Senator McCain gave a speech on Monday addressing the threat of man-made global warming. He joined Senators Clinton and Obama in pushing for a swifter reduction in carbon emissions.

Recently, Mr. McCain’s daughter told GQ magazine that her dad is “freaked out” by climate change. Unfortunately, “freaking out” stops us from seeing the big picture. The Earth is warming, and we are causing it, but that is not the whole story.

Mr. McCain worries that global warming means more heat waves will claim more lives. That is correct. But rising temperatures also will reduce the number of cold spells — and the cold is a much bigger killer than the heat. According to the first complete peer-reviewed survey of climate change’s health effects, global warming actually will save lives. It’s estimated that by 2050, global warming will cause almost 400,000 more heat related deaths each year. But at the same time, 1.8 million fewer people will die from the cold.

“Freaking out” also stops us from choosing the best solutions to a problem. Mr. McCain is embracing those that are talked about the most.

A cap and trade system is, in some ways, worse than a tax. With a tax, the costs are obvious. With a cap and trade system, the costs are hidden and shifted around. For that reason, many politicians tend to like it. It’s misleading not to recognize that the costs of cap and trade — financially and in terms of jobs, household consumption, and growth — will be significant.

Although the world has focused on reducing carbon emissions as the answer to climate change, new research for the Copenhagen Consensus project shows that this approach alone doesn’t make economic sense. Spending $800 billion over 100 years solely on curbing or mitigating emissions would lose money overall with returns of just $685 billion. For each dollar we would get 90 cents of fighting global warming.

The solution with the highest return on the investment is an investment in research and development which would cost $75 billion and offer an astonishing $1,186 billion reward. That’s a $16 return on a $1 investment.

The typical cost of cutting a ton of CO2 is about $20 right now, but we know that the damage from a ton of carbon in the atmosphere is about $2. We need to reduce the cost of cutting emissions from $20 to somewhere nearer to $2.

Ideally, every nation should commit to spending 0.05% of its gross domestic production exploring non-carbon-emitting energy technologies — be they wind, wave, or solar power — or capturing CO2 emissions from power plants. This spending could add up to about $25 billion a year, but it would be seven times cheaper than the Kyoto protocol, and it would increase global research and development tenfold. All nations would be involved, but the richer ones would pay the larger share.

Today, solar panels are ten times more inefficient than the cheapest fossil fuels. Only the very wealthy can afford them. Many “green” approaches right now do little more than make rich people feel like they are helping the planet.

We can’t solve climate change by just forcing more inefficient solar panels onto people’s rooftops. The solution is to dramatically increase R&D so that solar panels soon become less expensive than fossil fuels. Imagine if solar panels became cheaper than fossil fuels by 2050 — we would have solved global warming then, because switching to the environmentally friendly option wouldn’t be the preserve of rich Westerners.

The best legacy Mr. McCain could leave future generations is a world in which carbon emissions are low but incomes are high. It’s a possibility that is within reach.

He could propose that America spends 0.05% of its GDP on real research and development into low-carbon energy. That would give him the moral authority to ask the rest of the world to do the same when the Kyoto successor is negotiated in Copenhagen in late 2009. The total cost would be small so the likelihood of political success would be large.

With this move, Mr. McCain could leave behind the political mess and hypocritical in-fighting that marks Kyoto-type negotiations. He could show the leadership on climate change that has been lacking from the White House. He could tap into the creative spirit that America is known for, and there would be some extraordinary results.

Apart from the obvious good that would come from dealing with climate change, there would be many other creative inventions and spin-offs, a bit like how the Apollo program didn’t just land us on the moon, but also gave us micro-technology and CAT scanners.

By ignoring the hysteria and by thinking coolly about the issue — and by empowering Americans to unleash their creativity on this problem — Mr. McCain could put his nation on track to secure the world’s energy through the 21st century. That would be a remarkable legacy.

Mr. Lomborg, who was recently named one of the “50 people who could save the planet” by the Guardian, is the director of the Copenhagen Consensus Center and the author of “Cool It” and “Skeptical Environmentalist.”