May 31, 2017

Mind the Gap: Last Time Around

Stephen Eule

On May 2, 2017, we posted what we expected would be our final look at the Obama Administration’s Paris Agreement “gap”—the difference between President Obama’s greenhouse gas (GHG) emissions reduction goal for 2025 and estimates of what the policies his administration put in place would deliver. We concluded that current policies fall about 37% of the reductions needed to meet President Obama’s goal.

This May 2017 analysis used the Environmental Protection Agency’s (EPA) Draft 2017 Inventory of U.S. Greenhouse Gas Emissions and Sinks. Normally, only minor revisions are made to the emissions data between the draft and the final versions of this annual EPA report.

This year, however, there were very large revisions made to the “sinks” data, which provide estimates of the amount of carbon dioxide being sequestered from the atmosphere by “LULUCF”—Land Use, Land Use Change, and Forestry. Over the past few years, the sinks numbers in U.S. GHG inventory and other government reports have fluctuated a great deal from one report to the next, something we commented on here. In this year’s draft report, the recent data for sinks were in the range of about -350 million metric tons of carbon dioxide equivalents (MMTCO2), give or take. (Because sinks absorb atmospheric carbon dioxide, these amounts are entered as negative numbers.) In the final report, recent sinks numbers are more on the order of about -760 MMTCO2, a difference of roughly 400 MMTCO2. That’s huge, an amount much greater than the estimated impact of the Clean Power Plan.

The question is: Do these changes in sinks data do anything to close the gap? And the answer is: No, but they do pinch it a little. That’s because adjustments of similar magnitude were made to base year and also to our projections for future years, for the most part resulting in a wash. So instead of a gap of 37% we calculated in our May posting, using the adjusted numbers we estimate a still-large gap of 35%.

In the interests of accuracy, we have updated the May 2 post with the revised EPA inventory data. It is available here.