On the sidelines of a visit to the national headquarters of the Food Bank Against Hunger, following this weekend's food collection campaign, Marcelo Rebelo de Sousa was asked about the passage through Portugal of the Swedish activist, who should arrive in Lisbon on Tuesday morning, before travelling to Madrid to participate in the Climate Change Summit (COP25).

"The mayor of Lisbon, and rightly so, will welcome her, just as the members of parliament who sponsor his visit should receive her. I have a more discreet position there, which is to understand that it is a great joy to have her among us, it is a factor of mobilisation of everyone," he said.

When asked if he intends to personally greet Greta Thunberg, whose sailboat will dock at the Alcântara Docks, where he will hold a press conference, the head of state admitted to having hesitated, but decided not to do so.

"I thought twice, mixing it up could be considered political exploitation by me of a wider reality and I do not think I have that right," he said.

On the eve of the Madrid summit, De Sousa stressed that climate change is an issue of interest to the whole of humanity, not just to young people.

"The fact that one of the youngest symbols is among us is good, but it must cross the whole of society. We cannot make this a war between young and old; everyone has to realise that it is a common problem, that it has to be tackled together," he said.

Greta Thunberg crossed the Atlantic by boat to participate in a previous UN summit in New York (convened by the UN Secretary-General Antonio Guterres, last September) and at COP25 in Chile, but the unexpected change of location forced her to embark again, this time on a catamaran, to make the trip the other way around and arrive in time in Madrid, without having to catch a plane, and passing through Lisbon.

The COP25, which starts on Monday and ends on 13 December, was transferred urgently, on 1 November to Madrid, after Chile announced that it was giving up its organisation, due to an unprecedented social protest movement in the country.