In 2017, during the Australian parliamentary eligibility crisis, he was disqualified from parliament for holding British citizenship by descent in breach of section 44 of the constitution.

Prior to his election to the Senate he founded the Galileo Movement to lobby against the Gillard government's carbon pricing legislation.

[3] With his wife, in 1994 he established a management consultancy, Catalyst For Corporate Performance, and became involved in Eastern and alternative self-help techniques including meditation.

[7] From 2006 until his election to the Senate, Roberts was a full-time political activist, speaking at rallies against the Labor Government's carbon tax.

He met politicians, had universities launch academic inquiries into climate scientists and sent legal letters demanding the resignation of government ministers.

Roberts released a statutory declaration to the effect that he is only an Australian citizen, despite birth records showing that he had previously been identified as a British national.

[12] Doubts persisted about the status of Roberts' Indian citizenship after it was argued in the media that under a precedent set by the Supreme Court of India, he continued to be a 'presumed citizen' of the country.

However, the Court delegated the fact-finding task to a single judge, Justice Keane, before whom Roberts appeared on 21 September and who reported his findings on the following day.

Roberts' specific objection related to charts from Icelandic stations at Vestmannaeyjar and Teigarhorn, where temperatures from the 1930s and 1940s were adjusted down, removing the apparent warming recorded at that time.

However a senior Icelandic meteorologist with a specialty in historical climatology emailed Roberts that the temperature adjustments, which were made because of a daytime bias and relocation of one of the stations, were "quite sound ... absolutely necessary and well founded".

(a play on the initialism CSIRO) that, according to a report in The Australian newspaper, claimed global warming is a UN-inspired hoax to introduce an "antihuman" socialist New World Order, aided by bankers and politicians.

The essay was described as "conspiracist rubbish" by climate scientist David Karoly and "utterly stupid" by conservative commentator Andrew Bolt.

document contained an attack on the environment editor of one of Australia's major newspapers, Ben Cubby of The Sydney Morning Herald.

Cubby responded by commenting that the essay was "littered with errors of all kinds: a mish-mash of muddled conjecture, impossible leaps of logic, fundamental misunderstandings of the scientific method, misread and misquoted research that has been poorly cited, internal contradictions, confused dates, spelling mistakes, and strangled grammar.

[30] On 6 November 2016, Roberts delivered his response to the briefing, presenting a 42-page report titled "On Climate, CSIRO Lacks Empirical Proof", co-authored by Timothy Ball and Tony Heller.

[33] In an exchange between Roberts and physicist Brian Cox on the live television talk show Q&A on ABC TV broadcast 15 August 2016, Roberts claimed that engineer and blogger Steven Goddard (a pseudonym of Tony Heller) had shown the NASA temperature data for the 1930s were "warmer than recent decades".

"[28] In 2016, Roberts called for the repeal of section 18C of the Racial Discrimination Act 1975, which makes it an offence to publicly "offend, insult, humiliate or intimidate" another person because of their race.

He falsely attributed the passage of the section to Julia Gillard, despite the fact it was enacted in 1995 prior to her entry to parliament, and claimed that it had been passed to "nobble" conservative commentator Andrew Bolt, who had been successfully sued under the act in 2011.

Members of this movement aspire to exist outside both the social and legal bounds of society, and use colons and hyphens to evade what they claim is government enslavement via grammar.

[41][42] In 2011, Roberts wrote an affidavit to then Prime Minister Julia Gillard – addressing her as "The Woman, Julia-Eileen: Gillard., acting as The Honourable JULIA EILEEN GILLARD" — demanding that she sign a contract exempting him from paying the carbon tax and compensation of up to $280,000 if she didn't provide him with disclosure on 28 points, including evidence that "the Commonwealth of Australia CIK# 000805157 is not a corporation registered on the United States of America securities exchange".

Motives Driving Climate Fraud, Roberts states that international bankers (the Rothschilds, Goldman Sachs, the Rockefellers and the Warburg family) are surreptitiously trying to gain global control through environmentalism.

[46] In the document, Roberts cites Eustace Mullins, the American anti-Semite and Holocaust denier who claimed that international banks and the US Federal Reserve were part of a Jewish conspiracy to introduce global socialism.

[47] Roberts rejects the assertion that he is an anti-Semite, noting that two of the founders of the Galileo Movement were Jewish, and stated that "I respect and admire the Jews".

[48] Roberts commented on the 2016 US presidential election by stating that "the only safe space for Hillary [Clinton] to occupy is a prison cell",[49] and that he'd "settle for [her] going to Guantanamo, along with other terrorists".

[50] Roberts stated that his party, Pauline Hanson's One Nation, had hired former Trump economic adviser, Darren Brady Nelson.