There are seven popular food crops in this picture
“The switch from growth to decline in oil production will thus almost certainly create economic and political tension.”
…[B]iomass plantations with subsequent carbon immobilization are likely unable to “repair” insufficient emission reduction policies without compromising food production and biosphere functioning due to its space‐consuming properties. Second, the requirements for a strong mitigation scenario staying below the 2°C target would require a combination of high irrigation water input and development of highly effective carbon process chains. Although we find that this strategy of sequestering carbon is not a viable alternative to aggressive emission reductions, it could still support mitigation efforts if sustainably managed.
This leaves us with a rather clear, but hardly comforting overall conclusion: Holding the 2°C line seems only feasible if two sets of climate action work hand in hand. On the one hand, greenhouse gas emissions need to be reduced as early and as effectively as possible. In fact, an even more aggressive strategy than reflected by the [IPCC] RCP2.6 scenario should be pursued, aiming at the “induced implosion” of most fossil fuel‐driven business cases in the next couple of decades. On the other hand, tCDR [carbon dioxide removal] can significantly contribute as a “supporting actor” of the mitigation protagonist, if it gets started and deployed immediately. This means that the biological extraction of atmospheric CO2 as well as the suppression of CO2 release from biological systems must draw upon all possible measures — whether they are optimal or not, whether they are high‐ or low‐tech. We therefore suggest fully exploring the pertinent options available now, which include reforestation of degraded land and the protection of degraded forests to allow them to recover naturally and increase their carbon storage, e.g., within the Bonn Challenge initiative or the New York Declaration on Forests. Further options range from up‐scaled agroforestry approaches to the application of biochar and various no‐tillage practices for food production on appropriate soils. Also, it becomes overwhelmingly evident that humanity cannot anymore afford to waste up to 50% of its agricultural harvest along various consumption chains or to go on operating ineffective irrigation systems.
Whatever we do is likely to lead to death on a scale that makes all previous wars, famines and disasters small. To continue business as usual will probably kill most of us during the century. Is there any reason to believe that fully implementing Bali, with sustainable development and the full use of renewable energy, would kill less? We have to consider seriously that, as with nineteenth century medicine, the best option is often kind words and pain killers but otherwise do nothing and let Nature take its course.
Had we heeded Malthus’s warning and kept the human population to less than one billion, we would not now be facing a torrid future. Whether or not we go for Bali or use geoengineering, the planet is likely, massively and cruelly, to cull us, in the same merciless way that we have eliminated so many species by changing their environment into one where survival is difficult.