We Have Released a Monster: Previously Frozen Soil Is “Breathing Out” Greenhouse Gases


Katey Walter Anthony, a leading scientist in studying the escape of methane, at her research site where methane is collecting beneath the ice, in Fairbanks, Alaska, on October 21, 2011. With temperatures warming across much of that region, which scientists primarily believe is because of the rapid human release of greenhouse gases, permafrost is also warming, and signs are emerging that frozen carbon may be destabilizing.

A study published in the journal Nature has revealed an alarming new climate feedback loop: As Earth’s atmosphere continues to warm from anthropogenic climate disruption (ACD), soils are respirating carbon — that is, carbon is being literally baked out of the soils.

Microorganisms in soil generally consume carbon, then release CO2 as a byproduct. Large areas of the planet — such as Alaska, northern Canada, Northern Europe and large swaths of Siberia in Russia — have previously been too cold for this process to occur. However, they are now warming up, and soil respiration is happening there. As a result, these places are contributing far, far more CO2 and methane to the atmosphere than they ever have.

This phenomenon is already evidenced by a recently released study led by the US National Oceanic and Atmospheric Administration (NOAA), which Truthout reported on recently.

This means that even if all human fossil fuel emissions were halted immediately, soils would continue to release approximately the same amount of CO2 and methane emissions as the amount produced by the fossil fuel industry during the mid-20th century.

Another Tipping Point

The study showed that the uptick in soil respiration is set to add between 0.45 and 0.71 parts per million (ppm) of CO2 to the atmosphere each year between now and 2050.

Disturbingly, humans are already adding between 3.2 to 3.55 ppm of CO2 to the atmosphere as of this year, which is the first time CO2-increase rates have broken records two years in a row.

The amount of CO2 that soil respiration will add to the atmosphere — on top of what humans are directly adding — is significant.

Climate feedback loops, sometimes referred to as positive feedback loops, runaway feedback loops, or amplifying feedback loops, are important to understand if we are to truly comprehend the nature of ACD. Many feedback loops are already in play, and more are coming into being on a regular basis.

For example, when atmospheric warming caused by fossil fuel emissions leads to the melting of Arctic sea ice, the reflectivity lost by disappearing sea ice allows more solar radiation to heat the Arctic Ocean, which then causes more sea ice to melt. This is perhaps the most well-known climate feedback loop.

The discovery of the soil feedback loop intensifies concerns about our rapidly warming climate. Increasing soil respiration — also known as “the compost bomb” — is set to add between 30 and 55 billion tons of extra CO2 to the atmosphere over the next 35 years, as Earth’s temperature warming approaches 2C.

Moreover, the study categorizes its findings as conservative estimates. In fact, the Earth could well see as much as four times the amount of CO2 (2.7 ppm) from soil respiration alone if the phenomenon becomes more wide-ranging than expected. And given that scientific predictions rarely keep pace with how rapidly the planet is changing, it would not be surprising if the prevalence exceeds expectations.

Catastrophic for Humanity

Dr. Thomas Crowther, the lead researcher on the soil study, told The Independentthat, given that ACD is happening more rapidly than expected, the impending climate-denying Trump presidency could well be “catastrophic for humanity.”

He is not exaggerating: A lot can happen in four years, when it comes to climate disruption. In fact, every year makes quite a difference. The study shows that at a minimum, 0.45ppm of CO2 will be leached from northern soils every year between 2016 and 2050, with about 1C worth of atmospheric warming during that period.

The study also shows that if Earth is warmed to 2C above preindustrial baseline temperature levels by 2050, which is essentially a certainty in the best-case scenario, then an average of approximately 0.71ppm of CO2 will be released from soils every year through the year 2050.

The Earth has already warmed by more than 1C above preindustrial baseline temperatures. It is unlikely that human civilization can survive warming of 3.5C or higher, as humans have never lived on a planet that warm. However, we are currently on track for a minimum warming of 5 to 7C, or worse, by 2100.

“It’s fair to say we have passed the point of no return on global warming, and we can’t reverse the effects,” Dr. Crowther told The Independent when the study was released. “But we can certainly dampen them.”

Other climate scientists emphasized the importance of using the soil study to inform measures to mitigate the damage of ACD. Professor Ivan Janssens with the University of Antwerp called the study “very important,” because the response of soils to ACD could well be one of the largest sources of uncertainty in climate modelling.

“We urgently need to develop a global economy driven by sustainable energy sources and start using CO2, as a substrate, instead of a waste product,” Dr. Janssens told The Independent. He suggested that if significant progress is made on this front, it may still be possible to avoid catastrophic warming.

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scientists just confirmed a key new source of greenhouse gases


Countries around the world are trying to get their greenhouse gas emissions under control — to see them inch down, percentage point by percentage point, from where they stood earlier in the century. If everybody gets on board, and shaves off enough of those percentage points, we just might be able to get on a trajectory to keep the world from warming more than 2 degrees Celsius above the temperature where it stood prior to industrialization.

But if a new study is correct, there’s a big problem: There might be more greenhouse gases going into the atmosphere than we thought. That would mean an even larger need to cut.

The new paper, slated to be published next week in BioScience, confirms a  significant volume of greenhouse gas emissions coming from a little-considered place: Man-made reservoirs, held behind some 1 million dams around the world and created for the purposes of electricity generation, irrigation, and other human needs. In the study, 10 authors from U.S., Canadian, Chinese, Brazilian, and Dutch universities and institutions have synthesized a considerable body of prior research on the subject to conclude that these reservoirs may be emitting just shy of a gigaton, or billion tons, of annual carbon dioxide equivalents. That would mean they contributed 1.3 percent of the global total.

Moreover, the emissions are largely in the form of methane, a greenhouse gas with a relatively short life in the atmosphere but a very strong short-term warming effect. Scientists are increasingly finding that although we have begun to curb some emissions of carbon dioxide, the principal greenhouse gas, we are still thwarted by methane, which comes from a diversity of sources that range from oil and gas operations to cows.

How greenhouse gas behaves in the atmosphere

Play Video0:43
This high-resolution animation shows carbon dioxide emitted from fires and megacities over a five day period in June 2006. The model is based on real emission data so that scientists can observe how the greenhouse gas behaves once it has been emitted. (Global Modeling and Assimilation Office, NASA’s Goddard Space Flight Center)

The new research concludes that methane accounted for 79 percent of carbon dioxide equivalent emissions from reservoirs, while the other two greenhouse gases, carbon dioxide and nitrous oxide, accounted for 17 percent and 4 percent.

“There’s been kind of an explosion in research into efforts to estimate emissions from reservoirs,” said Bridget Deemer, the study’s first author and a researcher with Washington State University. “So we synthesized all known estimates from reservoirs globally, for hydropower and other functions, like flood control and irrigation.

“And we found that the estimates of methane emissions per area of reservoir are about 25 percent higher than previously thought, which we think is significant given the global boom in dam construction, which is currently underway,” she continued.

As Deemer’s words suggest, the study does not single out dams used to generate electricity — it focuses on all reservoirs, including those that are created for other purposes. It drew on studies on 267 reservoirs around the world, which together have a surface area of close to 30,000 square miles, to extrapolate global data.

Reservoirs are a classic instance of how major human alteration’s to the Earth’s landscape can have unexpected effects. Flooding large areas of Earth can set off new chemical processes as tiny microorganisms break down organic matter in the water, sometimes doing so in the absence of oxygen — a process that leads to methane as a byproduct. One reason this happens is that the flooded areas initially contain lots of organic life in the form of trees and grasses.

Meanwhile, as nutrients like nitrogen and phosphorus flow into reservoirs from rivers — being poured in by human agriculture and waste streams — these can further drive algal growth in reservoirs, giving microorganisms even more material to break down. The study finds that for these reasons, reservoirs emit more methane than “natural lakes, ponds, rivers, or wetlands.”

“If oxygen is around, then methane gets converted back to CO2,” said John Harrison, another of the study’s authors, and also a researcher at Washington State. “If oxygen isn’t present, it can get emitted back to the atmosphere as methane.”And flooded areas, he said, are more likely to be depleted of oxygen. A similar process occurs in rice paddies, which are also a major source of methane emissions.

In fact, Harrison said that based on the new study, it appears that reservoir emissions and rice paddy emissions are of about the same magnitude on a global scale — but rice paddy emissions have been taken into account for some time. Reservoir emissions often have not.
‘There are inventory compilers in each country that are responsible for compiling information about greenhouse gases to the atmosphere,” Harrison explained. “The [United Nations’ Intergovernmental Panel on Climate Change] writes the guidance, the cookbook that’s supposed to be used by these inventory compilers, and that guidance currently includes reservoirs only as an appendix, not an official part of any nation’s inventory. But that is likely to change as those guidelines get revised over the next two years.”

The research, said Deemer, complicates the idea that hydropower is a carbon-neutral source of energy, although she stresses that the authors aren’t saying that they’re against using large bodies of water to generate energy through dams. Rather, they’re arguing that the greenhouse gas calculus has to be included in evaluating such projects.

This problem is not an entirely new one: A major 2000 study in BioScience raised this issue, and the International Hydropower Association on its website acknowledges that “While hydropower is a very low-carbon technology, it is known that some reservoirs in certain conditions can release quantities of methane, a greenhouse gas. Reservoirs can also, in other circumstances, act as carbon sinks.”
But what is new about the current study is its synthesis of a large number of studies since 2000, and the determination that these emissions add up to something that is big enough to be taken seriously as part of the global carbon budget. It also finds that while some reservoirs are indeed “sinks” for carbon dioxide or nitrous oxide — meaning, they take up more of these gases than they emit — that was not true for methane.

The authors acknowledge the study does not represent a full “life cycle analysis” of reservoirs, taking into account how much carbon was stored (or emitted from) lands prior to their being flooded, and also what happens after reservoirs are decommissioned. Nor does it attempt to weigh the methane emissions from reservoirs used to generate hydropower against the amount of greenhouse gas emissions that would presumably be created if that electricity was instead generated by burning coal or natural gas.
But it clearly suggests a need to take these emissions seriously, and conduct further research.

“We’re trying to provide policymakers and the public with a more complete picture of the consequences of damming a river,” said Harrison.

Greenhouse Gases Reached Record Highs In 2014


<span class='image-component__caption' itemprop="caption">Cows and other livestock give off significant amounts of methane gas.</span>
JEAN-FRANCOIS MONIER VIA GETTY IMAGESCows and other livestock give off significant amounts of methane gas.

 GENEVA, Nov 9 (Reuters) – Greenhouse gas levels in the atmosphere reached a record high in 2014 as the relentless fueling of climate change makes the planet more dangerous for future generations, the World Meteorological Organization said on Monday.

“Every year we say that time is running out. We have to act NOW to slash greenhousegasemissions if we are to have a chance to keep the increase in temperatures to manageable levels,” WMO Secretary-General Michel Jarraud said in a statement.

Graphs issued by the United Nations agency showed levels of carbon dioxide, the maingreenhouse gas, climbing steadily towards the 400 parts per million (ppm) level, having hit a new record every year since reliable records began in 1984.

Carbon dioxide levels averaged 397.7 ppm in 2014 but briefly breached the 400 ppm barrier in the northern hemisphere in early 2014, and again globally in early 2015.

Soon 400 ppm will be a permanent reality, Jarraud said.

“It means hotter global temperatures, more extreme weather events like heatwaves and floods, melting ice, rising sea levels and increased acidity of the oceans. This is happening now and we are moving into uncharted territory at a frightening speed.”

The rise in carbon dioxide levels was being amplified by higher levels of water vapor, which were in turn rising because of carbon dioxide emissions, the WMO said.

Levels of the other two major man-made greenhouse gases, methane and nitrous oxide, also continued their relentless annual rise in 2014, reaching 1,833 parts per billion (ppb) and 327.1 ppb, respectively. Both increased at the fastest rate for a decade.

The U.N. panel of climate scientists estimates that concentrations of carbon dioxide, methane and nitrous oxide are at their highest in at least 800,000 years.

Jarraud’s annual plea for the world to do whatever it can to cut greenhouse gas emissions comes weeks before negotiators from more than 190 countries are due to meet in Paris to try to agree a new U.N. climate deal.

More than 150 countries, led by top greenhouse gas emitters China and the United States, have issued plans to limit greenhouse gas emissions beyond 2020. But the plans revealed so far will not curb emissions enough to meet a target agreed in 2010, to limit global warming to within 2° Celsius (3.6 Fahrenheit) of pre-industrial levels.

New monitoring system clarifies murky atmospheric questions.


A University of Colorado Boulder-led team has developed a new monitoring system to analyze and compare emissions from man-made fossil fuels and trace gases in the atmosphere, a technique that likely could be used to monitor the effectiveness of measures regulating greenhouse gases.

 

The research team looked at atmospheric gas measurements taken every two weeks from aircraft over a six-year period over the northeast United States to collect samples of CO2 and other environmentally important gases. Their method allowed them to separate CO2 derived from fossil fuels from CO2 being emitted by biological sources like plant respiration, said CU-Boulder Senior Research Associate Scott Lehman, who led the study with CU-Boulder Research Associate John Miller.

The separation was made possible by the fact that CO2 released from the burning of fossil fuels like coal, oil and gas has no carbon-14, since the half-life of that carbon radio isotope is about 5,700 years — far less than the age of fossil fuels, which are millions of years old. In contrast, CO2 emitted from biological sources on Earth like plants is relatively rich in carbon-14 and the difference can be pinpointed by atmospheric scientists, said Lehman of CU’s Institute of Arctic and Alpine Research.

The team also measured concentrations of 22 other atmospheric gases tied to human activities as part of the study, said Miller of the CU-headquartered Cooperative Institute for Research in Environmental Sciences. The diverse set of gases impact climate change, air quality and the recovery of the ozone layer, but their emissions are poorly understood. The authors used the ratio between the concentration level of each gas in the atmosphere and that of fossil fuel-derived CO2 to estimate the emission rates of the individual gases, said Miller.

In the long run, measuring carbon-14 in the atmosphere offers the possibility to directly measure country and state emissions of fossil fuel CO2, said Miller. The technique would be an improvement over traditional, “accounting-based” methods of estimating emission rates of CO2 and other gases, which generally rely on reports from particular countries or regions regarding the use of coal, oil and natural gas, he said.

 

“While the accounting-based approach is probably accurate at global scales, the uncertainties rise for smaller-scale regions,” said Miller, also a scientist at the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory in Boulder. “And as CO2 emissions targets become more widespread, there may be a greater temptation to underreport. But we’ll be able to see through that.”

A paper on the subject was published in the April 19 issue of the Journal of Geophysical Research: Atmospheres, published by the American Geophysical Union. Co-authors include Stephen Montzka and Ed Dlugokencky of NOAA, Colm Sweeney, Benjamin Miller, Anna Karion, Jocelyn Turnbull and Pieter Tans of NOAA and CIRES, Chad Wolak of CU’s INSTAAR and John Southton of the University of California, Irvine.

One surprise in the study was that the researchers detected continued emissions of methyl chloroform and several other gases banned from production in the United States. Such observations emphasize the importance of independent monitoring, since the detection of such emissions could be overlooked by the widely used accounting-based estimation techniques, said Montzka.

The atmospheric air samples were taken every two weeks for six years by aircraft off the coastlines of Cape May, N.J., and Portsmouth, N.H.

Fossil fuel emissions have driven Earth’s atmospheric CO2 from concentrations of about 280 parts per million in the early 1800s to about 390 parts per million today, said Miller. The vast majority of climate scientists believe higher concentrations of the greenhouse gas CO2 in Earth’s atmosphere are directly leading to rising temperatures on the planet.

“We think the approach offered by this study can increase the accuracy of emissions detection and verification for fossil fuel combustion and a host of other man-made gases,” said Lehman. He said the approach of using carbon-14 has been supported by the National Academy of Sciences and could be an invaluable tool for monitoring greenhouse gases by federal agencies like NOAA.

Unfortunately, NOAA’s greenhouse gas monitoring program has been cut back by Congress in recent years, said Lehman. “Even if we lack the will to regulate emissions, the public has a right to know what is happening to our atmosphere. Sticking our heads in the sand is not a sound strategy,” he said.

Source: University of Colorado