‘Where you live should not determine whether you live’. Global justice and the distribution of COVID-19 vaccines

ABSTRACT

In 2020, the world faced a new pandemic. The corona infection hit an unprepared world, and there were no medicines and no vaccines against it. Research to develop vaccines started immediately and in a remarkably short time several vaccines became available. However, despite initiatives for global equitable access to COVID-19 vaccines, vaccines have so far become accessible only to a minor part of the world population. In this article, I discuss the global distribution of COVID-19 vaccines from an ethical point of view. I reflect on what ethical principles should guide the global distribution of vaccines and what global justice and international solidarity imply for vaccine distribution and I analyse the reasons for states to prioritize their own citizens. My focus is on ethical reasons for and against ‘vaccine nationalism’ and ‘vaccine cosmopolitanism.’ My point of departure is the appeal for international solidarity from several world leaders, arguing that ‘Where you live should not determine whether you live’. I discuss the COVAX initiative to enable a global vaccination and the proposal from India and South Africa to the World Trade Organization to temporarily waive patent rights for vaccines. In the final section, I argue for global vaccine sufficientarianism, which is a modified version of vaccine cosmopolitanism.

KEYWORDS:

• COVID-19 vaccinations
• global justice
• international solidarity
• COVAX
• WHO
• WTO
• patent rights
• vaccine nationalism
• vaccine cosmopolitanism
• global vaccine sufficientarianism

Introduction

In 2020, the world faced a new pandemic. The corona infection hit an unprepared world, and there were no medicines and no vaccines against it. The world-wide consequences of the pandemic have been devastating leading to millions of deaths, hospitalizations, lockdowns, unemployment, hunger, human rights-violations, etc.

Vaccine research started immediately and in a remarkably short time several vaccines became available. Normally, it takes 10–15 years to develop new vaccines, but Pfizer and AstraZeneca received emergency use of their new vaccines already after a year. However, despite initiatives for a globally fair distribution of COVID-19 vaccines, vaccines have so far not become accessible to a large part of the world population. ‘Vaccine nationalism’ and the uneven distribution of vaccines have raised concern, primarily from the WHO and global NGOs like Oxfam and Doctors Without Borders (Vaccine Nationalism 2021; Oxfam 2020; Medicines Sains Frontiers 2021)

In this article, I discuss global distribution of COVID-19 vaccines from an ethical point of view. I reflect on what ethical principles should guide the global distribution of vaccines and what global justice and international solidarity imply for vaccine distribution, and I analyse reasons for national governments to prioritize their own citizens. My focus is on ethical arguments for and against ‘vaccine nationalism’ and ‘vaccine cosmopolitanism.’

My point of departure is the appeal for international solidarity from several world leaders, arguing that ‘Where you live should not determine whether you live’. I discuss the COVAX initiative to enable a global vaccination and the proposal from India and South Africa to the World Trade Organization (WTO) to temporarily waive patent rights for vaccines. In the final section, I argue for global vaccine sufficientarianism, which is a modified version of vaccine cosmopolitanism.¹

Global distribution of vaccines against COVID-19

In July 2020 five national leaders, including the Prime ministers of New Zealand, Spain, Sweden and Tunisia and the Presidents of South Korea and South Africa, published an article in Washington Post with the headline ‘The international community must guarantee equal global access to COVID-19 vaccine.’ They asserted that ‘ … we must urgently ensure that vaccines will be distributed according to a set of transparent, equitable and scientifically sound principles. Where you live should not determine whether you live, and global solidarity is central to saving lives and protecting the economy.’ (Trudeau et al. 2020)

In view of the present global distribution of health care resources the ideal – to quote the Washington Post article – that ‘ … Where you live should not determine whether you live …,’ implies a radical challenge. While high-income nations spend as much as $ 5000/person/year on health care for their citizens, in fact the US even the double, low-income nations like Mozambique and Kongo can only afford to spend $30–60/person/year (World Bank 2021). So, at the present, where you live indeed determines whether you live.

In the Washington Postarticle, the world leaders refer to COVAX (COVID-19 Vaccines Global Access Facilities) as instrumental for achieving the radical goal of global solidarity. COVAX is a collaboration between the World Health Organization (WHO), Gavi (a Vaccine Alliance) och CEPI (Coalition for Epidemic Preparedness Innovation). The objective of COVAX is ‘ … to accelerate the development, production, and equitable access to COVID-19 tests, treatments, and vaccines’ (WHO 2021) and the aim for 2021 was to distribute 2 billion doses and to achieve that 20% of each countries’ population was vaccinated by the end of the year. Despite the vast global gaps in health care resources, the vaccines are distributed equally between WHO member countries and not according to need.

Why then this focus on fair distribution of vaccines against COVID 19? Certainly, there could be equally relevant demands for fair distribution of also other vital health care resources, like medical equipment, medicines, etc., but when the world was facing the corona pandemic crossing all national borders, the need for a global perspective became evident and so did the extreme inequality in resources to buy vaccines, the only means to overcome the threat.

But perhaps the need for vaccines is lesser in low-income countries than in high-income countries? In high-income countries, the population is older and thus more vulnerable to COVID-19. However, health care systems in low-income countries are fragile, with no means to treat COVID-19 patients in intensive care. Further, the imposed lockdowns have secondary devastating effects like growing food insecurity, poor people losing the means for their daily survival and stricken by poverty-related diseases, and that youth loses educational opportunities (Josephson, Kilic, and Michler 2021). There also seems to be an undercounting of cases and deaths from COVID-19 in Africa. The number of infection cases could be as much as seven times higher than official data suggests, and the number of deaths from the virus two to three times higher (Beaumont 2022).² Overall, the consequences of COVID-19 might be at least as devastating in low-income countries as in high-income countries and, thus, the need for vaccines as great.

Vaccines against COVID-19 became available in a uniquely short time. Already when the new vaccines were at the development stage, several high-income countries and regions, like the USA and the European Union, quickly reserved vaccines for their own populations. It was reported that before the end of 2020, the richest countries already had bought 80% of the Pfizer vaccine (Kartal 2021). In January 2021, the WHO Director General Tedros Adhanom Ghebreyesus warned that the world was ‘ … on the brink of a catastrophic moral failure’ while wealthy countries were buying up available COVID-19 vaccines. ‘The price of this failure will be paid with lives and livelihoods in the world’s poorest countries,’ Tedros said (Vaccine nationalism 2021).

The moral failure that Dr Tedros warned against seems to have become a reality. Due to a lack of funding and disposal of vaccines, only 400 million doses across 145 countries were delivered by November 2021 (Irfan 2021). In January 2022, the European Commission had secured up to 4.2 billion doses of COVID-19 vaccines, and 1.2 billion doses have been delivered (European Commission 2022). So far (16 March 2022), while vaccination rates are as high as 70–80% in high-income countries, only ca 14% of the populations in low-income countries have received one dose (Our World in Data 2022). Although there are various reasons for this low vaccination rate, like weak public health infrastructures, complex storage of mRNA vaccines, vaccine scepticism, etc., the main reason is that rich countries hoard large amounts of vaccines (Aizenman 2021).

To increase the global production of vaccines, in October 2020 India and South Africa proposed to the World Trade Organization (WTO) that patent rights for COVID-19 vaccines should be waived, in accordance with the TRIPS-agreement that allows waving of patent rights to medicines and vaccines in situations of national emergency and extreme urgency. A state may then licence a company to produce generics when faced with a public health problem, according to the so-called Doha Declaration (Doha Declaration 2001). The proposal from India and South Africa got support from more than 100 nations, including the United States and France, and from WHO, UNAIDS, and NGOs like Oxfam and Doctors without Borders. However, the European Union and most of its member states have until now blocked the proposal (Cohen and Kupferschmidt 2021, Farge 2021).

What then is a globally just distribution of vaccines against COVID-19? What ethical principles should guide the global distribution? I will first discuss arguments for, what has been called, ‘vaccine cosmopolitanism’, which coheres with the moral judgement that ‘Where you live should not determine whether you live’. Vaccine cosmopolitanism entails that every human being irrespective of nationality has the same right to vaccination against fatal viruses. I will then discuss arguments for ‘vaccine nationalism’, implying that citizenship is a relevant factor for decisions on priorities of vaccination. Finally, I will discuss whether there is a middle position, and argue for modified vaccine cosmopolitanism.

Vaccine cosmopolitanism

‘Where you live should not determine whether you live’. This moral judgement has a strong appeal and can be supported by various ethical arguments.

According to a principle of human dignity, each human life is of equal importance and each human life is equally valuable (Collste 2002; Düwell 2014). Therefore, each human being has the same right to basic health care resources according to need, and, consequently, to be vaccinated against COVID-19 when needed.

Another argument for the judgement that ‘Where you live should not determine whether you live’ is based on the human condition. As humans, we have no influence over where and when we happen to be born. This is the outcome of the social and natural lottery. Luck or bad luck in the social and natural lottery, that is, if you for example are born by wealthy or poor parents or with genetically rich endowed or genetically poor endowed parents, should not determine your life chances. These are arbitrary facts from a moral point of view. This idea is the starting point for luck-egalitarianism; ‘ … no one should be worse-off because of her poor luck’, writes Kok-Chor Tan (Tan 2012, 88).

Even your birthplace is a result of the natural lottery. As Simon Caney asks: ‘Given that it is an injustice that some face worse opportunities because of their class or their ethnicity, is it not an injustice that some face worse opportunities because of their nationality?’ (Caney 2005, 123). While every human being is vulnerable to get infected by COVID-19, every human being has an equal right to be protected by vaccines, irrespectively of nationality. In line with this view, philosopher Nicole Hassoun writes, ‘A truly ethical proposal would treat all people equally and help countries get vaccines to people when they lack capacity to do so on their own’ (Hassoun 2020).

Which ethical principles should then guide the global distribution of vaccines against COVID-19? In the report Ethical Choices in a Pandemic, the Swedish National Council on Medical Ethics proposes two principles: global justice and international solidarity (Ethical choices, 2020). Similar principles are also proposed by other ethics councils (Nuffield Council 2020; Deutscher Etikrat 2021). These principles seem to be widely shared, and I will explicate them below. A principle of global justice could guide decisions in global institutions, and a principle of international solidarity could guide national decision-making, for example,when rich nations decide on how to balance their own domestic needs and the needs of poor nations. I argue that if these two principles inform the decisions on how to distribute COVID-19 vaccines globally, it will contribute to the realization of the moral judgement that where you live should not determine whether you live.

Global justice

The meaning of justice is widely debated in ethics, not least since John Rawls published A Theory of Justice in 1971 (Rawls 1971). This is not the place to recapitulate Rawls’s theory in detail. Shortly, Rawls elaborates a theory of a just society. In an ‘original position’ under a ‘veil of ignorance’ the parties are deprived of all knowledge of their personal characteristics and social and historical circumstances. They agree on basic principles of justice; according to the ‘general conception’ of justice; ‘All social primary goods … are to be distributed equally unless an unequal distribution … is to the advantage of the least favored’ (Rawls 1971, 303). This last condition is called ‘the difference principle’. Rawls’s theory is institutional. In a just society, social institutions, or in Rawls's words ‘the basic structure,’ are organized so that they are the subject of justice. In this article, I use a Rawlsian institutional concept of justice.

Although Rawls himself in The Law of Peoples argues against a global application of the difference principle (Rawls 1999, 116), several political philosophers have applied the theory globally and to global institutions (Beitz 1979; Pogge 1989; Tan 2005; Collste 2005). From a Rawlsian perspective, they argue that global justice refers to principles of justice that should regulate decision-making within global institutions.

According to the difference principle, inequalities in the distribution of primary goods, like health care resources, education, etc., are permissible only if they benefit the least well-off. This suggests that the distribution of vaccines against severe viruses like the coronavirus, as a primary health care resource, should be to the greatest benefit of the least advantaged. When applied to the global distribution of vaccines against COVID-19, global justice implies that the globally least advantaged, undoubtedly the populations in low-income countries, should be given priority.

There is no global state with institutions that could administer global distributions according to principles of justice. This fact is a common objection to the feasibility of a global application of Rawls’s principles (Nagel 2005). However, there is in fact a global basic structure. Regarding the question of justice and the global distribution of COVID-19 vaccines, the WHO and the WTO are potentially global institutions of primary interest.

The WHO is the United Nations’ agency for health issues. All nations are members of WHO and the World Health Assembly is the supreme decision-making body. The WHO has managed the international cooperation in combating the corona pandemic, including information, convening international expert networks, etc. The WHO is also as we noticed a main actor within COVAX. However, the WHO lacks power to influence the global distribution of vaccines and can only rely on charity initiatives like COVAX to distribute vaccines to low-income countries. The WHO Director has urged the rich nations to donate vaccines to the poor, but without any institutional power, the WHO cannot enforce these recommendations.

The World Trade Organization (WTO) is the international organization handling the rules of trade between nations. The WTO’s top decision-making body is the Ministerial Conference with representation of the 160 member countries. As noticed above, the WTO administers international patent rights and intellectual property rights, including patent rights to COVID-19 vaccines. Thus, in contrast to the WHO, the WTO has institutional power to influence the global distribution of COVID-19 vaccines. In this way, the WTO is a global institution in a Rawlsian sense. If the WTO decides to temporarily waive patent rights of COVID-19 vaccine production in line with the proposal of India and South Africa, this would facilitate the global production of vaccines and potentially increase access to vaccines in low-income countries. A waiver of patent rights would be a step towards global justice.

Both the WHO and the WTO can influence the distribution of COVID-19 in favour of low-income countries. The WHO through COVAX, and the WTO through modifying institutional regulations of patent rights at a global level. So far, COVAX has not fulfilled its aim. Hence, while COVID-19 is still ongoing, and other pandemics will probably follow, it seems that in the long run there is a need for institutional change to realize the principle of global justice. As Erondo and Singh writes, ‘ … ultimately vaccine donations are a temporary response. They cannot replace long-term solutions to vaccine inequity. A real solution is to democratise vaccine production. There must be a particular emphasis on production capacity and increased access to technologies and knowledge transfer’ (Erondo and Singh 2021). This, then, would require a waiver of patent rights for COVID-19 vaccines.

International solidarity

International solidarity is the second principle for vaccine distribution proposed by the above-mentioned national ethics councils. What then is the meaning and implication of a principle of international solidarity? According to the Collins dictionary, solidarity means ‘If a group of people show solidarity, they show support for each other or for another group, especially in political or international affairs … ’ (Collins 2021). Given this definition, international solidarity means that vaccines against COVID-19 should be distributed so that countries with resources to purchase vaccines, distribute them in support of low-income countries that lack these resources.

To sum up, the idea that where you live should not determine whether you live, could be supported by a principle of human dignity and by luck-egalitarianism. When the idea is applied to the global distribution of vaccines against COVID-19, principles of global justice and international solidarity are guiding ethical principles.

Intuitively, principles of global justice and international solidarity seem to be morally right, coherent and supported by strong arguments. Nevertheless, as we noticed, they have so far not been driving the global vaccine distribution. Instead, rich nations have hoarded vaccines for their own use. Vaccine nationalism has been the guiding idea. How could this be the case? Is there a moral underpinning of vaccine nationalism? These are questions for the next section.

Vaccine nationalism

As noticed, the actual global distribution of vaccines stands so far in sharp contrast to principles of global justice and international solidarity. This could be explained by the fact that nations are not acting according to moral principles, but instead according to national self-interest. The recent behaviour of a group of high-income countries to benefit themselves by hoarding vaccines has been labelled ‘vaccine nationalism’ by the UN General Secretary Guterres, and it results in the present unequal distribution (Vaccine Nationalism 2021). Does this fact imply that international solidarity, for example expressed by world leaders in the above-mentioned Washington Post article, is just meaningless rhetoric? Is it perhaps illusionary and idealistic to refer to principles like global justice and international solidarity in the discussion on the global distribution of vaccines against COVID-19?

The appeal by world leaders illustrates a tension between ethics and politics, between international solidarity and national self-interest. The Washington Post article could be interpreted as an expression of a commitment of world leaders, although they in practice prioritise their own populations. However, if we take these kinds of declarations seriously, they can at least encourage a critical self-assessment of realpolitik. Ethical principles as correctives to politics. And, if public media and NGOs constantly remind politicians of their declarations and promises, they might act in a spirit of solidarity.

On the other hand, vaccine nationalism could perhaps be morally justified.?Let me discuss some possible arguments for vaccine nationalism.

One line of argument could refer to a modern Hobbesian notion of a legitimate state. For example, Bernard Williams argues that there are some necessary basic legitimation demands that a state must fulfil. Each citizen should have reasons to comply with the state. The state is constituted by the consent of the citizens and the consent presupposes that their interests are taken account of (Williams 2005). This view of legitimation implies that the citizens could expect that the state achieves what is required to meet their needs during a pandemic, by for example managing a sustainable vaccine strategy.

Statism (also sometimes labelled nationalism) is another position that could justify vaccine nationalism. Statism does not assume that international politics is amoral, but that there are moral reasons for states to act according to their self-interests based on associative duties between citizens. Political leaders have, according to this position, special obligations towards their own constituency. The leaders are elected by the citizens under the presumption that they should act according to their interests. This is a kind of contractual obligation, based on important moral principles of trust, solidarity and promises. According to this position, political leaders have primary moral obligations to their fellow citizens that exceed any global obligations (Miller 1999). Therefore, citizens could for good reasons expect that their elected leaders see to that their need for vaccines against COVID-19 are satisfied.

According to realism in international politics, states follow – and ought to follow – a principle of self-interest. This is, as we can see, both a descriptive and a normative thesis. It says, first that states typically act out of self-interest, and second that they also ought to act this way. The basic justification for realism is that it is rational and prudent for political leaders to act according to national self-interests (Korab-Karpowicz 2017).

Realism in international politics is a commonly held view. But is it tenable? In its extreme forms, it rules out any criticism of political acts from a moral point of view. It excludes the possibility to criticize oppressive politics, yes, even aggressions and genocides from a moral point of view. The only relevant critique of this kind of acts would be from self-interest or for pragmatic reasons. If we accept that at least some outrageous political acts should be criticized from a moral point of view, for example with reference to human rights or international conventions, the realist thesis must be modified.

A modified realism holds that to achieve stability and order, states should domestically uphold some basic human rights, and internationally be fair and respect treaties, etc. However, states have no moral obligations towards other states or towards the global community.

Universalized statism implies that if all states act according to self-interest, it will gain the common, global interests. A problem with this justification is though that the capabilities of states to protect the interest of their citizens varies. The figures of different nations´ health care resources above illustrate the huge gaps between high-income countries and low-income countries with regard to providing sufficient health care for their citizens.

A middle way?

We have so far discussed arguments for vaccine cosmopolitanism and vaccine nationalism. We have found that there are strong arguments in favour of vaccine cosmopolitanism but also arguments for why healthcare coverage is politically bounded. Perhaps states both have global moral duties and special duties to their citizens? The duties to their citizens are based on a kind of contractual agreement and imply, for example, duties to provide health care, including vaccinations. The global moral duties would be less demanding, amounting to humanitarian duties to relief aid. This position is in line with how states have acted during the corona pandemic. Many high-income countries have both hoarded huge amounts of vaccines for their own populations, and supported COVAX financially and with donations of vaccines (Global leaders, 2021). However, this strategy does not account for the moral arguments for vaccine cosmopolitanism.

Even if we accept that states have special duties to their citizens, it does not rule out that they also should comply to cosmopolitan principles of distributive justice. First, states are engaged in global institutions, like the WHO and the WTO, and within these institutions they should comply with principles of justice. As Simon Caney writes, ‘They can … pursue their ends within the context of a fair overall framework’ (Caney 2005, 140). Second, in line with the statement ‘Where you live should not determine whether you live’, the principle of equal human dignity and the principle of luck-egalitarianism are more basic than duties to citizens. Hence, states are indeed justified to prioritize their own citizens, but on the condition that basic needs of all human beings are assured.

The idea that states have special obligations to their citizens when stricken by a pandemic seems reasonable. However, the question remains how these obligations should be balanced against the obligations of global justice and international solidarity? Perhaps, luck-egalitarianism is too demanding. It would imply that primary goods, including vaccines against COVID-19, ought to be distributed equally. A more realistic option, which also considers a state’s special duties to its citizens in a pandemic, is that states ought to provide vaccines and other health care resources to their citizens, but on the condition that the global population has sufficient resources, including access to vaccines, for managing the pandemic (which of course is difficult to determine) (Tan 2012). This view, we can call it global vaccine sufficientarianism, implies that when the global population has achieved a certain level, a threshold, of vaccine distribution, political leaders in high-income countries could prioritize their own population. Thus, global vaccine sufficientarianism is a position that takes both the principle of human dignity regardless of nationality or citizenship seriously and admits that states have special duties to their own citizens. In contrast to global vaccine sufficientarianism, vaccine nationalism disregards a principle of universal human dignity, and vaccine cosmopolitanism disregards that political leaders’ have special duties to their own constituency.

What then are the practical implication of global vaccine sufficientarianism for the distribution of vaccines against COVID-19? Access to COVID-19 vaccines is necessary for protection against being infected by the coronavirus and could be seen as a condition for living a good life. Global vaccine sufficientarianism implies that each human being irrespective of nationality has the same right to be vaccinated against COVID-19. In the current situation when 70–80% of the population in high-income countries are fully vaccinated, available vaccines should be allocated to low-income countries. In practice, this implies for example that vaccination of children who are less vulnerable to COVID-19, or booster shots to elderly who already are fully vaccinated, must wait in high-income countries, until adults (perhaps in priority order: health-care workers, elderly, etc.) in low-income countries have got at least two doses of vaccines.³ When this goal is reached; where you live, does not determine whether you live, at least not with regard to the coronavirus pandemic.

Emanuel et al. argues for an ethically justified middle ground position. They propose what they call ‘the fair priority for residents (FPR) framework’. The FPR framework implies that ‘ … governments are permitted to retain COVID-19 vaccine doses for their residents, but only insofar as they are needed to maintain a noncrises level of mortality’ (Emanuel et al. 2021). Global vaccine sufficientarianism has similar practical implications.

Finally, prioritization of vaccinations in low-income countries is not only motivated by principles of global justice and international solidarity but also by the long-term interests of the high-income countries themselves. No one is safe until everyone is safe. As long as the global pandemic continues in any part of the world, there is the risk it will spread due to present global communications. Furthermore, especially in regions with low vaccination rates, new mutations will appear (Larrry 2021).

Conclusion

In this article, I discuss the global distribution of COVID-19 vaccines from an ethical point of view. I propose two guiding ethical principles, global justice and international solidarity. I identify the WHO and the WTO as two global institutions that potentially could influence a just distribution of vaccines. However, decision-making regarding vaccinations and distribution of vaccines is in the hands of national governments and the WHO lacks power to influence these decisions. The role of the WHO is to lobby for a just distribution and to engage in charity, primarily via COVAX.

The WTO is a global institution with an impact on the distribution of COVID-19 vaccines. The WTO is responsible for global regulations of property rights and patent rights and many member states have proposed a temporary waiver of property rights to vaccines against COVID-19 to speed up the production. I argue that a waiver is in accordance with a principle of global justice benefiting the least advantaged, in this case, populations in low-income countries.

While a principle of global justice focuses on the global basic structure, a principle of international solidarity focuses on national decision-making. To decrease the global gaps regarding access to COVID-19 vaccines, high-income countries should increase their donations through COVAX and in other ways.

But are not governments in high-income countries obliged to prioritize their own populations, by means of, for example, immediate vaccinations against COVID-19? Yes, they have a prima facie duty to do so, but on the conditions that the basic needs of vaccines are globally secured. Thus, I argue for a middle position; global vaccine sufficientarianism, between vaccine cosmopolitanism and vaccine nationalism that takes both the principle of human dignity regardless of nationality or citizenship seriously and admits that states have special duties to their own citizens. In practical ethics, it implies that in a situation when vaccination rates reach 70–80% in the high-income countries, they have a moral obligation to prioritize vaccination in low-income countries.

In conclusion, global vaccine sufficientarianism,

1. encompasses both principles of global justice and international solidarity on the one hand, and the duties of governments to their own citizens on the other,

2. provides a mid-way solution between vaccine cosmopolitanism and vaccine nationalism,

3. corresponds to the declarations of world leaders of international solidarity in a time of pandemic, and could

4. be realized through the joint efforts of WTO, WHO, COVAX and other international as well as national actors.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

¹ I am grateful for wise comments from anonymous reviewers.

² A recent study published in the Lancet estimates the excess mortality due to the pandemic COVID-19 to 18 million. The number of excess deaths due to COVID-19 was largest in the regions of south Asia, north Africa and the Middle East, and eastern Europe (Wang et al. 2022).

³ This priority correspond to the “Fair Priority Model”, proposed by Emanuel et al that national priority allows for the amount of vaccine needed to keep the rate of transmission (Rt) below 1 (Emanuel et al. 2021).