The Megacities Carbon Project is an international, multi-agency pilot initiative to develop and test ways to monitor greenhouse gas emissions in megacities: metropolitan areas of at least 10 million people. Cities and their power plants are the largest sources of human-produced greenhouse gas emissions and are the largest human contributors to climate change.

The project will deploy a global urban carbon monitoring system that will eventually allow local policymakers to fully account for the many sources and sinks, or storage sites, of carbon and how they change over time. When fully established the Los Angeles network will consist of 15 monitoring stations around the LA basin. Most will use commercially available high-precision greenhouse gas analyzers to continuously sample local air. Megacities scientists will also periodically take to the road and to the skies to collect mobile measurements of the local atmosphere to better define individual emissions sources and environmental conditions.

Artist's concept of the LA Megacities Carbon Project observing system. Ground sensors atop towers and buildings measure carbon dioxide, methane, and carbon monoxide. Aircraft, mobile laboratories and satellites round out the network. (NASA/JPL-Caltech)

The Megacities project combines direct surface measurements of urban greenhouse gases from instruments located in air sampling stations atop radio towers and buildings, with broader, denser remote-sensing observations from aircraft, mountaintops, and satellites. Other instruments track winds and vertical motion of the atmosphere -- both of which are key to interpreting the greenhouse gas measurements.

NASA's recently launched Orbiting Carbon Observatory-2 (OCO-2) satellite is capable of detecting the enhanced levels of carbon dioxide over the world's largest cities, and is beginning to study LA in coordination with the Megacities team.