Permafrost and Wetland Emissions Could Cut 1.5°C Carbon Budget ‘by Five Years’
By Robert McSweeney
These natural processes are "positive feedbacks"—so called because they release more greenhouse gases as global temperatures rise, thus reinforcing the warming. They have previously not been represented in carbon budget estimates as they are not included in most climate models, the researchers say.
The findings suggest that human-caused emissions will be need to be cut by an additional 20 percent in order to meet the Paris agreement's 1.5°C or 2°C limits, the researchers estimate.
'Engines for Turning CO2 Into Methane'
Over the last year or so, there has been a flurry of new carbon budget studies—using slightly different approaches to estimate how much CO2 we can emit and still hold global temperature rise to no more than 1.5°C or 2°C above pre-industrial levels. Carbon Brief summarized all the 1.5°C budgets in a recent analysis piece.
Many of these studies use global climate models to make their estimates. However, there are some processes which affect the climate that are not yet incorporated into these models.
The new study, published in Nature Geoscience, aims to fill that gap. It focuses on two processes on the land surface: thawing permafrost and natural wetlands.
These are both positive feedbacks for the climate because, as they respond to rising temperatures, they cause the release of more greenhouse gases into the atmosphere.
Permafrost thawing causes disturbances to the soils. This photo was taken on Forsheim Peninsula, Ellesmere Island, Nunavut, Canada.A. Cassidy, UBC Geography / CC BY 2.0
These soils hold a huge amount of carbon, accumulated from dead plants and animals over thousands of years. Rising temperatures put this carbon at risk of being released, explained Dr. Chris Jones, head of the earth system and mitigation science team at the Met Office Hadley Centre. Jones is not an author on the new study, but his team was involved closely in the work. He told Carbon Brief:
"While [permafrost] is frozen, it is inert. As it thaws, this carbon is vulnerable to decomposition—like any other soil carbon. Depending on whether it is waterlogged or not this can be emitted to the atmosphere as CO2 or methane."
How much is released as CO2 and how much as methane is still uncertain, and is an active area of research. Methane is a potent greenhouse gas—approximately 26 times more powerful than CO2 at trapping heat in the atmosphere, although it only lasts for around a decade in the atmosphere.
In natural wetlands, plants absorb CO2 from the atmosphere as they grow. But, because they are waterlogged, when the plants decompose they release methane, rather than CO2. This makes wetlands "effectively engines for turning CO2 into methane," said Jones.
In the Amazon, for example, flooded forests actually release methane through the trees themselves.
Wetlands respond to a warming climate in three ways, Jones explained:
"As [the climate] warms, the local decomposition rate increases. Also, as rainfall changes, we may see increased or decreased areas of wetlands. This varies regionally and, again, is a large uncertainty across climate models. Finally, a direct effect of increased CO2 in the atmosphere is to increase the growth rate of the vegetation and, hence, increase the amount of CO2 being turned into methane."
The study is the first to bring all these factors together, he noted.
The researchers used a "multi-layered soil carbon model" called JULES (Joint UK Land Environment Simulator), explained lead author Dr. Edward Comyn-Platt, a land surface modeller at the Centre for Ecology & Hydrology. JULES has an improved representation of soil chemistry and the way that wetlands create methane.
With permafrost, for example, "this not only improves our estimates of the carbon stored in soils at high latitudes, but also allows us to estimate how much of this soil will be lost as the permafrost regions thaw," Comyn-Platt told Carbon Brief.
To estimate carbon budgets, the researchers use an "inverted" form of the model. This means that rather than plugging in pathways of future greenhouse gas emissions and seeing how global temperatures respond, the researchers input pathways of global temperature rise and use the model to estimate the corresponding levels of greenhouse gases in the atmosphere.
The study looks at three scenarios of future global warming: holding temperature rise at 1.5°C and 2°C, and one where warming "overshoots" 1.5°C, reaches 1.75°C, then returns to 1.5°C.
In their "control" model runs with no permafrost or wetland feedbacks, the researchers estimate the 1.5°C budget at 720bn-929bn tonnes of CO2 from the beginning of 2018—equivalent to 20-25 years of emissions at current rates.
This is slightly higher than some recent budgets because the JULES model tends to simulate a large amount of carbon uptake from the land surface, explained Comyn-Platt, freeing up space for more CO2 emissions in the budget.
The researchers then used the model to simulate the response of permafrost and natural wetlands to climate change. When the additional CO2 and methane emissions are incorporated, the available carbon budget shrinks substantially—falling to 533bn-753bn tonnes of CO2 for 1.5°C, or 14-20 years of emissions.
That means accounting for the impacts of permafrost and wetlands takes around five years off the 1.5°C budget. And, as the table below shows, the budgets for the 1.5°C overshoot and 2°C scenarios are similarly reduced.
This "nice work" shows that even if we were to get net emissions to zero in the next few decades, emissions would need to fall further in order to stabilize temperatures at 1.5°C or 2°C, said Piers Forster, professor of physical climate change at the University of Leeds and director of the Priestley International Centre for Climate. He told Carbon Brief:
"The extra carbon released from thawing permafrost and warming wetlands would continue beyond the date of net-zero emissions and this would need to be countered for in order to consider carbon budgets applicable for 2100 and beyond."
The study also highlights the constant evolution in the complexity of climate models, said Jones, with new model components being developed and run separately before being incorporated into global models.
The graphic below shows how new components have been added to global climate models over time.
In this case, the wetland model "scheme" will be shortly be brought into UKESM1—the UK Earth System Model run by the Met Office Hadley Centre and partners, said Jones. And the permafrost scheme "will follow in due course."
Methane Meltdown: Thawing Permafrost Could Release More Potent Greenhouse Gas Than Expected https://t.co/vP6G7WFkbw… https://t.co/3GS36bTgDu— EcoWatch (@EcoWatch)1521717907.0
Reposted with permission from our media associate Carbon Brief.
Yet another former Trump administration staffer has come out with an endorsement for former Vice President Joe Biden, this time in response to President Donald Trump's handling of the coronavirus pandemic.
- Trump Denies CDC Director's 2021 Timeline for Coronavirus Vaccine ›
- Trump Orders Hospitals to Stop Sending COVID-19 Data to CDC ... ›
- Two White House Staffers Test Positive for Coronavirus - EcoWatch ›
- Trump Admin to Disband Coronavirus Task Force - EcoWatch ›
- Pence Offers 'Prayers' as Hurricane Laura Hits Gulf Coast While ›
EcoWatch Daily Newsletter
Every September for the past 11 years, non-profit the Climate Group has hosted Climate Week NYC, a chance for business, government, activist and community leaders to come together and discuss solutions to the climate crisis.
- Covering the 2020 Elections as a Climate Story - EcoWatch ›
- Coronavirus Delays 2020 Earth Overshoot Day by Three Weeks ... ›
By Elliot Douglas
The coronavirus pandemic has altered economic priorities for governments around the world. But as wildfires tear up the west coast of the United States and Europe reels after one of its hottest summers on record, tackling climate change remains at the forefront of economic policy.
- German Business Leaders Call for Climate Action With COVID-19 ... ›
- Climate Activists Protest Germany's New Datteln 4 Coal Power Plant ... ›
By D. André Green II
One of nature's epic events is underway: Monarch butterflies' fall migration. Departing from all across the United States and Canada, the butterflies travel up to 2,500 miles to cluster at the same locations in Mexico or along the Pacific Coast where their great-grandparents spent the previous winter.
Millions of People Care About Monarchs<p>I will never forget the sights and sounds the first time I visited monarchs' overwintering sites in Mexico. Our guide pointed in the distance to what looked like hanging branches covered with dead leaves. But then I saw the leaves flash orange every so often, revealing what were actually thousands of tightly packed butterflies. The monarchs made their most striking sounds in the Sun, when they burst from the trees in massive fluttering plumes or landed on the ground in the tussle of mating.</p><p>Decades of educational outreach by teachers, researchers and hobbyists has cultivated a generation of monarch admirers who want to help preserve this phenomenon. This global network has helped restore not only monarchs' summer breeding habitat by planting milkweed, but also general pollinator habitat by planting nectaring flowers across North America.</p><p>Scientists have calculated that restoring the monarch population to a stable level of about 120 million butterflies will require <a href="https://doi.org/10.1111/icad.12198" target="_blank">planting 1.6 billion new milkweed stems</a>. And they need them fast. This is too large a target to achieve through grassroots efforts alone. A <a href="https://www.fws.gov/savethemonarch/CCAA.html" target="_blank" rel="noopener noreferrer">new plan</a>, announced in the spring of 2020, is designed to help fill the gap.</p>
Pros and Cons of Regulation<p>The top-down strategy for saving monarchs gained energy in 2014, when the U.S. Fish and Wildlife Service <a href="https://www.fws.gov/southeast/pdf/petition/monarch.pdf" target="_blank">proposed</a> listing them as threatened under the Endangered Species Act. A decision is expected in December 2020.</p><p>Listing a species as endangered or threatened <a href="https://www.fws.gov/endangered/esa-library/pdf/listing.pdf" target="_blank">triggers restrictions</a> on "taking" (hunting, collecting or killing), transporting or selling it, and on activities that negatively affect its habitat. Listing monarchs would impose restrictions on landowners in areas where monarchs are found, over vast swaths of land in the U.S.</p><p>In my opinion, this is not a reason to avoid a listing. However, a "threatened" listing might inadvertently threaten one of the best conservation tools that we have: public education.</p><p>It would severely restrict common practices, such as rearing monarchs in classrooms and back yards, as well as scientific research. Anyone who wants to take monarchs and milkweed for these purposes would have to apply for special permits. But these efforts have had a multigenerational educational impact, and they should be protected. Few public campaigns have been more successful at raising awareness of conservation issues.</p>
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="91165203d4ec0efc30e4632a00fdf57d"><iframe lazy-loadable="true" src="https://www.youtube.com/embed/KilPRvjbMrA?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
The Rescue Attempt<p>To preempt the need for this kind of regulation, the U.S. Fish and Wildlife Service approved a <a href="https://www.fws.gov/savethemonarch/pdfs/Monarch%20CCAA-CCA%20Public%20Comment%20Documents/Monarch-Nationwide_CCAA-CCA_Draft.pdf" target="_blank">Nationwide Candidate Conservation Agreement for Monarch Butterflies</a>. Under this plan, "rights-of-way" landowners – energy and transportation companies and private owners – commit to restoring and creating millions of acres of pollinator habitat that have been decimated by land development and herbicide use in the past half-century.</p><p>The agreement was spearheaded by the <a href="http://rightofway.erc.uic.edu/" target="_blank">Rights-of-Way Habitat Working Group</a>, a collaboration between the University of Illinois Chicago's <a href="https://erc.uic.edu/" target="_blank" rel="noopener noreferrer">Energy Resources Center</a>, the Fish and Wildlife Service and over 40 organizations from the energy and transportation sectors. These sectors control "rights-of-way" corridors such as lands near power lines, oil pipelines, railroad tracks and interstates, all valuable to monarch habitat restoration.</p><p>Under the plan, partners voluntarily agree to commit a percentage of their land to host protected monarch habitat. In exchange, general operations on their land that might directly harm monarchs or destroy milkweed will not be subject to the enhanced regulation of the Endangered Species Act – protection that would last for 25 years if monarchs are listed as threatened. The agreement is expected to create up to 2.3 million acres of new protected habitat, which ideally would avoid the need for a "threatened" listing.</p>
A Model for Collaboration<p>This agreement could be one of the few specific interventions that is big enough to allow researchers to quantify its impact on the size of the monarch population. Even if the agreement produces only 20% of its 2.3 million acre goal, this would still yield nearly half a million acres of new protected habitat. This would provide a powerful test of the role of declining breeding and nectaring habitat compared to other challenges to monarchs, such as climate change or pollution.</p><p>Scientists hope that data from this agreement will be made publicly available, like projects in the <a href="https://www.fws.gov/savethemonarch/MCD.html" target="_blank">Monarch Conservation Database</a>, which has tracked smaller on-the-ground conservation efforts since 2014. With this information we can continue to develop powerful new models with better accuracy for determining how different habitat factors, such as the number of milkweed stems or nectaring flowers on a landscape scale, affect the monarch population.</p><p>North America's monarch butterfly migration is one of the most awe-inspiring feats in the natural world. If this rescue plan succeeds, it could become a model for bridging different interests to achieve a common conservation goal.</p>
The annual Ig Nobel prizes were awarded Thursday by the science humor magazine Annals of Improbable Research for scientific experiments that seem somewhat absurd, but are also thought-provoking. This was the 30th year the awards have been presented, but the first time they were not presented at Harvard University. Instead, they were delivered in a 75-minute pre-recorded ceremony.