While preparing my last ccolumn advocating increased nuclear power to minimise global warming, I came across disturbing information that shook my confidence in our current determination to tackle climate change.
Apparently the roadmap specified in the historic 2016 Paris climate agreement, designed to prevent global warming from exceeding pre-industrial temperatures by 1.5 to 2 degrees (our world is now about 1.1 degree warmer than pre-industrial times), relying on data supplied by the Intergovernmental Panel on Climate Change (IPCC), cannot succeed even if all greenhouse gas (GHG) emission-reduction targets are met.
Achieving the Paris temperature target depends on technology, principally bioenergy with carbon capture and storage (known as BECCS), that sucks CO2 from the air. But it cannot be applied on the huge scale required, as explained by Eric Toensmeier and Dennis Garrity in Scientific American, August 2020.
BECCS essentially means growing massive amounts of woody plants (biomass) that absorb CO2 from the air during growth, then harvesting and fermenting the plants to create biofuels (eg alcohol) or burning them to generate electricity and permanently sequestering from the atmosphere the emissions from these fermentations and burnings, eg by trapping emitted CO2 in underground rocks. Replacement trees are planted and the cycle repeats.
Arable land
Most IPCC BECCS scenarios make the unwarranted assumption of unlimited availability of biomass. The landmark IPCC global warming of 1.5-degree report of 2018 estimates that large-scale BECCS requires land area about three times the area of India. Most land suitable for BECCS is now used for agriculture and large-scale BECCS would use up one third of the earth's arable land, making it impossible to feed the world's population.
It also calls for replacing existing forests with monocultures of high-wood-yielding trees such as eucalyptus. These vast monocultures would destroy ecosystems. Deploying large-scale BECCS to arrest global warming is not feasible, although smaller scale BECCS can make a contribution.
How we arrived at this pass is, to my mind, credibly explained by economic anthropologist Jason Hickel in the Guardian in a piece published in July 2017. He explains that when IPCC realised that the GHG emission-reductions necessary to limit global warming to 1.5 to 2 degrees would seriously hinder economic growth, an enormously unpopular prospect for politicians and industrialists, they factored in GHG reduction targets that would still allow economic growth. The 2016 PCA accepted these emission-reduction targets. IPCC made an act of faith that BECCS, unproven at that time, would be perfected in time to sufficiently supplement the inadequate GHG emissions reduction targets to meet the 1.5 to 2 degrees. The 2016 PCA is silent on the role of BECCS.
Hickel reports that if all PCA emission targets are met, but we do nothing else, the world is on target for greater than 3 degrees warming, possibly as high as 4.4 degrees. A warming of 4 degrees would precipitate a nightmarish world of blistering unprecedented heatwaves, sea-levels raised by 1.2 metres by 2100, 40 per cent of biological species at risk of extinction, withered rainforests, crop yields down by 35 per cent resulting in famines, possible desertification of Southern Europe – and more. What a legacy to hand our great-grandchildren!
Renewables
Hickel argues that our only hope of preserving a world fit for human civilisation is to achieve far more aggressive GHG emissions-reduction targets. Industrialised countries must reduce emissions by 8 to 10 per cent each year until net zero emissions are achieved by 2050, but our best efforts using all renewables and economies cannot achieve annual reductions greater than 4 per cent. To make up the balance, economic activity will also have to reduce 4 to 6 per cent annually in industrialised countries and by 3 per cent annually in poorer countries from 2025. Economic growth must give way to de-growth.
Many economists believe that the continuous economic growth experienced in the developed world over the past 80 years is essential for social wellbeing. But this view is distorted. Firstly, despite economic growth, many problems remain – large income inequalities, high crime rates, drug abuse, depression, high suicide rates, etc. Secondly, the frantic consumerism underpinning growth produces little happiness and contentment. Living with economic shrinkage would require re-ordering our values, prioritising generosity and sustainable living, conserving the environment and measuring success in terms of contentment not GDP.
If we must now commence aggressive de-growth to avoid bequeathing a nightmare world to future generations, so be it. The project is doable and may well gift us a silver lining of contented living.
William Reville is an emeritus professor of biochemistry at UCC