Methane Time Series (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption This graph shows a time series of the greenhouse effect of methane in Watts per square meter, measured at the Earth's surface over a ten-year period at a research site in northern Oklahoma. The red line is the trend in the time series, and the grey shading represents uncertainty. Credit Berkeley Lab Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.