The ascent of bitcoin could boost global warming to 2C in just two decades, according to a new analysis.
Cryptocurrencies have emerged in recent years as a novel means of completing financial transactions online, but experts have become increasingly concerned about their environmental impact.
The demand such currencies place on the energy system are enormous, and this drives up carbon emissions which in turn add to the overall global warming effect.
In a new study that examined the entire chain of events that leads to the creation of bitcoins, researchers at University of Hawaii at Manoa examined how the projected growth of this cryptocurrency would harm the climate.
By way of comparison, the scientists compiled data on the uptake of 40 different technologies ranging from dishwashers and e-books to electric power and the internet.
They used this information to estimate the rate of uptake this cryptocurrency will see in the coming years.
Based on their most conservative appraisal, the team found that the cumulative emissions from bitcoin would be enough to push global warming beyond 2C in 22 years. If the average rate of technology uptake is used instead, this number is closer to 16 years.
Bitcoins are “mined” in a process that is computationally demanding, with heavy hardware requirements, but the elusive nature of this process means that determining its carbon footprint can prove complicated.
To work it out, the scientists analysed the power efficiency of computers used in bitcoin mining, the location of miners around the world and the CO2 emissions from electricity in those countries.
“Currently, the emissions from transportation, housing and food are considered the main contributors to ongoing climate change,” said Katie Taladay, a master’s student and co-author of the paper, which was published in Nature Climate Change.
“This research illustrates that bitcoin should be added to this list.”
The finding that emissions from an expanding bitcoin could push the Earth beyond 2C of warming above the pre-industrial level is particularly stark given the Intergovernmental Panel on Climate Change’s recent report on the impacts of such a temperature rise.
The report’s authors warned that to avoid the worst impacts of climate change, such as coral reef extinction and Arctic ice disappearance, warming must be limited to 1.5C.
Though bitcoin has growing rapidly in the decade since it was introduced, this growth has somewhat stagnated over the past 10 months, suggesting fears about its climate impacts may be premature.
Professor Eric Masanet, a researcher at Northwestern University who was not involved in the study, cast doubt on the extreme outcomes predicted by its authors.
“While the future growth of cryptocurrencies like bitcoin is highly unpredictable, we do know that the global electric power sector is decarbonising and that information technologies – including cryptocurrency mining rigs – are becoming much more energy efficient,” he said.
“It appears the authors have overlooked these two latter trends in their projections, while simultaneously insisting on tremendous growth in cryptocurrency adoption.”
However, even if bitcoin does not match expectations for future growth, the researchers said it should be considered in future climate projections.
“Clearly, any further development of cryptocurrencies should critically aim to reduce electricity demand, if the potentially devastating consequences of 2C of global warming are to be avoided,” said Professor Camilo Mora, who led the study.
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