Carbon cuts made by the federal government's Direct Action climate change plan by 2020 would be wiped out by pollution from a single coal mine in just over a year, new data revealed at a Senate estimates hearing shows.

Officials from the Clean Energy Regulator said that projects paid for from the first three auctions of the Emissions Reduction Fund – the backbone of Direct Action – would trim pollution by just 42 million tonnes of carbon-dioxide equivalent by 2020.

Even if all the remaining funds were spent – with a fourth auction planned for November 16 – emissions reductions are projected to total only 92 million tonnes by the year 2020, officials told senators.

By contrast, the Adani coal mine proposed for Queensland's Galilee Basin would trigger emissions of about 79 million tonnes a year – nullifying the ERF's pre-2020 abatement in little over a year if it proceeded.