Last week, the U.S. Environmental Protection Agency (EPA) released an updated draft of its Greenhouse Gas Inventory, finding that total U.S. greenhouse gas emissions in 2014 were 6.8 billion metric tons of carbon dioxide equivalent--1 percent higher than in 2013, but 8 percent lower than the 2007 peak. The most revelatory revision: methane emissions figures for the oil and gas sector were 27 times higher than previous estimates. Over 20 years, that difference, says the Environmental Defense Fund, represents a climate impact equivalent to 200 coal-fired power plants.
News of the upward revision came amid a study from the University of California at Irvine (UCI) published in the journal Science that finds more than 100,000 tons of methane entered the atmosphere during a four-month natural gas leak in Southern California's Aliso Canyon. Before it was plugged in February, the leak doubled methane emissions in the Los Angeles region. It is the largest methane leak in U.S. history, and it is likely to keep California from meeting its 2016 greenhouse gas emissions targets.
Methane emissions, a potent greenhouse gas with a long-term global warming potential thought to be many times that of carbon dioxide, are currently unregulated.
At the annual IHS CERAWEEK conference last week, EPA Administrator Gina McCarthy alluded to her agency's proposal, last year, of methane leak detection and repair requirements for new oil wells. Methane emissions related to the oil and natural gas industry are "much larger than we ever anticipated," she said. "The data confirm that we can and must do more on methane. By tackling methane emissions, we can unlock an amazing opportunity to better protect our environment for the future."
Study Revises Carbon Budget Downward
A new study in the journal Nature Climate Change warns that the global carbon budget has been over-estimated and should be cut by at least half. In the abstract of their research, the authors state that for a greater than 66 percent chance of limiting warming below the internationally agreed temperature limit of 2 degrees Celsius relative to pre-industrial levels, "the most appropriate carbon budget estimate is 590-1,240 GtCO2 from 2015 onwards." They conclude that global CO2 emissions must be cut quickly to keep within a 2°C-compatible budget.
"At current rates, the carbon budget would thus be exhausted in about 15 to 30 years," said lead author Joeri Rogelj, a research scholar at the Energy Program of the International Institute for Applied Systems Analysis in Austria. "These numbers definitely indicate that we should not just sit and wait, because then the window for staying within the budget would become vanishingly small within decades."
The study analyzes differences among widely varying estimates for a carbon budget consistent with the 2°C target, finding that a major reason for the range is due to assumptions and methodologies in previous studies. Its own estimate differs from many previous estimates in part because it accounts for methane and other greenhouse gases and not only for carbon dioxide.
Despite COP21 Deal, No Increase Expected for European Union Emissions Targets
The Paris Climate Agreement, signed at the United Nations Climate Conference last year, calls for a review of countries' climate reduction goals in 2018, but a new document suggests the European Union (EU) may not be following that timeline (subscription).
As reported by Reuters, text prepared ahead of a Friday meeting of EU environment ministers on the Paris climate deal says the existing target--cutting emissions by at least 40 percent from 1990 levels by 2030--"is based on global projections that are in line with the medium-term ambition of the Paris Agreement."
"We have the deal," said EU Climate and Energy Commissioner Miguel Arias Canete. "Now we need to make it real. For the EU, this means completing the 2030 climate and energy legislation without delay, signing and ratifying the agreement as soon as possible, and continuing our leadership in the global transition to a low-carbon future."
This calculation is based on keeping emissions levels to 2 degrees Celsius--but the agreement signed in Paris aspires to hold nations to a global temperature increase of well below this level and to pursuit of an increase limited to 1.5 degrees Celsius. In Euractiv, former chief negotiator for the Netherlands and European Union, Bert Mertz, examines whether a sub-2 degrees Celsius goal is feasible and what might be needed for the EU to meet a more aggressive 1.5 degree Celsius goal. He finds that although the current goal is derived from a long-term target of 80 percent emissions reduction compared with 1990 levels, the EU would need to strengthen that target to 95 percent emissions reductions.
The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University's Nicholas Institute for Environmental Policy Solutions.
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