Pope Francis condemned the 'perverse attitudes' of climate change deniers and sceptics in an address to world leaders yesterday, in what may be taken as an implicit attack on the leadership of Donald Trump.

In a message delivered to the UN COP-23 Climate Change conference concluding today in Bonn, Germany, Pope Francis said climate change was 'one of the most concerning phenomenons that our humanity is living', according to Catholic News Agency.

'We need a solution that unites everyone, because the environmental challenge that we are living, and its human roots, involves and touches us all,' he said. The pontiff said that progress on combatting climate change was 'often frustrated by various motives that range from negating the problem to indifference, comfortable resignation or blind trust in technical solutions.

'We must avoid falling into these four perverse attitudes, which certainly don't help honest research and sincere, productive dialogue.'

Pope Francis implored international leadership and a 'shared strategy' on the issue, noting that it was two years since the 'historic' 2015 Paris Climate Agreement was established. Signatories of the agreement committed to reducing carbon emissions and stopping global temperatures from rising above two degrees Celsius.

Many will take the pope's challenge to climate change deniers as a thinly veiled barb against US President Donald Trump, who dramatically pulled out of the Paris Agreement earlier this year. His controversial move signaled a break from both the Obama administration and international consensus on the environment, and a nod to the significant climate change sceptic group amongst his supporters. It's not the first time the pope and Trump have clashed on public policy. 

In his conference message, Pope Francis said that some countries 'must try to assume a guiding role' and give due attention to impoverished and vulnerable nations particularly at risk from climate change. He said solutions should not just be considered on an economic and technical level, but on social and ethical levels too.

'I would like to reiterate my urgent invitation to renew dialogue about the way in which we are building the future of the planet,' the Pope said.