From Popovers to Popunders: The Kind of Decarbonization That Can Succeed

Stan Cox and Priti Gulati Cox

From the field and kitchen of discomfort food

So much carbon dioxide has now accumulated in the atmosphere that it’s no longer possible to prevent a dangerous rise in global temperatures through purely technological means. In other words, it’s too late to prevent catastrophic ecological damage and human suffering simply through building more renewable electric capacity and improving energy efficiency. 

Humanity can keep atmospheric carbon dioxide concentration within tolerable limits, but only if we do not aim to sustain today’s profligate material production and wealth accumulation, let alone continue increasing production. Instead, we must deeply reduce production and thereby shrink energy and material use.

In contrast, conventional green-growth thinking starts with “decarbonizing” the economy (by building more and more wind farms, solar parks, electric vehicles, energy-efficient appliances, etc.) in order to reduce carbon emissions per dollar of wealth generated, thereby making it possible, in theory, to sustain and even increase material production without increasing the rate of carbon emissions. But in practice, progress in decarbonization gets swamped out by growth in material production.

The energy supply required to meet current and expanding global demand can never be fully decarbonized. That’s because solar irradiation and wind energy, thinly and intermittently dispersed as they are, cannot substitute for the bonanza of highly concentrated, portable, storable energy from fossil fuels that we’ve enjoyed century and a half. Even if that were possible, building industrial parks across vast swaths of the Earth’s surface to harvest that energy would result in irreparable ecological damage. 

Policy should not start with the assumption that growth can be increasingly “decarbonized” by building more and more wind and solar capacity and improving energy efficiency indefinitely into the future; in any case, that is barred by non-repealable physical laws. Policy should instead aim to reduce total carbon emissions by reducing total material production. 

A downsizing economy will require a smaller and smaller energy supply; in time, energy demand will become modest enough that it can be fully satisfied with renewable sources, sustainably deployed. Fossil carbon emissions will be reduced to zero, while, if goods and services are distributed equitably, the reduced material output can be made sufficient to meet society’s material needs.

It’s not just us saying this. A highly respected international group of researchers recently evaluated the various climate-action scenarios laid out by the international climate-science body IPCC. They weighed each of the scenarios with regard to their relative ability to limit greenhouse warming to 1.5º C—a threshold once thought safe and now viewed as too hot but probably the best we can hope for at this point. 

Only a strategy that reverses growth in material production, concluded the researchers , can “substantially minimize many key risks for feasibility and sustainability compared with established, technology-driven pathways.” They showed that all pro-growth approaches will probably fail to keep up with growing demand for renewable energy, fail to sustain increases in energy efficiency, and fail to avoid extensive ecological damage. Could the world’s policymakers decide to be optimistic, roll the dice, and pursue green growth anyway, to see if humanity can make it work? They could, but by the time we find out that sure enough, green growth is leading to collapse, it will be too late to turn back.  


These dozen sourdough popovers can serve as a metaphor for reducing material production steadily over time, until it reaches a sustainable “steady state”. The first eight rolls in the lineup(right to left) were made with batter containing 1.5 percent ground charcoal (a stand-in for fossil carbon). The four at the end were made from the same batter, but before the charcoal was mixed in. 

 If we follow the implications of IPCC’s report Global Warming of 1.5º C or the UN’s latest Emissions Gap Report, then greenhouse emissions must be reduced very steeply within the next fifteen years. Accordingly, viewing this lineup as a time series, each popover would represent a period of about two years.

The first popover was made with an excess of batter, relative to the standard recipe. Each of the seven succeeding black popovers contains less batter, and therefore less total carbon, than the one before.
The last four, and smallest, popovers (let’s call them “popunders”) are of equal size and free of charcoal, with somewhat concave tops. They represent the continuation of production at a lower, now constant, rate—a rate that can be supported entirely by non-fossil energy sources.

To instead portray a green-growth scenario in this way would have looked very different. Starting with an almost full cup and increasing the amount of batter used for each successive popover not only would have resulted in a messy culinary catastrophe; it would have also required that carbon be added to all dozen rolls, because each would represent an economy far too large to be “powered” by non-fossil energy. Even with increased technological efficiency, which could be illustrated by gradually reducing the concentration of charcoal in the batter as the quantity of batter increased, the total quantity of carbon would not diminish and would probably increase, as over time, exponential growth outstripped diminishing returns on efficiency.  

Assorted Sourdough Popovers and Popunders

113g sourdough starter (discard or fed)

3 large eggs 

227g slightly warm milk

5g salt

120g all-purpose flour

8g powdered charcoal

Place a muffin pan in a 450°F preheating oven. Meanwhile, combine the starter, eggs, salt and milk. Add the flour and mix till just combined. Don’t over-mix. Weigh out and divide 60g of the batter into four small bowls—15g into each. Add the charcoal to the remaining batter and lightly mix it in till just combined. Once the oven is preheated, take the muffin pan out and spray generously with oil. Orienting the pan with four cups across and three down, start at the top left cup, pour the carbon batter right to the top with a little spilling over the rim. Then pour each of the 15g charcoal-free batter portions into the second, fourth, sixth and eighth cups (counting left to right and top to bottom). Pour the remaining charcoal batter into each of the remaining cups, measuring by eye, and reducing the amount of batter in each successive cup. There will then be the first cup, which is slightly overflowing; the third cup almost full to the rim; the fifth cup a little farther below the rim; the seventh cup about three quarters full; and so on, until the twelfth cup has slightly more than the cups that have 15g. Now all the 12 cups have batter in them — eight with the charcoal batter and four without. Place the pan in the oven and bake at 450°F for the first 15 minutes. Then turn the temperature down to 375°F and bake for another 18 minutes or so.  

discomfort food compost. Includes last week’s recipe: Sourdough Cinnamon Raisin Gritty-Swirl Bread

The Assorted Sourdough Popovers and Popunders recipe is modeled after our favorite popovers recipe by King Arthur.

The Gritty Reality of Solar Power

Priti Gulati Cox and Stan Cox

Time is fast running out. The world’s affluent nations, with their abundant greenhouse emissions, have to finally drag themselves across the starting line and begin phasing out fossil fuels at the accelerated pace that the climate emergency demands. And if they can manage to do that, they clearly will need to quickly build up wind and solar electric capacity to partially compensate for the shrinkage of oil, gas, and coal supplies while addressing the prospect of energy shortages by securing production of essential goods and services for everyone

Unfortunately, mainstream climate visions have strayed far from confronting the existential necessity to banish fossil fuels. They simply assume that the buildup of renewable energy will automatically chase fossil fuels out of our lives and fully replace them, watt for watt and Btu for Btu. These visions hold out the promise of a world in which a pristine, Sun-powered economy fulfills any and all of our material desires far into the future—a delicious, guilt-free cornucopia. But the green-growth promise is a mirage, and the realities of a high-production, wind- and solar-powered world will be much less tasty. 

Any industrial installation, including solar and wind farms, profoundly disrupts the landscape on which it sits. If it were possible to fully satisfy the bloated energy appetites of affluent nation by covering hundreds of millions or billions of acres of the Earth’s surface with power-harvesting hardware, the result would be irreparable ecological damage. 

Meanwhile, the manufacturing booms to supply such a sprawling proliferation of solar arrays, wind power plants, battery-backed electric grids, electric-vehicle fleets, and other hardware would require outrageously large inputs of metals such as lithium, cobalt, silver, copper, aluminum, nickel, iron, and a host of exotic rare earth elements. 

The global rush to mine these metallic ores is on, and the dire ecological and humanitarian consequences that always follow have spurred growing concern. But the mining and processing of a much more mundane, often overlooked mineral resource—sand—is also critical to renewable-energy expansion and terrible for the Earth and its human and non-human inhabitants.


The solar-energy industry, like digital electronics, is built on a foundation of silicon. Number 14 in the periodic table of the elements, silicon is abundant in the Earth’s crust. But the industries that mine and process sand, quartzite rock, and other sources of silicon dioxide to obtain pure silicon for use in solar equipment belie the popular, sunny green conception of an alternative-energy economy.   

Manufacturing a solar panel’s photovoltaic cells requires very high-quality silicon. Before the rapid growth in solar panel production took off, manufacturers could satisfy their need for the element by recycling flawed computer chips cast off by computer makers. As the solar industry’s demand for silicon exploded, however, they had to start producing their own supplies, by extracting pure silicon from sand and other minerals. 

Sand headed for solar uses must go through energy-intensive, and often toxic, processing. It begins with heating sand or quartzite rock, along with a carbon source like wood chips or charcoal, to 3,500 degrees F, resulting in a chemical reaction that produces metallurgical grade silicon. Both the energy for heating and the combustion of the carbon sources contribute to greenhouse warming. Producing one pound of this form of silicon generates an estimate pound and a half of carbon dioxide emissions.

Further refining the metallurgical grade silicon, in order to achieve the 99.9999% purity required in photovoltaic wafers, requires additional heating and chemical treatment. That process produces four tons of the highly toxic compound silicon tetrachloride for every ton of the desired product, polysilicon. And the ultrathin wafers that are sliced from polysilicon blocks for use in photovoltaic cells must be cleaned and smoothed, typically with extremely dangerous hydrofluoric acid.  

Sand’s central role in solar energy and its ecological impacts doesn’t end there. The glass sheet that covers and protects a solar panel must have higher transparency than ordinary window glass, to maximize light capture. That requires starting with sand that carries minimal impurities. Most desirable is sand mined from river beds—causing severe disruption of local and downstream ecosystems. Then even the highest quality sand must be deep-cleaned, which involves further energy- and chemical- intensive industrial techniques

And there’s more to solar energy’s footprint than silicon—for example, the panels’ requirements for large quantities of pure silver and the exploding demand for aluminum frames and supports. In sum, the broad ecological impacts of manufacturing, installing, operating, and, finally dismantling and disposing of a solar installation at the end of its life span include global warming potential (mostly from the silicon processing), ozone depletion, eutrophication of water bodies, and toxicity to humans and non-humans. The lifetime energy consumed is equivalent to a year and a half to three years of the solar farm’s energy output. And photovoltaic panels last only 25 years on average. Their power output declines year by year, and then they have to be replaced—and the cycle of ecological damage begins again.

The chief reason for recent, much-touted decreases in the cost of solar-generated electricity is the increasing share of solar component manufacturing being performed in China, with its low-wage labor force and cheap coal-fired power supply. A whopping 80% of the world’s solar-grade polysilicon is produced in China, with 45% in the northwestern province of Xinjiang alone. 

Recent news reports show how China’s solar-energy industry is having dire consequences not only for the environment but also for human rights and well-being. In Xinjiang, members of the persecuted Uyghur ethnic minority make up most of the labor force in the hazardous quartz mining and polysilicon manufacturing industries. And most of the Uyghurs are employed through the government’s so-called “surplus labor” and “labor transfer” programs. 

A 2021 investigative report from Sheffield Hallam University in the UK concluded, based on strong evidence, that these initiatives “are deployed in the Uyghur Region within an environment of unprecedented coercion, undergirded by the constant threat of re-education and internment” and are “tantamount to forcible transfer of populations and enslavement.” The researchers found that the supply chains of at least ninety solar energy companies worldwide included polysilicon produced by this forced-labor system.


We must be pragmatic, of course. If the world is going to start leaving oil, gas, and coal in the ground forever, an expansion of wind and solar energy capacity will indeed be necessary. (Some industry insiders turn to a reliable if rusty old saw in advising us that to make a “renewable omelet”, you have to break—and “melt”—some ecological eggs.) 

New energy development, however, must be pursued judiciously, minimizing ecological impacts and aiming for a much more modest energy capacity and less industrial production than we have today. Affluent societies worldwide will need to adapt to life with a much smaller and much more equitably shared energy supply; otherwise, we will keep extending our plunder of the Earth, jogging along on the same old ecologically destructive industrial treadmill.

Both of these sourdough cinnamon-swirl loaves above look yummy to the naked eye. They are very similar, but only one is edible. Both include the ingredients typically used in this type of bread. And, yes, both recipes, in accord with physical and biological reality, require that eggs be broken before being added to the dough. But while one of the loaves is—like the mainstream renewable-energy utopia—tasty and satisfying, the other is more realistic: its sweet center “swirl” contains a big dose of sand, rendering the loaf as absurd and indigestible as the cornucopian dream of unlimited “clean” energy.


Sourdough Cinnamon Raisin Gritty-Swirl Bread

From the field and kitchen of discomfort food

(makes one loaf)

for the dough:

113g sourdough starter (discard or fed)

180g all-purpose flour

180g whole wheat flour

2½ tsp yeast

1 tbsp clean, white, fine-grained sand

8g salt

1 large egg

71g melted (or room temp) butter

152g lukewarm water

for the filling:

50g clean, white, fine-grained sand

1½ tsp cinnamon

2 tsp perennial sorghum flour

1 large egg, beaten

74g raisins 

(Modification for Sourdough Cinnamon Raisin Sweet-Swirl Bread:

Use the above ingredients, but substitute sugar for sand in the dough and filling.)

Combine the dough ingredients and [‘no kneed’] knead (adding a little flour if needed) to form a smooth doughball. Place the doughball in a lightly greased container and let it rise, covered, for 1½ to 2 hours till doubled. Meanwhile, make the filling by mixing the sand with the cinnamon and sorghum flour. Lightly grease a 9” x 5” loaf pan and set aside. Transfer the risen doughball to a lightly greased surface and roll into a 6” x 20” rectangle. Leaving about a 1” bare strip on one of the 6” edges, brush the remaining 19” of the dough with the beaten egg and sprinkle it evenly with the filling and raisins. Starting with the 6” edge that has the filling, roll the dough into a log till you reach the bare strip and pinch it closed. Pinch-close the two ends as well. With the seam side facing down, transfer the log to the loaf pan and let it rise, covered, for about an hour. Preheat the oven to 350° F (or 3500° for the “Gritty-Swirl” version, if you want to try making polysilicon), and bake for 45 minutes. To avoid over-browning the top, you could place a piece of foil on top of the loaf after the first 20 minutes of baking.

The only ingredient that tells the two loaves apart is the clove in the center of the sweet-swirl version.

Stan Cox is on the editorial board of Green Social Thought and the author of The Green New Deal and Beyond (2020) and The Path to a Livable Future: Forging a New Politics to Fight Climate Change, Racism, and the Next Pandemic (November 2021).

These recipes are modeled after our favorite swirl bread recipe: King Arthur’s Cinnamon Raisin Sourdough Bread.