Either the ingenuity unleashed by the United States own special mix of free markets and government regulation will solve the climate change crisis or the rest of the world, having witnessed an American government content to stick its head in the sand, will forcibly compel the country into a green future. Such, at least, were the terms of the debate last night that wrapped up Day 1 of the State of the Planet conference at Columbia University.

Stanford University law professor David Victor --a legal expert on climate change and energy--and Vinod Khosla, a venture capital investor with a current focus on clean energy technology, argued that the U.S. will take the lead in trying to stem global warming, both by setting an example with domestic legislation to cut globe-warming pollution and by leading the world in innovative clean energy technology.

But Yale University law professor Daniel Esty, an environmental law and policy expert, and economist Michael Grubb of University of Cambridge in the U.K. countered that the rest of the world has already taken the lead--through efforts such as the Kyoto Protocol or the European Union's Emissions Trading Scheme-- and will not relinquish it.

"The U.S. is on the cusp of serious efforts to control emissions at home," Victor promised, citing efforts such as a climate bill pending in the U.S. that would impose mandatory limits on greenhouse gas emissions and the three remaining presidential candidates climate plans. "We have one world. The U.S. can and must and will engage in the efforts starting at home, starting with innovators and ultimately magnifying that worldwide," Victor added. Specifically he says the U.S. will impose stringent legislative caps on greenhouse gas emissions in the near future, develop technology to address the problem and then spread that technology cheaply throughout the world.

Not good enough, argued Esty, noting that more than just a U.S. response is required. "This is a global harm and we need a global response. We've seen how unilateralism works. We've lived it for the last seven years. It's not a successful strategy," he said, noting that the Kyoto Protocol involves more than 160 countries, pointedly not including the U.S. and therefore the best innovation potential is not here but abroad. And that's a good thing. "Innovation across the U.S. is good but innovation across the world is better. We cannot afford to leave anyone on the sidelines."

But the home for innovation--and the money to finance it--is in the U.S., Khosla argued. "What if engines consumed half as much oil? … What if renewable alternatives to oil were half the price of oil? … What if solar and geothermal power were both scalable and cheaper than coal and natural gas?" he said, a list of the kinds of technology start-ups in which he has already invested in the hopes of profiting from a clean energy revolution. "We don't have to force India and China to be part of global cap and trade if--and only if--these alternatives are cheaper than fossil [fuels]."

Yet, the U.S.--and much of the rest of the world--is spending most of its money on greenhouse gas-polluting energy, such as coal-fired power plants. "The world will spend around $20 trillion over the next few decades in energy sector. Most of that is still flowing and is projected to flow into higher carbon solutions," Grubb noted. "It is government action that will drive investment in the opposite direction." Technology innovation cannot get started anywhere without the appropriate government incentives and, because the U.S. still doesn't have a federal governmental policy, it is more likely that the rest of the world will develop solutions.

The crowd was decisively in favor of a global approach in which the U.S. plays a role but not necessarily even the leading one; about a 70-30 split by the moderator's count at the beginning and much the same at the end, not surprising for a crowd that drew heavily on academia and United Nations personnel. Few minds were changed (all too often the case when the subject is climate change).

But the truth is that both sides are right. The U.S. is the world's largest emitter and the developed country rich enough and innovative enough to produce technological fixes for the climate crisis. Speakers at the conference continue to warn that the U.S. must convincingly show how the carbon dioxide emissions from a coal-fired power plant can be captured and stored--and soon.

All the countries of the world--rich and poor, developed and developing--must come together because a ton of carbon dioxide emitted anywhere in the world affects every other part of the world now, Columbia University's Earth Institute economist Jeff Sachs noted earlier in the day. That global solution will be hard to come by, Esty argued, and turns fundamentally on issues of fairness and necessity. "Should every human being have an equal right to pollute the environment?" Khosla asked. "If India tries to be the same as the U.S., the world is toast. … The only answer is by making [energy] cheaper." And a whole lot less carbon intensive.