In The Land 28, Simon Fairlie and Peter Harper argue in separate articles that large-scale use of biomass energy can be carbon neutral and sustainable, and that it is an indispensable tool for ending societies' disastrous reliance on fossil fuels and, as Harper writes, for removing some of the carbon dioxide that is currently in the atmosphere.
I have been researching and warning about the impacts of large-scale bioenergy for almost 15 years, and I fully understand why it is so tempting to think that bioenergy can be part of a portfolio of tools for addressing the climate emergency.
There can be no doubt that we need to phase out fossil fuel burning as rapidly as possible if we want to have any hope of avoiding the worst impacts of climate change. Despite a remarkable, sustained fall in the cost of wind and solar power (by 89 percent for solar PV in just ten years)1, fossil fuels still meet over 85 percent of the world's energy demand2. Even the EU (with the UK included) only just met its 20 percent renewable energy target at the end of last year3, and 60 percent of that came from 'bioenergy and renewable waste'4 of which, in turn, 62 percent was made up of wood taken straight from forests and tree plantations.
Clearly, a rapid phaseout of fossil fuel burning – so vital for the future of all life on earth – is a monumental task, and one which will become even harder without burning a fair bit of biomass. Unfortunately, evidence of biodiversity loss and its drivers, of bioenergy impacts in recent and historical times, and from earth systems studies in general, all point towards one conclusion. If we want to prevent widespread collapse of ecosystems and thereby our life support systems, we need to significantly reduce global demand for agricultural commodities (including meat) as well as for wood. And for that, certainly for Europe and the UK, we need to reduce rather than increase, bioenergy demand. At the same time of course, we need to phase out fossil fuels, even though this would require steeper reductions in our energy use and a more comprehensive and expensive replacement of energy infrastructure than would otherwise be the case.
Lessons from History
Although the scale and pace of global deforestation today is unprecedented, the history of large-scale deforestation (some of it reversed during later periods), dates back thousands of years. Evidence suggests that, between 1000 BC and 1800 AD, most of Europe experienced "a constant decline in forest cover, interrupted by two local maxima: at AD 600, during the transition from Late Antiquity to the Early Middle Ages, and at AD 1400 shortly after the Black Death"5. This pre-industrial deforestation was driven by a combination of land clearance for agriculture and logging for timber and fuel. Historical evidence also shows that deforestation was far from an inevitable result of human population growth before the fossil fuel age: for example the Amazon forest is thought to have been home to 6.8 – 8 million people, many of them living in what are described as 'garden cities', prior to the colonial genocide.6 Their longest-lasting impact on the forest was an increase in the number of trees bearing edible fruits and nuts.7
Yet there is one scenario for which I cannot find a single historical example. No society has ever successfully relied on wood for construction, for fuel to meet people's need for warmth and cooking, and for supporting a thriving manufacturing sector including metal smelting, without causing regional deforestation or resorting to long-distance timber important. Renaissance Venice sourced timber for shipbuilding from as far as present-day Croatia and Greece and eventually sought to address shortages by essentially grabbing rights to communal forests in mainland Italy.8 The next and more extensive economic powerhouse of Europe, the Low Countries, relied so heavily on strip-mining of peat that Utrecht and Holland lost around one-tenth of their total land-area.9 In England, wood shortages were a recurrent concern from the Middle Ages onwards, and coal is thought to have overtaken wood as the largest fuel source by the 1620s.10
'Sustainable forestry' was successfully practiced in various regions by the late Middle Ages, such as extensive coppicing with stands in Moravia.11 However, as environmental historian Paul Warde states, none of Europe's 'organic' economies could ever supply more than 20 gigajoules per capita from wood and farming combined.11 Per capita energy use in the UK today is 107 gigajoules and, of course, population has substantially grown.12 In short, there is no historic precedent on which to base optimistic scenarios about 'sustainable biomass' on a scale that would make a dent in current fossil fuel use.3
Recent Impacts of Biomass Energy
Fairlie claims that as long as forests overall "are not declining in extent or density", biomass energy is essentially carbon neutral. There are two big problems with this. Firstly, right now, the overall amount of wood and carbon in forests isn't static – it is still growing. If the amount of wood and carbon in forests were to remain static then we would no longer have a forest carbon sink, i.e. forests overall would stop removing any additional carbon from the atmosphere. The IPCC estimates that, even when carbon emissions from agriculture, deforestation, peat drainage, etc. are accounted for, the 'land sector' – especially forests – still removes between 2.3 and 6 billion tonnes of CO2 from the atmosphere every year. Less carbon removed from the atmosphere warms the planet just as much as does more carbon emitted from burning coal. We can't afford either.
Secondly, satellite imaging shows a substantial increase in wood removals and in the size of forest clearcuts across much of Europe from 2016 onwards, compared to 2011-15, an increase which researchers from the EU's Joint Research Centre believe correlates with growing use of forest biomass energy.13 EU member states are both reporting and forecasting substantial reductions in the amount of CO2 their forests sequester every year.14 While bioenergy rarely competes with sawmills for the same timber, the fast growing demand for large quantities of relatively cheap wood incentivises ever more intensive logging, with trees not yet big enough or even too big for a sawmill, or ones which have grown crooked classed as 'residues'.15
The Fundamental Problem
Drax power station burns the equivalent of more than 1.2 times the UK's total annual wood removals (for all purposes), yet its biomass electricity meets less than 0.9 percent of the UK's final energy demand.16 With efficient heat recovery, this could potentially be increased to 1.6 percent – a huge amount of wood to meet a minute fraction of the energy we use. This comes down not to bad practices but to the fact that photosynthesis is not an efficient way of turning solar into chemical energy. Terrestrial ecosystems have evolved to recycle carbon just as they recycle nutrients and water. The fact that they are sequestering some of our emissions from fossil fuel burning at present is due largely to the CO2 fertilisation effect, a negative climate feedback on which we cannot rely indefinitely as the planet gets warmer.
In the short term, intensively managed tree or grass (e.g. sugarcane) plantations might appear to increase 'productivity' compared to natural ecosystems, but at the cost of depleting soil nutrients and often ground or other freshwater.17 The same applies to crop monocultures: we can try to grow a lot of miscanthus or willow, but they will only provide decent yields with sufficient water and nutrients. Declining soil fertility is already a major problem in the UK and globally, and trying to increase total harvests in order to produce bioenergy risks accelerating those losses.18
For all the talk of 'sustainable land management' and 'innovations', the only clear impact which humans have had on the land's productivity worldwide has been to double the amount of biomass removed and consumed compared to 1910, a figure which could be twice as high had bioenergy use not declined in the twentieth century, due to a vast expansion in fossil fuel burning.19 We are fortunate that wind and solar generation today are vastly more efficient and offers choices not available a century ago.
Final Reflection
Across the Scottish Borders and elsewhere, new plastic tube 'forests' of Sitka spruce saplings are appearing everywhere, part of Scotland's ambitious tree planting commitment. The amount of carbon they will sequester year on year has been plotted, and fifty years from now they will provide timber and fuel. That's the theory. But in Germany, forests, and especially planted conifers, are thinning and dying at a rate not seen since surveys began in 1984, the result of drought and pests, driven by climate change.
Ecologists are warning that the future of Germany's forests looks bleak even in the short term, unless forest conservation, resilience, and regrowth of mixed native species rather than a few conifer species are prioritised.20 In the Baltic States, timber companies' attempts to grow Sitka spruce are threatened by a rust fungus making its way across from Russia, moving west. And in Spain and Portugal, 'productive' eucalyptus and pine plantations are burning more often and more intensely than ever before as the climate heats up, sometimes with deadly consequences for humans. Staking the climate's future on trees planted today growing and sequestering carbon in decades to come is a risky business. Protecting intact diverse forests has far more benefit for the climate and biodiversity than planting new trees.21
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Almuth Ernsting is a researcher and campaigner at Biofuelwatch
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REFERENCES
1.https://ourworldindata.org/cheap-renewables-growth
2.https://ourworldindata.org/energy-mix
3. European Environment Agency 2021 https://tinyurl.com/Ernsting-3
4. EU figures, 2020 https://tinyurl.com/Ernsting-4
5. Kaplan, J et al 2009 'The prehistoric and preindustrial deforestation of Europe' Quaternary Science Reviews 28 https://doi:10.1016/j.quascirev.20 09.09.028
6. Palace, M et al 2017 'Ancient Amazonian populations left lasting impacts on forest structure' Ecosphere https://doi.org/10.1002/ecs2.2035
7. Ross, E 2017 'Amazon rainforest was shaped by an ancient hunger for fruits and nuts' Nature https://doi:10.1038/nature.2017.21576
8. Beaudoin, S 2014 'Lawyers And Sawyers: Venetian Forest Law And The Conquest Of Terrafirma (1350–1476)' (MA Thesis) https://tinyurl.com/Ernsting-8
9. https://www.lowtechmagazine.com/2011/09/peat-and-coal-fossil-fuels-in-pr...
10. Warde, P 2007 'Facing the challenge of climate change: energy efficiency and energy consumption' History and Policy https://tinyurl.com/Ernsting-10
11. Szabó, P et al 2015 'Intensive woodland management in the Middle Ages: spatial modelling based on archival data' Journal of Historical Geography 48 https://tinyurl.com/Ernsting-11
12. Sönnichsen, N 2020 Primary energy consumption per capita in selected European countries 2019 https://tinyurl.com/Ernsting-12
13. Ceccherini, G et al 2020 'Abrupt increase in harvested forest area over Europe after 2015' Nature https://www.nature.com/articles/s41586-020-2438-y
14. FERN 2020 EU legislation reveals steep decline in carbon stored in European forests https://tinyurl.com/Ernsting-14
15. https://www.biofuelwatch.org.uk/2020/residues-briefing/
16. https://www.biofuelwatch.org.uk/axedrax-campaign/
17. Patzek, T & Pimentel, D 2006 'Thermodynamics of Energy Production from Biomass' Critical Reviews in Plant Sciences 24 https://tinyurl.com/Ernsting-17
18. Environment Agency 2019 The State of the Environment: Soil https://tinyurl.com/Ernsting-18
19. Krausman, F et al 2013 'Global human appropriation of net primary production doubled in the 20th century' PNAS https://www.pnas.org/content/110/25/10324.short
20. Klöckner, Julia 2021 'Dürre, Stürme und Borkenkäfer schaden den deutschen Wäldern' Die Zeit https://tinyurl.com/Ernsting-20
21. Moomaw, W et al 2019 'Intact Forests in the United States: Proforestation Mitigates Climate Change and Serves the Greatest Good' Frontiers For Global Change https://doi.org/10.3389/ffgc.2019.00027