The Global Deal

The danger from climate change lies not only, or even primarily, in heat. Most of the damage is from water, or the lack of it: storms, droughts, floods, rising sea levels. The levels of warming that we risk would be profoundly damaging for all countries of the world, rich and poor. A transformation of the physical geography of the world also changes the human geography: where we live, and how we live our lives.

We do not know for sure by how much global temperatures will rise if we follow "business as usual." I choose 5°C here to illustrate the risks because there seems to be around a 50-50 chance of eventual temperature increases around this magnitude if we continue along likely current growth paths, or follow business as usual for much of this century. Increases of 5°C would be devastating, but there are deeply worrying probabilities of being above 6°C or more next century. And even in a very optimistic assessment of the consequences of business as usual, we can still expect a rise of around 4°C, the effects of which would also be profoundly damaging, triggering unstable dynamics we do not yet fully understand. Indeed, such risks occur at lower temperatures and concentrations of greenhouse gases.

The seriousness of a 5°C increase is clear when we realize that in the last ice age, around 10,000 years ago, the planet was 5°C cooler than now. Most of Northern Europe, North America and corresponding latitudes were under hundreds of meters of ice, with human life concentrated much closer to the equator. We have to go back 30 to 50 million years, to the Eocene period, to find temperatures as high as 5°C above pre-industrial times. The world’s land then consisted mainly of swampy forest. Temperature increases on this scale, and the consequent climate change, lead to massive dislocation, generate huge new vulnerabilities, and redraw patterns of habitation. They cannot be understood in terms of the difference between Stockholm and Madrid, or Maine and Florida, or the idea that we might just need a little more air conditioning and flood defense.

The central message is not, however, one of despair. These huge risks can be reduced drastically at reasonable cost, but only if we act together and follow clear and well-structured policies starting now. The cost of action is much lower than the cost of inaction — in other words, delay would become the anti-growth strategy. The low-carbon world we must and can create will be much more attractive than business as usual. Not only will growth be sustained, it will be cleaner, safer, quieter, and more biodiverse. We understand many of the necessary technologies and will create more; and we can design the economic, political and social structures that can take us there. We require clarity of analysis, commitment to action and collaboration. It is neither economically necessary nor ethically responsible to stop or drastically slow growth to manage climate change. Without strong growth it will be extremely difficult for the poor people of the developing world to lift themselves out of poverty, and we should not respond to climate change by damaging their prospects. Moreover, politically it would be very hard to gain support for action by telling people that they have to choose between growth and climate responsibility. Not only would it be analytically unsound, it would also pose severe ethical difficulties and be so politically destructive as to fail as policy.

This is not to claim that the world can continue to grow indefinitely. It is not even clear what such a claim would involve; societies, living standards, ways of producing and consuming all develop and change. A picture of indefinite expansion is an implausible story of the future, but two things are key: first, to find a way of increasing living standards (including health, education and freedoms) so that world poverty can be overcome; and second, to discover ways of living that can be sustained over time, particularly in relation to the environment. Strong growth, of the right kind, will be both necessary and feasible for many decades.