Sunday, December 27, 2015

Think of It as a Matter of Life or Something Other Than Life

By now there aren't many who remain unaware of the dangerous levels of carbon in our atmosphere, the greenhouse gas CO2. Most of us have climbed the mountain of research and understand the role played by CO2 in heating our atmosphere, our oceans and our continents.

We're less likely to grasp the other critical roles carbon plays in our lives. Start with the fact that all life on Earth is carbon-based, you too. There wouldn't be any food on the table without carbon, even if you're vegan. Plants grow through photosynthesis, combining solar energy and carbon drawn from the air, returning the oxygen to the atmosphere. It's this exchange that has led some to call the Amazon rainforest the "lungs of the planet."

Over the past five or six years I've been reading whatever I can find on another role played by carbon - in our soil. Cut to the chase: it is an essential component to soil health. Without it, soil can become sterile, incapable of supporting plant life. Look at it this way - carbon in soil good/carbon in the atmosphere not so good.

The Green Revolution, industrial agriculture (fueled by heavy applications of chemical fertilizers, herbicides and pesticides and by the rapacious use of already limited groundwater for irrigation) has allowed our numbers to more than double since the early 70s. However, like all things done to excess for too long, the consequences are beginning to show up.

One form of blowback is seen in places such as India where soil was turned into viable farmland through agricultural chemicals. In these places decades of intensive agriculture has turned the soil thin, less fertile, requiring twice the original application of ag-chemicals to yield a crop.

What happens is the nitrogen fertilizers over time destroy the soil carbon. The nitrogen affects the soil microbes, puts them on steroids if you will, and they then go after the soil carbon which they in turn transform into CO2. Without the soil carbon, plant matter doesn't properly decompose, humus isn't formed, the soil goes dry and lifeless.

Research suggests that there is more stored carbon in the first foot of soil than we currently have in our atmosphere. Chemical fertilizers are starting to release that carbon skyward but now there may be a second, carbon-releasing feedback kicking in - droughts resulting from climate change.

There's a new book out from Canadian water expert, Robert Sanford, and former BC deputy minister of sustainable resource development, Jon O'Riordan, "The Climate Nexus, Water, Food, Energy and Biodiversity in a Changing World."

'The Climate Nexus' includes some ominous information about the effect of higher temperatures and droughts on the capacity of soil to store carbon dioxide. That’s because research has suggested that when alpine soil becomes 2° C warmer over a period of time, it can release a quarter of its stored carbon. In fact, the book states that humanity has “just a half metre of soil standing between prosperity and desolation”.

There are approximately 400 parts per million of carbon-dioxide equivalent gases in the atmosphere. The international community has set the “maximum allowable concentration” of carbon-dioxide equivalent gases at 450 parts per million, according toThe Climate Nexus.

The book notes that John Harte at the University of California at Berkeley maintains there is four times more carbon in the first foot of soil around the world than there is in the entire atmosphere.

“Harte calculated that if you release a quarter of that into the atmosphere, the amount would be equal to the amount of carbon already in the atmosphere as a result of burning fossil fuels,” O’Riordan and Sandford write. “In other words, if we warm the world’s soils by 2°C, the amount of carbon dioxide in the atmosphere could double from its present 400 parts per million to 800 ppm.

800 ppm. is, by even the most optimistic interpretations, a world mankind has never known. Some claim plant life will thrive but they base that on photosynthesis and ignore what that much carbon will also do to soil biology and our already broken hydrological cycle. 

I wish we had three or four centuries to come to grips with this environmental nest of vipers but we don't even have three or four decades. Our governmental focus is on reducing greenhouse gas emissions, an attempt to slow the rate of global warming. That's a nice gesture, if the community of nations follows through with their promises, but it's best not to dwell on their historic track record on these things.

We have to concentrate on reducing atmospheric carbon levels, not just slowing their rate of growth. At the same time we also have to focus on getting more carbon back into our soils. There are ways we might do that but they're beyond the scope of a blog post. That is what I've been working on.

For those of you who don't grasp the urgency of this effort, consider this. The UN Food & Agriculture Organization last year issued a warning, based on a great deal of research and analysis, that at the rate we're degrading our planet's stock of viable farmland, what we have will be gone in 60-years. That's gone as in over, lights out.


Lorne said...

This is very sobering news, Mound, and once more confirms the dire situation we find ourselves in. Is this release of carbon from the soil something that the wider climate-change scientific community is discussing yet, or is it just concentrating on slowing down greenhouse gas emissions?

The Mound of Sound said...

It's a subject for discussion now, Lorne, as yet another 'natural feedback loop' of manmade global warming. Part of the problem is that everything has been eclipsed by the issue of man-made greenhouse gas emissions, largely CO2. That's a logical target because we have more ability to cause and to change it. Transitioning to alternate, clean energy instead of fossil energy is the obvious example.

The impact of drought on soil carbon is something that has occurred in the distant past but at an infrequency that obscured it - something of up to once every 100,000 years at least on the scale we might be facing soon. It's a vicious circle - drought leads to the loss of soil carbon that is the basis for humus that retains soil moisture.

That's why we have to adopt methods of getting carbon back into the ground even as we kickstart the faltering surface carbon cycle into operation again. It is fascinating, to me at least, how directly related are the hydrological and surface carbon cycles, both of them indispensable to life on Earth.

Owen Gray said...

Sixty years is the blink of an eye, Mound.

The Mound of Sound said...

From what I've learned, Owen, it would be a multi-decadal effort to restore the soil carbon balance globally. The good part is that other conditions have arisen that make it far more feasible if we choose to act.

The window for action on a global scale is narrowing rapidly. Still there's a role for it to play in the more advantaged 'developed world' that can be realized.

Anonymous said...

Go to China. More areas than not, where the soil is dead.

John's aghast said...

Shouldn't someone tell Christy about this? I mean if we've only got 60 years of soil life left maybe we shouldn't drown the Peace Valley?
Oh well, I guess we could sell a bunch of LNG and buy our veggies from China, or California or......?