Thursday, July 8, 2010

New Sulfur Dioxide Dataset

Steve Smith of the Pacific Northwest National Laboratory and his team have completed work on their dataset of sulfur emissions from 1850 to 2005 by country and year. The paper is available for discussion on Atmospheric Chemistry and Physics' website.

I've known for a while that this dataset was under development, which is the main reason why I haven't updated my own estimates of global sulfur emissions available from my website. This new dataset provides the same format of annual data for each country. But the data is updated by five years and is also broken down into different sources of emissions. Estimation uses bottom up methods constrained by official observations where those are available.

My key finding was that a historic reversal in the trend of global sulfur emissions occurred in the 1980s and 1990s with the steep upward trend being replaced by a flattening out in the 1980s and a substantial decline in emissions in the 1990s. The new dataset shows the beginning of a possible renewed increase in emissions though it's still a relatively small fluctuation:

This largely appears to be driven by increasing emissions in East Asia:

and to a lesser extent in other developing regions. The paper does, however, note that there is a lot of uncertainty associated with East Asian and, in particular, Chinese emissions. The data shows a similar pattern to my estimates:

The main difference is that emissions in the plateau of the 1970s and 1980s are estimated to be lower than in most previous studies largely because of lower estimates for the former Soviet Union and China in those years.

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