Science, Society, Sustainability
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ISIS Report 31/03/10

Greening China

Sustainable Agriculture, Green Energies and the Circular Economy

Sustainable organic agriculture could cut China’s greenhouse emissions and save fossil fuel use by more than 40 percent; decentralised, distributed green energies would do the rest for the circular economy Dr. Mae-Wan Ho

Invited contribution to the International Workshop on Sustainable Food and Agriculture, Remin University, Beijing 13-15 March 2010

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National surveys put food and agriculture under the spotlight

Two important national surveys in China have put food and agriculture under the spotlight. The results of its first national pollution census revealed that China’s intensive, high input agriculture is a worse polluter than its burgeoning industry. Wastewater runoff from farms accounted for 13.2 Mt of pollutants, more than one-third of the total 30.3 Mt discharged into water in 2007. Wang Yanliang of the ministry of agriculture acknowledged the high contributions from intensive livestock farming and excessive use of fertilizers and pesticides in the fields. The Chinese government is likely to more than double its investment to protect the environment in its next five-year plan [1] China's Pollution Census Triggers Green Five-Year Plan (SiS 46).

A second study led by Zhang Fu Suo at the China Agricultural University in Beijing revealed significant acidification of soils in China’s major croplands since the 1980s as the result of the overuse of nitrogen fertilizers [2] China’s Soils Ruined by Overuse of Chemical Fertilizers (SiS 46). Acidification of soils reduces productivity and can lead to aluminium and manganese toxicities. It is traditionally treated by liming, which will add considerably to production costs at a time when the price of chemical fertilizers has surged along with the price of fuel, and farmers’ income has plummeted despite rising government subsidies [3]. This is a stern reminder that intensive chemical agriculture depends heavily on fossil fuels, and leaves a big carbon footprint (see later).

The Chinese government announced it would spend more than 818 billion Yuan (US$119.8 billion) towards agriculture during 2010, an increase of over 93 billion Yuan on the previous year [4]. China’s agriculture still contributes over 11 percent to the nation’s GDP and employs 40.8 percent of the population [5, 6]

China’s food security is precarious, as it uses only 7 percent of the world’s land to feed 22 percent of world population [1]. Wen Tiejun, dean of the school of agriculture and rural development at Renmin University said China does not have to rely on chemical farming, and the government needs to foster low pollution agriculture.

Sustainable, low pollution agriculture is the heart of the green economy for China as for the rest of the world, and it is urgently needed if we are to survive the global multiple crises of food, fuel, and finance as extreme weather associated with climate change is already exacting its terrible toll in lives and lost property, and predicted to slash agricultural production [7] Sustainable Agriculture & Green Energy Economy, ISIS lecture)

Sustainable agriculture and green energies go together

ISIS and TWN have jointly produced a comprehensive report [8] Food Futures Now: *Organic *Sustainable *Fossil Fuel Free  in 2008, on how organic agriculture and localized food and energy systems can provide food and fuel security, mitigating and adapting to climate change, and freeing us from fossil fuel use altogether. The report is a unique combination of scientific analyses, case studies on farmer-led research, and especially farmers’ own experiences and innovations that often confound academic scientists wedded to outmoded and obsolete theories.

The companion volume released towards the end of 2009 [8] Green Energies - 100% Renewable by 2050 (ISIS/TWN publication), documents that the world is already shifting to renewable energies, and 100 percent green power is realisable by 2050, making use of available and rapidly improving technologies. The key is decentralised distributed generation that offers the maximum flexibility to take advantage of technological improvements, giving people autonomy and independence from obsolete and wasteful centralised power plants. Germany has demonstrated how to implement decentralised distributed renewable energies rapidly within the past five years, and is on course to become 100 percent renewable by 2050, according to its renewable energy industry sector.

Renewable energy is inexhaustible and does not run out. It is free once you’ve installed the equipment to capture it, and companies can’t meter it or cut you off. Most importantly, it is available to all, so no need to fight over it!

To be renewable is not enough, it must be ‘green’.’Green’ energies are renewable; environmentally friendly, healthy, safe, non-polluting and sustainable. That rules out nuclear, carbon capture and storage, biofuels, and its latest incarnation biochar [9].  Biofuels and biochar make clear why we need to think about food and energy together. Turning food crops into biofuels has been responsible for the steep food price increases that created hundreds of millions more hungry people. The push for biofuels in the US and Europe has resulted in accelerated deforestation, land conflicts and “land grab” in poor countries [7]. Tens of millions of hectares of African ‘spare land’ are being bought or long-leased by companies from rich countries, not just to grow bio-energy crops, but to grow food for export to feed people in their own countries. Bioenergy crops inevitably compete for land that could be growing food. I shall show later how the potential for energy from waste is more than enough to satisfy our needs.

This brings me to how ‘sustainable’ should be defined. It is to endure for hundreds or thousands of years like natural ecosystems, thanks to a natural circular economy of reciprocity and cooperation that renews and regenerates the whole (more later). For human beings, it is to use natural resources responsibly and equitably, to meet the needs of all in the present without compromising the needs of future generations. The world’s potential of green energies is truly enormous. Wind power has the potential to supply the world’s electricity needs 40 times or 5 times all its energy needs. Solar panels at a modest 10 percent efficiency covering 0.1 percent of the world’s land surface could provide all our energy needs. Methane from anaerobic digestion of organic wastes can save over 50 percent of our energy consumption, in combination with local organic food production. And there are many further possibilities, according to local resources: microhydroelectric, geothermal, tidal reef, deep water air-conditioning (but not on large scale), saline agriculture, and more.

Our enquiry into green energies concludes that the world can be 100 percent renewable by 2050.

·A variety of truly green and affordable options already exist, and more innovations are on the way.

·Policies that promote innovations and stimulate internal market for decentralised, distributed generation are key

·Global cooperation is crucial; developed nations have an international obligation to support developing nations to fight global warming with renewable energies.

Sustainable agriculture is the first fuel for the green economy

Sustainable agriculture produces food, which is fuel for human beings, without which there can be no economy, green or otherwise. It also satisfies our other basic needs such as fibres for clothing, wood for construction material, medicinal herbs, biomass for fuel, paper, etc. In extracting these goods from nature, we need to treat her as a cherished friend, which is where sustainable agriculture begins and ends. In return, nature pays us back handsomely

Sustainable agriculture saves energy and carbon emissions, prevents pollution of the environment, yields more than chemical agriculture, produces healthier food for the nation, results in more profit for farmers, creates more jobs, and when integrated with local green energies generation, forms the green circular economy we need to replace the unsustainable economic model. You can find the details in our green book [8]. I shall highlight some recent research and what it could mean for China to adopt sustainable organic agriculture. China is in a good position to set an example for the rest of the world.

More productive

It is a common myth that organic agriculture yields less than conventional chemically fertilized agriculture. A team of scientists led by Catherine Badgley at the University of Michigan in the United States refuted this common myth in a study that analysed 293 examples worldwide in which yields of organic production were compared with conventional chemical production to give an O/C (organic/conventional) ratio [10, 11]. The O/C ratios for 10 or the 11 major food categories of plant and animal products were greater than one, the exception was ‘meat and offal’, where the ratio was 0.998. The overall average was 1.321. In other words, organic agriculture is on average 32.1 percent more productive than conventional agriculture. Furthermore, green manure alone provides more than enough nitrogen, amounting to 171 percent of synthetic N fertilizer used currently.

Similarly, a seven year-long field experiment carried out with farmers in Ethiopia found that crops fed with organic compost out-yielded chemically-fertilized crops, the O/C ratio averaged over the four most commonly grown grain crops was 1.34 [12] (see Table 1). Thus, organic production again increased yields by about 30 percent.

Table 1  Average yields of four major crops over seven years and O/C ratios

CropNo amendmentChemicalOrganicO/C

Kathleen Delate of Iowa State University and Cynthia Cambardella of the US Department of Agriculture assessed the performance of farms switching from conventional to certified organic grain production [13, 14]. The experiment lasted four years: three years of transition to organic and first year of certified organic growth. They found that over the four years, corn yield in the organic system averaged 91.8 percent of conventional corn yield, and soybean in the organic system averaged 99.6 percent of conventional soybean yield. The small reductions in yields were due to bigger reductions during the first and second years of transition. By the third year, there were no significant differences in yields, but by the fourth year, both organic corn and soybean yields exceeded conventional yields. In the initial year of transition, an economic advantage could be gained by planting legume hay crops or crops with a low nitrogen demand in fields with low productivity, in order to increase fertility for the following corn crop. In the second year, yield differences were mitigated by rotation and compost application, providing sufficient nutrients for the organic grain crop. The importance of a soil-building cover crop, or legume grass mixture such as the oat-alfalfa mixture was apparent in the fourth year, when organic corn and soybean out-yielded the conventional crops.

Delate has been maintaining the 17 acre Long Term Agroecological Research site in Greenfield, Iowa, for the past 12 years, experimenting on four different rotation systems and comparing organic and conventional yields [15]. In the fourth year of the latest experiment, organic corn yields averaged across all rotations was 130 bushels per acre compared with the conventional corn yield of 112 bushels per acre. Organic soybean yields averaged 45 bushels/acre, exceeding the conventional yield of 40 bushels/acre. Over the 12 years of the experiment, the average corn yields are 171 bu/ac and 163 bu/ac for organic and conventional respectively. The 12 year average yields for organic and conventional soybeans are identical at 47 bu/ac.

More income for farmers

As demonstrated by Delate [15], the average production costs during the first two years of organic transition were lower than in the conventional production by $50/ac, chiefly due to the saving on chemical fertilizers and pesticides. On average, the organic crops return two times as much earnings over the four years. There is plenty of evidence that organic farmers earn more than conventional farmers all over the world [8].

More resistance and resilience

An important advantage of organic cropping systems is that they are more resistant to physical stresses such as floods and droughts, and biotic stresses such as pests and diseases. Moreover, they are more resilient, in that they recover faster from stresses. These qualities make them perfect for adapting to climate change thereby improving food security.

A study carried out in Nicaragua after Hurricane Mitch found that organic, agro-ecologically managed farms were more resistant to damage. They had more topsoil and vegetation, less erosion and economic losses compared to plots on conventional farms [16].

A long-term field trial at Rodale Institute in Kutztown, Pennsylvania involving 6.1 ha compared three different cropping systems: conventional, animal manure and legume-based organic, and legume-based organic. The results over 13 years showed that organic yields were not different from conventional, except in drought years, when organic yields were 28 to 34 percent higher than conventional [17, 18]. Organic soils holds more water, and water percolating through into the soil was 15 to 20 percent greater in organic soils.

Saving energy

It is estimated that a third or more of all energy used in US agriculture goes to commercial fertilizer and pesticide production, the most energy intensive of all farm inputs [19]. When conventional and organic cropping systems were compared for energy use, it becomes clear that the major energy saving comes from chemical fertilizers. For example, the Glenlea long-term study of rotation cropping at the University of Manitoba found that organic agriculture without chemical fertilizer and herbicide required 35.4 and 45 percent of the energy inputs of the conventional counterparts [20], with fertilizer inputs accounting for 51 and 43.4 percent of the energy savings. Similar results have been obtained in other studies [8].

It takes approximately 80 MJ of fossil fuel energy to make and transport 1 kg of fertilizer N to the farm [21]. China used 32.6 Mt fertilizer N in 2007 [2], which amounted to 2.61 EJ of energy (3.6 percent of national energy consumption of 72.2 EJ in 2006), or 57.9 Mt of oil (14.6 percent of national oil consumption) [6]. China imports both oil and coal. I have not included the energetic costs of pesticides, which could be 10 to 20 percent more.

Saving the climate

Phasing out nitrogen fertilizers saves an equivalent of 57.9 Mt of oil, emitting 179.5 Mt CO2 (2.38 percent national emissions). Moreover, using organic as opposed to chemical fertilizers reduced N2O emissions 22 percent in a rice-duck system in south China [22]. N2O has a global warming potential of about 300 compared with CO2. China’s N2O constituted 8 percent of its 7.527 Gt national greenhouse gas emissions in 2005, of which 70 percent is attributable to agriculture [23]. A 22 percent reduction in N2O on switching from chemical to organic fertilizer would reduce 1.23 percent of national greenhouse emissions, i.e., 92.7 Mt CO2e. So phasing out N fertilizers would result in a total saving of 272.2 Mt CO2e, or 3.62 percent of national emissions.

The biggest savings are due to organic soils, which sequester a lot of carbon. A long term study at the Rodale Institute in Kutztown, Pennsylvania, USA, found that organic soils sequester on average 4.114 tonnes of CO2/ha/y [24], while soils in conventionally managed crops did not increase in carbon content.  China has 166 million ha of crop lands in 2007 [25]. If all the croplands were converted to organic, the amount of carbon sequestered would be 682.9 Mt of CO2, or 9.07 percent of national emissions.  Thus, a total of 917.9 Mt CO2 would be mitigated each year, representing 12.19 percent of national emissions.

China has a further 66 million ha of average- and low-yielding farmlands, 4.4 million ha of wasteland, and 400 million ha of plains and grass-covered hillsides, 5.44 million ha of usable fresh water areas and 2 million ha of coastal tidal flat areas that are not yet fully explored for agriculture, as pointed out in an Asian Development Bank report [26]. Sue Edwards of the Institute of Sustainable Development based in Addis Ababa describes how she and her colleagues have successfully rehabilitating degraded land into fertile croplands [12], which may be relevant to how China’s additional land could be explored for agriculture. Permanent pastures, properly managed, are ideal for raising livestock sustainably, while sequestering huge amounts of carbon in the deep roots of the perennial grasses [27] Organic Agriculture and Localized Food & Energy Systems for Mitigating Climate Change, SiS 40).

Anaerobic digestion

China has been supporting anaerobic digestion for industry and rural households since 2003. However, its use on farms is still quite limited. Dong Renjie and colleagues at the China Agricultural University of Beijing have drawn attention to the increasing quantities of livestock wastes from agriculture, which emit lots of greenhouse gases, especially CH4, amounting to 800 Mt a year. Half of that could be mitigated, however, if the livestock wastes were subjected to anaerobic digestion [28]. At the same time, it would yield 13.9 Mt of methane containing 0.774EJ of energy to use as fuel and mitigate an additional 53.5 Mt CO2e emissions in substituting for fossil fuels.

Anaerobic digestion could include human manure (traditionally used as crop fertilizer in China). Agriculture is estimated to employ 40.8 percent of the population [5, 6]. A study by NASA to prepare humans for space-travel indicates that the average human produces about 100 g of solid manure containing 25 g of volatile solids (VS), plus about 2 litres of urine containing another 25 g VS and 6 g of toilet paper, making 56 g VS [29]. Anaerobic digestion of the wastes from 40.8 percent of 1.4 billion (571 million) would yield 11.671 Mt VS a year, resulting in 2.0168 Mt of methane or 0.112 EJ energy.

In addition, China has unused primary agricultural and forestry residues estimated at  263.285 Mt/y in dry mass, and secondary agricultural and forestry residues of 47.889 Mt/y [25]. Plant biomass has a higher yield of methane, up to 0.266 kg per kg total solid [30]. Thus, the total biomass from unused primary and secondary agricultural and forestry residues could generate 82.756 Mt of methane or 4.6 EJ of energy. Incidentally, anaerobic digestion of potato wastes achieved a 95 percent recovery of theoretical energy content, much higher than fermentation into ethanol [31]. The proposal to convert biomass wastes into second generation biofuels such as cellulosic ethanol [16] should be carefully reviewed and compared with anaerobic digestion, a much cheaper and mature technology that can benefit farmers the most, especially those in developing countries [7].

According to Li Jingming, Technology Development Centre, Ministry of Agriculture, who spoke on Sunday 14 March [32], the Chinese government is aiming for 40 million household anaerobic digesters and 4 000 large digesters that will produce a total of 19 billion m3 methane by 2010. By 2020, there will be 80 million household digesters and 8 000 large digesters producing 44 billion m3 methane.

The advantages of anaerobic digestion are well-known (see Box 1 [33]). The enormous energy potential from wastes in the form of methane coupled with its overriding environmental and agronomic benefits stand in stark contrast to the many harmful consequences of producing biofuels from energy crops, first or second generation.

Box 1

Advantages of anaerobic digestion of organic wastes

·Produces an abundant, readily available source of bioenergy that does not take land away from growing food

·Takes a wide range of feedstock, including livestock and human manure, crop and food residues,  paper, bakery and brewery wastes, slaughterhouse wastes, garden trimmings, etc, and the yields of methane generally better in mixed waste streams

·Biogas methane is a clean cooking fuel, especially compared to firewood (and dung)

·Methane can be used as fuel for mobile vehicles or for combined heat and power generation

·Methane-driven cars are currently the cleanest vehicles on the road by far

·Biogas methane is a renewable and carbon mitigating fuel (more than carbon neutral); it saves on carbon emission twice over, by preventing the escape of methane and nitrous oxide into the atmosphere and by substituting for fossil fuel

·Conserves plant nutrients such as nitrogen and phosphorous for soil productivity

·Produces a superb fertilizer for crops as by-product

·Prevents pollution of ground water, soil, and air

·Improves food and farm hygiene, removing 90 percent or more of harmful chemicals and bacteria

·Recycles wastes efficiently into food and energy resources for the circular economy

A combination of organic agriculture and anaerobic digestion in China has the potential to mitigate at least 23 percent of national greenhouse gas emissions and save 11.3 percent of energy consumption (see Table 2). In other words, sustainable agriculture with anaerobic digestion saves more than the agricultural sectors’ emissions and energy use, and contributes to other sectors of the green economy. Most importantly, it prevents up to 13.2 Mt pollutants leaching into the nation’s water supply.

CO2e savings(% National)Energy savings(% National)
Organic agriculture
N fertilizers saving179.5 Mt(2.38%)2.608 EJ(3.61%)
N2O prevented92.7 Mt(1.23%)
Carbon sequestration682.9 Mt(9.07%)
Total for org. agri.955.1 Mt(12.69%)2.608 EJ(3.61%)
Anaerobic digestion
Livestock manure ghg saving400.0 Mt(5.31%)
methane produced53.5 Mt(0.71%)0.774 EJ(1.07%)
Hum manure methane7.7 Mt(0.10%)0.112 EJ(0.16%)
Ag.& for. res. methane317.8 Mt(4.22%)4.600 EJ(6.37%)
Total for AD779.0 Mt(10.35%)5.486 EJ(7.60%)
Total overall734.1 Mt(23.04%)8.166 EJ(11.31%)

Implementing the circular economy with green energies and sustainable agriculture

China has been promoting the circular or recycling economy for some time, and enacted the Circular Economy Promotion Law in 2008 [32]. At the 4th China International Recycling Economy Summit in October 2009, Chinese experts called on the government to promote circular economy to boost China’s economic recovery [34]. Yang Boling, former president of the Chinese Academy of Sciences, urged government at all levels to make plans to advance the circular economy and improve controls on energy use and pollution. But he said it would be difficult during the financial crisis.

Actually, it is not difficult at all. When you transform the dominant linear monoculture model to the circular model, you turn output into input again. Switching to a circular green economy means more efficient use of energy and resources, hence providing quick profit in energy savings.

Anaerobic digestion is obviously a key technology in the recycling economy, as it recycles organic wastes efficiently into food and energy resources. This is most clearly seen in the eco-farm concept introduced by Dr. Xue Dayuan, Chief Scientist of Environmental Protection of Biodiversity [35]. I call it the Dream Farm [36] - formalized from the scheme of waste-management engineer George Chan - an abundantly productive farm with diverse crops, livestock and fish ponds, built around anaerobic digestion of livestock and other organic wastes; the biogas generated satisfying energy needs.

George Chan, in turn, learned about circular economy from the Chinese peasants who perfected the dyke-pond system of Pearl River Delta [37]. The Chinese peasants, like many traditional indigenous farmers, know that nature runs on the circular economy, which is why it is sustainable. There are many dyke-pond systems. In one version, pigs, elephant grass, mulberry and silkworms are raised on the dykes, the wastes and elephant grass go to feed up to 5 species of carp in the ponds. The pond water is used to ‘fertigate’ the crops on the dykes, and pond mud used as additional fertilizer. The system was so productive that it supported 17 people per ha in its heyday. This is the kind of productivity that China needs for its limited land.

I have proposed a Dream Farm 2 [33] (see Fig. 1) which, in addition to anaerobic digestion, explicitly incorporates green energies at small to micro-scale (and include permanent pastures and woodlands). This mix of energies not only ensures a reliable supply, but can reduce energy use by at least 30 percent through exploiting ‘waste’ heat from power generation, and preventing energy loss in long distance distribution and transmission.

Figure 1 Dream Farm 2

The diagram is colour-coded. Pink is for energy, green for agricultural produce, blue is for water conservation and flood control, black is waste in the ordinary sense of the word, which soon gets converted into food and energy resources. Purple is for education and research into new science and technologies. The advantages of Dream Farm 2 are presented in Box 2.

Box 2

The advantages of Dream Farm 2

·Thermodynamically optimized for efficient use of resources and productivity

·Energy use at the point of production improves efficiency by up to 60 percent

·Runs entirely on renewable energies without fossil fuels, hence saving up to 100 percent of carbon emissions

·Increases sequestration of carbon in soil and in standing biomass

·Reduces wastes and environmental pollution to a minimum

·Conserves and purifies water and controls flooding

·Produces a diversity of crops, livestock and fish in abundance

·Fresh and nutritious food free from agrochemicals produced and consumed locally for maximum health benefits

·Provides employment opportuni8ties for the local community

·Demonstrates circular zero-entropy economy at work

·Assembles in one showcase all the relevant technologies that can deliver sustainable food and energy and a profitable zero-carbon green economy

·Provides an incubator for new energy and food technologies

·Provides hands-on education and research opportunities at all levels from infants to university students and beyond

·Promotes similar farms all over the world

Approximately 57 percent of China’s carbon emissions come from the energy sector, according to the energy mix given by the International Energy Agency [25]. An efficiency saving of 30 percent would mean a reduction of 17.1 percent in carbon emissions. The green potential of Dream Farm 2 is given in Table 3. As can be seen, Dream Farm 2, if generally adopted in China, would mitigate 40 percent of greenhouse emissions, and save 41 percent of energy consumption, only counting anaerobic digestion. So, with the addition of solar, wind or microhydroelectric as appropriate, such farms could compensate, in the best case scenario, for the carbon emissions and energy consumption of the entire nation. The key to the success of Dream Farm 2 is local production and local consumption for both food and energy.

Table3  Green potential of Dream Farm 2

CO2e savings(% National)Energy savings(% National)
Organic agriculture955.1 Mt(12.69%)2.608 EJ(3.61%)
Anaerobic digestion779.0 Mt(10.35%)5.486 EJ(7.60%)
Energy savings local gen.1 287.1 Mt(17.10%)21.660 EJ(30.00%)
Total2 983.6 Mt(40.14%)32.363 EJ(41.21%)

Circular economy of the organism and sustainable systems

Finally, circular economy describes how organisms transform energy and materials most efficiently.  My book [38] The Rainbow and the Worm, The Physics of Organisms  was first published in 1993, and is now in its third enlarged edition.

When you transform the linear into circular, you turn output into input again, thus, you end up conserving energy and resources and the system renews itself (Figure 2).

Figure 2   From linear to circular economy

In the ideal, the organism’s circular economy satisfies the zero-entropy condition (Fig. 3), entropy being made up of dissipated or waste energy.

Figure 3   The zero-entropy model of organisms and sustainable systems

The zero-entropy ideal depends on coupled cycles of activities at every scale, activities that generate energy are directly linked to those requiring energy; thereby minimising the dissipation of energy and materials, and even the wastes exported to the environment is minimum, which makes sense, as the organism depends on the environment for input. Sustainable ecological and agroecological systems work precisely in the same way (Fig. 4). Lots of life cycles are coupled together, and the ‘wastes’ of one organism is nutrient for another.

Figure 4   The circular economy of organisms and sustainable systems

The green economy (Figure 5, left) contrasts strongly with the dominant brown economy.

The brown economy is based on infinite growth fuelled by maximum dissipation and exploitation of people and planet. It does not close the circle to build up structure or dynamic cycles. Boom and bust are inherent to the brown economy, so financial collapse is nothing new. More seriously, it has destroyed the earth’s habitats and brought us climate change.

The circular green economy is built on reciprocity and cooperation. It closes circles and builds balanced dynamic structures that sustain the whole, and enable us to thrive in balance with the earth.  As you can see, more lifecycles can be added into the system to make it bigger, provided these lifecycles are linked by reciprocity and cooperation. It is intuitive to see the different lifecycles as biodiversity; the more biodiversity, the more productive the system. This balanced growth at every stage is the essence of sustainable development. We should have no hesitation to opt for the green economy now.

Figure  5   The green versus the brown economy