(ANSA) - Vatican City, December 15 - Pope Benedict XVI on Tuesday issued a stark warning about the dangers of environmental destruction, as the United Nations climate change summit entered its final phase. In his official message for Catholic World Day of Peace, published ahead of its January 1 date, the pontiff said that neglect and misuse of the plant were as great a threat to humanity as war and terrorism.

The pope said it was ''irresponsible'' not to take seriously the clear ''signs of a growing crisis'' and called on industrialized nations to take action. He called on developed countries to accept their ''historical responsibility'' for climate change. ''It is important to acknowledge that among the causes of the present ecological crisis is the historical responsibility of the industrialized countries,'' the pope said.

Benedict appealed to industrialized countries to adopt a ''profound, long-term review of our model of development''.

''The international community and national governments are responsible for sending the right signals in order to combat effectively the misuse of the environment,'' he said. He called for ''clearly-defined juridical and economic rules'' but said industrialized countries must also take into account ''the solidarity we owe to those living in the poorer areas of our world and to future generations''.

The message from Benedict, a strong advocate of renewable energy who has issued repeated warnings over environmental sustainability, was published as the UN's climate chief warned that negotiations at the conference in Copenhagen were moving too slowly.

The Executive Secretary of the UN Framework Convention on Climate Chang Yvo de Boer said there had been considerable progress in some areas but warned there was still ''an enormous amount of work and ground to be covered'' before the conference could deliver its objectives. The summit will enter its high-level phase on Tuesday night, as world leaders start arriving in Copenhagen to agree on a final deal. But despite intense negotiations since opening on December 7, expectations of any agreement being signed before the summit ends Friday are shrinking. The G77-China bloc of developing nations staged a five-hour hour walk-out on Monday in protest at what they say were efforts by rich nations to jettison the Kyoto protocol. The first stage of the Kyoto treaty, which imposes stringent emissions-cutting commitments on industrialized countries, is due to expire at the end of 2012 but requires members to enter a second round of pledges after this. However, industrialized countries now want to merge the protocol into a single new treaty, concerned that those not party to the original agreement, including the US, will escape with overly light commitments. Developing nations believe Kyoto members are trying to wriggle out of its tougher restrictions. They only returned to the talks after the Danish chair agreed to two lines of negotiations, one on renewing the existing protocol and the other working out a separate deal for poorer nations. Over 110 world leaders will attend the final phase of the summit, with US President Barack Obama scheduled to give a speech on Thursday. Italian Premier Silvio Berlusconi will not attend after an attack in Milan left him in hospital with a broken nose and teeth.

A draft agreement by Denmark as summit host calls for emission cuts by rich countries of 25-40% from 1990 levels by 2020.

Italy is bound by EU targets, which demand a 20% reduction in greenhouse gas emissions by 2020 on 1990 level, which could rise to 30% depending on the outcome of the summit. The EU also requires member states to meet 20% of their energy needs from renewable sources by that date.

A poll released in Italy last week suggested the percentage of Italians concerned about climate change had fallen over the last two years.

The research by social research non-profit group Observa found just 72% of Italians were convinced of global warming compared to 90% during a similar survey in 2007.