Corporate Banner
Satellite Banner
Scientific Communities
Become a Member | Sign in
Home>News>This Article

How to Count Methane Emissions

Published: Tuesday, April 29, 2014
Last Updated: Tuesday, April 29, 2014
Bookmark and Share
Study provides new metric for comparing the greenhouse gases methane and carbon dioxide.

In formulating policies to address greenhouse gas emissions, or evaluating the potential impact of different energy technologies on global climate change, one of the thorniest issues is how to account for the very distinctive characteristics of various different gases.

For example, methane is a potent greenhouse gas, as well as a significant byproduct of using natural gas - advocated by many as a “bridge” to a lower-emissions future. But a direct comparison between methane and carbon dioxide, the most abundant greenhouse gas emitted by human activities, is complicated: While the standard figure used for emissions trading and technology evaluation says that, gram for gram, methane is about 30 times as potent a greenhouse gas as CO2, scientists say that’s an oversimplification.

As reported in a paper published in the journal Nature Climate Change, authored by MIT assistant professor of engineering systems Jessika Trancik and doctoral student Morgan Edwards, this conversion factor (called the global warming potential, or GWP) may significantly misvalue methane. Getting this conversion factor right is challenging because methane’s initial impact is much greater than that of CO2 - by about 100 times.

But methane only stays in the atmosphere for a matter of decades, while CO2 sticks around for centuries. The result: After six or seven decades, the impact of the two gases is about equal, and from then on methane’s relative role continues to decline.

Static measures, such as the GWP, give a false sense of the gases’ impacts, and could lead to unintended climate outcomes when used as the basis for policies and planning, Trancik says. Instead, she and Edwards argue for the use of what they call “dynamic metrics,” which lead to a conversion factor that changes over time in a predictable way.

“With CO2, one cares about the cumulative emissions,” Trancik says. “But with methane, the timing of emissions matters.” The issue for regulators and planners, she says, is: “How can we take emissions timing into account, in a metric equation that is simple and predictive enough to be used?”

The authors develop a kind of metric that incorporates limited information about the future - an intended “stabilization level” for the Earth’s climate - but doesn’t require knowledge about the exact climate scenario to be followed. The researchers develop two such metrics, the instantaneous climate impact (ICI) and the cumulative climate impact (CCI); the latter is more conservative in earlier years.

The paper shows that the choice of how to quantify the effect of methane versus CO2 can have a bigger effect on the ultimate climate outcomes than uncertainties in how much leakage of methane occurs in the natural gas production system, which has recently drawn much more attention from researchers and policymakers. For this reason it is important to choose an accurate metric, and understand its properties.

“Any equivalency metric is going to be imperfect,” Trancik says, “which is why it is important to test metrics and understand their properties.” But using a measure that accounts for significant changes to the climate over time should allow for more realistic assessments of the effects of policy decisions - such as in setting environmental regulations, or deciding where to focus research investment.

While it is generally assumed that the climate impact of natural gas to produce electricity is approximately half that of coal, she says, that comparison depends on timing: The figure is true today, but within three decades, compared with coal-fired power plants, the advantage of natural gas is roughly halved under common stabilization goals. Similarly, compressed natural gas as a transportation fuel actually ends up being worse than gasoline within a couple of decades, the authors report.

In the case of natural gas, it’s not the emissions from the plants burning the gas that produce methane; rather, it is the leakage of methane - the main component of natural gas - during drilling and transportation of the fuel. So there is potential to reduce the impact of natural gas by investing in better control of such leakage, Trancik says.

More accurate comparisons of the effects of methane and CO2 can also be important when evaluating technologies that produce emissions of more than one type of gas. For example, the study found that algae-based biofuels that incorporate a biodigester may leak enough methane to outweigh the emissions benefits over corn ethanol - a consideration that may weigh on decisions about which technology designs should be invested in and how they should be regulated, she says.

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,800+ scientific posters on ePosters
  • More Than 4,000+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Biomedical Imaging at One-Thousandth the Cost
Mathematical modeling enables $100 depth sensor to approximate the measurements of a $100,000 piece of lab equipment.
Tuesday, November 24, 2015
Game for Climate Adaptation
MIT-led project shows a new method to help communities manage climate risks.
Friday, November 06, 2015
Using Ultrasound to Improve Drug Delivery
New approach could aid in treatment of inflammatory bowel disease.
Friday, October 23, 2015
Drug-Resistance Mechanism in Tumor Cells Unravelled
Targeting the RNA-binding protein that promotes resistance could lead to better cancer therapies.
Friday, October 23, 2015
Quantum Physics Meets Genetic Engineering
Researchers use engineered viruses to provide quantum-based enhancement of energy transport.
Friday, October 16, 2015
Messing With The Monsoon
Manmade aerosols can alter rainfall in the world’s most populous region.
Friday, October 02, 2015
A Natural Light Switch
MIT scientists identify and map the protein behind a light-sensing mechanism.
Tuesday, September 29, 2015
Biologists Find Unexpected Role for Amyloid-Forming Protein
Yeast protein could offer clues to how Alzheimer’s plaques form in the brain.
Monday, September 28, 2015
How Flu Viruses Gain The Ability To Spread
New study reveals the soft palate is a key site for evolution of airborne transmissibility.
Friday, September 25, 2015
Viruses Join Fight Against Harmful Bacteria
Engineered viruses could combat human disease and improve food safety.
Friday, September 25, 2015
Targeting DNA
Protein-based sensor could detect viral infection or kill cancer cells.
Tuesday, September 22, 2015
Targeting DNA
Protein-based sensor could detect viral infection or kill cancer cells.
Tuesday, September 22, 2015
Personalized Heart Models For Surgical Planning
System can convert MRI scans into 3D-printed, physical models in a few hours.
Friday, September 18, 2015
Learning About Human Health Using Sewage
PhD student Mariana Matus studies human waste to understand individual and community health.
Thursday, September 17, 2015
Intensity of Desert Storms May Affect Ocean Phytoplankton
MIT study finds phytoplankton are extremely sensitive to changing levels of desert dust.
Tuesday, September 01, 2015
Scientific News
High Throughput Mass Spectrometry-Based Screening Assay Trends
Dr John Comley provides an insight into HT MS-based screening with a focus on future user requirements and preferences.
How a Genetic Locus Protects Adult Blood-Forming Stem Cells
Mammalian imprinted Gtl2 protects adult hematopoietic stem cells by restricting metabolic activity in the cells' mitochondria.
Genetic Basis of Fatal Flu Side Effect Discovered
A group of people with fatal H1N1 flu died after their viral infections triggered a deadly hyperinflammatory disorder in susceptible individuals with gene mutations linked to the overactive immune response, according to a recent study.
New Tech Vastly Improves CRISPR/Cas9 Accuracy
A new CRISPR/Cas9 technology developed by scientists at UMass Medical School is precise enough to surgically edit DNA at nearly any genomic location, while avoiding potentially harmful off-target changes typically seen in standard CRISPR gene editing techniques.
The MaxSignal Colistin ELISA Test Kit from Bioo Scientific
Kit can help prevent the antibiotic apocalypse by keeping last resort drugs out of the food supply.
"Good" Mozzie Virus Might Hold Key to Fighting Human Disease
Australian scientists have discovered a new virus carried by one of the country’s most common pest mosquitoes.
Non-Disease Proteins Kill Brain Cells
Scientists at the forefront of cutting-edge research into neurodegenerative diseases such as Alzheimer’s and Parkinson’s have shown that the mere presence of protein aggregates may be as important as their form and identity in inducing cell death in brain tissue.
Closing the Loop on an HIV Escape Mechanism
Research team finds that protein motions regulate virus infectivity.
New Class of RNA Tumor Suppressors Identified
Two short, “housekeeping” RNA molecules block cancer growth by binding to an important cancer-associated protein called KRAS. More than a quarter of all human cancers are missing these RNAs.
Potential Treatment for Life-Threatening Viral Infections Revealed
The findings point to new therapies for Dengue, West Nile and Ebola.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,800+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,000+ scientific videos