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Saturday 31st July 2021 06:24 AM
From Coal to Gas: How the Shift Can Help Stabilize Climate Change
Led by Katsumasa Tanaka, a top climate risk researcher at the National Institute for Environmental Studies in Japan, the study inspected global scenarios for transitioning from coal to gas using a novel approach that applied metrics developed for climate impact assessments to the coal-gas controversy the first time. Concentrating on the world's leading power generators — China, Germany, India, and the United States — the study examined the impacts from a number of direct and indirect emanation of such a shift on both shorter and longer timescales ranging from a few decades to a century.
"Many previous studies were somewhat ambivalent about the climate benefits of the coal-to-gas shift," said Tanaka. "Our study makes a stronger case for the climate benefits that would result from this energy transition, because we carefully chose metrics to evaluate the climate impacts in light of recent advances in understanding metrics."
"Given the current political situation, we deliver a much-needed message to help facilitate the energy shift away from coal under the Paris Agreement," Tanaka said. "However, natural gas is simply not an end goal; we regard it as a bridge fuel towards more eco- friendly forms of energy in the long run as we move toward decarbonization."
Concerns about methane leakage from natural gas have been intensively debated, particularly in the United States given the increasing use of fracking over the past decade. Recent scientific efforts have increased understanding of the level of methane leakage in the United States, but the potential effects of methane leakage stay on highly uncertain in the rest of the world.
"Our conclusion that the benefits of natural gas outweigh the possible risks is robust under a broad range of methane leakage, and under uncertainties in emissions data and metrics," Tanaka said.
This study was partly supported by the Environment Research and Technology Development Fund (2-1702) of the Environmental Restoration and Conservation Agency in Japan, with additional support from the Institute for Advanced Sustainability Studies in Germany and the Research Council of Norway.
Multiple Metrics to Simultaneously Examine Short- and Long-Term Climate Impacts
Emissions metrics, or indicators to evaluate the impacts to climate vary from different emission types, are useful tools to gain insights into climate impacts without the need for climate model runs.
These metrics work like weighting factors when calculating CO2-equivalent emissions from the emissions of a variety of greenhouse gases. Even so, the resulting climate impacts observed through CO2-equivalent emissions are sensitive to the specific metrics chosen.
"Because the outcome can strongly depend on which metrics are chosen and applied, there is a need for careful reflection about the meaning and implications of each specific choice," said Francesco Cherubini, a professor at the Norwegian University of Science and Technology. "Each emission type elicits a different climate system response. The diverging outcomes in previous studies may well stem from the type of metric that was chosen."
The study combined multiple metrics to address both short- and long-term climate impacts in parallel. It was uncovered that natural gas power plants have both smaller short- and long-term impacts than coal power plants, even when high potential methane leakage rates, a full array of greenhouse gases and air pollutants, or uncertainty issues are considered.
To ensure that possible regional disparities were taken into account in the global study, the study compared global metrics with regional metrics to more precisely examine impacts.
"We considered a suite of so-called short-lived climate pollutants (SLCPs), such as SOx, NOx, and black carbon, that can be emitted from these plants," said Bill Collins, a professor at the University of Reading, in the United Kingdom. "This required a regional analysis because climate impacts from SLCPs depend on where they are emitted, due to their short lifetimes in the atmosphere."
Future Directions and Policy Relevance
The study by Tanaka and coauthors is an important part of an emerging body of literature that reaffirms the need to phase out coal in an effort to reduce rising global temperatures and slow or reverse negative impacts of climate change.
Future related work could think about supply chains and trade within and across nations and other environmental factors, besides work on enhancing the consistency of metrics for assessing climate impacts.
"Air quality is not part of our analysis, but including it would likely strengthen our conclusion," said Tanaka. Other environmental effects, such as drinking water contamination and induced seismic activities, could also add important dimensions to the debate."
This article is originally posted on manufacturing.net