Purpose Investments Inc. is adding to the number of funds that seek to offset emissions with its new carbon neutral classes of cryptocurrency ETFs.

The Toronto-based firm launched the Purpose Bitcoin ETF and the Purpose Ether ETF earlier this year. The carbon neutral series for each, which began trading Tuesday on the Toronto Stock Exchange, are offered as new classes of the existing ETFs.

“We believe in the potential of cryptocurrency, but we can’t ignore the carbon impact of Bitcoin and Ethereum mining,” said Som Seif, founder and CEO of Purpose Investments, in a statement.

“We hope these carbon neutral ETF classes will provide our sustainability-minded investors an opportunity to invest in crypto while addressing the environmental impact this amazing asset can have.”

Emissions from crypto mining have received considerable attention from environmentalists. As of November, the Cambridge Bitcoin Electricity Consumption Index showed that Bitcoin activities consume about 117 terawatt-hours of electricity annually — more than the Netherlands or Pakistan.

Purpose isn’t the first firm to try to offset the carbon emissions of its cryptocurrency funds. Earlier this year, Ninepoint Partners LP announced that it would buy offsets for the Ninepoint Bitcoin ETF, and Accelerate Financial Technologies launched a “carbon-negative” Bitcoin ETF in August.

The new series isn’t Purpose’s first foray into carbon neutral products. In June, Purpose partnered with London, U.K.-based HANetf Ltd. to launch a carbon-offset ETF in Europe focused on clean energy companies.

Evolve Funds Group Inc. applied carbon offsets to broad indexes when it launched carbon neutral products tracking the S&P 500 and S&P/TSX.

Proponents of carbon offset funds say traditional screening limits the investable universe and other environmental, social and governance criteria can be confusing or even misleading.

However, some responsible investing advocates don’t see relying on offsets as a viable solution to climate change, as it removes the onus on companies to reduce their emissions.

Purpose partnered with carbon removal platform Patch Technologies Inc. for the new series of crypto funds. Patch will measure the funds’ daily carbon footprint and then purchase carbon offsets every week for climate projects the firm has vetted, a release said.