In a letter to the Australian prime minister, the pope also urges global action to curb climate change, inequality and terrorismPope Francis: ‘There are constant assaults on the natural environment, the result of unbridled consumerism, and this will have serious consequences for the world economy.’ Photograph: Riccardo De Luca/APPope Francis has called on G20 leaders to be “examples of generosity” in meeting the needs of refugees, while also taking action against inequality and environmental attacks.

In a letter to the Australian prime minister, Tony Abbott, who is hosting the G20 summit in Brisbane this weekend, the pope emphasised the need for efforts to curb climate change, eliminate the root causes of terrorism and prevent financial system abuse.

Australia is determined to ensure the main focus of the G20 is on growing global economic growth and has resisted calls to include climate change as a substantive agenda item.

The pope told Abbott the G20 preparatory work highlighted “the fundamental imperative of creating dignified and stable employment for all”, but he urged leaders not to forget that many lives were at stake behind the political and technical discussions.

“Throughout the world, the G20 countries included, there are far too many women and men suffering from severe malnutrition, a rise in the number of the unemployed, an extremely high percentage of young people without work and an increase in social exclusion which can lead to criminal activity and even the recruitment of terrorists,” the pope said in the letter released by the Vatican on Tuesday.

“In addition, there are constant assaults on the natural environment, the result of unbridled consumerism, and this will have serious consequences for the world economy.

“It is my hope that a substantial and productive consensus can be achieved regarding the agenda items. I likewise hope that the assessment of the results of this consensus will not be restricted to global indices but will take into account as well real improvements in the living conditions of poorer families and the reduction of all forms of unacceptable inequality.

“I express these hopes in light of the post-2015 development agenda to be approved by the current session of the United Nations assembly, which ought to include the vital issues of decent work for all and climate change.”The pope referred to “the terrible backdrop of military conflicts” and called for “an ever broader agreement which can lead, through the United Nations legal system, to a definitive halt to the unjust aggression directed at different religious and ethnic groups, including minorities, in the Middle East”.

“It should also lead to eliminating the root causes of terrorism, which has reached proportions hitherto unimaginable; these include poverty, underdevelopment and exclusion,” the pope said.

“It has become more and more evident that the solution to this grave problem cannot be a purely military one, but must also focus on those who in one way or another encourage terrorist groups through political support, the illegal oil trade or the provision of arms and technology. There is also a need for education and a heightened awareness that religion may not be exploited as a means of justifying violence.”

Military conflicts left “deep scars” and resulted in unbearable humanitarian situations around the world, the pope said.

“I take this opportunity to ask the G20 member states to be examples of generosity and solidarity in meeting the many needs of the victims of these conflicts, and especially of refugees,” he said.

The pope also called on G20 leaders to protect citizens from other “forms of aggression” including “abuses in the financial system such as those transactions that led to the 2008 crisis, and more generally, to speculation lacking political or juridical constraints and the mentality that maximisation of profits is the final criterion of all economic activity”.

“A mindset in which individuals are ultimately discarded will never achieve peace or justice,” he wrote. “Responsibility for the poor and the marginalised must therefore be an essential element of any political decision, whether on the national or the international level.”

The pope said he invoked “divine blessings on all taking part” in the Brisbane summit “and on all the citizens of the G20 countries”.

He told Abbott: “With this letter I express my appreciation for your work, prime minister, and I offer my prayerful encouragement for the deliberations and outcome of the summit … I offer you my prayerful best wishes for the successful conclusion of Australia’s presidency and I willingly assure you of my highest consideration.”