Robert Alloway is co-founder of Viridian Zero Carbon.

With world leaders gathering in Glasgow for COP26, Bitcoin boosters and naysayers continue to clash over its 50 million-tonne -- and growing -- carbon footprint, and whether cryptocurrencies are a force for good on climate change or part of the problem.

According to a recent 70-page report from Bitcoin pioneer NYDIG, a subsidiary of Stone Ridge Asset Management, Bitcoin does not have a carbon problem.

The rationalizations are not new. They have been asserted time and again by Bitcoin figureheads in presentations, white papers, tweets and opinion pieces in newspapers all over the world. These arguments generally fall into one of three groups: bitcoin exceptionalism, "whataboutism" and the inevitability of green power.

Bitcoin exceptionalism refers to the notion that the cryptocurrency is so revolutionary that it will replace the banking system, save us from hyperinflation and achieve world peace. Therefore, any carbon emissions are a minor cost compared to the benefits to humankind.

Proponents of "whataboutism" argue that what constitutes worthwhile energy use is entirely subjective. Compared with refrigerators, air conditioners, the global banking system and the U.S. military, Bitcoin's carbon emissions are relatively small and therefore should be ignored.

A final rationalization for Bitcoin's current carbon footprint is that power consumption begets investment in supply: Humanity will generate ever greater quantities of cheaper, greener power, and all Bitcoin mining will eventually and inevitably use surplus renewable power.

True or false? It does not matter. Debating these arguments is just a distraction. The simple fact is that the Bitcoin network does not need to be powered by fossil fuels. Crypto is an easy industry to decarbonize because the input is just electricity, and the output is data. COP26 participants face a daunting enough challenge with hard-to-decarbonize industries, such as aviation and steel. Bitcoin is low-hanging fruit.

So why are only 40% to 60% of Bitcoins, depending on who you believe, mined with renewable power? Dirty miners continue to use fossil fuel because of four market failures.

First, the carbon content of the electricity that miners buy is not reflected in its cost -- the idea that renewable power is always the cheapest power is a myth. Second, the carbon content of the bitcoins that miners produce is not reflected in their selling price. This failure to price carbon content is a classic market externality.

Third, the cost of many carbon offsets reflects their poor quality. A Bitcoin miner might claim to be "carbon neutral" through offsets that do not deliver the climate benefit promised. The cost for reducing a tonne of CO2 through such offsets is therefore artificially low, making carbon "neutrality" a cheap greenwash.

Finally, despite equity investors' newfound focus on ESG criteria, the equity valuation multiples -- and hence cost of capital -- of Bitcoin miners do not reflect their carbon intensity.

Do not be distracted by the carbon footprint of a U.S. Navy carrier group or the possible threat of hyperinflation -- the Bitcoin community needs to correct the market failures perpetuating dirty mining. Bitcoin investors must change the economic incentives of Bitcoin miners by enabling them to monetize their use of renewable power. They can do so while taking responsibility for the network's carbon footprint.

Bitcoin and cryptocurrencies are unique among investment assets because their value is dependent on the continued mining of new coins, now and in the future, to constantly validate the ledger. The value of a kilo of gold does not depend on ongoing gold mining, but the value of a bitcoin is dependent on the continuing operation of the Bitcoin network.

Hence, no bitcoin can be "green" just because it was mined without CO2 emissions. Every Bitcoin investor is responsible for their share of the ongoing carbon footprint of the entire bitcoin network, without which their bitcoins would be worthless.

Tyler and Cameron Winklevoss, the founders of cryptocurrency exchange Gemini Trust Co., acknowledged this responsibility in June when they spent $4 million offsetting six months of their share of Bitcoin's CO2 footprint -- about 0.035% of their holding's value.

Tyler Winklevoss, left, and Cameron Winklevoss, spent $4 million offsetting six months of their share of Bitcoin's CO2 footprint -- about 0.035% of their holding's value.   © AP

Unfortunately, the money was spent buying oversupplied U.S. regional greenhouse gas compliance credits for $11.79 a tonne, which will have a negligible impact on atmospheric CO2 levels and zero impact on miners' incentive to use renewable power.

Imagine instead if Bitcoin holders mitigated their share of the network's emissions, and in doing so paid a subsidy to the miners using renewable power. Mining would become a zero-carbon industry in short order, not just "carbon neutral" and not by 2030.

We do not talk about "carbon neutral" cars because electric vehicles are a sustainable alternative to the internal combustion engine. Why would we be satisfied with "carbon neutral" bitcoins?

If we create the right economic incentives for Bitcoin miners to use renewable power, they will switch to renewable power. This industry can move quickly when it wants to -- look at the mining equipment moved out of China since the summer.

Bitcoin already has enough boosters and naysayers; history will be the judge of its success. The carbon footprint is fact, not "fear, uncertainty and doubt," and every Bitcoin holder has an ongoing responsibility for cleaning it up.