Carbon Counter Project

With increasing public attention on changing climate, it is useful to have a "real-time" estimate of a single integrating metric that expresses the combined atmospheric levels of the long-lived greenhouse gases contributing to that change. Such a metric can help convey to the public how fast these levels are increasing, how close we are to the stabilization levels relevant to policy discussions, and the progress, or lack thereof, in slowing the rate of increase. Three key issues that arise in making such a calculation are: (1) long-lived greenhouse gases include multiple gases with varying lifetimes and radiative properties, (2) there are inevitable lags between the time measurements are taken to when they can be checked and assembled to produce an estimate of global average levels (usually expressed as mole fractions), and (3) these mole fractions are subject to seasonal and other cyclical variations that need to be removed if we want to clearly reveal the underlying long term trends. In this project we address these issues by development of a model that fits a suitable integrating metric that is calculated using global network measurements for greenhouse gases. We evaluate the accuracy with which this model can simulate the actual metric, and also provide "real-time" estimates of the de-seasonalized metric using its values in the recent past.

Carbon Counter sign This project is contributing to the "Know The Number" climate-change awareness initiative sponsored by Deutsche Asset Management designed to raise people's understanding of the risk of global climate change. The calculations produced in the MIT Joint Program's effort are being fed to a nearly 70-foot electronic carbon counter sign in the heart of midtown Manhattan, New York. The electronic counter sign, outside Madison Square Garden and Penn Station, and a related website provide a global digital feed beginning June 18, 2009, that displays the trend in greenhouse gas emissions into the atmosphere.