Analogies and lessons from COVID-19 for tackling the extinction and climate crises.

As environmental scientists working in countries whose COVID-linked deaths already exceed their military casualties from all campaigns since 1945, we believe there are significant messages from the handling of this horrific disease for efforts addressing the enormous challenges posed by the ongoing extinction and climate emergencies.

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Like the climate and the extinction crises, the SARS-CoV-2 pandemic perhaps may at first have seemed like a relatively localised problem, far-removed from most people’s everyday lives. But a disease epidemic is, at its heart, a phenomenon of positive feedbacks, with each new case spawning others. Human impacts on our planet are likewise characterised by positive feedbacks. Unravelling ecological inter-dependencies and interacting threats accelerate the extinction of species. Anthropogenic warming can trigger state shifts in ecosystems, which further increase net emissions. Moreover, there are significant time lags in the dynamics of each problem — such as between infection and presentation of symptoms; between removal of habitat and the protracted extinction of species whose small and disconnected populations are thereby all but doomed to extinction; and between greenhouse gas emissions and the full effects of thermal expansion and ice-sheet melting on sea-level rise. These time lags mean that all three systems are also characterised by considerable momentum. As a result, left unchecked for too long, our ecological and climate impacts, like those of COVID-19, have swiftly grown to become existential threats [1,2].

Their lagged impacts, non-linear escalation and complex, still poorly-understood dynamics mean that recognising and mounting effective responses to each challenge require governments to listen to independent scientists. But, as we now know, such voices were and are being tragically ignored during this pandemic, as indeed were many years of warnings from epidemiologists and wildlife-disease experts of the immense risks of novel zoonoses emerging from wildlife markets [3,4]. Scientists have likewise been warning for decades of the probability that human actions will be triggering a sixth mass extinction, and of the dire consequences of major human-induced shifts in the Earth’s climate. Yet, with these environmental catastrophes unfolding over decades — rather than months in the case of COVID — even now government responses to them, as reflected in international commitments, are patchy and inadequate [5,6].

We suggest that there are three other striking similarities among the COVID, extinction and climate crises. The first is that there is no substitute for early action. In the case of the pandemic, epidemiological modelling highlights the importance of early intervention [7,8]. Empirical analysis using date of lockdown as a proxy for the timing of intervention confirms this, revealing a clear link across OECD countries between when they issued strong ‘stay-at-home’ instructions and COVID-attributed mortality (Figure 1 ). A regression controlling for potential economic and demographic confounds suggests that had lockdown been enacted a week earlier, there would have been approximately 17,000 fewer deaths through to 21 May 2020 in the UK, and nearly 45,000 fewer in the USA. Likewise, delaying action on climate change such that the world experiences +2.0°C rather than +1.5°C warming will expose an estimated 62–457 million more of the world’s poorest people to multi-sector climate risks [9]. Species conservation actions are less likely to succeed the longer they are delayed [10], and the power–function relationship between species number and habitat area means that, as conversion proceeds, marginal reductions in habitat area cause ever-greater species losses.

Figure 1

The importance of early action in tackling the COVID-19 pandemic

The residual natural logarithm of COVID-related deaths per million people is plotted against when (in days) lockdown was introduced relative to when deaths reached one per million, for the 32 OECD countries which introduced restrictions on people’s internal movements. To address potentially confounding variables the response variable is ln(observed deaths per million) – ln(predicted deaths per million), with the prediction derived from a linear model using as predictors national population density, % of the population that is urban, % of the population over 70, per capita GDP, Gini coefficient, the time between the WHO declaring a public health emergency and the country’s 100th confirmed case, and total number of tests conducted. Overall model r2 = 0.46; the regression line shown has β = 0.0949, SE = 0.0315, p = 0.006; shading shows 95% confidence intervals. A simpler model with no covariates has overall model r2 = 0.38, β = 0.1076, SE = 0.0253, p < 0.001. Further details in Supplemental information.

Second, in each case mounting effective and acceptable interventions requires decision-makers and citizens to act in the interests of society as a whole and in the interests of future generations. In the COVID crisis, young and working people have made sacrifices for the older and more vulnerable. For the climate and extinction crises, effective action requires that wealthier people forgo extravagance both for the present-day poor and for all future generations. Just as the ‘harvest’ of at-risk elderly people is not a socially acceptable price to pay for an early return to pre-pandemic economic activity, neither is giving pre-eminence to economic growth at the expense of a substantial fraction of all species on Earth [1] or a stable climate. Instead, at the very least, the people, species and ecosystems most vulnerable to our everyday behaviours must be safeguarded through deliberate and well-enforced protection. More generally, viruses, circulating greenhouse gases and the processes by which we threaten nature do not remain confined to local or even national boundaries. Hence, tackling them effectively necessitates coordinated and simultaneous cooperation among individuals, subnational authorities and nations. The actions of powerful mavericks can threaten us all.

Third, even examined in narrow financial terms, as the immense toll of the COVID crisis on livelihoods and the global economy becomes clearer, estimates suggest that delayed action may ironically have reduced prosperity as well as cost lives. IMF forecasts [11] of economic growth through to the end of 2021 are lower in those countries with higher current death rates (compound growth in GDP per capita 2019-2021 vs COVID-related deaths per million has β = -3.63 x 10-5, SE = -1.56 x 10-5, n = 37 OECD countries, p = 0.03). Preventive actions to reduce the risk of future zoonotic pandemics appear to be highly cost-effective [12]. The notion that paying short-term costs may be vital to securing longer-term prosperity is echoed in several assessments of the overall economic consequences of responding to the climate and extinction crises [13, 14, 15]. On both environmental fronts, intervening now rather than delaying further is critical to securing our future wellbeing and that of our children and grandchildren.

Scientists are not inventing the threats of catastrophic climate change or of mass extinction. These threats are real and they are upon us. There are many steps we can take even now to greatly diminish both crises. Government and individual responses to the pandemic show us that swift and decisive changes are quite possible. In this light, the consequences of continued environmental inaction are too grave to contemplate.