When we think of carbon emissions we tend to think of dirty emissions from car and truck exhausts or belching smokestacks of coal fired power stations.

We might even extend those thoughts to ‘food miles’ or embodied impacts of materials in our homes or buildings. But when was the last time you wondered what the carbon emission impacts of your IT footprint is? Did you ever? How much energy does it take to charge your phone or notebook or tablet? Even then at least there is a direct causal connection, you have to actually plug it into a power socket so its at least identifiable.

But when have we ever thought about our Wi-fi or internet service as being a source of emissions? Those big servers that we now think of as ‘The Cloud’ (think Google Drive, Microsoft OwnCloud, Apple iCloud, DropBox, and so many more) have been growing so fast that they are now be coming a major source of climate impacts in their own right. If the Cloud were a country, it would currently rank as the world’s sixth biggest emitter.

Some of the fastest growing services are now also climate culprits – TV, video and music streaming services like YouTube,  Apple Music, GoogleMusic, Pandora, Stan, Foxtel, Optus Amazon and even social media sites like Facebook, Twitter, Linkedin  and Instagram generate such volumes of web-traffic they are becoming significant climate emission generators.

According to online community SumofUs.org, Netflix alone constitutes one third of all internet traffic in the USA. Streaming services on the internet such as connected TVs, game consoles and mobile devices already accounts for more than 60 per cent of all web data traffic  globally, and the latest forecasts suggest this will rise to more than 80 per cent by 2020.

This is driving an amazing and indeed spiralling increase in the amount of information that needs to be stored and transmitted by electricity-hungry data centres. Up until 2003, the world had accumulated a total of five exabytes (five billion gigabytes) of stored digital content. By 2015 that amount was being consumed every two days, as annual consumption reached 870 exabytes.

According to a Cisco 2016 report, as more video is streamed and more of the world’s population goes online, annual data traffic is forecast to reach 2,300 exabytes by 2019.

The explosion of online retailing is also a culprit in this space. While there is much controversy about whether it is more carbon efficient to buy online or in brick and mortar retail shops, there is no doubt that the individual transport of small packages and their emissions and excess packaging typical of online purchases is likely to be adding additional impacts compared to physical shopping.

The Bitcoin Internet currency is another culprit. Bitcoin is a distributed, worldwide, decentralized digital money, that according to a 2015 post on Reuters, and calculations by Christopher Malmo, (writing on the Vice blog, Motherboard), showed that a single bitcoin transaction consumes enough electricity to power 1.57 US households a day. Taking his calculations a step further, Malmo compared Bitcoin’s power usage with that of VISA, the world’s largest payment processing network. Using the available data, he shows that VISA processed 58.5 billion transactions in 2013, using enough electricity to power 50,000 US households a day. That, he says, makes Bitcoin about 5,033 times more energy intensive per transaction.

The equipment to run the Bitcoin network currently uses 256 times greater calculating power than the world’s top 500 supercomputers, combined.

The exact carbon footprint of the Bitcoin system is unknown, but at least one estimate of today’s value of roughly $1,000 per bitcoin, shows the electricity consumed by the Bitcoin mining ecosystem has an estimated carbon footprint – or total greenhouse gas emissions – of 8.25 megatonnes (8,250,000 tonnes) of CO2 per year, according to research by Bitcarbon.org. That’s 0.03 per cent of the world’s total greenhouse gas output, or equivalent to that of the nation of Cyprus.

If Bitcoin’s value reaches $100,000, that impact will reach three per cent of the world’s total, or that of Germany. At $1 million – which seems farcical but which may not be out of the realm of possibility given the artificially limited Bitcoin supply – this impact rises to 8.25 gigatonnes, or 30 per cent of today’s global output, and equivalent to that of China and Japan combined.

In the end, according to Professor John Quiggin (an ARC Laureate Fellow in economics at the University of Queensland), Bitcoins will attain their true economic value of zero. But as long as Bitcoin, and similar ‘crypto-currencies’ persist, the mining process will continue to damage the environment by wasting energy to no purpose.

Another major source of future growth in climate emissions due to data growth is the exploding Internet of Things (IoT) – remote digital sensors, devices, appliances, wearables and autonomous transport like driverless cars that already are, or will soon be, connected to the internet.

A drive toward reducing these impacts using renewables is being led by companies like Apple and Google, who are making aggressive commitments and progress towards 100 per cent clean energy. Amazon recently began putting pressure on their own cloud service to power their service from renewables. In response to a 2016 Greenpeace report, an Amazon spokeswoman told Fortune recently that the company closed out 2016 using 45 per cent renewable energy and seeks to hit 50 per cent by the end of this year. The Netflix renewables use was recently graded a climate ‘D’ in that same report.

All told, almost 20 global tech companies have committed to 100 per cent renewable energy, but its not enough. Our ability to measure and compare the environmental performance of data centres is significantly hindered by the lack of transparency within the sector and the limitations and inconsistency of industry-adopted metrics.

If you want to check out how your various internet services are rated, download and use this new Google Chrome extension by Greenpeace, the ‘Click Clean Scorecard’.

As end users, something we all must be willing to do if we are to continue to enjoy and benefit from the internet, cloud and streaming services while putting brakes on runaway climate change is choose services that make the 100 per cent renewables commitment and apply pressure to our internet, gaming and streaming providers, selecting services based on renewable inputs and indeed installing renewables ourselves wherever possible.