A cross-party group of MPs has raised doubts over whether the growing energy demand from digital technology and the proliferation of internet-connected gadgets can continue to be offset by energy efficiency improvements.

More efficient smartphones, networking gear and data centres have so far largely staved off increased power demand from the internet and computing – which now accounts for about 6% of global electricity use.

But there is uncertainty over whether those efficiency gains can keep going, according to a report bythe Policy Connect thinktank, which was advised by the all-party parliamentary climate change group of MPs.

The authors said there was “much work” to be done to ensure the digital economy was environmentally sustainable.

They urged the government to map the amount of energy consumed by computing and the internet, something which has been done in Germany and Sweden but not yet in the UK.

Antoinette Sandbach, a Conservative MP in the group, said: “We must take the necessary steps to ensure that we minimise the impact of internet use on the environment.”

The power stations required to fuel online activity has come under increasing scrutiny as demand for data-hungry services such as video streaming have grown.

Campaign group Sandbag recently identified bitcoin as an emerging new source of demand and Iceland has warned that energy use from mining for the cryptocurrency is set to overtake demand from homes. Mining for bitcoin now uses more electricity than Ireland consumes, according to one estimate.

The report’s authors said bitcoin was particularly energy inefficient and should not tar the reputation of all crytocurrencies. “Bitcoin is particularly energy inefficient and this inefficiency is not a feature of all blockchain technology or of digital currencies,” said Lucy McMahon. For example, the technology underpinning one alternative to bitcoin, Ethereum, is planning to switch to a less energy-intensive mechanism.

Information communication technology is estimated to account for about 3.6% of global electricity demand and 1.4% of carbon emissions. The figures differ because many data centres are increasingly run off renewable energy.

When entertainment such as film, music and games, and office printers are included, the share of power demand rises to 6%.

So far, improvements in the energy efficiency of everything from routers to computers has increased enough to offset growing data demand and more devices. But the report warned: “In such a fast developing sector, the future is more uncertain. It is unknown whether efficiency gains will continue, or whether they will slow or even stall.”

The group urged the government to lead by example and run super-efficient data centres powered by renewables. In the public sector, four-fifths of data centres are in small server rooms, missing out on some of the efficiency gains that tech firms such as Facebook and Google enjoy from large-scale data centres.

Sophia Flucker, a director at Operational Intelligence, a consultancy which advises data centre owners, said: “There is still room for improvement in data centres’ use of energy, particularly for older facilities. However, growth tends to keep up with and outpace the gains from energy efficiency, so in the future we can expect our digital lives to account for an increasing share of global energy use.”