## 4 What Will the Energy Be Used For?
### Agriculture  
In their 2022 paper [PERSON] and [PERSON] [12] provocatively titled one section: 'Agriculture: Humanity's greatest mistake?' The footprint of the global agricultural system is indeed vast. [PERSON] et al. [66] reported that: '[... ] ecosystems across most of the terrestrial biosphere, from 75 to 95% of its area, have now been reshaped to some degree by human societies'. Of these human-modified areas, the authors reported that 51% were in 'intensive anthromes', 30% in 'cultured', and just 19% were 'wildlands'. They also argued that such a transformation is not recent; humans have been extensively transforming biomes for the past 12 millennia. Given its vast reach, global agriculture has a crucial impact on ecological sustainability. Agriculture provides not only most of the food we eat, but also materials such as wool, cotton and jute. Nor is all food grown consumed by humans: large quantities of grain, especially corn, sugar cane and edible oil seeds are used to make transport fuels. Such biofuel production is anticipated to increase out to 2031, due to a rise in sugar cane -based ethanol [67]. Some researchers (e.g., [PERSON] et al. [68]) doubt that these food-based biofuels used to replace petroleum-based transport fuels do actually produce any CO\({}_{2}\) savings when a full accounting of all environmental effects is made. Much grain is also fed to livestock animals, along with other foodstuffs; again, use for this purpose is expected to continue its rise [67]. Just as it was argued above that shifting to more energy-efficient transport modes could be an important means of reducing emissions, so many researchers are now arguing for a shift to more energy-efficient means of satisfying our nutritional needs, with the key change a wholesale move away from animal products to more a vegetarian-style diet, see, e.g., [69; 70; 71; 72; 73]. As the authors [74] have earlier written, summarising [PERSON] et al. [72]: 'Meat production (like agricultural production in general), produces not only CO\({}_{2}\) emissions, but also emissions of the other major GHGs, methane (CH4) and nitrous oxide (N\({}_{2}\)O). Production of meat, especially from ruminant livestock, incurs more GHG emissions per kilojoule of food energy than plant-based food, such as grains, because of energy conversion losses at each trophic level'. [PERSON] [72] reported that if the world consumed no animal-based food at all, 8 GtCO\({}_{2}\)-eq of emissions, or nearly 20% of 2021 global emissions of 40.8 GtCO\({}_{2}\)-eq [28], could be avoided annually. With some meat and dairy use, the savings would be lower, but still significant. [PERSON] et al. [70] also argued that such dietary changes are more important from a CC mitigation viewpoint than intensification of agricultural production. As was shown for transport, merely replacing the energy used in agriculture, such as diesel fuel, by RE sources will only make a minor difference to the vast ecological damage caused by global agriculture [8]. These include soil erosion, desertification, water pollution and eutrophication of rivers and coastal waters, groundwater depletion, and loss of soil carbon. Cutting down on food waste can be another important means of reducing the environmental harm caused by agriculture, since it reduces the amount of food that needs to be produced. As a recent report from the United Nations Environment Programme (UNEP) [75] stressed: 'Food waste also burdens waste management systems, exacerbates food insecurity, making it a major contributor to the three planetary crises of climate change, nature and biodiversity loss, and pollution and waste.' [PERSON] and [PERSON] [76] found that 'roughly 1/3 of food produced for human consumption, amounting to 1.3 billion tonnes annually, is lost or wasted [... ]'. In lower income countries, this loss is relatively higher at the harvesting level, but in wealthier countries, the waste is relatively higher at the consumer level.