**10. Conclusions and perspectives**

There is a palpable sense climate change is likely due to GHGs and aerosols. There is debate though, as to who or what is more blamable for their emissions. This controversy was illustrated with attributions to the hot summer of 2010 in Russia. A group of authors attributed the cause to natural events [29], while another attributed it to human actions [30]. Yet a third group argued that both sides may be correct, subject to how the data is checked [31]. So, what should citizens/ people/ the public believe? There are reports that nature continues to contribute climate change agents [22–25, 173–175], and human activities are also doing the same [9, 26–28, 176–180]. Since at present, there is no human ability to bar natural contributors of these agents (e.g., stellar outbursts, volcanic detonations), it becomes obligatory that the human-made agents must be restricted, especially in the current Anthropocene era. This author suggests human talents and ingenuity be expended on constraining anthropogenic sources and creating mitigating alternatives.

Remarkably, climate change is no respecter of borders, be it local, national, regional, or international; and not on land, at sea, in air, or in space. Climate change does not respect wars and nations at war. Heatwave of 2010 affected countries in

#### *Dialing Back the Doomsday Clock with Circular Bioeconomy DOI: http://dx.doi.org/10.5772/intechopen.113181*

Europe. Helsinki in Finland recorded a daily mean temperature of 26.1°C; Kiev in Ukraine, 25°C at night, and Moscow in Russia reached a daytime temperature of 38.2°C [181]. Climate change is killing humanity; humanity should stop killing humanity. From Ukraine to Sudan, all wars on planet earth must stop. Countries should cooperate to fight common enemies of humanity (including climate change, hunger, disease, inadequate- health facilities, potable water and electricity supply, etc.); not fight each other. The industrially advanced nations that contributed most of the emissions breaching planetary boundaries, also have the resources and ability to adapt and manage the fallouts. The onus is on the technological economies to use the usual 20/20 hindsight to share answers and assist, encourage, and guide developing countries. Doing so would enable developing nations to avert the mistakes advanced countries made in their developmental trajectories.

This chapter identified ways circular bioeconomy minimize exceedances of planetary boundaries, mitigate climate change, and dial back the doomsday clock. Approaches of IRA and AD were discussed. AD is a wise way to recycle resources of land, nutrients (e.g., N, P, K), carbon, water, and sunlight [83, 101, 102, 108, 109, 115, 153, 158, 167, 182, 183]. AD converts organic matter into valuable energy carriers (e.g., biogas, biomethane, electricity, and biofertilizer) for beneficial domestic and industrial applications. In particular, the solutions of renewable bioenergy and biofertilizer provision, attenuation of carbon dioxide footprint, ozone and waste management, as well as monetization, cost savings, and energy justice were presented. These solutions are anchored to IRA in general, but more specifically to AD; a mature, cost-effective, and environment-friendly technology. Both approaches, however, could be scaled to the industrial competence of virtually any country on earth. To strengthen the robustness and sustainability of these approaches/ solutions, three additional answers are pinpointed:

*No till crop management.* This method was applied to maize (*Zea mays*, L.) farming and offered better economic, environmental, and ecosystem benefits as compared to other practices tested [184]. No till was also found to be advantageous in phosphorus accumulation, availability, and overall soil ecosystem function [185].

*Reduction of food waste.* Near 1.3 to 1.8 billion metric tons of food ≈ 30% of global food output is wasted annually [186, 187]. Because 24 to 30% of GHGs emanate from agriculture [59, 187], up to 10% of GHGs may be attributable to wasted food, besides emissions inherent in food decaying in trash cans, landfills, and dumpsites. Consequently, reduction of food waste would contribute to climate change mitigation.

*Reduction of local pollution.* Nations may attend to local pollutants like those generated by the transport sector. This is because local pollutants respond to the environmental Kuznets curve (EKC); **Figure 5**. EKC hypothesis applies an inverted U-shaped relationship to pollution and economic prosperity. Income increases with pollution until a peak regarded as the turning point is reached. As **Figure 5** shows, after the peak threshold, further rise in income results in decrease in pollution indicators [188–191].

The chapter also highlighted the implications of circular bioeconomy for the space food system. Along with AD and IRA; CELSS, BLSS, NNC, circularity, and molecular pharming were identified as strong links to sustainable space enterprise food system. Despite the challenges of microgravity, decades of research efforts have demonstrated the possibility and capability of growing plants in microgravity environments.

Food is an indispensable requirement for life on earth and in space. Its provision in terms of production, processing, consumption, and disposal must be carefully

**Figure 5.** *A generalized schematic of the environmental Kuznets curve (EKC) hypothesis.*

managed to minimize the footprints of resources consumption and external costs of GHGs and aerosols on the one hand. On the other hand, the provisioning should maximize solutions that mitigate climate change. AD in the context of circular bioeconomy appears to embody viable climate mitigation solutions. Recycling with AD judiciously utilizes biomass resources to generate climate mitigation solutions (e.g., bioenergy, biofertilizer); and simultaneously reducing the waste management menace. Evidently, mitigating climate change with a circular bioeconomy would enable dialing back the doomsday clock for the betterment of humanity. Studies that engage in quantitative determination of the contributions of these solutions (including their scientific foundations, environmental strengths, and financial viabilities) would be endeavors deployed in the appropriate path.
