

Beech trees have important advantages over the species that used to dominate the area. First, they often shade out other species competing for sunlight. Second, the local deer prefer the taste of sugar and red maple saplings to beech ones. The changing climate is changing the composition of forests and managers will have to adapt, researchers say.

Dr. Aaron Weiskittel is a forest biometrics and modeling professor at University of Maine and one of the study’s authors. “There’s no easy answer to this one,” he said to the Associated Press, “It has a lot of people scratching their heads. Future conditions seem to be favoring the beech, and managers are going to have to find a good solution to fix it.”

Sugar maples, one of the important species declining in the northeastern U.S., are also expected to decline in numbers in the northern Midwest due to climate change. A twenty-year study published in January found that as global temperatures continue to rise, sugar maple growth in the northern Midwest will be stunted and the species population will decrease.

Researchers point out that forests soak up 25 percent of the greenhouse gases that are emitted each year, so continuing to learn about how forests will respond to the changing climate should be prioritized.