The commissioner also told Novy Przemysl (New Industry) on 21 May that he opposed the EU's climate targets and that its policy on phasing out coal plants was a "disaster" for Poland.
A translation of the article was sent to EurActiv and the Guardian by Greenpeace.
News of Lewandowski's climate scepticism came a day after Poland prevented the EU's Environment Council in Luxembourg from toughening its CO2 emissions targets, just one week before Warsaw takes over the EU's rotating presidency on 1 July.
"The thesis that coal energy is the main cause of global warming is highly questionable," the commissioner said. "Moreover, more and more, there is a question mark put over the whole 'global warming' as such."
The 60-year-old member of Poland's ruling centre-right Civic Platform group also described the EU's 2020 goals – for a 20% cut in energy use, a 20% cut in CO2 emissions, and a 20% share of renewables in the energy mix – as "too ambitious for the Polish economy".
"Polish politicians have to persuade [the EU] that there cannot be a quick jump away from coal energy," he said. "For Poland it would be a disaster."
Although there is a consensus among the world's scientists that the warming of global temperatures observed in recent decades has been caused by human activity, some sceptics disagree, and are often funded by powerful backers.
One Greenpeace study found that the oil giant ExxonMobil had given $22 milliion to climate-sceptic groups since 1998.
Commission 'clearly united' on climate change
A spokesman for European Commission President José Manuel Barroso told EurActiv that Lewandowski's views were a private matter.
"The Commission is clearly united on climate action," Michael Karnitschnig said. "This is not a challenge or a major issue."
But environmentalists pointed out that Lewandowski had not spoken to the magazine in a personal capacity, and remained in charge of a budget worth €130 billion.
"The commissioner should fully explain himself and clarify what he said," Greenpeace spokesman Joris den Blanken told EurActiv. "If not, the consequences for his role in the European Commission should be considered."
Lewandowski's spokesman, Patrizio Fiorilli, denied that the commissioner's comments on global warming were "abnormal", extreme or isolated. But he declined to say whether Lewandowski stood by them.
"His problem – his position – is that 90% of Poland's energy comes from coal and he is concerned at the pace of change," Fiorilli told EurActiv.
The commissioner believed that Poland needs more time and infrastructural help to move away from coal, he said.
"You can't have a measure that applies to 27 member states regardless of their starting positions," Fiorilli added.
After the Environment Council (21 June), in which Poland formed a blocking minority of one against EU climate proposals, Britain's Energy Minister Chris Huhne lamented what he called "a dark day for Europe's leading role in tackling climate change".
"I'm deeply disappointed that the only country in the EU that could not accept a good compromise on how we can move Europe to a low-carbon economy was Poland," he said in a statement.
Poland has been the most vehement critic of EU climate policies, ever since it spearheaded a revolt against proposals for the bloc's 2020 targets back in 2008.