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Viewing posts from February, 2024

The trouble with carbon

Posted by Peter Donovan 3 months, 1 week ago in policy and framing /

Many states, including Oregon, have passed legislation with incentives for agricultural and forestry practices that are presumed to constitute "natural climate solutions." Oregon's Natural and Working Lands Proposal rightly recognizes soil health as a priority for Oregon's working lands.

Soil has long been understood as a more-or-less inert substance, a dance floor or stage for the more visible dramas of above-ground plants and crops, animals, roads, and buildings. Soil science became the categories, constituents, and properties of soil. But as some acute observers and thinkers a century ago realized, soil is also a "fountain of energy" to use Aldo Leopold's words. Enormous flows of matter and solar energy, mostly invisible, flow in and out of soil.

During a drought an engineer, thinking of energy only as the "energy sector" of the human economy, once wondered to me if the energy needed to desalinate seawater and pump it over the land could come from a yet-to-be-developed nuclear fusion reactor.

A wider view of energy understands that soil moisture—water in soil pores and cavities, water films coating soil particles—is a consequence of the sun's fusion reactor powering the evaporation and distribution (as vapor or droplets) of enormous volumes of water on earth, and consequent precipitation onto earth's surfaces, a quarter of which are soil. Globally, about a third of the sunlight energy reaching the surface does the work of evaporating water, over 400 horsepower per acre on average.

Movements of water, with water's enormous capacity to absorb, release, and move heat energy from sunlight, are the greatest influence on weather and climate. Water, ice, and water vapor can reflect the sun's energy, keep some of it from escaping (as a greenhouse gas), and move it with ocean currents, moist winds, and atmospheric turbulence. Water also responds to a warming climate by changing or intensifying these dynamics. The major risks to human civilization from a warming climate are water-related: drought (associated with groundwater declines, crop failures, failing agricultural communities, refugees, even famine); floods and severe storms; and changes in sea level and ocean currents.

Far below water cycling in its direct use of sunlight energy is the photosynthesis that drives carbon cycling. Photosynthesis—globally around one horsepower per acre, averaged across seas, ice sheets, and land—depends on water. Puny as it is compared to water cycling, this carbon cycle—the work of living organisms—is transformative for our planet because it does complex chemistry. Life's accomplishments include oxygenating the earth's atmosphere, growing spongy, water-holding soil out of rock, and contributing its remains and residues to earth's crust in the form of limestone, shale, chalk, and fossil fuels. More recently, human life's activities include large-scale oxidation or burning of this fossil carbon, as well as oxidation of carbon in trees and soil, adding greenhouse gases to the atmosphere.

In the 1920s Russian geochemist Vladimir Vernadsky observed that life is the most powerful geologic force. But there was little practical context or use for that insight.

Climate change, along with ecological degradation, has delivered a practical context. Water cycling and carbon cycling are the two complementary legs on which climate change marches. The carbon leg has received the most attention. Understanding the carbon cycle mainly in terms of greenhouse gases in the atmosphere—carbon pollution, carbon footprint—leads to a simplified understanding of carbon cycling as a kind of balance, where emitting carbon dioxide into the atmosphere might be balanced or offset by carbon "sequestration" or "drawdown" in trees, soils, or rocks. Instead of the circle of life, carbon becomes a commodity.

Monitoring solar energy

Posted by Peter Donovan 3 months, 1 week ago in policy and framing /

In working on, I continue to wonder what sort of visualizations of energy flow and change over time might be useful to producers.
Some of the usual concerns of applied soil and range science might be summarized as: