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Northern Cities Run Hot and Cold

You wouldn’t look at a list of the 50 coldest cities in the United States and think, “boy, I bet those cities have a real urban heat island problem” – would you?

But for several of the cities on this list, that’s exactly what’s going on. Albany, NY, and Des Moines, IA – both in fairly northern regions of the United States – made the list of coldest cities, while still suffering from significant urban heat island problems.

Friendly reminder that – even in some of the coldest regions of the world – reflective surfaces can help them address these problems, and help cities become more resilient to climate change.

7 Actions for Cities to Seriously Address Climate Change

Cities are where more than half the world lives, and where all future population growth will occur. By many estimates, cities are already responsible for more than half of climate change. While Congress remains dysfunctional, cities are rapidly becoming the most interesting and innovative developers and adopters of programs to cut CO2 emissions. They increasingly are taking on the responsibility of achieving deep CO2 emission reductions that virtually all climate scientists tell us we must achieve.

I participated in the recent VERGE day-long City Summit, and was impressed by how much effort and innovation around climate change reduction is occurring in cities. More than 1,000 U.S. mayors, who represent some 60 million Americans, have signed on to the U.S. Conference of Mayors’ Climate Protection Agreement, committing to cut city-wide CO2 emissions below 1990 levels. Houston, Philadelphia and Los Angeles recently launched the Mayors’ Nation Climate Action Agenda (PDF), a joint commitment to an inter-city cap-and-trade program to reduce CO2 emissions by 80 percent by 2050.

For the most part, however, cities have not yet gotten serious about implementing substantial policies to cut CO2 emissions. Following are seven actions cities can and should take in order to reduce emissions by more than half while saving money.

1. Adopt cool roof, green roof and solar harvesting strategies

Half of city surfaces are roads, parking lots, sidewalks or roofs. These generally absorb over 75 percent of the sun’s energy, converting it into heat that increases urban temperature and global warming, both of which increase smog formation and energy bills. The low reflectivity of these surfaces imposes huge unnecessary social and environmental costs.

It is cost-effective today to double the reflectivity of most city roofs and paved areas. Through the work that Capital E is doing with Washington, D.C., the National Housing Trust, the American Institute of Architects and others, we have found that by adopting cool roofs, green roofs and solar PV on roofs, most cities dramatically can improve comfort and health while cutting energy costs.

Cool and green roofs and solar PV should be evaluated on a full costs and benefits basis — including health — to inform policies.

2. Integrate smart-building platforms with existing systems

City agencies commonly have different building energy management systems and a range of often incompatible energy using devices, controls and systems. Buildings — even LEED buildings — can be made to operate better if they are managed through a smart building platform that integrates with all existing systems, including building energy systems, controls and sensors, and uses near real-time data from these systems to optimize energy use and comfort.

A strategy such as ESCO 2.0 features integrated, near real-time, smart energy data, and controls and optimization to actively manage a portfolio of buildings. A recent NRDC study (PDF) of three efficient commercial buildings, including a newly commissioned LEED building, that adopted a smart-building optimization platform called AtSite cut energy use by 8 to 17 percent with almost no new equipment investment.

One advantage of an ESCO 2.0 strategy is that it allows a shift from expensive scheduled maintenance to maintenance triggered by near-real time equipment performance. Another benefit is improved comfort. This kind of open platform also allows virtually unlimited flexibility in adding in new equipment or applications.

3. Enter into long-term agreements to buy new renewable energy

Today a lot of cities, among other building owners, buy short-term (typically two-year) Renewable Energy Credits. These are in essence transferrable, inexpensive accounting claims for the environmental benefits associated with renewable energy. But in reality RECs are almost entirely from projects that are already completed (often many years earlier), and the RECs have little or no impact on driving new renewable energy investments.

To drive new renewable energy investments, cities should skip RECs and instead contract to buy renewable energy on terms long enough to actually allow new project financing. To do so, cities should enter into long-term purchase power agreements with renewable energy power developers to buy clean energy at fixed rates — typically below the rate they are currently paying.

This long-term purchase commitment means revenue certainty for the project developer, enabling equity and debt financing for project construction. Smaller cities can band together to do larger, joint PPAs for renewable energy, in turn bringing down the cost of clean energy.

These PPAs can be executed by almost any city today, would achieve real CO2 reductions and generally would cut the long-term cost of electricity. City government can invite in-city groups, such as schools and hospitals, to participate in city PPAs to enable even larger cost and environmental savings.

4. Insist that cities’ energy efficiency investments be counted in cap-and-trade programs

About half the U.S. population lives in states with cap-and trade programs (including California and members of the Regional Greenhouse Gas Initiative) that place a dollar value on CO2 as a way to encourage investments that cut CO2 emissions. But while large industries, corporations and utilities can participate, cities are excluded from these programs. This makes no sense.

A national initiative called CO2toEE seeks to allow energy efficiency investments by cities and other building owners to receive the value of the CO2 reductions that result from their energy efficiency investments. This initiative has broad and growing support from state and national real estate and energy organizations and NGO groups — and cities should join to push for this common-sense and important design change in carbon trading programs.

The value of the CO2 received by cities would offset a significant part of the capital cost of deeper energy efficiency investments, increasing the funding for deep energy efficiency investments.

By allowing city and building energy efficiency to participate, cap-and-trade markets also would become larger, deeper and more efficient, and would drive large additional investments into energy efficiency. This is essential if cities are to achieve deep reductions in their CO2 emissions.

5. Measure, count and reduce the CO2 embedded in cities’ buildings and roads

Most cities that count their CO2 emissions and invest in reducing CO2 still ignore the enormous volume of CO2 that results from constructing their buildings, roads and other infrastructure.

Cement production is responsible for about 6 percent of the world’s CO2 emissions. A recent review of California’s 500 mile high-speed train found that it would take about a decade of CO2 emissions reductions from rail trips replacing car, truck and plane trips to offset the CO2 emissions from the production of cement required to build the train’s infrastructure. And it can take an energy-efficient building six or eight years of operations to equal the CO2 emissions from the cement used in construction. In fact, the most recent release of the national green building design standard, LEED v4, awards points for reduction of embedded CO2.

What if, instead of generating CO2 emissions, cement sequestered CO2? What if cities measured their embedded CO2, and then used their infrastructure — roads, parking lots, sidewalks and their buildings — to sequester CO2?

6. Invest in new versions of ancient building products that can reduce or sequester CO2 in buildings

Wood sequesters CO2, and the recent development of advanced structural wood products such as cross-laminated timber allow 10 or 20 story buildings to be built of wood.

A much larger CO2 sequestration opportunity is low or negative carbon cement. Cement, first used by Mesopotamians and Romans, is also being reinvented. Cement produces almost a ton of CO2 per ton of cement (cement is made by burning limestone at over 2500 degrees.) Several companies produce low or negative carbon cement.

The most interesting of these companies is Blue Planet, which sequesters flue gas from power plants in cement, sand and aggregate (cement is combined with sand and aggregate to make concrete). Blue Planet can sequester up to 1,500 pounds of CO2 per ton of cement. In its current work at the DOE National Carbon Sequestration Center and in other partnerships, Blue Planet is targeting an 80-percent CO2 reduction from fossil fuel plants, such as natural-gas fired power plants. The process also sequesters other damaging pollutants, such as PM2.5, heavy metals and NOx.

7. Incorporate best-estimate CO2 costs into design and investment decisions

Even in places such as California that have active carbon markets, the market price for carbon is far below its real cost. Because climate change already imposes large costs, cities increasingly want to account for global-warming costs in their investment decisions.

A dozen federal agencies, including the Treasury Department and the Environmental Protection Agency, developed a rigorous cost analysis called the social cost of carbon (PDF). First released in 2010 and updated in 2013, it found the real cost of CO2 to be in the $40/ton range, with additional identified costs not included. Based on a Congressional request, the report and its methodology were extensively reviewed by the General Accounting Office, which a few months ago issued a report that entirely confirmed the social cost of carbon analysis and findings.

A good strategy — recently adopted by the Federal Green Building Advisory Committee which I chair — is to include the social cost of carbon in all construction and energy-related design decisions. In effect it is revenue neutral because it is used just to make better design decisions.

While this will take years to implement in federal agencies, cities can and should move rapidly to adopt this rigorous and conservative cost of carbon in their own design and investment decisions. This would allow better, more cost-effective investment and design decisions that reflect the real cost of climate change. (British Columbia’s adoption of a substantial cost of carbon helped achieve deeper CO2 reductions, lower overall taxes and faster economic growth than other Canadian provinces that did not adopt a carbon price.)

Enabled by organizations such as the Urban Sustainability Directors Network, C40 Cities and the Global Cool City Alliance, cities have become the most promising and important forum to drive deep CO2 reductions. Cities increasingly have the political will to get serious about climate change and to lead their countries to a very low-carbon future consistent with protecting the planet and future generations from the worst of climate change. The clock is ticking.

This article is based on a presentation Nov. 10 at the National Academy of Sciences/Institute of Medicine.

Disclosure: I work with several of the above companies and organizations as a board member/adviser/investor.

Greg Kats serves on the Board of the Global Cool Cities Alliance.

This article was originally posted on November 13, 2014 at (


On November 6th, I gave a talk at the annual gathering of the Northern California Chapter of the American Public Works Association. The talk was titled, “Keeping you Communities Cool: Tools for Reducing Urban Heat”. It started with an introduction to the growing problem of urban heat and the scientific fundamentals behind cool materials. Because the audience was composed primarily of representatives from municipal agencies, many of them focused on stormwater management and transportation, I focused largely on cool pavements, and only touched briefly on cool roofs and shade trees. The bulk of the presentation focused on the benefits that can be derived from large scale introduction of cool pavements and the range of pavement options that are available.

The audience was remarkably engaged and we were able to have a good discussion about the trade-offs between some of the different pavement options, the state of the science, and some of the challenges of advancing the use of cool pavements and shade trees when working in municipal public works departments. One example is that the public tends to like having black paved surfaces because it makes them feel as though their roads and parking lots are new and in good repair!

My presentation is available on the Knowledge Base:

Lead IPCC Author Warns of Extreme Heat Waves

National Public Radio’s Rachel Martin spoke recently with Michael Oppenheimer, the coordinating lead author of the synthesis report of the IPCC’s Fifth Climate Assessment.  During the interview, Oppenheimer noted that the urban heat island effect will become more of a threat in the years to come, warning that heat waves will become more frequent and more extreme…

MARTIN:  Up to this point, it’s been hard to pin down where the effects of climate change are going to be most profound.  Does this report tell us anything about specific places in the world that are especially at risk?

OPPENHEIMER: Well, I would first point to three types of places…

The third area I point to which effects people particularly in cities anywhere in the United States, which already have an urban heat island effect – well, I’d point to the extra frequency with which we’re getting already and are going to get more in the future – heat waves.  In Europe in 2003, about 40,000 people died in the heat wave.  We just can’t afford to have that risk increasing over time.  We’ve got to get on top of our missions or else it’s going to get out of control.

Oppenheimer closed by noting that we’re making progress in reducing greenhouse gas emissions, but that we’re not moving fast enough.  He described this report as a wake-up call to governments, noting that the opportunity to avoid a dangerous warming is disappearing.   The time to act is now.

You can listen to the full interview here.

Cool Roofs in the IgCC

The final action hearings for the 2015 International Green Construction Code were held in Ft. Lauderdale, FL in early October.  GCCA Executive Director, Kurt Shickman and I attended the hearings to defend GCCA’s cool roof proposals and to fight to keep some anti-cool roof proposals out of the code. For the first time since GCCA began its cool codes program, we were joined by several representatives from the cool roofs industry.  Specifically, many members of the Chemical Films and Fabrics Association made the trip to Ft. Lauderdale to testify in support of our cool roofs agenda.

GCCA was particularly focused on supporting two of its proposals: GG 166, which proposed an increase in the reflectivity levels for low sloped roofs (which was recommended for approval by the code development committee), and GG 163, which proposed expanding the cool roof requirement into climate zone 4a and 4b (which was recommended for disapproval by the code development committee). GCCA was also hoping to overturn the committee’s decision to support GG77, which proposed turning the existing cool roof requirement into a jurisdictional elective, and to keep GG 164 from passing, which moved the cool roof requirements into the energy chapter of the IgCC, therefore discounting the urban heat island benefits of cool roofs.

GCCA was very pleased to be able to negotiate a compromise with a number of its opponents at the hearing, specifically the Asphalt Roof Manufacturer’s Association and EPDM Roofing Association.  As a result of that compromise, we were able to secure increased reflectance levels (albeit lower than what we had originally proposed), avert the jurisdictional elective, and keep the urban heat island chapter of the code intact.  Our opposition secured an exemption for ballasted roofs in the cool roofs code, which we were opposed to, but were willing to compromise on to secure our other wins.

Unfortunately, we were unsuccessful in winning GG163, which would have expanded the cool roof requirement for low-slope roofs into climate zones 4a and 4b.  Despite having excellent testimony, evidence, and representation, the momentum from the code development hearings was too strong. While we are disappointed, the vote was closer than it has ever been before.  We are excited about working on future code development efforts along with our new industry partners.

Capturing the Peak Demand Reductions from Cool Roofs

A new paper from Dr. James Hoff highlights the significant, and previously unquantified, peak energy cost savings that cool roofs deliver.  Up until now, energy analyses of cool roofs only looked at the impact on base power consumption but ignored the impact of capacity demand charges.  Turns out, those demand charges can be a big part of the bill!  By detailing all of the energy saving benefits of cool roofs, this paper shows that cool roofs make a lot of sense throughout the country.  Check it out here.

Cool Roofs Are Cooling Homes in India

Climate change is driving up temperatures in cities around the world.  When things heat up, many of us simply reach for the thermostat and the air conditioner does its job.  In many parts of the world however, air conditioning isn’t an option and the rising temperatures mean homes become uninhabitable.   But there is a simple and affordable solution – a cool roof can bring down the temperature indoors by a few degrees, which is enough to allow people to sleep in their beds at night.

That’s where programs like the Cool Roof Project – through the Asian Cities Climate Change Resilience Network, and the Rockefeller Foundation – can help.  This program is installing cool roofs in Indore city, India, and residents are already getting relief from the urban heat.  From the Rockefeller Foundation

At Mamta Chouhan’s house, located in one of the 50 locations where cool roof technology has been implemented, a perceptible difference in indoor temperature is seen during high heat days.  The 200 families who have participated in this project have felt similar impacts as well.

Vijay Bhargava, a resident of Indore, reports that TARU came to him and others with an idea to reduce the temperature in their homes. “I didn’t believe it at first,” he admits, “but then they shared the details, including the potential benefits, and I changed my mind.  Afterwards, we felt a five or six degree change.  Incredible!”

He adds that he and his family couldn’t even sit upstairs in the summer before.  “Now, we can sit anywhere in the house, not feeling a difference whether we’re upstairs or downstairs.  It’s meant that we’ve been able to reduce our air conditioning usage substantially.”

They’re collecting data to document the many benefits of this program, and hope to convince local government, real estate developers and other interested parties to include cool roofs in future projects.   Stay tuned!

Quarter-hourly real time monitoring of urban temperatures from Space

Real time monitoring of the diurnal variations in the distribution of the land surface temperatures (LST) across a city is significant to a range of issues, including heat wave risk, energy demand and heat-related health issues. Geostationary satellites, such as Meteosat Second Generation- Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI) viewing Europe, Africa and a part of S. America, are the only remote sensing platforms that can offer continuous monitoring of LST distribution at quarter-hourly basis. The high temporal resolution of many meteorological geostationary satellites is unparalleled for the diurnal study of the Surface Urban Heat Island (SUHI) phenomenon, since it can reveal the most subtle changes. However, their coarse spatial resolution of 3-5 km has prohibited their extensive use for urban studies. The only way to exploit the dataset from this monitoring platform for urban applications is to employ computational methods for sharpening the data down to 1 km or better.

A system for real time and online monitoring of the thermal urban environment using geostationary satellite images is being developed at the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens (IAASARS/NOA) in Greece. The system comprises separate modules, namely: satellite image acquisition, cloud screening, and sharpening of LST. Satellite images are acquired from MSG-SEVIRI EUMETCast station installed at IAASARS/NOA. The cloud screening delineates the cloud-free pixels allowing the LST derivation to be applied only to clear sky thermal infrared radiances. Lastly, LST imagery is downscaled down to 1 km spatial resolution using Support Vector Regression Machines (SVM) and iterative gradient boosting.

The summer months of 2014 were the first operational ones: our system produced thousands of sharpened LST images every quarter-hour in real time. Our vision is to develop the system for all the cities with population greater than 1 million in the SEVIRI disk (117 cities in total). The system can be potentially used for heat-related health issues, energy demand applications, urban planning, Urban Heat Island studies and more.

A short video of what we do:

Are you interested in collaborations? Let us know!

Dr. Iphigenia Keramitsoglou is a Senior Researcher at IAASARS/NOA and co-Leader of the Group on Earth Observations (GEO) Global Urban Observation and Information Task. She is member of the Program Management Board of BEYOND project that is partly financing this activity.

Record Breaking Heatwave Hits Australia

It’s springtime in the Outback and things are heating up in Australia.  Summer doesn’t begin until December, but record temperatures have already been set at 20 stations throughout the country recently, topping out at 108.6 F in the town of St. George.  Heatwaves are hitting earlier and lasting longer than usual.  Climate Progress has the story…

A spokesman from Australia’s Bureau of Meteorology told the Sydney Morning Herald that the heat wave was significant not just for its high temperatures, but for its duration. Wanaaring, Australia set a record of eight days of 95°F temperatures, a stretch of time that beats the town’s previous record of seven days in 1997. Broken Hill, Australia also experienced a longer stretch of October heat than usual: five days of 95°F or higher weather, up from the town’s previous October record of three days in a row.

Rob Sharpe, a meteorologist at Weatherzone, told the Herald that this heat wave was the “first big heat event of the warming season.” But Australia has been no stranger to heat waves in recent years. Last year was Australia’s hottest ever recorded, with an average annual temperature of 73.4°F — 2.16°F higher than the average for 1961-1990.  The country also started 2014 with extreme temperatures, in a heatwave that began in 2013 and continued into the new year: in early January, parts of Australia reached 122°F, with some reports of temperatures as high as 129°F.  This year, southeastern Australia also endured a record-breaking fall heat wave, with May temperatures up to 9°F higher than usual.

Imagine hitting 108 F in early May here in the northern hemisphere (Washington, DC) … it looks as if Australia’s in for a long hot summer.  Maybe they should consider reworking their building codes to incentivize or even require cool roofs & reflective pavements.  Stay tuned.

GCCA Executive Director Speaks at GreenBuild Conference

Thousands of people gathered in New Orleans, LA earlier this week for the annual Greenbuild conference, to share ideas, network, tour local green buildings and hear from many terrific speakers.  From the conference website:

Greenbuild is the world’s largest conference and expo dedicated to green building.  The green building community gathers to share ideals and mutual passion at Greenbuild, sparking a contagious buzz throughout the week.

When industry leaders, experts and frontline professionals dedicated to sustainable building in their everyday work come together, the result is a unique and palpable energy. Participants are invigorated and inspired.  They find themselves equipped to return to their jobs with a renewed sense of purpose.

GCCA Executive Director, Kurt Shickman spoke at this event about the many problems caused by the urban heat island effect, and the ways reflective surfaces can help bring relief to overheated city dwellers, reduce energy consumption, and reduce carbon emissions.  Take a look…