In Berkeley, we are fortunate to have such events as Science at the Theater, where Lawrence Berkeley National Lab researchers give talks on their work at the Berkeley Repertory Theatre. The lectures are free and get a pretty sizeable audience.

On Monday, October 11, I was in the audience as researchers from Lawrence Berkeley National Laboratory (and the beloved Art Rosenfeld) gave a presentation titled “Cool Roofs, Cool Cities.” The post below consists of Part 4 of my record of the presentation – Art Rosenfeld gives an overview of how cool roofs and cool cities can leader to a cool planet. All portions are included in chronological order.

An ellipsis (…) indicates that I was not able to capture the words or thoughts skipped. The presentation is transcribed as accurately as possible – punctuation choices are mine. I also added any images.

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I’m going to bring us into modern times and the question of global warming … Two thousand years ago, people tried to figure out how to keep houses cool, then a couple hundred years ago, we tried to figure out how to keep the cities cool, and now we’re trying to figure out how to keep the planet cool.

Taking a trip around the world … [looking at photos].

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Image credit: Wikimedia Commons

In Bermuda, they use sloped white roofs to collect water.

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Image credit: Wikimedia Commons

In Santorini, Greece, even the sides of the buildings are white.

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Image credit: Wikimedia Commons

In Hyderabad, people like to sleep on the roof to be cool at night.

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Here’s a Wal-Mart store in Northern California with white roof – they’ve done 4500 of their stores, and have 1500 to go.

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Here’s an overview of UC Davis … Since 2005, the CEC Title 24 has required that if a roof is flat, cool roofs are required …

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Image credit: Wikimedia Commons

Here’s the University of Tucson in the middle …  residential areas nearby also have white roofs … …

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Here’s Washington, DC (federal) … The House and Senate office buildings do not have white roofs.

The most fun was this – this is the Pentagon. I went to a hilarious meeting – I got invited to give a talk at the Pentagon. There were innumerable generals and such around …

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Now what about the Earth? … Part of what keeps the earth cool is ice and snow, which is decreasing in size … It would be nice to add some more white … …

Atmospheric climatologists have been aware of this issue for years, and back in the 1980s, Jim Hansen published a paper wondering whether cooling cities would make a difference – and he got an answer of about a 1/10^th of a degree … But we weren’t so worried in those days … But we asked, maybe there’s a better way to sell this? … Look, carbon dioxide reflects heat, that’s called a positive radiation forcing onto the ground. And white roofs reflect heat … Carbon dioxide has a price … So we’ve got to do it per unit … 1000 square feet, winds up being about 10 tons of carbon. Suppose we multiply this by about 3 billion, since there are about 3 billion units of roof in cities, then avoid the heating effect of 25 billion tons of carbon dioxide…over the life of the roof. So let’s say 1 billion tons a year for 25 years … This winds up being 300 million cars off the road for 20 years … There are only about 600 million cars right now …

So what to do now? First, get other states to follow California… Arizona and Florida and Georgia have followed suit with cool roofs … The problem is a lot of the rest of the country, the hot part … the United States relies  on model building codes, and states are not required to adopt them. They can make them stronger and adopt them, but they are not required to adopt them. Texas doesn’t have any, the cities there have taken the lead …  DOE is going white, the Marine Corps is going white …

We’re going to launch a private club called 100 Cool Cities, with some DOE help, where were’ going to approach the 100 largest cities, which gets us  to a population of 200 million, where we’ll talk to them about cool roofs and try to get it into the building code … This will involve the Sierra Club, the Clinton Global Initiative, USGBC, ICLEI, the Energy Foundation, the Alliance for Climate Protection, ACEEE, and others …

Steve Chu will offer assistance to the first few countries to sign up to address this issue … …

So things are moving along nicely, and thank you very much.

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Part 1 is posted here. Part 2 is posted here. Part 3 is posted here.

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