The IPCC is apparently even waking to the reality that wishful thinking about the timeline for decarbonization or hoping for the future possibility of massive bioenergy with carbon capture and storage does not make it pragmatically possible. There is new discussion promoting a required degrowth of the world economy.
https://mronline.org/2019/08/30/degrowt ... abundance/
"The primary reason for this problem is that economic growth is projected to drive energy demand up at a rate that outpaces the rollout of clean energy capacity (Raftery et al., 2017). This has already presented a problem in the 21st century. Today the world is producing 8 billion more megawatt hours of clean energy each year than in 2000, which is a significant increase. But over the same period, energy demand has grown by 48 billion megawatt hours. In other words, new clean energy capacity covers only 16% of new demand. It is of course technically possible to scale up clean energy output to cover total global energy demand (Jacobson and Delucchi, 2011). But the question is whether it is feasible to do so at a rate that is fast enough to respect the carbon budget for 1.5 or 2°C, while at the same time growing the global economy at the usual pace.
We can assess this question by looking at projected rates of decarbonization. If we assume that global GDP continues to grow at 3% per year (the average from 2010-2014), then decarbonization must occur at a rate of 10.5% per year for 1.5°C, or 7.3% per year for 2°C. If GDP slows down and grows at only 2.1% per year (as PWC predicts), then decarbonization must occur at 9.6% per year for 1.5°C, or 6.4% per year for 2°C. All of these targets are significantly beyond what existing empirical models indicate is feasible (see Hickel and Kallis, 2019). A few brief examples will serve to illustrate this point. Schandl et al. (2016) indicate that decarbonization can happen by at most 3% per year under highly optimistic policy conditions. The C-ROADS tool (developed by Climate Interactive and MIT Sloan) projects decarbonization of at most 4% per year under the most aggressive possible abatement policies: high subsidies for renewables and nuclear power, plus high taxes on oil, gas and coal. In a recent review of existing evidence, Holz et al. (2018) find that the rate ofdecarbonization required to meet the Paris targets is “well outside what is currently deemed achievable, based on historical evidence and standard modelling.”
IPCC scientists and authors have been aware of this problem for some time. In the Fifth Integrated Assessment Report (AR5), they dealt with it by assuming the future existence ofspeculative “negative emissions” technologies. The theory is that while business-as-usual growth will cause emissions to exceed the carbon budget in the medium term, that is fine so long as we find a way to remove carbon from the atmosphere later in the century. The dominant proposal for achieving this is known as BECCS, or bioenergy with carbon capture and storage. BECCS entails developing large tree plantations around the world to absorb CO2from the atmosphere, harvesting the biomass, burning it for energy, capturing the emissions at source and storing the waste underground. In AR5, the vast majority of scenarios for 2°C (101 of the 116) rely on BECCS to the point of achieving negative emissions.
BECCS is highly controversial among scientists, however. There are a number of concerns. First, the viability of power generation with CCS has never been proven to be economically viable or scalable (Peters, 2017). Second, the scale of biomass assumed in the AR5 scenarios would require plantations covering land two to three times the size of India, which raises questions about land availability, competition with food production, carbon neutrality, and biodiversity loss (Smith et al., 2015; Heck et al., 2018). Third, the necessary CO2 storage capacity may not exist (De Coninck and Benson, 2014; Global CCS Institute, 2015).
Anderson and Peters (2016) conclude that “BECCS thus remains a highly speculative technology” and that relying on it is therefore “an unjust and high stakes gamble”: if it is unsuccessful, “society will be locked into a high-temperature pathway”. This conclusion is shared by a growing number of scientists (e.g., Fuss et al., 2014; Vaughan and Gough, 2016; Larkin et al., 2017; van Vuuren et al., 2017), and by the European Academies’ ScienceAdvisory Council (2018).
Responding to these concerns, the IPCC (2018) has for the first time published a scenario for reducing emissions in line with the Paris Agreement that does not rely on speculative negative emissions technologies. Developed by Grubler et al. (2018) and known as Low Energy Demand (LED), the scenario works by reducing global energy consumption by 40% by 2050, which makes it much more feasible to achieve a transition to 100% clean energy. The key feature of this scenario is that global material production and consumption declinessignificantly: “The aggregate total material output decreases by close to 20 per cent fromtoday, one-third due to dematerialization, and two-thirds due to improvements in materialefficiency.” LED differentiates between the global North and South. Industrial production and consumption declines by 42% in the North and 12% in the South. Given improvements in energy efficiency, this translates into industrial energy demand declining by 57% in the North and 23% in the South.
The LED model represents a “degrowth” scenario–a planned reduction of the material and energy throughput of the global economy. Its inclusion in the IPCC report as the only scenario that does not rely on questionable negative emissions technologies suggests that degrowth may be the only feasible way to achieve the emissions reductions required by the Paris Agreement. This is a major milestone in climate mitigation theory. What is appealing about this approach is that it not only addresses emissions and climate change, but also reduces ecological impact across a range of other key indicators, including deforestation, chemical pollution, soil depletion, biodiversity loss, and so on (Rockstrom et al., 2009; Steffen et al., 2015)."