Earth Overshoot Day 2019 - marking the day when humanity exceeds nature’s renewable ecosystem resources for the year - was the earliest ever, on July 29, using 1970 as the last year where the date fell on December 31. This represents using 1.75 planet’s worth of ecosystem resources and provides a different framing to what is presented in The Uninhabitable Earth by David Wallace-Wells1, first articulated an article in July 2017 on worst-case scenarios for global warming. The article created a sensational effect, as is also the case with this widely reviewed book. As Manuel Castells points out in his book Communication Power, the capacity to frame an issue is critical. Our prevalent environmental discourse is a narrative primarily referring to global warming, climate change and carbon emissions, as presented in a series of IPCC reports.

One of the latest dates from October 2018 is a policy document on the impacts of global warming at 1.5°. Paragraph A1 states: “Human activities are estimated to have caused approximately 1.0 °C of global warming above pre-industrial levels, with a likely range of 0.8 °C to 1.2 °C. Global warming is likely to reach 1.5 °C between 2030 and 2052 if it continues to increase at the current rate. (high confidence)” Note that it is stated that human activities have caused the whole warming above preindustrial levels, with no mention of the percentage of this increase that might be natural. Climate experts all acknowledge that natural cycles do play a role in climate fluctuations, but there is disagreement about the extent of this effect, which some put as high as 75%, although this figure is rarely mentioned in the press.

C2 states: “Pathways limiting global warming to 1.5 °C with no or limited overshoot would require rapid and far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems (high confidence). These systems transitions are unprecedented in terms of scale, but not necessarily in terms of speed, and imply deep emissions reductions in all sectors, a wide portfolio of mitigation options and a significant upscaling of investments in those options (medium confidence).” This paragraph highlights the scale of transformation required in order to limit global warming. There is currently no political will or strategy to achieve this kind of transformation.

C3: “All pathways that limit global warming to 1.5 °C with limited or no overshoot project the use of carbon dioxide removal (CDR) on the order of 100–1000 GtCO2 over the 21st century. CDR would be used to compensate for residual emissions and, in most cases, achieve net negative emissions to return global warming to 1.5 °C following a peak (high confidence). CDR deployment of several hundreds of GtCO2 is subject to multiple feasibility and sustainability constraints (high confidence).” Here it is stated that CDR is essential to achieving this target, which involves either geoengineering through solar radiation management or carbon capture. I have discussed the first option in previous reviews, arguing that a certain amount of this is already going on, and also highlighting, like Peter Wadhams, that we cannot afford to stop it once we have started without provoking runaway warming. And the scale of the required CDR programme is rightly regarded by Wallace-Wells as politically and indeed economically quite unrealistic.

D1 continues: “Estimates of the global emissions outcome of current nationally stated mitigation ambitions as submitted under the Paris Agreement would lead to global greenhouse gas emissions in 2030 of 52–58 GtCO2 eq yr (medium confidence). Pathways reflecting these ambitions would not limit global warming to 1.5 °C, even if supplemented by very challenging increases in the scale and ambition of emissions reductions after 2030 (high confidence). Avoiding overshoot and reliance on future large-scale deployment of carbon dioxide removal (CDR) can only be achieved if global CO2 emissions start to decline well before 2030 (high confidence).” Taking this analysis as a whole, it is a grim prospect where emissions are likely to continue and little if any mitigating action will be taken.

This IPPC frame is used by the author for his analysis, but as I indicated the beginning, Earth Overshoot Day provides a different and much broader frame focusing on consumption of resources and implicitly on overall human impact on the planet - consumption multiplied by population, which is still increasing at 220,000 net per day. He does refer to the argument that natural cycles are making a contribution but makes no mention of any of the elements of analysis in terms of, for instance, the Atlantic Multi-Decadal Oscillation or even the cyclical effects of El Niño, which has been active in the last couple of years. A good estimate of the percentage of natural and human causes of warming is surely basic, as is understanding trends involving other factors - such as solar activity - which may well produce cooling in the future. Instead, the IPCC story assumes that 100% of warming is anthropogenic. The percentage involved does not alter our overall situation and the need for mitigation and adaptation, but it does provide a modification of the frame. Another frame is provided by the work of Lester Brown, with his costed analysis on how to make a transition to an eco-economy by using a fraction of annual expenditure on arms.

Human impact involves not only the burning of fossil fuels, but also population increase and impact, overfishing, overgrazing, overuse of water, intensive livestock breeding, loss of topsoil, forests and biodiversity, and pollution of the air and oceans (including plastic). Jason Drew and I analysed many of these factors in our book The Protein Crunch in terms of cumulative lifestyle effects and environmental depletion, especially changing dietary preferences among the rising middle class in India and China - hence the title. There are many more pressing issues than simple carbon emissions from fossil fuels, even if this is reflected across many areas.

Wallace-Wells does address many of these within his framework of analysis, pointing out that our current situation is a best case scenario of the future and identifying many linkages between natural systems, which he identifies using a metaphor of cascades. The second part is entitled Elements of Chaos and details heat death, hunger, floods, wildfire, freshwater issues, dying oceans, unbreathable air, plagues of warming, disasters that are no longer natural and the overall potential outcomes of economic collapse and climate conflict. All this makes very grim reading, and is based on nearly 70 pages of scientific references and conversations with many of the authors who share their overall sense of alarm while maintaining a scientific reticence. All the factors he cites are set to intensify with increases of temperature and a few figures show just how unsustainable our trajectory is: we will need twice as much food by 2050, a system that already contributes 30% of carbon emissions; in tandem, agriculture will require 50% more water over the same period, while parts of urban Africa and India are already in crisis; the deforestation policies of Brazil's President Bolsonaro the equivalent of the carbon emissions of the US and China between 2021 and 2030; between 1992 and 1997, the Antarctic ice sheet lost on average 49 billion tonnes of ice each year, while the average between 2012 and 2017 was 219 billion; population in Africa is forecast to increase from 1 billion to 4 billion by 2100; and we are currently burning 80% more coal than in 2000.

The third part, entitled The Climate Kaleidoscope, covers fossil fuel capitalism, the church of technology, the politics of consumption, history after progress, and ethics at the end of the world. Since the 18th century, the human ideal has been one of progress and growing prosperity, but now we face the prospect of a collapse of our ecological and economic systems brought about by this very process of economic growth. As Wallace-Wells repeatedly argues, we ourselves have been writing this script and continue to write it. Developing countries aspire to the same level of prosperity, which European levels would require the resources of three planets. The prospect of a collision with nature is ultimately inevitable both through the frames of overexploitation of resources and population growth on the one hand, and the carbon emissions scenario on the other. His horrifying portrait of suffering is, as he argues, elective: ‘if humans are responsible for the problem, they must be capable of undoing it.’ We do in fact have the tools we need (but no mention of population here): ‘a carbon tax and the political apparatus to aggressively phase out dirty energy; a new approach to agricultural practices and a shift away from beef and dairy in the global diet: and public investment in green energy and carbon capture.’ (p. 227)

However, there is no sign that our institutions and leaders are in fact up to this momentous task, focusing as they do on short-term economic and political issues, and indeed we are all complicit as passengers on Spaceship Earth. At a time when unprecedented cooperation is required, many are retreating into populism and nationalism, looking after their own interests. A collectively intelligent species would realise the extent of our predicament and take pre-emptive action, but we are not yet collectively intelligent enough to do so, in spite of our conceit. As Catherine Ingram argues despairingly in a recent article, we are in fact facing extinction; and as James Lovelock has pointed out, the Earth will go on without us. Business as usual will be the default scenario until a series of catastrophes strike on a sufficient scale, as this seems to be the only language we have evolved to understand - the equivalent of a planetary near death experience. This is a profoundly depressing prospect to individually intelligent people, but it is hard to envisage a more positive collective scenario, even if we should continue our efforts to evolve and implement one. In that sense, this book is a wake-up call that may in fact not succeed in waking us up in time.

1 David Wallace-Wells, The Uninhabitable Earth, Penguin Random House, 2019, 309 pp.