America’s millionaires are far less likely than rich folks in other countries to invest sustainably, and financial advisors have the power to change that, new research shows.

Only 12 percent of wealthy investors in the U.S. allocate a portion of their portfolio to a sustainable investment strategy, compared with a global average of 36 percent, according to a survey by UBS Global Wealth Management. Of the 10 countries included in the research, the U.S. ranked dead last, and the U.K. didn’t fare much better at 20 percent.

China topped the list at 60percent, followed by Brazil, United Arab Emirates and Italy, where more than 50percent of investors had some allocation to sustainable investments.

UBS polled 5,300 high-net-worth investors (those with at least $1 million in investable assets) during June and August and considered whether they hold at least 1percent of their portfolios in sustainable investments.

Whether they do or not depends a lot on their financial advisor. Nine of 10 investors who hold sustainable investments in their portfolio say their advisor played a key role in that decision.

“In our view, the advisor is absolutely critical to driving sustainable investing adoption,” said Andrew Lee, head of sustainable and impact investing at UBS Global Wealth Management.

This raises the question: When it comes to adopting sustainable investment practices, do U.S. investors trail their counterparts in other countries because U.S. advisors trail theirs?

It’s difficult to know for sure, but one variable is regulation. Government policies related to sustainable investing have helped bolster the practice in some markets.

Meanwhile, in the U.S., some advisors may still be unsure about how advising a client to adopt such a strategy relates to fiduciary duty, Michael Young, manager of education programs at U.S. SIF, said in an email.

FAs may also have uncertainty about how to add relevant products and/or what exactly their strategy will be, Young added.

“There has been progress in the educational offerings for financial advisors, but it may take time for FAs to move from the learning to implementation phase,” he said.

Interestingly enough, the worry that sustainable investing will negatively impact financial returns doesn’t appear to drive the decision among the wealthy investors UBS surveyed—93 percent of those who hold sustainable investments believe they will generate equal or better returns compared with traditional investments, and three-quarters of non-adopters agree.

What does hold people back is confusion. The most common reason non-adopters gave for staying on the sustainable investment sidelines is they simply don’t know if it does any good, with 72 percent of them saying that gauging impact is difficult.

The mishmash of terminology found in the sustainable investing marketplace continues to cause confusion as well—72 percent of those surveyed (66 percent in the U.S.) said they find the terms perplexing.

“I see this as a category that has been sold rather than bought, because of all of the confusion around terminology and … really the alphabet soup the industry has created over the years,” said Sameer Aurora, head of client insights at UBS Global Wealth Management.

This makes educating advisors, who can then educate their clients, particularly important.

“The role of the advisor in demystifying and clarifying becomes really, really key,” Aurora said.

One bright spot for the U.S. sustainable investing market is that when Americans commit to something, we really commit. The U.S. survey participants with sustainable holdings had the highest average allocation of any country, with 49 percent of their portfolio committed to a sustainable strategy compared with an overall average of 36 percent.

UBS included three sustainable investing strategies in its definition: integration, where environmental, social and governance (ESG) factors are integrated into investment analysis; exclusion, which excludes certain sectors or companies, such as weapons manufacturers or fossil fuel producers; and impact investing, defined as actively investing to generate both a financial return and measurable social or environmental impact.