A document that nearly all countries are parties to is called the UN Framework Convention on Climate Change (UNFCCC). This document was signed at the Earth Summit, a famous international event held in Rio de Janeiro, Brazil, in 1992. The UNFCCC’s objective is “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic [i.e., human-caused] interference with the climate system.” There have been many meetings called Conference of the Parties meetings, or COP meetings. Each COP meeting attracts thousands of attendees and lasts about 12 days. COP 13 was held in Bali, Indonesia, in December 2007. I was there. Two months earlier, the world had learned that the 2007 Nobel Peace Prize was to be awarded equally between Al Gore, the American politician, and the IPCC, the Intergovernmental Panel on Climate Change. The outcome of the Bali meeting was deeply disappointing, but not surprising. Governments and businesses worldwide, and ultimately, humankind as a whole, will determine what actions will be taken. Climate science, however, is able to provide highly useful input to this policymaking process.

In the preceding chapters, I examined four liabilities in the standard reading of Kant. As commentators continue to green the philosophical canon with figures as diverse as Confucius, Plato, Leibniz, Spinoza, Goethe, Heidegger, Nietzsche, Marx, Arendt, and Habermas, so also has it become apparent that a greener Kant is now possible. A greener Kant is also valuable, especially for rethinking the challenges of climate change. In Chapters 1 and 2, I showed why these liabilities and their attribution to Kant make sense: When Kant’s philosophy is limited to very specific texts from a single period in Kant’s intellectual career – the Groundwork, Critique of Pure Reason, and Critique of Practical Reason – red flags abound. And while I argued that strict Kant commentators such as Guyer, O’Neill, and Varden do a formidable job defending Kant in his letter, they fail in bringing his philosophy up to speed with issues regarding the climate crisis. Interpreters of Kant in spirit also do an admirable job.

Many of us have an Uncle Pete, for whom the climate change issue is not a science topic at all. It is just one more way for the authority of the state to control the lives of citizens. This view has nothing to do with science, and no argument based only on science can change it. For Uncle Pete, attacking climate science and scientists is simply a disguise for what really concerns him, a government that in Pete’s view seizes power, limits freedoms, increases taxes, regulates markets, and diminishes prosperity. As a climate scientist, I can say something with very high confidence about what will happen if we do nothing, which is Pete’s preferred policy. Vast numbers of people will become environmental refugees, and we will see the destabilization of governments, especially in failed and failing states. In wealthy and powerful countries, such as the United States, governments coping with severe climate change will surely have to act forcefully, including using emergency powers, as in wartime, to preserve order and to minimize chaos and damage. Doing nothing is likely to force governments to do exactly what Uncle Pete fears most: seize power and limit freedoms.

An important aspect of the climate change challenge is simply that too many people rarely or never talk about it. Any issue that we refuse to talk about can quickly become one that we will do nothing about. We also know that discussing a problem can often help in solving it. Preparing well is the first step to understanding climate change well and then communicating this knowledge well. My colleague Susan Joy Hassol and I have this guiding philosophy that underlies our approach to climate science communication: Use simple clear messages, repeated often, by a variety of trusted messengers. Trusted messengers can have an enormous impact and can motivate people to bring about change. Think of Mahatma Gandhi, or Nelson Mandela, or Martin Luther King Jr. Become something of an expert yourself first, at least in certain areas of climate change science, and only then try to communicate what you have learned.

There are many parallels between climate change and medical topics. Some can be useful in educating people and politicians. It is frustratingly difficult to get people and their governments motivated to act to avert climate change. Yet people are intensely interested in threats to their own health. Many Americans have improved their health by making major changes that are directly attributable to the results of medical science. Real progress has been made in making Americans, and their government, more aware of unhealthy behavior. Medical science has achieved a measure of pervasive respect that climate science can only envy. Journalists covering a medical discovery do not mistrust researchers or insist on hearing from “the opposing view.” When reporting on research showing the need for Americans to eat more sensibly and be physically active, the media does not treat these advances in medical science in terms of a dispute. Journalists do not feel obliged to seek out medical contrarians “for balance.” Medical metaphors and parallels between the two fields (such as “prevention is better than cure”) can thus be powerful aids to communicating.

My family and I decided to replace the furnace in our house, one that burned natural gas, with an electric heat pump system. We also installed a solar photovoltaic system including an array of solar modules or panels on our roof. In that way, we could generate most of the electricity used by our house from renewable solar energy. Weaning the entire world from fossil fuels, however, is a staggeringly complex and difficult task. Imagining a better world for tomorrow is relatively easy. Getting to that better world, starting from the existing world of today, is not easy at all. Vaclav Smil, in his 2022 book How the World Really Works: A Scientist’s Guide to Our Past, Present and Future, makes the case that this task will require immense changes in many areas where fossil fuels are now vital to the production of massive amounts of materials indispensable to modern civilization. Smil calls ammonia, steel, concrete, and plastics, “the four pillars of modern civilization.” All four pillars require very large amounts of fossil fuels to produce. Smil estimates that completing the transition of weaning the world from fossil fuels will likely take several decades or even longer.

Chapter 1 motivates a Kantian analysis of climate change by examining early criticisms against Kant in the field of animal ethics. If Kant’s philosophy is ill-suited for justifying concern for nonhuman animals, its suitability for broader environmental issues remains unclear. After evaluating passages from Kant’s critical texts that motivate these criticisms, I assess a classic set of objections to the standard reading of Kant’s theory from Christina Hoff. After analyzing attempts by contemporary Kant scholars to respond to her challenge, I conclude with the merits of the standard reading of Kantian ethics for the sixth mass extinction debate.