On the second day of the climate summit in Paris, negotiators sent heads of state home and got down to the real business. To many countries, it boils down to one question: who pays?
Today, the world's poorest countries pushed the developed economies to fulfill a promise to provide $100 billion to developing countries. This case has been made consistently by one of the most important delegations in Paris: India.
Indian soon will be the biggest importer of coal, and the largest source of new demand for oil. Post-war America used to be that country. But India, population wise, is four Americas. And hundreds of millions of its people are just starting to move up the energy ladder.
"The state of Bihar is home to 100 million people," said University of Chicago economist Michael Greenstone. "Per capita electricity consumption is about 200 kilowatt hours per person per year. In the U.S. it's about 65 times higher."
The problem is India is already the world's third-biggest emitter of carbon dioxide. And as its people plug in, even an ambitious build-out of solar energy will still require additional power from coal, the cheapest source of electricity.
So India's emissions, under its Paris climate pledge, could double. Many call this a growth-climate paradox.
"It is now India's time to be in the ascendancy," said Varun Sivaram, fellow at the Council on Foreign Relations. "But with this growth is going to come both domestic problems, like air pollution and congestion, as well as international problems like climate change."
At the Paris talks, the Indian delegation is pushing for developed countries to provide billions in aid for a clean energy transition. When that money and technology comes, India can consider more emissions cuts.
"The challenge with India is India cannot afford to play with what's over the horizon," said Richie Ahuja of the Environmental Defense Fund's India office. "It has got so many urgent here-and-now problems that it will ratchet up ambition as it can see the horizon."
And ratcheting up the ambitions of India and every other country is a topline goal in Paris. Under current pledges, average planetary warming is projected to reach five degrees Fahrenheit.