Filipe Duarte Santos said at a conference on climate change in Lisbon organised by UNESCO that rising sea levels could lead to a human catastrophe unlike anything ever seen before.

Portugal has 11 biosphere reserves and four natural geo-parks, classified by UNESCO and that play an important role in mitigating climate change, he said.

The country’s Foreign Affairs Minister, Augusto Santos Silva, said that Portugal had a responsibility in the area of climate change as it would be one of the countries most affected by it but it was also one of the most determined in fighting its effects.

Meanwhile, seven in ten natural UNESCO World Heritage sites are at risk of being affected by climate change, expert Filipe Duarte Santos warned at the conference on “UNESCO Territories and climate change” in Lisbon.

Duarte Santos, who is the head of the national commission for the environment and sustainable development, said 71% of UNESCO’s natural sites, included in a list of over 1,000 that are defined as world heritage, will be affected by climate change.

The concentration of carbon dioxide has increased 42% since the pre-industrial era, he said.

The expert also warned that the earth’s temperature, which had been on a downward process for 52 million years, would take the opposite course for some hundreds of years.

He explained that 52 million years ago the temperature was on average 10 degrees higher than today’s and started to drop since then.

Fossil fuels create most CO2 emissions (62%), he pointed out, adding that since 1970 the temperature has been rising, leading extreme weather conditions to become more frequent and sea levels to rise.