While too soon to attempt a global and definitive account of the Covid-19 crisis, this pandemic and its consequences will undoubtedly have dedicated chapters in future history books. Beyond the dramatic loss of life, the worldwide repercussions of this event in terms of socio-economic impacts and political measures are already unprecedented, with, inter alia, countless schools and companies closed, and about half of the world’s population put in quarantine. Assessing the precise financial and economic impacts of the shock will come later. It seems however critical to analyse what lessons can be drawn from this systemic international crisis in anticipation of the future ones, especially regarding climate change.
Echoing the current preoccupations, it should be noted that climate disruption entails significant health risks. The WHO estimates that climate change will significantly increase mortality due for instance to malaria, dengue, diarrhoeal diseases, heat or undernutrition. As an example, the re‐emergence of malaria in the Chinese temperate province of Anhui since 2000  indicates that these are not just speculative projections. In addition, 25% of the permafrost near the surface could be lost with a 2°C global warming (70% in a 5°C scenario) according to the IPCC, which some fear could unlock diseases. Witness the release of anthrax bacteria in Russia in 2016, attributed by some experts to the unusually warm weather. In 2014, scientists even revived a virus that had been trapped in Siberian ice for 30,000 years. Thus, the World Bank considers that climate change could be a factor of fast-spreading, catastrophic outbreaks.
Besides, climate change induces profound physical evolutions that go far beyond health risks. More frequent extreme climatic events and the sea level rise will destroy infrastructure, the increase in average and peak temperatures will harm labour productivity in most countries, aridification and the degradation of ecosystems will increase food insecurity, etc. These phenomena will likely generate political instability and hundreds of millions of migrants. Climate change therefore dramatically increases the probability of Covid-19-like events, that is to say “fat-tailed events” with world- and economy-wide impacts. One of the worrying lessons of the current crisis is the low resilience or even unpreparedness of the global economic system to this kind of shock, even though health, food, energy, information and community networks have shown their immense value by softening some of the blows.
The 2008 financial crisis had already brought to light the vulnerabilities of the contemporary economic system, with close financial and trade relations spreading local shocks. This led to interesting evolutions such the black swan image developed by Nicholas Taleb or the efforts, although largely insufficient, to implement stress tests and stricter international prudential ratios. However, in a recent report, the BIS warns that “climate change could […] lead to green swan events” due to the “interacting, nonlinear and fundamentally unpredictable” dynamics involved. In this context, the BIS pleads for an “epistemological break” in risk management.
Calibrating crisis prevention and resolution systems for massive perturbations is crucial in preparing for a warmer world. First and foremost, to mitigate future shocks, the compass of every economic actor and government must now point to the rapid end in the dependence on fossil fuels. Second, the resilience of society’s overstretched vital functions mentioned above should be reinforced. Finally, the Covid-19 crisis is teaching us two very important lessons that ought to be useful in the fight against climate change: (i) international cooperation trumps isolationism to resolve a global crisis; and (ii) ignore scientists at your peril.
 The WHO considers that other climate change-related risks, more difficult to quantify, like economic damages, major heatwave events, river flooding, water scarcity, or human security will also significantly increase mortality. See WHO, 2014. Quantitative risk assessment of the effects of climate change on selected causes of death, 2030s and 2050s. World Health Organization Report.
In addition, the WHO considers that meeting the targets of the Paris climate agreement would save over one million lives a year from air pollution alone by 2050. See WHO, 2018. COP24 Special report: Health & Climate Change. World Health Organization Report.
 In 2100, 75% of the world's population would be exposed more than 20 days a year to so-called "life-threatening" climatic conditions (combination of extreme heat and humidity, those conditions having empirically led to significant increases in mortality) in a “business as usual” scenario. See Mora et al., 2017. Global risk of deadly heat. Nature Climate Change.
 See Tong et al., 2017. Perceptions of malaria control and prevention in an era of climate change: a cross-sectional survey among CDC staff in China. Malaria Journal.
 IPCC, 2019. Special Report on the Ocean and Cryosphere in a Changing Climate
 The disease had been last seen in the area in 1941. See: https://www.theguardian.com/world/2016/aug/01/anthrax-outbreak-climate-change-arctic-circle-russia
 See Yong, 2014. Giant virus resurrected from 30,000-year-old ice. Nature News & Comment, 3 mars 2014
 See for instance Burke et al., 2015. Global non-linear effect of temperature on economic production. Nature
 Estimations of “climate migrants” by 2050 range from 250 million to 1 billion people. See for instance the Lancet countdown 2018 report.
 See for instance Weitzman, 2011. Fat-Tailed Uncertainty in the Economics of Catastrophic Climate Change. Review of Environmental Economics and Policy.
 See Taleb, 2010. The Black Swan: The Impact of the Highly Improbable.
 BIS, 2020. The green swan: Central banking and financial stability in the age of climate change. Bank for International Settlements Report.
 Although the current results of international cooperation are not satisfying, its potential benefits to solve the health crisis, let alone the economic crisis, are fairly clear: sharing of data to understand the evolution of the virus and the treatments that work (or not), exchange of medical equipment or drugs according to the evolution of the epidemic outbreaks, etc.