Does sprawl make the urban heat island effect worse?

urban heat island effect by city
urban heat island effect by city

Cleveland experiences the fourth strongest urban heat island effect in the United States. Could our sprawling development patterns be to blame? (courtesy of Debbage and Shepherd, 2015).

A few weeks ago, NASA officially announced that the record-breaking, “Godzilla” El Niño event that dominated much of our weather over the past year plus had finally come to an end.

But while the monster has returned to its hibernation deep below the surface of the Pacific Ocean, its impacts have already been and will continue to be felt across the United States. Around the same time that it made this announcement, NASA also revealed that April and May were the warmest such months on record in the US, meaning that every month since October 2015 has broken the existing record for that month. This eight-month streak of heat is, obviously, unprecedented. To date, the average temperature in 2016 is 1.9°F (1.08°C) above the average for the 20th century, making it a full 0.43°F (0.24°C) above the mark for the first five months of 2015.

You remember 2015, right? The warmest year on record? Well, not for long. NASA scientists are already more than 99% certain that 2016 will break that record, just as 2015 had claimed the mantle from 2014.

The impacts of 2016’s extreme heat

The extreme heat is having clear effects. It is contributing to wildfires consuming wide swathes of the West. Ozone levels are higher than normal across the country, as high temperatures foster the development of harmful, ground-level ozone more readily. So far, Greater Cleveland has already experienced six days when ozone levels exceed 70 parts per billion (ppb), the most at this point since 2012.

But the most acute impact of high temperatures heat-related mortality, a subject that I’ve written about considerably. Extreme heat is the deadliest type of disaster in the US, killing more people than hurricanes, floods, tornadoes, and lightning strikes combined each year. As I’ve discussed in the past, climate change is only exacerbating this issue; the World Meteorological Organization (WMO) noted that the global death toll from extreme heat rose by around 2,300% from 2000-2010, compared to the previous decade.

change in disaster deaths by decade

The change in the number of deaths, by disaster, from 1991-2000 to 2001-2010 (courtesy of WMO).

Nearly all regions have seen a spike in dangerous heat, but the risk of heat-related mortality is not distributed evenly. While an individual’s vulnerability to extreme heat is the function of a number of factors, one of these is where s/he lives. Generally speaking, those of us living in cities are at greater risk due to the so-called urban heat island (UHI) effect. I won’t go too far into the science behind the UHI effect; suffice it to say that the combination of dark surfaces, a lack of urban trees, and the production of waste heat from various sources like air conditioners increases the temperature of cities, relative to rural areas. According to the U.S. EPA, the temperature of a large city can be more than 20°F higher than surrounding rural areas under the right (or wrong?) conditions.

Last September, Forbes published an article examining the scale of the UHI in various cities throughout the US. Strikingly, it included a map (see above) stating that Cleveland has the fourth strongest UHI effect in the country. Now, if you’re one of the literally tens of people who has inexplicably read something I’ve posted on this site, you may be familiar with my general dislike of sprawl. I’ve discussed research linking it to population decline, limited social mobility, climate change, and poor air quality, among other things.

So, I wondered, could Cleveland’s strong UHI effect be the result of our development pattern? Given that sprawl affects so many important phenomena, it seems reasonable to assume it would have an effect on UHI, right? To the peer-reviewed literature! [Cue 1970s Batman transition music].

Is suburban sprawl actually linked to the urban heat island effect?

At first glance, it may seem odd to posit that suburban sprawl would play a role here; the phenomenon is called the urban heat island effect, after all. But a handful of studies strongly suggest that sprawling development patterns do, in fact, exacerbate the UHI effect.

Two of the most convincing papers come from Brian Stone, Jr., a professor at the Georgia Tech School of City and Regional Planning and an expert on urban environmental planning and climate change.

In a 2006 study (paywalled) that he coauthored with Jon Norman from the University of Wisconsin-Madison, Stone examined the link between land use patterns and the UHI effect in Atlanta. The researchers broke properties into groups based on four variables: extent of impervious surfaces, lawn and landscaping, tree canopy, and the number of bedrooms per residential structure. This categorization enabled them to study the magnitude of surface warming produced by property type.

Stone and Norman concluded that the size of residential lots – in other words, residential density – was closely tied to black body flux, a measure of surface warming. As one moves from the highest density lot type to the lowest density, the amount of surface heat released increased 6-fold. Other land use features closed tied to suburban and exurban development – namely large lawns – also exacerbate the UHI effect. A one unit increase in the area of a plot covered by lawn and landscaping increases the net black body flux by 0.51 units.

As the authors conclude,

The results of this analysis provide compelling evidence that the size and material composition of single-family residential parcels is significantly related to the magnitude of surface warming in the Atlanta study region. Specifically, smaller, higher density parcels were found to be associated with a lower net black body flux than larger, lower density parcels…

[The] results of this study support the hypothesis that lower density, dispersed patterns of urban residential development contribute more surface energy to regional heat island formation than do higher density, compact forms.

Connecting sprawl and the UHI across cities

On its own, one study does not prove the relationship. Fortunately, Stone followed up with a 2010 paper that he co-wrote with Jeremy Hess and Howard Frumkin of the University of Washington, which studied the connection between urban sprawl and the number of extreme heat events (EHEs) in 53 cities from 1956-2005.

To measure the relationship, they took the correlation between the mean annual change in the number of EHEs from 1956-2005 and the sprawl ranking for each of the cities in 2000. Whereas the most compact cities experienced 5.6 more extreme heat days in 2005 than in 1956, that number was 14.8 for the most sprawling cities. In other words,

The most sprawling cities experienced a rate of increase in EHEs that was more than double that of the most the most compact cities…These findings are consistent with the hypothesis that urban sprawl contributes to EHE frequency.

Exploring some competing research

Now, I should note that there is other research that does not jibe with Stone’s work. Last year, Neil Debbage and Marshall Shepherd of the University of Georgia took another look at urban form and the urban heat island effect. Using a different measure for UHI (the difference in average rural and urban temperatures) and a different measure for urban form (an index measuring various variables of city shape, contiguity, and land uses), Debbage and Shepherd studied the degree to which city configuration affected urban heat in the 50 largest US metro areas from 2001-2010.

Contrary to Stone, Debbage and Marshall found that both more compact and more sprawling cities experience a stronger UHI effect, provided they are highly contiguous. That is, the contiguity of urban form may matter more than its composition; designing cities so that they are made up of either cul-de-sacs or skyscrapers as far as the eye can see makes them more vulnerable to extreme heat. According to the authors,

A ten percentage point increase in the spatial contiguity of high-intensity urban development, the equivalent of shifting roughly from Orlando to Seattle, was predicted to enhance a city’s average UHI intensity by 0.4°C…[In turn] a ten percentage point increase [in low-intensity urban development] was predicted to enhance a city’s annual average UHI intensity by 0.3°C. Therefore, as suggested by the bivariate analysis, both low and high-density urban land uses appear to amplify the UHI effect if they are high contiguous.

Importantly, Debbage and Marshall note that, while compact development may not solve the UHI on its own, it does provide a litany of other benefits, from improved air quality to better public health. Accordingly, urban planners may want to promote less contiguous, higher density urban development by designing networks of smaller green spaces, expanding the urban tree canopy, and installing white and green roofs throughout cities. A 2014 study by Stone and colleagues found that implementing these types of policies can offset projected increases in heat-related mortality due to climate change by anywhere from 40-99%.

Wait, so does sprawl make the UHI effect worse?

So what can we take away from all of this?

First, yes – the evidence does suggest that sprawl exacerbates urban heat islands. Low-density, suburban-style development increases the amount of impervious surfaces, which raises lowers the surface albedo of urban areas. It also increases the amount of excess waste heat that cities produce, as larger houses require more energy. And sprawl typically leads to forest clearance for development, reducing the extent of the urban tree canopy. All told, these factors increase the amount of heat cities generate, and they prevent this additional heat from dissipating rapidly at the urban fringe.

Second, the fact that sprawling development patterns are not the only type urban form that increases the UHI effect may not be as relevant as it may seem. While dense urban areas may also promote UHIs, they also make it easier to address both the causes and effects of heat-related mortality risks. Residents of dense cities produce fewer carbon emissions per capita, mitigating climate change. And the economies of scale in these dense neighborhoods increases the efficacy of mitigating extreme heat; opening a cooling station or installing shade trees are more effective in these areas, for instance.

All told, we can add the urban heat island effect to the list of social problems that sprawl makes worse. Maybe we should rename it the (sub)urban heat island effect?

When it comes to bike lanes, if you build it, they will shift

bike to work day
bike to work day

Cleveland area commuters congregate downtown for Bike to Work Day on May 20 (courtesy of Bike Cleveland).

When it comes to mobile emissions, not all bike rides are created equal.

The cyclist who drives her bike into downtown to take part in Critical Mass or rides along the Towpath on a Saturday afternoon does not actually eliminate vehicle miles traveled (VMT) or reduce greenhouse gas (GHG) emissions to any extent. (This is why the National Bike Challenge’s methodology tends to irk me).

None of this is to say that these rides are somehow inferior or less than those taken for transportation; they’re not. Recreational riding is good for public health, enjoyable, and it increases the number and visibility of cyclists on roads. But it is somewhat disingenuous to claim they improve air quality or mitigate climate change.

How do we calculate the emissions savings from bike projects?

Now, we already know that shifting people from cars to bikes can go a long way towards promoting these ends. The problem is that we lack good tools to let us demonstrate this on the small scale. How do we prove, definitively, that investing in a particular piece of bike infrastructure gets people to change their travel mode? And how can we calculate the associated emissions reductions?

In some ways, recreational cycling may make this process more difficult. Traditional methods, like bike counts, don’t distinguish between those who are riding for recreation and those who are riding for transportation. Knowing the difference between the two and being able to isolate that segment of the latter who would have otherwise driven is essential for cycling advocates. We need to be able to quantify the demonstrable benefits of bike infrastructure in order to get funding for projects under certain programs, particularly the Congestion Mitigation and Air Quality (CMAQ) Improvement program.

In part because we struggle to get accurate data, bike infrastructure projects remain a small sliver of overall CMAQ projects. The Federal Highway Administration (FHWA) estimates, for instance, that CMAQ needs to invest $3.5 million in bike projects to reduce one ton of fine particulate matter (PM2.5), compared to just $38,000 for diesel vehicle retrofits and $76,000 for idle reduction programs. Perhaps the cost-benefit ratio for bike projects would improve if we had better data on how bike infrastructure directly affects mode choice.

New research may provide an answer

Fortunately, researchers are beginning to develop better tools to do just this. In a new study (paywall) in the journal Transportation Research Part A, researchers Seyed Amir H. Zahabi, Annie Chang, Luis F. Miranda-Moreno, and Zachary Patterson explore how the built environment and accessibility to bike infrastructure affects mode choice and GHG emissions among commuters in Montreal.

In the study, the authors broke Montreal down into a series of 500-square meter neighborhoods based on population density, employment density, cycling network density, transit accessibility, and land use mix. It defined neighborhoods using one of five typologies: downtown, urban, urban-suburb, inner suburb, and outer suburb.

Using this approach, they sought to answer two main questions. First, what are the effects of the built environment and the network connectivity of the transportation system on cycling rates during the period in question (1998-2008)? Second, how did cycling rates and the associated GHG emissions change over this period?

In order to study the first question, they estimated the effects of the neighborhood typologies on cycling rates. However, this isn’t as straightforward as it may seem. One cannot directly estimate this effect on mode choice, as people often self-select into certain types of neighborhoods that fit their preferred mode. For example, I consciously looked for apartments in certain parts of Washington, DC so that I could be within a short walk of a Red Line station. The same holds for cyclists, who may choose to live in more bike-friendly areas.

When your independent variable (in this case, neighborhood type) is not completely independent from your dependent variable (commute mode choice), we say they are endogenous. The researchers employed a statistical approach, known as a simultaneous equation model, which allows them to control for this endogeneity.

Drawing the link between bike lanes and GHG reductions

To study their second research question, they utilized a variable that allowed them to measure the distance a person lives from the nearest bike path or lane. This enabled them to consider how increasing or decreasing that distance may affect commute mode choice and GHG emissions.

It’s this second question that I want to focus on, as it gets to the heart of the issue I raised earlier. Fortunately, the authors provide some concrete evidence that investing in bike infrastructure does foster mode shift. When it comes to bike lanes, if you build it, people really do come.

Based on their results, they found that reducing the distance that a person lives from the nearest bike facility increase the odds that s/he will bike to work by 3.7%. In Montreal, the city expanded its bike network to 648 kilometers (402.6 miles) in 2014, from 603 km (374.7 miles) in 2008. The expansion directly led to a 1.7% decrease in vehicle GHG emissions within the city.

This reduction stacks up well with alternative emissions control options. As the authors conclude,

As in other studies, it is found that cycling infrastructure accessibility is positively linked to bicycle usage, playing a positive role in reducing transportation GHG emissions, by shifting the mode share of bikes. Although this effect may appear small (about 1.7%), it is as big as the estimates we have found in our previous research when converting all the transit diesel buses to hybrid technology and electrifying the commuter trains in Montreal at the same time. This is to say that the GHG benefit from adding low-cost new cycling infrastructure can be as important as other more costly strategies.

Hopefully this type of research can provide further, tangible justification for incorporating bike infrastructure in the urban toolkit to tackle climate change. We need to build real (preferably protected) bike lanes in order both to increase the number of people biking regularly and broaden the type of people biking from hardcore recreational cyclists to normal people using bikes as a transportation mode. Because, while recreational biking is great, only transportation biking can help us solve these pressing crises

Ozone levels have fallen dramatically, though you probably didn’t notice

cleveland skyline smog
cleveland skyline smog

Smog obscures the Cleveland skyline in this picture from July 20, 1973 (courtesy of the National Archives/U.S. EPA).


As someone who has spent most of his life in the city of Cleveland and bikes to work across the Lorain-Carnegie Bridge on a daily basis, I feel like I have a close, personal relationship with air pollution here.

I can tell when the steel mills and other factories in the Industrial Flats are releasing more sulfur dioxide (SO2) than normal from the distinctive odor of rotten eggs. I have entirely too much experience trying to avoid the clouds of diesel particulate matter as they belch forth from GCRTA’s older buses. I have inhaled more than my fair share of nitrogen dioxide (NO2) from passing vehicles.

The dynamics of ground-level ozone

But one common urban pollutant that I cannot and will never be able to smell or see or taste is ground-level ozone. It is completely colorless and odorless. The only way you can notice ozone is from afar, as it helps obscure your view of cities on particularly hazy days. But even then, you can’t really “see” it, as the ozone is just one component of the smog that envelops cities.

Ozone is a sneaky little bastard. It forms above us in the troposphere, travels dozens to hundreds of miles downwind, and then silently works its way into our airways. Only when you have already inhaled it can you possibly begin to notice ozone, as it irritates and inflames tissue in your nose and lungs.

Fortunately, thanks largely to regulations put in place over the past several years by the U.S. EPA, ozone levels have been falling consistently around the country. According to EPA, ozone declined by one-third nationwide, from 1980 to 2014.

But while long-term ozone concentrations certainly affect public health, environmental and public health officials typically focus more on the impacts of spikes in the pollutant over the shorter term. The short-term health effects of rising ozone levels can be significant. According to a landmark 2004 study from Michelle Bell and colleagues, when ozone increases by 10 parts per billion (ppb), mortality rates in Cleveland increase by roughly 1% during the next week. These daily spikes also lead to additional hospitalizations, missed school days, and missed workdays due to asthma and other respiratory conditions.

For these reasons, U.S. EPA requires local officials to monitor ozone and advise the public when they project that ambient levels are expected to exceed 70 ppb. Unfortunately, the Cleveland area has already experienced three days this year on which concentrations exceed 70 ppb. Two of these occurred last week, given that air temperatures increased significantly as high pressure moved into the region.

Yet, as NASA pointed out recently, reductions in emissions of ozone precursors – namely nitric oxides (NOx) and volatile organic compounds (VOCs) – have gone a long way towards limiting the number of exceedance days over the past few years. Without these emissions reductions, Cleveland would have experienced roughly 4-5 more exceedance days in 2011 than we actually did, as the map below shows.

ozone exceedance days avoided 2011

Ozone exceedance days avoided in 2011 as a result of emissions reductions over the past decade (courtesy of NASA).

The benefits of this reduction are tangible, in both blood and treasure. But, at a more basic level, it provides greater peace of mind for all of us. Parents no longer have to worry as much about keeping their children indoors to protect them from pollution. Those of us with asthma don’t have to think about altering our behavior to spend less time outside.

Despite the hype, ozone levels are declining

Given the recent media coverage about worsening air quality worldwide, the fact that ozone levels continue to decline throughout most of the U.S. may come as something of a surprise. I mean, the American Lung Association just gave Cleveland an F for air quality a month ago. But, when you actually get beyond the sensationalized headlines and dig into the data, you’ll find that our air is cleaner than it is has ever been, and it is far cleaner than it was even a decade ago.

Now, none of this should be taken to mean that we can get complacent or that air quality is no longer a pressing challenge; nothing could be further from the truth. I would venture that there are relatively few people more concerned about or aware of air quality issues in this region than I, but I am also among the first to acknowledge the progress we have made and continue to make. But don’t take my word for it. Let’s actually look at the data.

Perhaps the easiest way to chart changes in ozone, over time, would be to look at the average daily ozone levels for the region. In order to do so, I collected data on daily ambient ozone concentrations for Northeast Ohio from 2005-2015 from EPA’s Air Quality System (AQS). This is charted below.

mean annual o3 level 2005-2015

Mean daily ozone levels in Northeast Ohio from 2005-2015.

While there appears to be a fairly small – but steady – decline since 2005, this is not necessarily the most valuable metric to use. First, because ozone  is a secondary pollutant, it is highly dependent upon weather conditions to form. This means that ozone levels can vary dramatically from one day to another, based upon ambient temperatures or whether or not it is raining. Secondly, there is relatively little reliable science on the health impacts of ozone at levels below 50 ppb.

The number of ozone exceedance days has fallen considerably

A more accurate way to account for changes in ozone levels is to examine the number of exceedance days per year. But, because EPA continues to update the National Ambient Air Quality Standard (NAAQS) to reflect changes in science, this does not give us a true apples-to-apples comparison. It wouldn’t be accurate, for example, to claim that air quality did not improve from 2000 to 2015 if a city had 10 exceedance days in each year, given that the NAAQS was 85 ppb during the former year and 75 ppb during the latter.

Because there are several ozone monitors operating in the region, I took the highest daily ozone value from among these monitors and used that as the regional value for a given day. To get a true comparison, I counted day as an exceedance if at least one monitor within the 8-county region registered a value of 71 ppb or more, given that the current NAAQS is 70 ppb.

annual o3 exceedance days 2005-2015

Number of ozone exceedance days per year in Northeast Ohio from 2005-2015, using a 70 ppb cutoff.

As you can see, there has been a nearly precipitous decline in the number of exceedance days over the past decade. While there is some interannual variation, based upon weather (e.g. 2012), the overall trend is undeniable. While the region averaged 43.3 exceedance days per year from 2005-2007, that number fell to just 7 per year from 2013-2015.

Another way to frame changes in ozone levels is to consider the average ozone concentration within the region on a given exceedance day. It may be more harmful for public health to have 10 exceedances with an average concentration of 80 ppb than to have 15 exceedances that average 71 ppb. Fortunately, this metric has also declined significantly since 2005. While the data are fairly noisy, they also demonstrate a strong overlap with the number of exceedance days per year. In other words, during years when we have more exceedances, ozone levels on those days tend to be higher.

mean annual o3 exceedance level 2005-2015

Mean annual ozone exceedance level per year from 2000-2015.

Clearly, by basically any measure, ozone levels have fallen considerably in the region over the past several years, which has directly enhanced public health and well being. In a 2013 study, EPA scientists Neal Fann and David Risely estimated the nationwide public health benefits due to decreases in ozone concentrations from 2000 to 2007. During this period, a 3.5 ppb decrease in national ozone levels prevented between 880 and 4,100 premature deaths. Northeast Ohio, in particular, benefited from this trend; Cuyahoga County avoided more than 30 premature deaths per year during this period, more than all but a handful of counties in the country.

But climate change threatens this trend

But, as I’ve noted before, climate change threatens to stymie this progress. Rising temperatures and changes in precipitation and wind patterns may create conditions more favorable to ozone formation in the future.  Based on a recent EPA report, ozone levels may spike by 1 to 5 ppb, depending on much surface temperatures increase. To account for this effect, I identified those days from 2005 to 2015 on which ozone concentrations peaked between 66 and 70 ppb. As the chart below illustrates, the number of exceedance days would have increased markedly during this period, if the temperature increases associated with climate change had already taken effect. On average, there would have been an additional 13.9 exceedance days per year, ranging from a low of 4 in 2009 to a high of 29 in 2006.

o3 exceedance days with & without climate change

The number of ozone exceedance days in Northeast Ohio from 2005-2015 before and after accounting for the impacts of climate change.

The system works, if you let it

Ultimately, these trends point to a clear conclusion – the air pollution control system in this country works. Donald Trump may want to ban the EPA, but – and this is shocking, I know – I’m going to go ahead and call bullshit on his claim that “we’ll be fine with the environment” afterwards. The clear improvement in air quality that we have seen in this country would not have been possible without the passage of the 1970 Clean Air Act Amendments or the creation of the EPA, which has enforced them. We are all the beneficiaries of the system that has been in place over the past four-plus decades.

But this progress is not a given. As we’ve seen, climate change – itself a product of air pollution – threatens to harm air quality in the long-term. If we get complacent or, worse yet, try to roll back these gains, we will all suffer. Ozone is a fickle and complicated bastard that can strike where and when you are not expecting it. Let’s not give it that chance.

Actually, fuel economy standards are a great way to tackle carbon emissions

plug-in hybrid prius
plug-in hybrid prius

A Toyota Prius plug-in hybrid vehicle (courtesy of Wikimedia Commons).

It feels like it’s been ages since I wrote a post taking down something that someone else has written. I get the impression that is what people enjoy on the World Wide Web these days, plus it’s pretty fun to rip apart a person’s specious argument – using peer-reviewed literature and well-sourced facts, of course.

With that in mind, I feel somewhat obligated to address an op-ed I read in the Los Angeles Times on Monday from Salim Furth, a research fellow at the conservative think tank The Heritage Foundation. In the piece, Furth argues that state and federal fuel economy standards are a poor policy tool for limiting mobile greenhouse gas (GHG) emissions and that they unfairly harm low-income families. Instead, he calls for California state officials to focus their attention on land use reforms that would “allow denser, environmentally conscious construction” to “make residents less dependent on car.”

On the surface, this seems reasonable. I’ve written in the past about how promoting denser, infill development patterns in sprawling metro areas like Cleveland could go a long way towards improving air quality and limiting GHG emissions. To the extent that Furth is calling for these sorts of policies, we are probably on the same page.

Except, when you dig into his argument, it collapses like the proverbial house of cards. As the folks at Climate Nexus argued, “Instead of suggesting policy that would preserve more land to act as a carbon sink, Furth writes that California should instead relax the permitting process so that development is even easier.” And this is exactly what he argues. While it’s true that NIMBY-ism can inhibit the development of denser, multifamily housing (see: Washington, DC), it takes a certain amount of rhetorical gymnastics to assert that the fault lies with environmental regulations. I guess that’s what you get when dealing with stuff from Heritage.

Comparing fuel economy to land use planning

But none of this gets to the central thesis of Furth’s argument – that fuel economy standards are less effective tools for curbing GHG emissions than “streamlined” permitting and “more permissive zoning laws.” Why enforce regulations that cost the average family roughly $4,000 to only mitigate global climate change by a fraction of a percent?

Leaving aside the fact that Furth demands California repeal state fuel economy rules that even he admits were superseded by President Obama’s 2011 CAFE standards, does his main point hold water? Well, he never actually provides a shred of evidence to support his argument, for one. How can we know if the CAFE standards will cut GHG emissions less than land use reform if we don’t have numbers for the latter?

Fortunately, there exist a number of studies and reports that dig into the potential for land use reform to mitigate climate change. At the local level, several of these analyses have come from metropolitan planning organizations (MPOs), which are federally-mandated agencies that conduct transportation and environmental planning activities for urban areas.

Back in 2008, California lawmakers passed SB 375, the Sustainable Communities and Climate Protection Act, which requires every MPO in the state to develop a sustainable communities strategy (SCS) that outlines its approach to meeting its GHG emission reduction target. These targets are established by the California Air Resources Board (CARB). To what extent can land use planning by MPOs contribute to these these goals? And do the projected reductions in GHG emissions exceed those from fuel economy standards?

In a word, no. CARB estimated (PDF) in 2010 that regional transportation and land use policies can only account for one-sixth of the GHG reductions generated by federal CAFE and low-carbon fuel standards through 2020. That proportion will likely increase after 2020, as the full effects of those long-term policies are realized, but they still pale in comparison. Given that Furth is writing about California, you think he’d be aware of these data.

Evidence from outside California

Findings from MPOs in other states back up CARB. Washington, DC’s MPO found similar results (PDF). The region’s leaders set a goal of reducing GHGs 80% versus a 2005 business as usual (BAU) scenario by 2050. According to their analyses, enacting new land use and transportation policies at the metro level can only make up 3.3% of this 80%. Increasing CAFE standards to 99 could account for 30% of the reduction, however, making this approach 10 times more effective. While raising CAFE standards would likely lead to something of a rebound effect by making driving cheaper, the results are still impressive.

The Puget Sound Regional Council (PDF) – Seattle’s MPO – has also modeled the potential GHG savings from various policies. They found that more compact development and better pricing transportation could cut GHGs by 6% and 9% compared to BAU, respectively. Emissions control strategies, like stricter fuel economy standards and the electrification of the vehicle fleet, have the potential to cut GHG emissions by 25-43%, depending on how aggressive they are. Even in the more conservative scenario, these standards outperform land use controls. The benefits of land use policies take an outsized role in Seattle, as transportation accounts for two-thirds of the city’s total emissions, because it’s electric grid is so much cleaner than the national average. Accordingly, Seattle is the best case scenario for Furth’s argument, but it still falls short.

ghg savings from different scenarios

Potential GHG reductions from various policy instruments under different scenarios (courtesy of Puget Sound Regional Council).

 

And just to hammer my point home further, the Transportation Research Board (TRB) published a comprehensive report on this topic back in 2009. The authors modeled the impacts on GHG emissions from 2000 to 2030 and 2050 under two scenarios, which assumed that 25% and 75% of all new housing would be be built in compact development areas, respectively.

While scenario 1 only sees GHG emissions fall 1.3-1.7% by 2050, while scenario 2 bumps this number up to 8-11%. But, again, tightening CAFE standards wins the day. The study finds that adding aggressive fuel economy requirements to scenario 2 can increase the GHG reduction potential up to 39-51%. The report states, “In short, over the longer time frame (i.e. to 2050), the impacts of continuing improvements in fuel economy beyond 2020 on energy use and CO2 emissions significantly outstrip those from more compact development.”

As is so often the case, an op-ed emerging from The Heritage Foundation is tripped up by the think tank’s old nemesis – math.

In the effort to cut GHG emissions and battle climate change, we don’t need to privilege better land use planning at the expense of tighter fuel economy standards. We need to harness every policy tool at our disposal, and these are two great tastes that taste great together. While it’s true that better fuel economy can undermine some of the GHG benefits of compact land use, we should clearly pursue these approaches in tandem. For, in the long-run, more compact, mixed-use development and more efficient vehicles are both important tools for improving air quality, reducing transportation costs, revitalizing our neighborhoods, enhancing public health, and battling climate change.

What impact will climate change have on air quality?

sammis power plant
sammis power plant

The Sammis Power Plant near Steubenville, Ohio, which the PUCO agreed to allow FirstEnergy to continue operating through 2024 on the backs of ratepayers (courtesy of EarthJustice).

Though it’s hardly a secret that I view climate change as the preeminent issue of this generation, I usually try to bring some sobriety to the apocalyptic current that some of my fellow climate hawks bring to the table. Whether it’s casting a skeptical eye on the hype about climate change and conflict or challenging the use of the term “climate refugee,” I try to stay fairly level headed.

So it would seem reasonable that I would be somewhat wary of the hype surrounding the major new report from the U.S. Global Change Research Program on the public health impacts of climate change. I mean, as Kyle Feldscher of the Washington Examiner tweeted, somewhat snarkily,

But, here’s the thing, sometimes when Chicken Little screams that the sky is falling, you really do need to look up. And that’s the case with climate change. As this report lays out in tremendous detail, the public health implications of inaction are staggering, whether it’s the estimated 11,000 additional deaths per year from heat-related mortality, an increase in vector- and water-borne illnesses, or a spike in the frequency and intensity of disasters, things are going to suck unless we do something like yesterday.

Importantly, due to the lengthy atmospheric lifetimes of greenhouse gases (GHG), particularly CO2, some of these impacts are already baked into the cake. While the report makes it clear that we can stave off the worst effects on public health by taking immediate action to curb GHG emissions, the fact remains that we will inevitably have to adapt to that which we cannot mitigate and suffer that which we cannot adapt to. But since most of my focus is on air quality issues these days, I wanted to take a closer look at that chapter in the report.

Tracing improvements in air quality

First, it’s crucial that we note how much air quality has improved in the United States since the passage of the 1970 Clean Air Act Amendments (CAAA). According to the U.S. EPA, ambient levels of the six criteria air pollutants fell by a combined 63% from 1980 to 2014, including an astounding 99% for lead. All this occurred even as GDP grew by 147%.

This trend has paid significant dividends for Northeast Ohio. In Cleveland, for instance, the 3-year average for carbon monoxide (CO) from 1972-1974 was 17.3 parts per billion (ppb), well in excess of the 10 ppb standard. From 2012-2014, this value had fallen to just 4.3 ppb, a 75% decrease. Back in 1978, the 3-year average level of sulfur dioxide (SO2), which is generated largely from burning coal, stood at a mind boggling 497 ppb. In 2014, that level was down to 71 ppb, below the EPA’s 75 ppb standard.

The benefits of this dramatic improvement in air quality have been staggering. One study from the EPA found that, by 2020, the 1990 CAAA will prevent 230,000 premature deaths and generate benefits totalling $2 trillion. According to renowned University of Chicago economist Michael Greenstone, the 1970 CAAA extended the life expectancy of the average American by 1.6 years, totalling more than 336 million additional life-years. Here in Cleveland, we live, on average, 2.3 years longer because of this landmark piece of legislation.

But, as I’ve discussed before, a lot of people seem to think that these numbers mean we’ve moved beyond air pollution, that it’s something we’ve relegated to the past. That’s clearly not the case, given that a 2013 study estimated air pollution led to more than 200,000 premature deaths in 2005. In Cleveland, that number was 1,363, with the majority (62%) of deaths coming from electricity generation (466) and transportation (384). Clearly we have a long way to go, and incremental improvements in air quality will do a lot to winnow this number down further.

Will climate change affect this trend?

But that’s where climate change comes into play. The two primary bogeymen in the world of air quality are ground-level ozone and fine particulate matter (PM2.5). The formation of both of these pollutants depends heavily on meteorological conditions, particularly the former. When the conditions are right, ozone and PM2.5 levels can spike, with serious consequences for anyone who breathes air.

Now, obviously the most important thing that environmental officials can do is work to reduce emissions of ozone precursors, along with direct PM2.5 and its precursors. If there are simply fewer nitrogen oxide (NOx) and volatile organic compound (VOCs) molecules floating around, there will inevitably be less ozone in the air.

And this is true – to a point. That’s why the EPA estimates that, thanks to existing regulations like the controversial Mercury and Air Toxics Standard (MATS) and the Tier 3 Vehicle Emissions standard, ozone and PM2.5 levels will continue to decline. The agency projects, for instance, that ozone levels in Cuyahoga County will fall to 59 ppb in 2025 from 75 ppb currently.

Unfortunately, this fails to account for the impacts of climate change. Global warming is likely to make the types of meteorological conditions conducive to ozone formation – hot, still summer weather – considerably more common going forward. As the report’s authors note, “consequently, attaining national air quality standards for ground-level ozone will also be more difficult, as climate changes offset some of the improvements that would otherwise be expected from emissions reductions.”

To illustrate this effect, let’s look at recent history in Cleveland. From 2008 (when the EPA finalized its 75 ppb standard) through 2011, there were an average of 9.5 days each year when ozone levels exceeded the standard. This number plummeted further during the previous two mild summers, with 1 day and 3 days in 2014 and 2015, respectively. But then there’s 2012, the hottest year on record in the region. During that summer, we had 28 exceedance days, the highest number since 2002.

What will climate change’s impact be on air quality?

So what, exactly, does the report project? Well, it uses data from a 2015 paper by a group of EPA scientists that aims to “quantify and monetize the climate penalty” from higher ozone levels tied to climate change through 2030. Because the effects of climate change on PM2.5 are so difficult to suss out, the report focuses exclusively on ozone.

The authors use two global climate change scenarios, known as Representative Concentration Pathways (RCP) to estimate the effects. RCP 8.5 is a worst case scenario, while RCP 6.0 is slightly less pessimistic model that assumes we will take some action to curb emissions.

These models allow them to estimate the number of climate change-attributable, ozone-related premature deaths and illnesses in the US. While RCP 6.0 leads to somewhere between 37 and 170 premature deaths each year, RCP 8.5 could generate 420 to 1,900 additional early deaths. The authors find that “the economic value of these adverse outcomes ranges from $320 million to $1.4 billion for the RCP 6.0 scenario and from $3.6 to $15 billion for the RCP 8.5 scenario.”

climate change ozone impacts

The projected impacts of climate change on ozone levels and ozone-related mortality in the US for RCP 6.5 and RCP 8.0 (courtesy of Fann et al.)

These health impacts will not be distributed evenly, as the map above shows. Here the Midwest, particularly along the Great Lakes, significant global warming could drive ozone levels up by more than 5 ppb leading to tens or dozens of additional deaths. These findings are similar to those from a 2007 study (PDF) by Michelle Bell et al. in the journal Climatic Change. This study examined the impact of significant climate change on ambient ozone levels in 50 US cities by 2050. Bell et al. concluded that ambient summertime ozone levels would jump by 4.4 ppb, and every city studied would see an increase in the number of exceedance days by 2050. The average city would experience 5.5 more exceedance days per year, a 68% increase compared to the 1990s, while Cleveland could see a spike of 140%, from 7.5 to 18 days per year. The study uses the 1997 ozone standard of 85 ppb, meaning that the number of exceedances would likely be much higher for the current 2015 standard of 70 ppb. All told, ozone-related mortality was projected to increase 0.11-0.27%.

While this seems relatively insignificant, I should note that ozone is not a major cause of air pollution-related death here. If climate change was to have comparable impacts on particle pollution levels, these costs would increase by orders of magnitude. Unfortunately, this remains a real possibility. One study estimates that, while global PM2.5 concentrations may fall by up to 18%, they could increase by anywhere from 1 to 4 micrograms per cubic meter in the eastern US.

Ultimately, it’s not the projected number of additional deaths or asthma exacerbations that matters. What this report shows is that we have done an excellent job of cutting levels of harmful air pollutants, even as we increased emissions of a seemingly harmful one – CO2. But now, unless we take immediate action to slash the latter, all our great work on the former is at risk.

SB 310 makes it far harder for Ohio to comply with the Clean Power Plan

obama clean power plan
obama clean power plan

President Obama delivers his speech announcing the final Clean Power Plan on Monday, August 3 (courtesy of Susan Walsh/Associated Press).

Last Monday, President Obama stood at the podium in the East Room of the White House to announce “the single most important step America has ever taken in the fight against global climate change” – the final Clean Power Plan (CPP). As the President noted in his remarks, this final rule amounts to “the first-ever nationwide standards to end the limitless dumping of carbon pollution from power plants” into our atmosphere. The EPA projects that, if fully implemented, carbon emissions from US power plants should be 32% lower in 2030 than in 2005.

Here in Ohio, the rule was met by a mixture of excitement from those of us who want the country to take action on climate change and outrage from those who oppose such steps. Attorney General Mike DeWine joined 11 other attorneys general in a lawsuit to derail the rule, while notorious Ohio coal firm and serial litigant Murray Energy intends to file no fewer than 5 separate suits.

Changes to the final Clean Power Plan that affect Ohio

Given all of this controversy over the CPP, it may be wise to take a step back and consider just how the rule would affect Ohio. Last year, I explored how Ohio fared in the proposed CPP and how the state’s clean energy standards put it on a solid path towards meeting its carbon reduction targets. While that analysis was relevant at the time, we need to revisit it, as the final CPP is different from the proposed version in a lot of ways. For the sake of this post, here are a few of the key changes that will affect Ohio:

  1. State compliance plan date: Under the proposed CPP, states needed to submit their compliance plans to the EPA by June 30, 2016. The final rule pushes this date back to September 6, 2018, but with a caveat. States still need to submit either a final plan or an interim plan in 2016, but they can request a 2-year extension of the deadline if they meet certain criteria. This matters, as Ohio EPA Director Craig Butler has already stated that he will wait until to submit a plan until he sees how the rule fares in the federal court system, which may take years.
  2. Emissions cuts to begin later: Whereas the proposed CPP required states to begin cutting carbon emissions in 2020 and continue through 2030, the final rule delays that effective date until 2022. This 2-year delay is important for Ohio as a result of SB 310, as I will explore later.
  3. Changing the way that emissions reductions are measured: Originally, the EPA planned to measure emissions reductions as the change in how many pounds of carbon emissions a state produces per megawatt hour (MWh) of energy it produced (“rate-based”). But the Agency has now added a “mass-based” approach, which shows reductions in the actual tons of carbon states emit. Additionally, EPA has changed the state-by-state targets to account for the fact that the utility sector operates within 3 broader regions. As a result, Ohio’s rate-based target was strengthened from 1,338 lbs/MWh to 1,190, up to 37.4% from a 27.7%. The mass-based reduction remains at a comparable 27.85%.
  4. Eliminating the energy efficiency benchmark: The proposed CPP created federal guidelines for state compliance plans that included 4 main building blocks: improved coal plant efficiency, more use of natural gas, increasing renewable energy generation, and improving demand-side energy efficiency. EPA has removed the energy efficiency building block, which has significantly reduced the CPP’s legal vulnerability. Fortunately, EPA did not scrap demand-side energy efficiency entirely. Instead, it will allow states to include it as part of their state compliance plan.

How Ohio can meet its Clean Power Plan requirements

Fortunately, Ohio is well-positioned to meet its emissions reduction targets under the CPP, as multiple analyses have shown.

In a 2013 analysis, the World Resources Institute found that, if Ohio fully implemented its renewable portfolio standard (RPS) and energy efficiency resource standard (EERS) that the state passed nearly unanimously back under SB 221, it could cut its carbon emissions by 17% through 2020.

WRI’s analysis also calculated the emissions savings from the other 2 building blocks in the CPP. It estimated that Ohio could cut its emissions by 7% by 2020 if it increased the operating capacity of its existing natural gas fleet (building block 2). The state could further cut emissions by 2% if it improved its coal plant efficiency by 2.5% (building block 1). Combined, these four actions would get Ohio to a 26% cut by 2020, before the CPP’s requirements even kick in. And if Ohio continued to implement its EERS and RPS beyond their current end date, the state would be able to meet and exceed its required carbon targets.

wri ohio emissions clean power plan

Ohio can cut its carbon emissions by up to 24% through 2020, depending on the policies it implements under the Clean Power Plan (courtesy of World Resources Institute).

SB 310 will make increase the costs of compliance

While Ohio is currently in decent shape, SB 310 will unquestionably make it more difficult and more expensive for the state to comply with the CPP.

The two-year freeze on the RPS and EERS will deprive the state of renewable energy and energy efficiency gains that it could count towards future benchmarks. Though it pushed back the date when states have to demonstrate emissions cuts by 2 years, EPA wants to encourage states to reduce their carbon emissions before that point. Accordingly, the final CPP creates a Clean Energy Incentive Program (CEIP), which allows states to get credits for renewable energy generation and energy efficiency measures taken in 2020 and 2021 and apply these to reduction targets in subsequent years. For every 1 MWh of wind or solar that a utility brings on line, it will get a 1 MWh credit towards future emissions reductions. And for every 1 MWh saved through energy efficiency projects in low-income communities, utilities will get a 2 MWh credit.

Because SB 310 freezes Ohio’s RPS and EERS for 2015 and 2016, the RPS and EERS benchmarks will be lower during 2020 and 2021. RPS benchmarks will decline to 6.5% and 7.5% from 8.5% and 9.5%, respectively, while the efficiency requirement for 2020 will be halved to 1%. According to projections from the Public Utilities Commission of Ohio (PUCO), the state’s major electric utilities would have generated almost 25.9 million MWh of renewables in 2020 and 2021; however, thanks to SB 310, this number will fall by nearly 25% to 19.4 million MWh.

The freeze will also cut into the amount of low-income energy efficiency projects carried out in the state. From 2009-2012, Ohio’s major electric utilities realized  55,084 MWh in energy savings from low-income projects. This accounted for just under 1% of total savings. Based on estimates from the American Council for an Energy-Efficient Economy (ACEEE), Ohio was on course to save 56,410 MWh from energy efficiency in 2020 and 2021 before SB 310. Using revised energy savings from the Natural Resources Defense Council (NRDC), which account for SB 310’s effects, this number would fall to 46,866 MWh. Because these savings get double credit in the CEIP, Ohio will lose out on 19,048 MWh of emissions reduction credits (ERCs).

All told, the 2-year freeze on Ohio’s clean energy standards enacted under SB 310 will cause the state to miss out 6,476,386 MWh of ERCs. If we assume that each of those MWh would have offset a unit from a fossil fuel plant, we can estimate how many tons of carbon emission reductions the state will lose. EPA has calculated that Ohio’s power plants release 1,900 pounds of CO2 per MWh; as such, Ohio will lose ERCs worth roughly 6,152,567 short tons of CO2. Applying a social cost of carbon at $40 per ton means that this one effect of SB 310 will cost the state more than $246 million.

But that doesn’t account for any potential reductions in the RPS and EERS benchmarks. The bill’s language makes it perfectly clear that the Ohio legislature intends to “enact legislation in the future… that will reduce the mandates.” Any future reductions to these clean energy standards will make it that much harder for Ohio to comply with the Clean Power Plan.

What should Ohio’s elected officials do?

Clearly, SB 310 carries a big price tag for Ohio. The state’s elected officials should take action on three fronts to address this issue.

First, the legislature needs to pass a bill restoring Ohio’s clean energy standards as enacted under SB 221. It should not wait until the freeze comes to an end on December 31, 2016. Instead, legislators should use the final report from the Energy Mandates Study Committee, which is expected to be released this fall, as a reason to restore the standards effective January 1. Interestingly, OEPA Director Butler told Gongwer (subscription required) that, despite his reservations, he realizes restoring the standards from SB 221 would help Ohio meet its emission reductions targets. Beyond this step, however, the legislature should look to pass a follow-up bill by the end of the next session that will extend and, preferably, strengthen these standards through at least 2030.

Second, Ohio should begin exploring how it can partner with other states to form a regional carbon trading system. The final CPP explicitly allows and even encourages states to pursue this route. Several Midwestern states have been meeting under the auspices of the Great Plans Institute to discuss this option, but Ohio has conspicuously been absent. It would be in the state’s best interest to work with its neighbors in order to lower the cost of compliance.

Third, Ohio needs to double down on low-income energy efficiency. According to Policy Matters Ohio, the state currently weatherizes roughly 7,000 homes per year. This number accounts for just 1.5% of the households in the state who seek emergency assistance for their utility bills each year. Not only will ramping up low-income weatherization allow the state to get additional credits through the CEIP, it will generate tangible benefits. Every $1 million invested in weatherization leads to the creation of 75 jobs.

Ultimately, SB 310 has cost Ohio considerably, but it’s not too late to mitigate those effects. Every day that Ohio continues to languish under this bill will continue to add to those costs. It’s time to act.

Update (8/13/2015, 3:45pm): Since I posted this, the Union of Concerned Scientists has updated its state-by-state projections on the Clean Power Plan. In June, they concluded that Ohio was on track to meet and actually exceed its 2020 interim reduction benchmark under the proposed CPP. The new analysis finds that Ohio is now on track to achieve 84% compliance with its rate-based goal and 130% compliance with its mass-based goal for the 2022 benchmark. Without implementing additional policies, however, the state would only 44% and 56% of its rate- and mass-based targets, respectively.

Additionally, I noted that, based on the EPA’s social cost of carbon ($40 per ton), the emissions reductions that Ohio will miss in 2020 and 2021 as a result of SB 310 would carry a cost of more than $246 million. This number does not account for the costs of other air pollutants that power plants release in addition to CO2. Based on a 2010 study, which reviewed the literature on the air quality co-benefits of carbon reductions, the average air quality benefit for developed countries per ton of CO2 is $44. Based on this number, Ohio would not only incur climate change-related costs of $246 million, it would also forego air quality improvements worth more than $270 million. Combined, SB 310 will cost the state nearly $517 million in 2020 and 2021 alone.

Why developed countries should back loss and damage in Paris

schoolchildren typhoon haiyan
schoolchildren typhoon haiyan

School children in the Philippines contemplate the aftermath of Typhoon Haiyan (courtesy of Pio Arce/Genesis Photos).

A number of critical issues remain unresolved, including whether countries should set a maximum safe threshold for carbon emissions and what protocols will be put in place to ensure that parties are transparent and accountable for their emissions reduction commitments. One of the trickiest outstanding issues is the question of loss and damage. For years, developing countries have called for developed states to compensate them for the negative effects of climate change, such as more frequent flooding and more intense droughts.

While developed countries committed to provide financing for climate mitigation and adaptation through the development of the Green Climate Fund in 2009, it is widely acknowledged that there are impacts of climate change which we can neither prevent nor prepare for. These residual effects are at the centre of the loss and damage debate.

This issue particularly came to the fore at the 2013 Warsaw Conference, which took place in the immediate aftermath of Typhoon Haiyan, which devastated parts of the Philippines and killed more than 6,300 people.

Yeb Sano, the Philippines lead negotiator, delivered an impassioned speech in Warsaw pushing the issue. Sano, whose hometown had been flattened by the storm, fasted throughout the conference in solidarity with Haiyan survivors. He called for parties “to make clear the difference between humanitarian aid and climate change compensation in the context of historical responsibility.”

These efforts paid off, as negotiators created the Warsaw international mechanism for loss and damage, which created a standing committee to research the issue and advise the UNFCCC over the next two years.

At last year’s conference in Lima, negotiators reaffirmed their commitment to discuss the issue, outlined the membership of an Executive Committee, and approved a two-year work plan. But discussions remain in a preliminary phase, and many developing states remain concerned that the Paris talks may fail to address the question adequately. Small island states, in particular, view loss and damage as an existential question, as climate change may threaten their very survival.

To read the rest, head over to the original post at RTCC.

Climate change will lead to more deadly traffic accidents

A rendering of the proposed Cleveland Midway, a network of protected cycle tracks that would run across the city (courtesy of Bike Cleveland).

A rendering of the proposed Cleveland Midway, a network of protected cycle tracks that would run across the city (courtesy of Bike Cleveland).

In recent years, there has been a considerable amount of attention paid to transportation issues in climate change circles. This makes sense, given that the transportation sector is the second largest source of greenhouse gas (GHG) emissions in the United States. Mobile sources produced 1,806 million metric tons of CO2 equivalent (MMtCO2e) in 2013 (27%), trailing just electricity generation, which accounted for 21% of total emissions (2,077 MMtCO2e). Emissions from the transportation sector have also grown by 16.4% since 1990, making it the second fastest growing emissions source behind agriculture.

Accordingly, the Obama administration has taken a number of steps to address the issue. These include corporate average fuel economy (CAFE) standards for passenger vehicles, new investments in electric vehicles (EVs), proposed stricter rules for emissions from heavy-duty trucks, and the recent endangerment finding for GHGs from air travel. Each of these steps will be important if the US is to meet its goal to cut overall GHGs by 26-28% by 2025, as outlined in the administration’s pledge for the upcoming Paris Conference.

How climate change affects transportation

But the other side of this equation – how climate change will affect the US transportation sector – has garnered far less focus. The 2014 National Climate Assessment included a detailed chapter on the transportation sector, and the Federal Highway Administration (FHWA) manages a pilot program to help transportation agencies assess their systems’ vulnerability to a changing climate. We know, for instance, that more extreme rainfall could wash out roads, that sea level rise endangers coastal transportation infrastructure, and that accelerated freeze-thaw cycles may increase the costs of road maintenance. But much research in this area remains to be done.

A few weeks ago, Resources for the Future, a leading environmental economics think tank, released a report that examines one as yet unexplored issue – how climate change may influence traffic accident rates. I’ll admit that the idea that climate change could affect the number of car accidents in the US seemed a bit far fetched to me a first. People tend to jump through all sorts of hoops in order to connect everything to climate change these days. But this report provides a convincing case that, barring aggressive action both to cut carbon pollution and become more resilient, climate change could make our roads even more dangerous.

The connection between weather and traffic accidents

In order to explore the relationship between climate and traffic accidents, economists Benjamin Leard and Kevin Roth first examined existing evidence on how changes in weather patters affect accident rates. Using data from the National Highway Traffic Safety Administration (NHTSA) on the number of traffic accidents that result in property damage, injuries, and fatalities for 20 states, the authors identified the existing relationships between temperature and precipitation fluctuations and traffic accidents. When temperatures fall below 20ºF, accidents that result in property damage increase by 9.3%. The relationship between temperature and accidents that lead to injuries is weak, but it appears highly significant for fatal traffic accidents. In contrast to property damage accidents, fatal accidents are 9.5% more likely on days when temperatures climb above 80ºF.

The relationship between precipitation and traffic accidents is more complex. Both rainfall and snowfall increase the incidence of property damage accidents; when rain and snow totals exceed 3 centimeters, accidents increase by 18.8% and 43.3%, respectively. This effect changes when we consider accidents leading to injuries and fatalities. In the former category, rain and snow totals over 3 centimeters lead to 14.4% and 25.9% increases in accidents, a relative reduction of 23.4% and 40.2%, respectively, compared to property damage accidents. But Leard and Roth found that fatal traffic accidents are actually less common on days with rainfall. On days with 1.5-3 centimeters of rain, fatal accident rates fall by 8.6%; this result is highly statistically significant. In contrast, this same amount of snowfall leads to 15.5% more fatalities. According to the authors, these results indicate “that drivers behaviorally compensate for these conditions,” but these adjustments are not enough to reduce the elevated accident risk presented by snowfall.

Importantly, the study also finds a strong correlation between weather conditions and the number of trips people make by foot, bike, or motorcycle (the authors term these “ultralight duty vehicles,” or ULDs). Unsurprisingly, these ULD trips decrease significantly as temperatures dip below 40ºF and as the precipitation begins to fall. Put a different way, as the weather improves, an increasing number of people choose to walk, bike, or motorcycle. This increases their exposure to automobiles, elevating the risk that they may be the victim of an accident. Accordingly, when the authors removed pedestrians, cyclists, and motorcyclists from their models, fatality rates fell by roughly half.

Climate change will cause more traffic fatalities

The authors then used these observed relationships to project how climate change could affect traffic accident rates in the future. They utilize the IPCC’s A1B scenario – a middle of the road scenario that assumes global temperatures will rise by around 4ºC – to project changes in weather and traffic accidents through the end of the century. According to the Climate Action Tracker, we are currently on pace for 3.6-4.2ºC of warming in the absence of further action, making A1B a good model for this study.

As global temperatures increase, precipitation will gradually shift from snowfall to rain. The authors find that this change will decrease the number of annual traffic fatalities by roughly 253. However, the changing climate will also induce an increase in the number of trips people take by foot, bike, and motorcycle – leading to an additional 849 traffic fatalities per year – which brings the net change to 603 additional deaths per annum. This spike in traffic fatalities will carry an annual cost of $515.7 million. All told, by 2090 climate change will lead to an additional 27,388 traffic-related fatalities in the US, carrying total costs of approximately $61.7 billion.

Now, I should note that this study does not explicitly address a few issues.

Research shows that as the number of pedestrians and cyclists increases, the chance that they will be struck by a car declines. Each time that the number of pedestrians and cyclists doubles, the risk that they will be injured in an accident falls by a third. But this decline in the relative risk of injury does not overcome the increase in the absolute number of injuries, which actually rises by a similar percentage. Leard and Roth’s study finds similar results. Furthermore, their use of fixed effects should account for this safety-in-numbers effect.

Moreover, the study does not directly account for the fact that expanding bike and pedestrian-friendly infrastructure tends to make roads safer and reduce the number of accidents. Protected bike lanes, for instance, can cut the risk of injury by up to 90%. To be fair, Leard and Roth admit that this is a potential shortcoming of their study, noting that failing to control for this effect “overstates the long-run impacts of climate change.” They also explicitly point out the important role that these types of interventions can play in climate adaptation planning,

Our results do not indicate that reliance on walking, biking, and motorcycling imply large fatality rates, as other developed English speaking and western European nations have per-capita fatality rates that are often less than half that of United States. Some countries like Sweden with extraordinarily low fatality rates have pursued a variety of urban design and legislative changes to reduce fatalities with policies such as replacing intersections with roundabouts to slow vehicles where they are likely to encounter pedestrians. Relatively simple changes like these may prove to be effective, although unglamorous, adaptation strategies to climate change.

How can this study inform climate policy?

I have two main takeaways from this study.

1. Climate change will affect nearly every aspect of our lives, and we will never be able to fully anticipate and prepare for it. That’s what happens when humanity performs a global science experiment on the planetary systems that facilitated the development of human civilization.

2. It provides even more evidence of the benefits of investing in better infrastructure for cyclists and pedestrians, particularly when accounting for climate change. It emerges as a win-win-win.

Promoting active transportation is a vital component of any mitigation strategy, as every mile we don’t drive keeps roughly one pound of CO2 out of the atmosphere.

This type of people-centric infrastructure  also represents an important step that local governments can take to enhance their resilience to the impacts of climate change. We know that it may help to offset potential increases in fatal accidents due to climate change. But, more than that, it can also serve as a key lifeline to supplement existing road networks, which may be endangered by a changing climate. When roads are washed away and subway tunnels flooded, being able to ride your bike or walk to access resources and social services becomes that much more important.

Lastly, these types of investments would be valuable even in the absence of climate change, as they improve quality of life. Active transportation benefits air quality and public health, which reduces premature mortality and health care costs. Complete streets can also raise property values, increase business activity, create jobs, and make neighborhoods safer. All of these things make communities more vibrant and better able to withstand external shocks, whether from economic or climatic forces. In this way, pedestrian and cyclist-friendly infrastructure is exactly the type of no-regrets investment that climate resilience experts say we should be making now, regardless of the inherent uncertainties.

Karachi’s Heat Wave a Sign of Future Challenges to Pakistan’s Fragile Democracy

A man (R) cools off under a public tap, while others wait to fill their bottles, during intense hot weather in Karachi, Pakistan, June 23, 2015. A devastating heat wave has killed more than 400 people in Pakistan's southern city of Karachi over the past three days, health officials said on Tuesday, as paramilitaries set up emergency medical camps in the streets. REUTERS/Akhtar Soomro - RTX1HPUL

A man (R) cools off under a public tap, while others wait to fill their bottles, during intense hot weather in Karachi, Pakistan, June 23, 2015. A devastating heat wave has killed more than 400 people in Pakistan’s southern city of Karachi over the past three days, health officials said on Tuesday, as paramilitaries set up emergency medical camps in the streets (courtesy of Reuters).

Karachi, the world’s second largest city by population, is emerging from the grips of a deadly heatwave. A persistent low pressure system camped over the Arabian Sea stifled ocean breezes and brought temperatures in excess of 113°F (45°C) to the city of 23 million people in June. The searing heat disrupted electricity and water service, making life nearly unbearable. All told, officials estimate the heatwave killed at least 1,200 Pakistanis, more than twice as many as have died in terrorist attacks this year.

But meteorology alone cannot explain this turn of events. Rather, as with all disasters, Karachi’s heatwave is rooted in a complex web of natural and man-made factors. “The emergency is the product of a perfect storm of meteorological, political, and religious factors,” notes The New York Times.

Karachi’s rapid growth has heightened people’s exposure and vulnerability to heat. Since 2000, Karachi’s population has doubled, making it the fastest growing megacity in the world. This population explosion has overwhelmed the capacity of local government. At least half of all Karachiites live in informal settlements, with little access to infrastructure and vital services. Unplanned expansion has also led to widespread environmental degradation. Karachi’s annual concentration of fine particulate matter is 11.7 timesWorld Health Organization standards (and more than double that of Beijing), making it the fifth most air-polluted city in the world. Karachi also faces an acute water crisis. Some of its poorest residents survive on just 10 liters per day, one-fifth of daily drinking requirements, while some estimates suggest more than 30,000 people die from water-related diseases every year.

Wide swathes of trees and other vegetation have been cleared for roads and buildings, limiting shade and exacerbating the urban heat island effect (the process by which urbanized areas absorb and retain solar radiation, significantly increasing local temperatures). Add to this the city’s construction boom which creates a major demand for manual labor and the onset of the holy month of Ramadan – during which Muslims can neither eat nor drink before sundown – and you have a recipe for disaster.

To read the rest, head over to the original post at New Security Beat.

Condoms are key for promoting responsible consumption

community health worker
community health worker

A community health worker talks to women in SIerra Leone (courtesy of H4+ Partnership).

At first blush, the idea that one action to reduce conspicuous consumption could bring about a sustainable future seems far-fetched. Sustainability is all-encompassing. There is no silver bullet; we need a thousand silver BBs. But not all actions are created equally. Some are so central that, without them, we cannot hope to bring about the future we want. Ensuring that all 7 billion people have the access to and education needed to properly use condoms is one such action.

Worldwide, more than 200 million women have an unmet need for contraception. This gap has startling consequences. In 2012, at least 85 million pregnancies were unintended. If every woman who wanted to avoid pregnancy could access modern contraceptives, there would be 22 million fewer unplanned births and 15 million fewer unsafe abortions each year.

The condom is perhaps the most important tool for tackling this issue. This simple piece of latex tackles a host of problems that undermine sustainability.

First, condoms help fight the scourge of HIV/AIDs and other sexually transmitted infections (STIs). More than 1.5 million people died of AIDS-related diseases in 2013, while 35 million people live with HIV/AIDS. In turn, people contract nearly 350 million cases of STIs, like gonorrhea and syphilis, each year. These preventable infections make life far more challenging and can even be deadly. One such disease, HPV, is the leading cause of cervical cancer, which kills hundreds of thousands of women annually.

Second, condoms are vital for curbing population growth and addressing climate change. If contraceptive use increased by 14%, we could prevent 1 billion births by 2050. This step will be key for keeping global temperatures below 2ºC. Curbing population growth could, on its own, produce 16-29% of the emissions reductions we need to stave off dangerous climate change. This issue will be particularly important in the developed world, where each person’s carbon footprint is far larger. Here in the United States, where half of all pregnancies are unplanned, the average person uses 25 times more resources in his/her lifetime than one in a developing country. Clearly, condoms can reduce carbon emissions and tackle conspicuous consumption in tandem.

Third, ensuring that everyone can use condoms will increase our level of resiliency. Pregnant women and infants are uniquely vulnerable to a number of threats, like natural disasters and diseases. During the 2004 Indian Ocean tsunami, women were four times more likely to die. And, because mosquitoes are attracted to pregnant women, malaria hits them especially hard. Infection during pregnancy causes 10,000 maternal and 200,000 infant deaths every year in Africa. Reproductive health, particularly contraceptive use, needs to be a centerpiece of health and disaster management planning.

Fourth, the condom can be a key tool for women’s empowerment. Every day, millions of women are trapped by the issues related to unprotected sex. Giving them the ability to choose when and how they reproduce is essential to putting their destinies in their hands. Condoms can help reduce the amount of time a woman spends pregnant, curb postpartum depression, and slash maternal deaths. As the WHO noted, “Without fertility regulation, women’s rights are mere words. A woman who has no control over her fertility cannot complete her education, cannot maintain gainful employment…and has very few real choices open to her.”

Clearly, while the condom is not a sufficient tool for a sustainable future, it is a necessary one. Condoms help liberate men and women alike from illness, vulnerability, environmental harm, and a lack of choice.