The idea of a ‘steady-state economy’, a signal theme in the environmentalist politics of the 1970s with understandable appeal, has been refloated by ‘no growth’ thinkers in France and, most recently, by Herman Daly, in discussion with Benjamin Kunkel in nlr 109. If, as I shall argue here, steady-state economics is an ambiguous construction that actually offers little to egalitarian environmentalists, then on what foundations might an alternative green political economy be built? Neither population nor gdp will be its fundamental metric, but rather land scarcity. This is the concept that emerges—or rather re-emerges—as the most precious resource in any solution that brings the benign possibilities of geo-engineering to bear on the problem of faltering biodiversity and the entailments of an adequate deployment of renewable energy systems. A brisk panorama of the ‘Little Ice Age’ will help make these airy ideas solid.

‘Behold the liquid Thames now frozen o’er / That lately ships of mighty Burthen bore’, may seem to be the opening lines of a poet’s imagined world, but it recalls the actual freezing of London’s great waterway in 1740.footnote¹ Although there are records of the river freezing since the fifteenth century, the frequency of such cold winters increased dramatically during the seventeenth century to about once a decade, often enough for ‘Frost Fairs’ to become a municipal institution. Between London Bridge and Blackfriars Bridge city-dwellers played skittles, baited bears and feasted atop a strangely solid Thames. Other regions too experienced bizarre shifts in climate during the Little Ice Age, an era of widespread cooling from the sixteenth to nineteenth centuries. Icelanders starved when the frozen sea choked off their ports, Alpine Swiss dreaded glaciers expanding to swallow their villages and Manhattanites could walk to Staten Island. The poor harvests of the cool, wet seventeenth century have been held responsible for starving peasants and feeding instability: the Thirty Years’ War, the Fronde, the English Civil War, the decline of the Ming dynasty, and war between Russia and Poland-Lithuania.footnote² Hints of what caused the big chill were to be found in empty towns along the Mississippi.

In 1541 Hernando de Soto travelled along that mighty waterway and encountered a string of densely inhabited, warring settlements: Coosa, Mabila, Pacaha, Chicaza and Cofitachequi. Little is known today about Mississippian society aside from its penchant for moats and mounds; when the next European ventured there in 1682, the region was uninhabited. Most likely, epidemics of Old World origin had broken out between the two expeditions, which was hardly an unusual fate for the time. In 1492, the Americas had teemed with perhaps sixty million inhabitants, a population equaling Europe’s; but the ensuing cataract of genocide, enslavement, war and epidemics reduced the indigenous population to fewer than 6 million by the mid-1600s. A slow demographic recovery began in South America a hundred years later, though mass deaths among First Nations have never truly ceased. But the de-peopling of the New World meant millions of hectares of maize, potato, squash and other crops lay fallow in the seventeenth century. Forest encroached on abandoned fields. Much of the verdant splendour of the New World that awed Europeans was the result of nature’s reconquest of ancient agricultural land. Botanical regrowth on a bi-continental scale sequestered between 17 and 38 gigatonnes of carbon, lowering the store of atmospheric co2 by up to 10 parts per million (ppm). This was a significant share of the total co2—then, 276 ppm; today, 411 ppm—and enough to lower temperatures in the northern hemisphere by 0.6°c.footnote³

The Little Ice Age not only provides insight into the far-reaching ecological repercussions of colonialism, it also hints at the possible democratization of Natural Geo-Engineering—accelerating carbon sequestration through natural processes, as a means of safely ameliorating climate change.footnote⁴ A rival approach, Artificial Geo-Engineering, would put iron filings or limestone into the oceans and aerosols into the skies to reflect sunlight into space. Given the complexity of the global climate system, this tinkering is terribly risky even if increasingly likely. In a future closer than one expects, entrepreneurial scientists and their private corporations will aim to fire aerosols into the atmosphere by means of artillery, high-flying airplanes or balloons. Real-life experiments, despite their illegality, have already been carried out and patents sought.footnote⁵ In contrast with this, giving up territory to nature through democratic choice is a safe way to counteract carbon pollution with unambiguously beneficial environmental multiplier effects.

However, Natural Geo-Engineering requires a lot of land. The mere thought of recreating a bloodless second Little Ice Age to avert a capitalist climatic Armageddon restores the central role of land scarcity to economics after an absence of two centuries. For as it happens, two other goals of the environmental movement—preserving biodiversity and switching to a zero-carbon energy system—also require expanses of continental scope. There are many reasons to forsake nuclear power and fossil fuels and embrace solar- and wind-based energy; but—outside very windy and sunny countries—the latter have extremely low ‘power densities’. Power density describes the relationship between energy produced or consumed relative to a system’s surface area, measurable in watts per square metre. While the richest deposits of fossil fuels can have power densities near 20,000 w/m², even shabby ones like Alberta’s tar sands have a power density of 1,000 w/m². This is why only half of one per cent of us territory is dedicated to the ‘business as usual’ energy system.footnote⁶ In contrast, the highest power density for solar- and wind-powered infrastructure seems to be about 10 w/m², and it is often less than half of that in sub-par locations. A fully renewable system will probably occupy one hundred times more land than a fossil-fuel-powered one. In the case of the us, between 25 and 50 per cent of its territory, and in a cloudy, densely populated country such as the uk, all of the national territory might have to be covered in wind turbines, solar panels and biofuel crops to maintain current levels of energy production. While ongoing tinkering will improve renewable energy systems, they will never have the power densities of fossil fuels.footnote⁷ It is land scarcity, rather than rare natural resources, that is the ultimate limit to economic growth: energy consumption must be cut.

In addition to averting Artificial Geo-Engineering and fossil-fuel use, perhaps the third most pressing goal of the contemporary global environmentalist movement is to forestall the ‘Sixth Extinction’.footnote⁸ The current haemorrhaging of flora and fauna species is occurring at a rate one thousand to ten thousand times faster than normal; a speed comparable only to the last great extinction 66 million years ago, when a huge asteroid careened into the earth and set off the volcanic eruptions of the Deccan Traps.footnote⁹ Even if the explosion of present-day extinctions remains a quiet catastrophe, it will ultimately prove to be no less deadly to life on Earth. The principal cause of extinction is habitat loss, as underlined by the recent work of E. O. Wilson. Though notorious in the Reagan era as the genetic-determinist author of Sociobiology, Wilson is first and foremost a naturalist and conservationist. He estimates that, with a decrease of habitat, the sustainable number of species in it drops by roughly the fourth root of the habitable area. If half the habitat is lost, approximately a tenth of species will disappear, but if 85 per cent is destroyed, then half the species would be extinguished. Humanity is closely tracking this equation’s deadly curve: half of all species are expected to disappear by 2100. The only way to prevent this is to leave enough land for other living beings to flourish, which has led Wilson to call for a utopian programme of creating a ‘half Earth’, where 50 per cent of the world would be left as nature’s domain. Even though much has been lost, he argues that thirty especially rich biomes, ranging from the Brazilian cerrado to the Polish-Belarussian Białowieża Forest, could provide the core of a biodiverse, interconnected mosaic extending over half the globe.footnote¹⁰ Yet, at present only 15 per cent of the world’s land-area has some measure of legal protection, while the fraction of protected areas in the oceans is even smaller—less than 4 per cent.

Arguably, it is a virtue that these three goals—Natural Geo-Engineering, renewable-energy systems and ‘half-earth’ habitat protection—are so land-hungry: constraint clarifies thought, and there are simply very few ways to find sufficient space. Furthermore, a focus on land scarcity also reveals new connections and opportunities; after all, cuts in consumption are needed to provide space for both wind farms and rewilded ecosystems, and the latter require a high degree of biodiversity to function effectively as carbon sinks, yet their ability to be effective carbon sinks depends on a rapid transition to renewable energy systems before climate change irreversibly undermines the integrity of ecosystems. Once land is reclaimed as an integral economic category, and goals of natural preservation and global economic equality are championed, then suddenly a new red–green political economy emerges. What follows, then, explores what such a programme would involve, initially by way of an extended thought-experiment. Extrapolated from the three fundamental aims of Natural Geo-Engineering, biodiversity and renewable-energy systems, the project might take on any number of mantles: ‘egalitarian eco-austerity’, ‘eco-socialism’ or, borrowing from Wilson, ‘half-earth economics’, to emphasize both the necessary scale of ambition and its crucial spatial aspect. First, though, a critical look at some of the most salient alternatives: the ‘steady state’ of Daly’s ecological economics and the possibilities for technological solutions.