Humanity faces two fundamental challenges this century. The first is to lift billions of people out of poverty and give them the opportunity to live healthy and dignified lives. The second is to ensure that this development does not destabilize the climatic and ecological systems that have enabled the rise of humans and other life on Earth. The problem is that these two goals are increasingly at odds.

Reconciling the twin imperatives of conservation and development is not easy. ‘Sustainable development’ is a catchphrase that neatly defines what the world must ultimately achieve, but nobody knows precisely what it looks like at full scale. Later this year, governments will finalize a set of sustainable development goals to guide international aid (see also page 432), and in December global leaders will gather to discuss the latest climate agreement at a summit in Paris. Any deal will be burdened by inevitable compromises that allow space for polluting development as the world seeks better and cheaper solutions.

The latest attempt to create a framework for thinking about this dilemma comes from 18 environmental activists and academics, who published an ‘Ecomodernist Manifesto’ last week (see The essay paints a hopeful picture of technological progress while placing importance on the kind of intensive development that has characterized humanity’s rise so far. Only by concentrating our impact within the urban, industrial and agricultural context can we achieve a “good Anthropocene”, or age of human influence, the authors argue.

Coal, oil and natural gas have improved many lives, and the essay points out that the long arc of development is already tending towards better, cleaner and more-efficient energy technologies — just not fast enough. At least in the short term, the authors contend, poor countries are right to focus on improving the lives of their citizens, even if that means expanding their use of fossil fuels until cheaper and cleaner solutions are available. These ideas are framed in terms of a larger “decoupling of humanity from nature”. What this means, precisely, is left to the imagination, but the essay also underscores the role of modern agriculture, which has freed up labour, enabled the rise of cities and reduced the amount of land that we need to feed humanity. Rather than lament this trend, the authors argue that it must be encouraged and hastened.

Governments cannot write people out of the equation.

The essay stands in sharp contrast to the gloomy outlook often provided by environmentalists and scientists. A little scepticism is warranted. For the long haul, the authors place faith in a new generation of solar cells combined with efficient energy-storage technologies, advanced nuclear fission — and even fusion energy. In the medium term, hydropower could play a part, in the same way that technologies for the capture and sequestration of carbon could improve fossil fuels over this time scale. The authors focus on large-scale power generation, but may be too quick to write off current wind and solar technologies, which can have a useful role in reducing demand for centralized power today. The wise deployment of efficient bioenergy resources may also be helpful, in tandem with agricultural intensification.

It is not yet clear what the climate fix will look like. What is clear is that governments need to invest in a portfolio of energy research, development and demonstration. They must implement strong climate policies that will push companies towards technologies that produce less air pollution and fewer greenhouse-gas emissions. They need to invest in agricultural research to secure the necessary food crops, and provide farmers and ranchers with the tools required to maximize production. And they need to set limits on the land that can be developed.

Governments cannot write people out of the equation, and hard choices will have to be made. But the first step is to point everybody in the right direction. Human ingenuity takes many forms, and we may yet surprise ourselves.