Ethical debt instruments are catching investors’ attentions and appetites.

The number of green bonds issued hit a record high in the third quarter, up nearly 50 percent as compared to last year’s issuance.

Green bonds underwrite sustainable energy and environmental programs, among other earth-friendly initiatives.

Moody’s, the credit rating agency that tracks these bond types, reports that some $95 billion worth of green bonds was issued over the first three-quarters of the year, and estimates another $25 billion will be added in the last quarter, bringing total volume above $120 billion for the first time.

China and France were the lead issuers of green bonds, followed by the U.S.

Standard & Poor’s, another credit rating agency, notes countries that have ratified the Paris climate agreement—from which the U.S. has famously backed out of—need to spend $5.3 trillion to live up to the agreement’s commitments to combat climate change.

Increasingly, private investors are lapping up the mechanisms that help make the planet more sustainable, such as clean energy, and which make communities more resilient, such as seawalls and floodgates that defend against rising sea levels and wicked weather.

Still, some issuers are taking advantage of the interest in green bonds and are “greenwashing” debt instruments that do not live up to sustainable missions. Greenwashing means faking environmental friendliness, and as there is no universal definition for a green bond, it’s not so difficult to do. Instead, investors must rely on certifications that help constitute what make certain debt instruments “green.”

Both Moody’s and S&P say there are greenwashing issues to be addressed, but do not taint the majority of green bonds issued.

Meanwhile, the earth is growing further into debt. Which in this case is a very good thing for the planet.