Climate Explained: Methane Is Short-Lived in the Atmosphere but Leaves Long-Term Damage
Алексей Филатов / Getty Images
By Zebedee Nicholls and Tim Baxter
Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.
If you have a question you'd like an expert to answer, please send it to email@example.com
Methane is a shorter-lived greenhouse gas - why do we average it out over 100 years? By doing so, do we risk emitting so much in the upcoming decades that we reach climate tipping points?
The climate conversation is often dominated by talk of carbon dioxide, and rightly so. Carbon dioxide is the climate warming agent with the biggest overall impact on the heating of the planet.
But it is not the only greenhouse gas driving climate change.
Comparing Apples and Oranges
For the benefit of policy makers, the climate science community set up several ways to compare gases to aid with implementing, monitoring and verifying emissions reduction policies.
In almost all cases, these rely on a calculated common currency - a carbon dioxide-equivalent (CO₂-e). The most common way to determine this is by assessing the global warming potential (GWP) of the gas over time.
The simple intent of GWP calculations is to compare the climate heating effect of each greenhouse gas to that created by an equivalent amount (by mass) of carbon dioxide.
In this way, emissions of one gas - like methane - can be compared with emissions of any other - like carbon dioxide, nitrous dioxide or any of the myriad other greenhouse gases.
These comparisons are imperfect but the point of GWP is to provide a defensible way to compare apples and oranges.
Limits of Metrics
Unlike carbon dioxide, which is relatively stable and by definition has a GWP value of one, methane is a live-fast, die-young greenhouse gas.
Methane traps very large quantities of heat in the first decade after it is released in to the atmosphere, but quickly breaks down.
After a decade, most emitted methane has reacted with ozone to form carbon dioxide and water. This carbon dioxide continues to heat the climate for hundreds or even thousands of years.
Emitting methane will always be worse than emitting the same quantity of carbon dioxide, no matter the time scale.
How much worse depends on the time period used to average out its effects. The most commonly used averaging period is 100 years, but this is not the only choice, and it is not wrong to choose another.
As a starting point, the Intergovernmental Panel on Climate Change's (IPCC) Fifth Assessment Report from 2013 says methane heats the climate by 28 times more than carbon dioxide when averaged over 100 years and 84 times more when averaged over 20 years.
Many Sources of Methane
On top of these base rates of warming, there are other important considerations.
Fully considered using the 100-year GWP and including natural feedbacks, the IPCC's report says fossil sources of methane - most of the gas burned for electricity or heat for industry and houses - can be up to 36 times worse than carbon dioxide. Methane from other sources - such as livestock and waste - can be up to 34 times worse.
While some uncertainty remains, a well-regarded recent assessment suggested an upwards revision of fossil and other methane sources, that would increase their GWP values to around 40 and 38 times worse than carbon dioxide respectively.
These works will be assessed in the IPCC's upcoming Sixth Assessment Report, with the physical science contribution due in 2021.
While we should prefer the most up to date science at any given time, the choice to consider - or not - the full impact of methane and the choice to consider its impact over 20, 100 or 500 years is ultimately political, not scientific.
Undervaluing or misrepresenting the impact of methane presents a clear risk for policy makers. It is vital they pay attention to the advice of scientists and bodies such as the IPCC.
Undervaluing methane's impact in this way is not a risk for climate modellers because they rely on more direct assessments of the impact of gases than GWP.
The idea of climate tipping points is that, at some point, we may change the climate so much that it crosses an irreversible threshold.
At such a tipping point, the world would continue to heat well beyond our capability to limit the harm.
There are many tipping points we should be aware of. But exactly where these are - and precisely what the implications of crossing one would be - is uncertain.
Unfortunately, the only way we can be sure of where these tipping points are is to cross them. The only thing we know for sure about them is that the impact on lives, livelihoods and the places we love would be beyond catastrophic if we did.
But we cannot ignore disturbing impacts of climate change that are already here.
The scientific understanding of climate change goes well beyond simple metrics like GWP. Shuffling between metrics - such as 20-year or 100-year GWP - cannot avoid the fact our very best chance of avoiding ever-worsening climate harm is to massively reduce our reliance on coal, oil and gas, along with reducing our emissions from all other sources of greenhouse gas.
If we do this, we offer ourselves the best chance of avoiding crossing thresholds we can never return from.
Zebedee Nicholls is a PhD Researcher at the Climate & Energy College, University of Melbourne.
Tim Baxter is a Fellow - Melbourne Law School; Senior Researcher - Climate Council; Associate - Australian-German Climate and Energy College, University of Melbourne.
Disclosure statement: Zebedee Nicholls is affiliated with The University of Melbourne's Climate & Energy College. He is funded by the Australian Government via the Australian Government Research Training Program (RTP). Tim Baxter is employed by the Climate Council, a non-profit organisation providing independent, authoritative information on climate change and its solutions to the Australian public and has previously been employed under various Australia Research Council grants.
Reposted with permission from The Conversation.
- Methane Emissions From Onshore Oil and Gas Equivalent to 14 ... ›
- EPA Expected to Allow More Methane Emissions From Oil and Gas ... ›
- Methane Levels Dramatically Increase in U.S. - EcoWatch ›
The excess carbon dioxide emitted by human activity since the start of the industrial revolution has already raised the Earth's temperature by more than one degree Celsius, increased the risk of extreme hurricanes and wildfires and killed off more than half of the corals in the Great Barrier Reef. But geologic history shows that the impacts of greenhouse gases could be much worse.
- Earth Is Hurtling Towards a Catastrophe Worse Than the Dinosaur ... ›
- Are We Doomed If We Don't Curb Carbon Emissions by 2030 ... ›
- Humans Release 40 to 100x More CO2 Than Volcanoes, Major ... ›
EcoWatch Daily Newsletter
By Teri Schultz
Europe is in a panic over the second wave of COVID-19, with infection rates sky-rocketing and GDP plummeting. Belgium has just announced it will no longer test asymptomatic people, even if they've been in contact with someone who has the disease, because the backlog in processing is overwhelming. Other European countries are also struggling to keep up testing and tracing.
Meanwhile in a small cabin in Helsinki airport, for his preferred payment of a morsel of cat food, rescue dog Kossi needs just a few seconds to tell whether someone has coronavirus.
<div id="bfda0" class="rm-shortcode" data-rm-shortcode-id="c60b1a0dedbedbe5e0ce44284aff852f"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1308390775328251906" data-partner="rebelmouse"><div style="margin:1em 0">Covid-19 dogs started their work today at the Helsinki Airport at arrival hall 2B. Dogs have been trained to detect… https://t.co/nw4mrw6eJM</div> — Helsinki Airport (@Helsinki Airport)<a href="https://twitter.com/HelsinkiAirport/statuses/1308390775328251906">1600779644.0</a></blockquote></div><p>If it were left to Kossi and his pals, crowds of potential virus carriers could be cleared in a fraction of the time for a fraction of the cost with none of the physical discomfort that accompanies the current nasal swab test based on the polymerase chain reaction (PCR) method.</p>
No Human Nose Needed<p>A dog can sniff a cloth wiped on a wrist or neck and immediately identify if it comes from someone who has contracted the virus as much as five days before any symptoms appear which would lead a person to go into isolation. "A dog could easily save so so, so many lives," University of Helsinki veterinary researcher Anna Hielm-Bjorkman told DW, who says their testing has shown an accuracy level of nearly 100%.</p><p>It was originally her idea to see whether Kossi, a talented disease-detection dog, could redirect his skills in sniffing out mold, bedbugs and cancer to detecting the new virus just as it started to spread in Europe. "It took him seven minutes to figure out 'okay, this is what you want me to look out for," Hielm-Bjorkman said. "So that totally blew our minds."</p><p>Susanna Paavilainen, the executive director of the Wise Nose scent-detection foundation and the woman who saved Kossi from euthanasia in a Spanish shelter eight years ago, immediately started retraining her dogs to find the coronavirus.</p><p>Miina, who used to track a young girl's blood sugar levels by scent, quickly came on board, along with two others already working in disease detection. In all, they hope to train 15 dogs in the first phase.</p><p>Hielm-Bjorkman said once they discovered the new capabilities, while the normal academic procedure would be to test, publish and get peer-reviewed, their first instinct was to get the dogs into service. "[Researchers] who are actually publishing," she noted wryly, "are not at the airports."</p>
Wags, Not Wages<p>But for that, they needed permission and ideally, some funding. Vantaa Deputy Mayor Timo Aronkyto, who is also responsible for airport security, saw the benefit straight away. "It took me two minutes," he told DW.</p><p>However, his funding options were limited to about $390,000 total for the four-month pilot project aiming to prove that results from the dog tests are at least as accurate as the PCR test. Anyone who tests positive at the voluntary canine site is requested to go to the medical unit for confirmation.</p><p>The interest of Aronkyto, a trained physician, is rooted in both health and wealth. "Our testing at the airport costs more than 1 million [euros] (USD $1.2 million) a month at the moment," he said, explaining he expects that to go up to €3 million (USD. $3.5 million) per month in winter. "These dogs would be much cheaper," he pointed out.</p><p>He's optimistic support will grow as data from the current pilot project accumulates, explaining there is already work underway to change Finnish legislation so eventually sniffer dogs would have the same "authority" as customs dogs.</p><p>Aronkyto anticipates one animal performing both functions in the near future. He plans to continue this level of funding from his city budget into next year but that doesn't train new dogs nor expand the capacity beyond the four that split shifts currently at the airport, even as infection rates rise.</p>
Helsinki Hesitates<p>Notably, however, the Finnish government has not signaled it would like to pick up the program itself, despite a huge surge in publicity and, as Hielm-Bjorkman and Paavilainen emphasize, interest from other countries. Travelers have been eager to participate, waiting in line more than an hour at times.</p><p>Finnish ambassador in Ramallah, Palestine, Paivi Peltokoski, praised the experience after a recent trip but, apparently, her enthusiasm is not overly contagious.</p>
<div id="d9823" class="rm-shortcode" data-rm-shortcode-id="61d382f115fe66a44eb793d9ebee3d94"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1318564228450615299" data-partner="rebelmouse"><div style="margin:1em 0">I was tested negative by two #coronadogs upon arrival at the #Helsinki airport in #Finland. Later a medical test ve… https://t.co/cGlWQn8DJb</div> — Päivi Peltokoski (@Päivi Peltokoski)<a href="https://twitter.com/PaiviPeltokoski/statuses/1318564228450615299">1603205184.0</a></blockquote></div><p>"If the government would see this already as something that they would believe in," Hielm-Bjorkman said, she could envision training hundreds of dogs, stationing sniffers at concert halls or sports matches or elderly care homes. She adds there's a need for a "paradigm shift" for both medical professionals and the public.</p><p>Usually it's doctors telling patients if they're sick, she explained, and "here it's a dog handler."</p>
Little Political Will on German Project<p>This situation is not limited to Finland. In Germany researchers also <a href="https://www.dw.com/en/german-sniffer-dogs-show-promise-at-detecting-coronavirus/a-54300863" target="_blank" rel="noopener noreferrer">announced promising results</a> with canines <a href="https://www.dw.com/en/coronavirus-german-military-training-sniffer-dogs/a-54062180" target="_blank" rel="noopener noreferrer">detecting COVID-19</a>, but no dogs have been used anywhere so far. And then, says Professor Holger Volk of the University of Veterinary Medicine Hanover, there has been insufficient political will or funding to move the project forward, something he called "very troubling" especially with a resurgent infection rate.</p><p>"When we started this whole project, we we did it because we wanted to help to stop the pandemic," Volk told DW. "It's really has been a very frustrating ride. I have had a lot of naysayers in the whole process. If I wasn't a very determined person, having done a lot of research, I would have probably stopped it."</p><p>He agrees with Hielm-Bjorkman's assessment that "it's just not in the perception of doctors that dogs are able to do this precise work." But he also echoes her faith in the vast potential of their discovery. "If you had a dog who could sniff every day quickly your cohort of workers, for example," he said, "think about the impact. You could continue having a workplace."</p><p>Speaking of workplaces, Susanna Paavilainen is starting to think if Finland doesn't want to unleash the dogs' potential at home, she and Kossi might accept one of the many requests from all over the world to provide training. "We can move because Kossi likes warm weather," she says, petting her star sniffer.</p>
An annual comprehensive report on air pollution showed that it was responsible for 6.67 million deaths worldwide, including the premature death of 500,000 babies, with the worst health outcomes occurring in the developing world, according to the State of Global Air, which was released Wednesday.
- U.S. Air Quality Decreased in Recent Years, Study Finds - EcoWatch ›
- Air Pollution Shortens Life Span by Three Years, Researchers Say ... ›
- Cleaner Air in Europe Has Resulted in 11,000 Fewer Deaths, New ... ›
- Half of U.S. Air Pollution Deaths Linked to Out-of-State Emissions ... ›
By Hannah Seo
If you've been considering throwing out that old couch, now might be a good time. Dust in buildings with older furniture is more likely to contain a suite of compounds that impact our health, according to new research.
- How Chemicals Like PFAS Can Increase Your Risk of Severe ... ›
- PFAS Chemicals Contaminate U.S. Food Supply, FDA Confirms ... ›
- This Strategy Protects Public Health From PFAS 'Forever Chemicals ... ›
Poor eating habits, lack of exercise, genetics, and a bunch of other things are known to be behind excessive weight gain. But, did you know that how much sleep you get each night can also determine how much weight you gain or lose?