The One Nation senator Malcolm Roberts has used his first speech to pour scorn on modern climate science, call for Australia to leave the United Nations and question the reliability of data from Australian government departments and agencies.

He railed against the level of taxation in Australia and thanked his colleagues in the Galileo Movement, such as Ian Plimer, the radio host Alan Jones and the late professor Bob Carter, for their constant questioning of climate science. He said he loved to ask questions to get to the truth, like Socrates.

And he promised voters he would represent their interests, rather than worry about what “the establishment” wants.

“All of us, as One Nation senators, are going to say the things that need to be said and do the things that need to be done,” he said on Tuesday.

“We are not worried what the establishment says about us. We are not here for the establishment. We’re here for every day people.”

Roberts thanked Pauline Hanson for giving a voice to “the forgotten people” and for giving him the opportunity to become a senator.

“Twenty years ago, Pauline, the establishment ridiculed you. At the same time, they quietly started implementing some of your policies.”

He also thanked “the amazing James Ashby,” who helped One Nation in the recent federal election. Ashby is a former media advisor to the former federal speaker Peter Slipper. He accused Slipper of sexual harassment during one of the most controversial episodes in recent political history.

Roberts said his own passion for politics and policy had been “unleashed” during the “grassroots uprising of the Australian people” against the reviled and dishonest carbon dioxide tax.

He then questioned the consensus that global temperatures have been rising as a consequence of industrialisation.

He said that, from the 1930s to the 1970s, during the period of the greatest industrialisation in human history, atmospheric temperatures actually “cooled”.

“Another inconvenient fact, temperatures statistically have not been warming since 1995,” he said.

“Temperatures are now cooler than 130 years ago and this is the reverse of what we’re blatantly told by the Bureau of Meteorology that has manipulated cooling trends into false warming trends.”

He said Australians could not rely on information from Australian government bodies and institutions.

“I have used freedom-of-information requests, correspondence and reports from the heads of the CSIRO, the Bureau of Meteorology, the UN [and] universities to show there is no data proving human use of hydro-carbon fuels effects climate. None,” he said.

“Yet the core climate claim is that carbon dioxide from our human activity will one day, some day, catastrophically warm our planet.”

He called for Australia’s politicians to pursue comprehensive tax reform, saying taxes were so high that voters had to work from Monday to mid-morning Thursday to pay them.

“The purpose of great institutions such as this parliament, and broadly politics, is to protect life, protect property and to protect freedom,” he said.

“Government has sadly transitioned though into a beast that only wishes to control peoples’ lives.”

He said One Nation wanted to establish a peoples’ bank because private banks could not be trusted to work in the country’s interest. He said the international banking sector was “one of the greatest threats to liberty and life as we know it”.

He then called for Australia to leave the United Nations, that “socialist monolithic monster” full of “unelected swill”.

“Australia must leave the UN,” he said. “We need an Aus-exit.

“The people of Australia are desperate to regain our sovereignty. We need to rebuild our nation.”