Tony Abbott is sending Trade Minister Andrew Robb rather than Environment Minister Greg Hunt to accompany Julie Bishop at the United Nations climate conference in Peru.

Bishop, as Foreign Minister, is in charge of negotiating internationally on climate policy. The Lima meeting is already underway: the Australian ministers will be there next week.

One might have thought that Hunt, who deals with climate policy internally, would have had a good claim to be her ministerial partner. He is in charge of Australia’s just-legislated “direct action” plan, the centrepiece of the government’s climate policy, which he negotiated through a difficult Senate passage.

Frank Jotzo, an associate professor at the Australian National University, said most countries would have their environment ministers at the Lima conference, or their climate ministers if they had them. “Very few countries will have their trade ministers there,” he said.

In opposition Hunt hoped to be the international negotiator in a Coalition government – but Bishop got the job.

Hunt was a long-time supporter of an emissions trading scheme. Although he later dropped that support when Tony Abbott became leader, some sources say the Abbott office continues to have some suspicions of him on the climate issue.

Hunt’s spokesman said the minister had not asked to go to the conference because the negotiations fell under the Department of Foreign Affairs and Trade. “It was never on the cards that he was going to go.”

Other sources said Abbott had requested Robb’s participation from an “economic perspective”. Robb was also in Latin America for other engagements, the sources said.

Asked about the choice, the Prime Minister’s Office said Australia would be represented by “the Foreign Minister as well as the Minister for Trade and Investment given the significant economic and investment issues that will be discussed.

"As the Prime Minister said in Brisbane at the G20, actions that provide strong and effective action to address climate change will support sustainable development, economic growth and certainty for business and investment.

"Australia is a high performer when it comes to actually delivering on real action to tackle climate change. We will achieve a 5% on 2000 by 2020 target, which is a 19% reduction on business as usual.”

John Connor, CEO of the Climate Institute, welcomed “that this is seen as an economic issue. Ultimately what the G20 taught the government is that climate change is an economic challenge – one of risk and opportunity.”

Robb and Hunt both have interesting backstories in the internal Liberal politics of climate change, from the periods when Brendan Nelson and then Malcolm Turnbull led the Coalition is opposition.

In 2008, when the Coalition was committed to an emissions trading scheme, shadow treasurer Turnbull, Hunt, the environment spokesman, and Bishop, the deputy Liberal leader, opposed Nelson’s desire to link an ETS to when the big emitters took action rather than to a specific date.

In 2009, when Turnbull was leader, climate spokesman Robb – who had been on sick leave from the frontbench – spectacularly repudiated Turnbull’s proposed compromise with the Rudd government to get Labor’s ETS through parliament.

Robb’s dramatic intervention, made during a long party room meeting on the highly contested issue, was a devastating blow to Turnbull’s leadership, which was under pressure over his stand on the ETS and his non-consultative style.

Robb has documented the story in his book Black Dog Daze. Turnbull quickly lost his job and Abbott became leader.

The Lima conference is a step on the way to the Paris summit on climate in a year’s time, due to conclude a new international agreement.

In her opening address at the conference earlier this week, the executive secretary of the United Nations Framework Convention on Climate Change, Christiana Figueres, set out goals for the Paris summit.

“First, we must bring a draft of a new, universal climate change agreement to the table and clarify how national contributions will be communicated next year.

"Second, we must consolidate progress on adaptation to achieve political parity with mitigation, given the equal urgency of both.

"Third, we must enhance the delivery of finance, in particular to the most vulnerable.

"Finally, we must stimulate ever-increasing action on the part of all stakeholders to scale up the scope and accelerate the solutions that move us all forward, faster.”

Figueres said 2014 was likely to be the hottest year on record and emissions continued to rise.

While Australia has said it will achieve its 5% reduction target by 2020, it is resisting making a contribution to the Green Climate Fund, set up to help developing countries deal with climate change.