LA turns into a climate lab!

Scientists from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., and elsewhere are turning the entire Los Angeles metro region into a state-of-the-art climate laboratory. From the ridgeline, they deploy a mechanical lung that senses airborne chemicals and a unique sunbeam analyzer that scans the skies over the Los Angeles Basin. At a sister site at the California Institute of Technology, researchers slice the clouds with a shimmering green laser, trap air samples in glass flasks, and stare at the sun with a massive mirrored contraption that looks like God’s own microscope.

These folks are the foot soldiers in an ambitious interagency initiative called the Megacities Carbon Project. They’ve been probing L.A.’s airspace for more than a year, with the help of big-name sponsors like the National Institute of Standards and Technology, the Keck Institute for Space Studies, and the California Air Resources Board. If all goes well, by 2015 the Megacities crew and colleagues working on smaller cities such as Indianapolis and Boston will have pinned down a slippery piece of climate science: an empirical measurement of a city’s carbon footprint.

The idea is to prepare a set of climate archetypes that can be applied to different megacities. The L.A. area is on the ocean, ringed by mountains, and often holds emissions in place like a lidded bowl. Perhaps what the Megacities team learns about emissions here will also apply in Mumbai, India, which has a similar geography.

Historically, researchers have tried to understand anthropogenic global warming by looking at it from the big picture — first across the planet, then by regions and countries. But two things happened in the past few years that turned their frame of reference. First, they realized that the emissions of a large landmass are extremely difficult to measure. Second, they encountered a climate gridlock in the United States government.  It became clear to environmental stakeholders that if any policy was going to happen on cutting emissions, it was going to be at the scale of states and cities.

They now suspect that cities are some of the worst offenders when it comes to generating greenhouse gases, especially so-called megacities with more than 10 million residents, like Los Angeles, New York, Tokyo, and Mumbai. Urban areas and their enabling power plants are thought to pump out about 70 percent of humankind’s total fossil-fuel emissions. With the world’s urban population expected to nearly double by 2050, the boom in development could release a flood of greenhouse gas, as more city dwellers torch colossal quantities of coal and oil to power their cars, feed their stoves, and crank their air conditioners.

A major issue is that governments estimate the volume of emissions with indirect measurements, such as tracking the carbon output of power plants or surveying the number of people riding mass transit or buying gasoline. Nobody is really testing greenhouse gases above cities on a focused, long-term basis, which is crucial in verifying whether the measurements urban governments use to make policy decisions are accurate.

Only one spacecraft in orbit right now is monitoring greenhouse gases, Japan’s Gosat (Greenhouse Gases Observing Satellite), and its resolution isn’t good enough to give an accurate picture of a city’s emissions. But in the next few years, NASA plans to launch the Orbiting Carbon Observatory (OCO-2) satellite and install a new instrument (OCO-3) on the International Space Station. Both devices will periodically take snapshots of the “chemical weather” over population centers.

Hopefully the climate footprint of cities will emerge sharp and clear, giving indications of how to proceed.