Green investment insiders concede that climate change-focused and clean energy funds will get tossed around just like any other set of stocks – and are sometimes even more vulnerable.

And in the recent economic turmoil, that’s certainly been the case. Established green funds have indeed taken some hits through the third quarter of this year, with relative stalwarts like Winslow Green Growth Fund down 40 percent from the period extending January to the beginning of October and New Alternatives LW down 30 percent over the same period.

“Some green funds have a high concentration in more volatile sectors such as renewable energy, and these funds will experience more ups and downs due to the immaturity of these younger industries,” Carsten Henningsen, chairman of Oregon-based Portfolio 21, said in an interview with The Yale Forum. His fund was down 22 percent through the first three quarters of this year, though it has a solid nine-year history behind it.

Still, there is good news amid all the gloom for the world of green investment.

The number of such funds continues to grow, and the drops in value this year have been no more dramatic than those for other traditional funds, suggesting that this emerging sector may have some real staying power.

In any case, managers remain focused on the long term.

“As the ecological crisis worsens and biocapacity constraints become more obvious, we believe companies that are more resource efficient will continue their competitive advantage,” Henningsen wrote in an e-mail.

An examination of about 20 green funds shows that most losses this year – with some exceptions – have been roughly consistent with the declines of other indexes, according to Jason Myers, chief investment officer at Boston-based Newport Capital Advisers Inc. Some of the funds have been around for such a short time, though, that assessments are difficult, Myers said.

“Increasingly, there’s a place in one’s diversified portfolio for green funds,” he said. “However, it’s an emerging sector, and one should be aware of the elevated volatility.”

The Social Investment Forum (SIF), a group that represents hundreds of socially responsible institutions and professionals, on October 16 released a survey noting that select members had, since January 2007, doubled their number of mutual funds that focus “exclusively on clean energy/tech investing.”

Moreover, despite the turbulent times, banking giant Wells Fargo, which on October 11 launched its first “sustainability fund,” says it will choose the stocks of 30 to 50 companies based on environmental, social, and governance, criteria.

Some fund managers also see positive signs in the fact that some individual alternative energy companies are making money.

“Clean energy stocks have been crushed this year despite the fact that revenues and profits are growing rapidly,” Adam Seitchik, lead portfolio manager for Green Century Balanced Fund, in Boston, said in a statement accompanying the SIF findings. But he added that “among solar stocks we follow, revenues are likely to rise between 60 and 140 percent this year, and between 45 and 200 percent next year, and most of the companies are solidly profitable.”

Rob Day, a blogger who focuses on the sector, thinks there could be some “hiccups” among cleantech company revenues in the next six months, and then a period of slower growth. This direction follows a red-hot market in renewable energy in the U.S. over the past two years. Because of the rough economic climate, Day wrote recently, “I think we’re going to see some big-name cleantech startups implode.”

That could have an effect on the green mutual funds that have focused on these young companies. Solar companies in particular have seen some significant losses, with wild swings in their stock values.

Jennifer Kho at Greentech Media wrote recently that some insiders “say the solar industry is somewhat buffered from the economic storm and could help stabilize it, while others say the difficulty in raising capital could be a problem for companies trying to grow manufacturing and install projects.” But she points out that deals are still being worked out, and capital continues to be raised even amid the turmoil.

Much also hinges on Washington and, of course, the presidential and congressional elections.

Congress has passed extensions of renewable credits, music to the ears of green fund managers. “The recent passage of sweeping federal tax incentives in support of clean energy will only serve to accelerate the already exciting growth within this sector,” Jack Robinson, portfolio manager for the Winslow Green Growth Fund, said in a recent statement.

Democratic presidential nominee Senator Barack Obama has also pledged $150 billion of research investment in renewables. David Darst, chief investment strategist at Morgan Stanley, has predicted that the renewable energy sector, particularly solar and wind, could be beneficiaries under an Obama administration.

In the background, of course, looms the impact of a U.S. cap-and-trade scheme, something both presidential candidates support. Observers predict across the board that it will likely provide more opportunities for green investment, creating a more sanguine long-term picture for the sector.