Fungi & Nitrous Oxide, The Forgotten Greenhouse Gas
Nitrous oxide (N2O) is a known greenhouse gas (GHG) that is more potent than CO2 and is a contributing factor in ozone layer depletion, yet little has been published on natural sources of this compound. Despite the importance of fungi in several soil functions, the production of N2O by fungi has only been studied in a limited number of strains. A new report in the journal Nature has revealed that may types of fungi naturally produce N2O. Obviously this is more of that “settled science” the climate alarmists forgot to mention.
Decades ago, when the climate alarmist clique shifted from freaking out about global cooling to hyperventilating over global warming, they realized that they needed a simple cause for their predicted calamity, a cause that could be easily linked to human activity. Realizing that blaming H2O was too much of a stretch even for the scientifically innocent public (who can fight against water?) they settled on another atmospheric gas, carbon dioxide. CO2 was much less known than H2O and it was easy to link the vital substance to human emissions from burning fossil fuels. No matter that CO2 is essential to plant life, and hence to all life on Earth. No, CO2 was the smoking gun and humanity the perpetrator of crimes against nature.
But H2O and CO2 are not the only greenhouse gases that contribute to keeping our planet from freezing over. Indeed, there are a number of other contributing factors, including nitrous oxide which has the 100 year global warming potential 298 times greater than that of CO2 due to its much longer atmospheric half life. In “ N2O production, a widespread trait in fungi,” Koki Maeda et al. have taken a look into the production of this overlooked GHG by that ubiquitous lifeform, fungi. Their motivation is given in the article abstract:
N2O is a powerful greenhouse gas contributing both to global warming and ozone depletion. While fungi have been identified as a putative source of N2O, little is known about their production of this greenhouse gas. Here we investigated the N2O-producing ability of a collection of 207 fungal isolates. Seventy strains producing N2O in pure culture were identified.
I have written about N2O, also known as laughing gas, before but this new study identifies its natural sources. Sixty-two percent of the total global N2O emissions are from natural and agricultural soils, 6 and 4.2 Tg N/yr, respectively according to Andrew J. Thomson. Thomson and colleagues summarized the findings of an interdisciplinary conference on “Nitrous oxide (N2O) the forgotten greenhouse gas,” held at the Kavli Royal Society International Centre, in 2011. In their paper, “Biological sources and sinks of nitrous oxide and strategies to mitigate emissions,” they broke down the sources of N2O as shown in the figure below.
Note that the data depicted in the pie chart are from the AR4 IPCC report, so it is obvious that climate scientists know about N2O, they just don't talk much about it. This is because introducing other contributing factors to climate change, particularly one primarily from natural sources, complicates the narrative. It is so much easier to sell the public the CAGW mantra: CO2 causes global warming, humans cause CO2, therefore we cause global warming.
It is understandable that climate alarmists are loath to confuse the public with facts, particularly complicated facts. Maeda et al. took on a complicated task, given the proliferation of fungal strains in the wild. They tried to identify common genetic factors that linked those fungi that were most active in the production of nitrous oxide. Just how big a puzzle they were trying to solve is indicated by the Neighbour-joining phylogenetic tree of nirK amino acid sequences shown in the figure below.
“Both copper-containing nitrite reductase (encoded by the nirK gene) and P450nor (nitric oxide reductase) are key enzymes involved in fungal denitrification” they state. “However, P450nor belongs to a superfamily of proteins that are widely distributed among fungi and known to be involved in a wide variety of physiological reactions, which prevents the use of the corresponding genes as molecular markers to target denitrifying fungi.”
The researchers summarize their findings this way: “Collectively, our results indicate that N2O production is a common trait in fungal taxa that are frequently abundant in soils, although this feature seems to be more a strain-specific than a species-specific trait. It also underlines the importance of quantifying the fungal contribution to terrestrial N2O emissions.”
Here is another little mentioned factor in climate change, one seldom acknowledged by the harbingers of ecological doom. That N2O production is a common and widespread trait in fungi means there is little chance that this contributor to climate change can be successfully regulated. In fact, N2O helps point out the folly of those who think they can control Earth's climate by diddling with human CO2 emissions. As complicated as regulating carbon dioxide is, it is only a small part of the complicated system that is Earth's climate engine.
In simplifying their case for anthropogenic global warming, in order to implicate mankind as the cause of climate change, climate scientists have dumbed down their science to the point that it really isn't science at all. By making climate change all about CO2 they have enabled simpletons and demagogues like John Kerry and Al Gore to reduce science to a bedtime story used to scare little children. Real scientists know that climate change is more complicated than that, yet they remain mute as dilettantes and charlatans rail on about a single greenhouse gas—carbon dioxide. They totally ignore other GHGs like H2O, CH4, and N2O, not to mention aerosols, land cover change, solar variation, cloud variability, etc. Does that sound like science to you?
Be safe, enjoy the interglacial and stay skeptical.