·       Black Roads Get Hot in the Sun - Cause Heat Pollution leading to Health Hazard: They are really bad for our environment (hear our podcast). It is a local and global crisis. Black Roads in a global warming crisis is just stupid?? Studies confirm serious issues. A recent MIT study states that black roads increase city heat on average by 1.3C-4C (2.3F-7F), heat waves by 41% and there are twice as many life threatening heat wave days because of black roads in the summer (Ref. 2, 7). However, cities with high irradiance (sun per day) in certain humid areas are more severe and estimates are far worse (see our calculator) due to dark surfaces up to 10C is estimated for streets and roofs. Studies indicate that these heat waves are a high health hazard all over urban areas. Studies since 2005 show that cool roads are not more expensive. The devil is in the details and it is time to stop painting the Earth Black, its bad behavior. New roads - even hotter by 4^oF (see Picture). Even surrounding rural highways effect UHI heat. Reducing solar heat pollution will reduce air conditioning heat also lowering urban temperatures.

 

·       Black Earth - Roads, Roofs & Cars Excite Greenhouse Gases (GHGs): The Sun creates heat on any surface but is worse on black Earth surface due to its color. To make matters worse, 62% of this heat comes right back due to greenhouse gases (GHGs). That is what GHGs do, the Earth heats, especially black surfaces in the sun, this heat rises and much of it is absorbed by GHGs in the atmosphere. Then the GHGs re emit it in all direction with 62% on average coming back to Earth. To make matters worse, hot roads warm the air expanding it so warm air holds more water vapor. Why do we care, because water vapor is the strongest greenhouse gas and this causes more warming. But that keeps going in a water vapor feedback loop, warming cause more water vapor which causes more warming etc. Therefore, black roads, roofs, cars and dark building heat actually increase and create water vapor GHGs which is much worse than CO2 in its ability to absorb and re-radiate. The truth is, we do not know the extent of the global warming damage caused by the dark surfaces we create, but we need to stop this bad behavior of painting the Earth black now.

 

Which causes more global warming in a sunny parking lot - A white gas car or a black EV car?? Is a black EV car defective??

Black Cars are Defective

·       Negative Solar Geoengineering: Continuing to manufacture black roads, dark roofs, cars & buildings is terrible behavior in a climate crisis. One helpful solution is solar geoengineering which reduces the Sun's energy from being absorbed by Earth similar to a mirror that reflects the sun away from the Earth. Yet, we are busy painting the Earth black with dark roads, roofs, dark buildings, and cars. This is negative solar geoengineering and ruins our chances to make positive advances in solar geoengineering (Ref. 1). We need to brighten the Earth not paint it black.

·       Studies & Their Info: (2005-Present)

· 2020 MIT Study (Ref. 2, 7): A MIT pavement study (Azarjafari et al., 2020) concluded that in all U.S. urban areas, an increased temperature of 1.3°C-4°C occurs in summer months and heatwaves are 41% more intense with 50% more heatwave days due to asphalt pavements. MIT also concluded that cool pavements are just as economical to install and maintain. Expansion of cities is increasing rapidly where 55% of the world’s population lives and this is expected to grow to about 70% by 2050 (wo).rldbank, 2020. However, cities with high solar heat pollution can be far worse especially in humid areas. (see our calcultor).

· 2005, 2014  EPA Study (Ref. 3, 4): This study also claimed similar to the MIT study that it was a major issue for cities. Cool roads should be used everywhere and they are not more expensive.

· How much heat does a black road create (Ref. 5): One acre of a black road or roof yields about 2.5GWh per year. This is about 7.5 times more energy in heat than a solar power plant produces where studies found they average about 0.33 GWh per acre per year. This also equates to 74,000 gallons of gasoline energy per yr. for 1 acre of a black road.

· Global Warming (Ref. 6): Black roads are estimated to have about a 1.1% global warming influence. Changing to concrete would increase the reflectivity by about a factor of 5 and reduce global warming by about 5.5%. This is conservative - there are factors that are not well known such as the amount of water vapor feedback dark surfaces produce.

·       How Much Global Warming is Caused by Urbanization Ref. 6 and 9

According to a new study, Ref. 9, worldwide measurements find that urbanization causes 12.7% of global warming.  According to a recent study, Ref. 6, this is broken down where 6.5% is due to solar heating of dark surfaces including building sides, streets and roof tops, while another 6.5% is due to energy consumption that turns into heat like heating our homes. Below is a chart with the break down.

 

References:

1. Feinberg A (2023) Annual Solar Geoengineering: Mitigating Yearly Global Warming Increases, Climate 12, no. 2: 26. https://doi.org/10.3390/cli12020026

2. MIT Study on Roads: AzariJafari, H., Kirchain, R., Gregory, J. “Mitigating Climate Change with Reflective Pavements.” CSHub Topic Summary. 2020. Volume 2020, Issue 3. https://cshub.mit.edu/sites/default/files/images/Albedo%201113_0.pdf

3. EPA 2005 Study Cambridge Systematics (2005). Cool Pavement Report, Heat Island Reduction Initiative.https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.648.3147&rep=rep1&type=pd

4. EPA 2014 Reducing Urban Heat Islands: Compendium of Strategies, https://www.epa.gov/sites/default/files/2014-08/documents/coolpavescompendium_ch5.pdf, last accessed 1/3/201=23

5. Feinberg A (2022) Solar Geoengineering Modeling and Applications for Mitigating Global Warming: Assessing Key Parameters and the Urban Heat Island Influence, Frontiers in Climate, https://doi.org/10.3389/fclim.2022.870071

6. Feinberg A 2023. "Urbanization Heat Flux Modeling Confirms It Is a Likely Cause of Significant Global Warming: Urbanization Mitigation Requirements" Land 12, no. 6: 1222. https://doi.org/10.3390/land12061222

7. Pavements are responsible for a Lot of the UHI effect: https://news.mit.edu/2021/countering-climate-change-cool-pavements-0822

8. Cities are 10-15C hotter: https://joint-research-centre.ec.europa.eu/jrc-news-and-updates/cities-are-often-10-15-degc-hotter-their-rural-surroundings-2022-07-25_en

9. Zhang, P.; Ren, G.; Qin, Y.; Zhai, Y.; Zhai, T.; Tysa, S.K.; Xue, X.; Yang, G.; Sun, X. Urbanization effects on estimates of global trends in mean and extreme air temperature. J. Clim. 2021, 34, 1923–1945

10.  Here our podcast 

Download the DfRSoft Climate Calculators (Excel): Contains Four calculators.  Calculator 1 Helps you to estimate How Much Cool Roads, Rooftops, Ect, can reduce city temperatures. Also Includes three more calculators: (Download Excel Calculator Here). Calculator 1 is a powerful but easy to use calculator estimates how much cooler your UHI city could be with cool roads, roofs, and/or building areas. The calculator reproduces a 2020 MIT LA study on cool road estimates for air temperature reduction as a verification. Other calculators include Calculator 2 for Annual Solar Geoengineering, Calculator 3 provides the global warming earth energy budget for two different time periods. Calculator 4 estimates the Urbanization global warming effect due to ISA and APH release. All Calculators includes simple instructions for use. It is based on Dr. Feinberg's peer reviewed physics based modeling publications that includes inputs for background climate GW effects and UHI microclimate estimates.

 

Negative Solar Geoengineering Examples: It is bad behavior painting the Earth Black. These are simple color choice. Before we can mitigate global warming with positive solar geoengineering, we need to stop the negative behavior first.

    

     

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