EDWARD KERSCHNER chief investment strategist, Citi Global Wealth Management in New York.

Kerschner: This is a fundamental shift in the economy. It’s not frothy or bubbly. With the dot-coms, most of it was conceptual, easy to create. Most solutions to climate change involve real, physical assets. When you need hard assets, it’s harder to get a speculative bubble than when things are driven by concept.

Seth Scholar: This is mainstreaming like crazy right now. And there are real risks that come with that—some of the same risks with the tech bubble, like too much money chasing too few opportunities. There is an innovation pace that is fast and furious that’s going on right now, and a lot of money is chasing it. You have to worry about valuations. During the tech boom, while there was a bubble, there were also real, valuable things coming out of it. I don’t think this is any different. After the bust, we saw lasting changes, and the same thing will happen here.

Should an investor think of climate change as a portfolio sector, or is it a theme that can affect an entire portfolio in different ways?

Leonard: Clearly, there is a sector allocation opportunity similar to biotech or medical services. But we think of it less as a sector and more as a theme. For us, it’s more about efficiency than climate change. We need to move toward efficiency in energy and petroleum.

ROBERT WEISSENSTEIN chief investment officer, Credit Suisse Private Banking Americas in New York.

Weissenstein: I don’t think there is an allocation. There is an acknowledgement that it’s an important investing theme. You have to make sure you understand the implicit and explicit exposure you’re getting out of this. You might not buy Wal-Mart because it’s green, but its plan to sell low-impact bulbs will be big, so there’s implicit exposure there.

Are there more opportunities in the United States than in other parts of the world?

Kerschner: You have to think of it as a global story. There’s the impact of drought in Australia and opportunities in biodiesel in Malaysia. We have 85 or 86 stocks that we believe are positioned to benefit. Of those, only 20-odd stocks are U.S. companies.

Weissenstein: We have to wean ourselves off of old ways of manufacturing, and we have to be in a cleaner place. But look at what’s going on in developing economies. They don’t have infrastructure to retrofit. Most cars in Brazil run on ethanol. They don’t have gas stations to transition over to ethanol. They don’t have factories that need retrofitting. So they have a running start in a perverse way. It’s the leapfrog effect that we saw with mobile phones. That speaks to what goes on in those economies from a practical and investment standpoint.

There are also issues like clean water. We’ve been talking to venture capital firms that invest in whatever it takes to deliver clean water to remote villages. Why does it matter to an investor? If you improve infrastructure, economic growth ticks up, and that has a cumulative effect on the global landscape. You can spend your time more effectively because you’re not cleaning water and you’re not dealing with as many health issues. You have new business—and activity and markets rise from that.