Thursday, December 8, 2016

How Can Transportation in the USA Become Carbon Free by 2050?

Also discussed here: Report: Global Warming Solutions (Environment America Research & Policy Center, Oct. 24, 2016)

Today we review a report that recommends 50 steps aimed at state and federal program and policies that could make the USA’s transportation system carbon free by 2050. The steps include making carbon reduction strategies a key priority by exploiting the growth of electric vehicles, autonomous vehicles and the sharing of cars and bicycles, adding more effective public transit, employing smart pricing policies and phasing out carbon intensive vehicles and fuels. co2-emissions-by-country  

Key Quotes:

“Efficient electric vehicles that can be powered by clean, renewable electricity are entering the marketplace faster than the hybrid cars of a decade ago “

 “An explosion of technology-enabled services – from carsharing to bikesharing to Lyft and Uber – has begun to revolutionize transportation in many cities. “

Public transportation reduces vehicle travel (and greenhouse gas emissions) by about 10 percent in U.S. cities, and cities across the country are considering bold plans to expand access to high-quality transit.”

“Cities around the world have shown that smart pricing policies can reduce congestion and encourage the use of low-carbon modes of travel.”

 “autonomous vehicles can be deployed in ways that can support efforts to reduce greenhouse gas emissions – especially if they facilitate the use of shared mobility services, vehicle electrification and smart pricing, and if public policy limits any increases in vehicle travel resulting from automation.”

  • Climate concerns should inform every transportation policy decision…Only seven states have enforceable, economy-wide limits on carbon pollution, and, as of 2012, the vast majority of states and metropolitan planning organizations did not even consider greenhouse gas emissions in agency planning processes.
  • Low-carbon transportation should be at the front of the line for public funding … Between 1956 and 2014, 79 percent of all government capital expenditures on transportation went toward highways,
  • People should be rewarded for making low-carbon transportation choices….income tax exclusion for commuter parking subsidizes rush hour driving to the tune of more than $7 billion per year.
  • Carbon-intensive vehicles and fuels should be phased out…Federal policies have failed to tap the potential of lower-carbon fuels, with the federal Renewable Fuels Standard currently serving largely to encourage the use of corn ethanol
  • Public policy should encourage climate-friendly communities…some localities have begun to lift mandatory minimum parking requirements that add to the cost of new housing development and consume precious and limited urban space.
  • Public policy should foster innovation…Key state and federal policies hamper innovation by failing to account for changing circumstances such as the emergence of shared mobility services or growing demand for urban living, or by locking officials into spending or policy practices more attuned to the needs of a previous generation.”

Tuesday, December 6, 2016

What Happens to Coastal Cities Vulnerable to Sea Level Rise?

Adapting to rates versus amounts of climate change: a case of adaptation to sea-level rise ( 9 page pdf, Soheil Shayegh, Juan Moreno-Cruz and Ken Caldeira, Environmental Research Letters, Oct. 4, 2016)

Today we review the most immediate aspect of climate change- its impact in terms of sea level rise and how best to adapt to this financially, given that many coastal cities are threatened including London, New York, and Tokyo. The authors consider four scenarios given the current rate of rise of 44 cm/100 years which is expected to increase by almost a factor of ten to 344 cm/100 years as Antarctic ice continues to melt over the next 1,000 years for a 60 m rise in sea level. The scenarios include: taking no action, creating a buffer zone, adapting to change in rise and building dikes to withstand increased sea levels. The optimum distance from the sea for safety increases from 310 m to 481 m as the rate of rise of sea level doubles. Insurance based on static risk need to be revised to a more flexible approach based on rate of rise.

Key Quotes:

“climate is likely to continue changing far into the future. Here, we show how considering rates of change affects the projected optimal adaptation strategy.”

“Recent studies indicate that sea-level may continue to rise for millennia, ultimately leading to up to 60mof sea-level rise” “optimal investment strategies depends on taking into account future rates of sea level rise, as well as social and political constraints….Unrestrained fossil-fuel combustion with release of CO2 to the atmosphere has the potential to ultimately melt all of Antarctica at rates of sea-level rise averaging up to 3 cmyr−1 over the next 1000 years “

“Over the next 1000 years, sea-level is projected to rise at an average rate of 3.44 cm yr−1, if all available fossil fuel resources are combusted and the CO2 released to the atmosphere”

 “In the scenarios where rate of change is taken into account …, the optimal distance from the shoreline for investment increases from 310 to 481m as the rate of sea-level is doubled from 1 to 2 cm yr“

 “Failure to recognize the need for adapting to the rate of climate change undervalues the benefits of early adaptation strategies and increases vulnerability to climate change.”

Flood insurance policies traditionally estimate the likelihood of a flood by assigning a probability to such event. New insurance policies can be designed by taking into account the ongoing rate of sea-level and updating the flood likelihood.”

Thursday, December 1, 2016

How do Travel Demand and Economics Affect the Development of Urban Road Networks?

A Model of the Rise and Fall of Roads (33 page pdf, Zhang, Lei, Levinson, David M, Systems Symposium at the Massachusetts Institute of Technology, Mar. 2004)

Today we review a seminal paper from over a decade ago that examines the dynamics of road development in a major mid-West American city (Minneapolis-Saint Paul) using a model that combines measures such as travel demand statistics (usually found on Origin Destination studies) with the economics of road pricing or tolls, geographical constraints (such as rivers and mountains) and how these change with newer technology over time (in this case over 20 years). Roads represent both figuratively and physically the link that join the issues addressed in this blog: how traffic is linked to pollution and how pollution is linked to health. Of particular interest is the way that travel demand and road volume capacity (VC) interact with road tolls and the cost of road construction and the resulting revenue that may be used to ease congestion, in addition to the overall design of the road network and design for a major urban area. road-links  

Key Quotes:

 “In 1900 there were 240 km of paved road in the United States … and this total had increased to 6,400,000 by 2000 …with virtually 100% of the U.S. population having almost immediate access to paved roadways.”

“questions yet to be answered: (1) How do the existing links (roads) develop and degenerate? (2) How are new links added to the existing network? (3) How are new nodes added to the existing network?” “the Twin Cities transportation network which comprises nearly 8,000 nodes and more than 20,000 links, using network data collected since year 1978”

Specific questions on the rise and falls of roads:
  1. “Why do links expand and contract?
  2. Do networks self-organize into hierarchies?
  3. Are roads (routes) an emergent property of networks?
  4. What are the parameters to be calibrated in a microscopic network dynamics model?
  5. Is the model computationally feasible on a realistic transportation network?
  6. Is the model capable of replicating real-world network dynamics?”
economic growth is a two-way interaction between the economy and technology; technological research transforms the economy that finances it.. transportation investment drives the growth that funds it.” “In developed countries where transportation infrastructure has reached its saturated stage, it is rare to see new network growth from a tabula rasa. Even in an empty place without any previous developments, natural barriers such as rivers and mountains still impose constraints on future network growth.”

“Longer, faster, and high-demand (traffic flow) links should be able to generate more revenues. If not maintained appropriately, link LOS [Level of Service] will decrease over time due to physical deterioration caused by the environment and traffic.”

“link expansion cost is positively correlated to lane-miles of expansion and road hierarchy (interstate, state highway, county highway, etc.), while negatively related to the distance from the nearest downtown” “most roads carry flows well below their capacity and a few roads operate at VC [volume capacity] ratios near or slightly higher than one. Practically, over a long period of time, no road can carry flows more than its capacity.”

 “some important system properties, such as road hierarchies and self-organization in transportation networks, can be predicted through a microscopic evolutionary process, a demonstration that such a microscopic agent-based model of network dynamics can be feasibly applied to large-scale realistic transportation networks, and an enquiry into how this concept can be realized and produce useful modeling tools for planners.”

Tuesday, November 29, 2016

The Tire and Brake Share of Traffic-Related Air Pollution

Studded tyre Español: Neumático de invierno co...
Studded tyre Español: Neumático de invierno con clavos, modelo Nokian Hakkapeliitta 4 (Photo credit: Wikipedia)

Key Quotes: 

Tyre rubbish is the 13th largest source of air pollution in Los Angeles, California, a city famous for its smog. A recent study showed links between PM2.5 particles and the daily death rate in 6 Californian counties. When the PM2.5 count was high, so was the death rate” 

 “research now contends possible links to lung cancer from recycling some of the 1 billion dead tyres used in, for example, the surfaces of playgrounds. Some are calling it the new asbestos” 

“there are over 1 billion cars on the road globally and on top of that just as many motorbikes and scooters. Add to that the pneumatic tyres used on trucks and public transport such as metro train systems and buses and we have a considerable source of road rubber. A road with 25,000 vehicles using it each day can produce up to nine kilograms of tyre dust per kilometre.”

 “Oslo announced a plan to ban all cars from its city centre in 2019; and Norway is in the process of preparing a bill that would issue a nation-wide ban of the sale of petrol-powered cars. In places such as Tuscany, cars are banned in city centres except for residents.”

Thursday, November 24, 2016

How Can Cities Reduce Methane Emissions?

Mitigation of methane emissions in cities: how new measurements and partnerships can contribute to emissions reduction strategies (39 page pdf, Francesca M. Hopkins, James R. Ehleringer, Susan E. Bush, Riley M. Duren, Charles E.Miller, Chun-Ta Lai, Ying-Kuang Hsu, Valerie Carranza, James T. Randerson, Earth’s Future, Sep. 10, 2016)

Today we review research into methane emissions from cities which along with other greenhouse gases contributes to climate warming. Cities themselves account for 70% of GHG emissions globally. Unlike CO2 however, methane emissions are more easily managed at the city level whether they come from transportation and the increased shift to natural gas as a fuel for city vehicles or, secondarily, from landfills where methane is emitted from decomposing organic materials or, thirdly, from leaks in the systems delivering natural gas to users. One of the major problems is the lack of accurate inventories of methane emissions which in some cities results in an underestimate of 50%. Some efforts being made in the transportation sector to reduce CO2 emissions include shifts to the use of propane or natural gas but these may have unintended consequences in terms of their contribution as a radiatively active gas to the greenhouse effect. Landfill emissions may be reduced by simply reducing the amount of waste generated though pricing of garbage or encouraging home composting.


Key Quotes:

“Methane differs from CO2 in that mitigation is technologically and economically feasible… Unlike CO2, a large fraction of methane is lost as fugitive emissions from engineered systems, such as leaks from natural gas pipelines.”

 “some strategies to reduce CO2 emissions, such as substituting natural gas for other fossil fuels such as coal and diesel, may have the unintended consequence of increasing radiative forcing by increasing fugitive methane emissions.. methane emission rates are currently underestimated in greenhouse gas inventories … and thus it is unclear if switching to methane-based fuels provides a net benefit for climate mitigation.”

“the most important sectors for urban methane emissions are energy, waste, agriculture, and transportation, respectively …Energy and transportation primarily emit fossil methane derived from natural gas, whereas waste treatment and agriculture produce biogenic methane from the process of anaerobic decomposition”

Natural gas vehicle use has grown rapidly over the past decade, and will continue to grow globally, particularly in developing countries in South Asia and Latin America …In the United States, use of natural gas as a transportation fuel is growing most rapidly for heavy duty and mass transit vehicles”

“Methane production can be prevented by reducing the amount of waste that ends up in landfills— cities have implemented this approach with pay-as-you-throw pricing and diversion of organic waste to alternative treatment such as composting”

 “Methane from wastewater is the fastest growing emission source outside of fossil fuels, expected to increase by 19% over the next two decades as population grows, particularly in developing economies”

“recent studies have used CO and CO2 inventories to quantify methane emissions in Los Angeles, revealing emissions up to 50% larger than inventory estimates”

Tuesday, November 22, 2016

The Future of the World and Cities in It

Indoor and Built Environment
Indoor and Built Environment (Photo credit: Wikipedia)
Urban futures: anticipating a world of cities (6 page pdf, Geci Karuri-Sebina, Karel-Herman Haegeman and Apiwat Ratanawaraha, Foresight, Sep. 10, 2016)

Key Quotes: 

“Modern urbanisation has led to a larger number of megacities (over 10 million inhabitants) and rapidly growing smaller towns and cities. In 1950, only two megacities existed in the world; New York-Newark (USA) and Tokyo (Japan). By 2015, it is reported that 35 megacities were in existence, the largest of these being Tokyo and Shanghai (China), each with populations of over 30 million inhabitants” 

“rapid urbanisation is hailed as being a transformative force, improving economic prospects and quality of life for the majority, alleviating poverty, driving innovation and productivity, working towards social inclusion and contributing to national and regional development“

 “On the other hand, there are also real tensions and contradictions that emerge. For example, similar to economic activity and growth, unemployment/joblessness and poverty are largely urban….they also remain the loci of major political conflicts, driven by racial and cultural tensions and diverging citizen values, which are increasingly propelled by the proliferation of digital media”

 “The trend of urbanisation is also accompanied by efforts in various parts of the world to decentralize political and administrative functions to local governments so as to enhance good governance.” 

“Urban challenges are tremendous, and the types of challenges addressed in anticipatory initiatives are seemingly suitably vast, ranging from sustainability, the built environment, energy, culture and mobility to security and food security, exposure to flood and drought hazards, values, multicultural aspects” 

“The 21st century will not be dominated by America or China, Brazil or India, but by The City. In a world that increasingly appears ungovernable, cities – not states – are the islands of governance on which the future world order will be built”  

Thursday, November 17, 2016

How is Air Pollution Linked to Type 2 Diabetes?

Association Between Long-Term Exposure to Air Pollution and Biomarkers Related to Insulin Resistance, Subclinical Inflammation and Adipokines (Abstract, Kathrin Wolf, Anita Popp, Alexandra Schneider, Susanne Breitner, Regina Hampel, Wolfgang Rathmann, Christian Herder, Michael Roden, Wolfgang Koenig, Christa Meisinger, Annette Peters, KORA-Study Group, Diabetes, Aug. 8, 2016)

Also discussed here: Air pollution a risk factor for diabetes, say researchers (ScienceDaily, Sep.8, 2016) And here: Diabetes Research - Risk Factor Air Pollution (Press Release, Helmholtz Zentrum München, Sep. 8, 2016)

And here: Air pollution exposure found to be risk factor for type 2 diabetes (Green Car Congress, Sep. 8, 2016)

Today we review research from Germany which examined the level of air pollution at the places of residence of 3,000 participants and how this relates to blood marker levels such as impaled glucose metabolism and the risk of Type 2 diabetes. Results indicate that a 7.9μg/m3 increment in particulate matter <10μm was associated with insulin resistance and that NO2, in particular, had a highly significant effects with pre-diabetic individuals as opposed to those who were either diabetic or not.


Key Quotes:

“the German Heart Centre analyzed the data of nearly 3,000 participants of the KORA study who live in the city of Augsburg and two adjacent rural counties”

“Exposure to air pollution at the place of residence increases the risk of developing insulin resistance as a pre-diabetic state of type 2 diabetes.”

 "The results revealed that people who already have an impaired glucose metabolism, so-called pre-diabetic individuals, are particularly vulnerable to the effects of air pollution…In these individuals, the association between increases in their blood marker levels and increases in air pollutant concentrations is particularly significant! Thus, over the long term -- especially for people with impaired glucose metabolism -- air pollution is a risk factor for type 2 diabetes."

“Among all participants, a 7.9μg/m3 increment in particulate matter <10μm was associated with higher HOMA-IR and insulin” “Nitrogen dioxide was associated with HOMA-IR, glucose, insulin, and leptin. Effect estimates for pre-diabetic individuals were much larger and highly statistically significant, while non-diabetic and diabetic individuals showed rather weak associations”

"Lowering the threshold for acceptable air pollution levels would be a prudent step…We are all exposed to air pollution. An individual reduction by moving away from highly polluted areas is rarely an option."