The United Nations has started looking for an alternate venue for the annual global climate change summit for the second time after Chile said it could not host the event.

"We are currently exploring alternative hosting options," said Patricia Espinosa, executive secretary of the United Nations Framework Convention on Climate Change (UNFCCC).

According to experts, this year's climate talks ­— Conference of Parties (COP25) — is crucial as the Paris Climate Change Agreement comes into effect next year. Earlier, Brazil abandoned plans to host the climate change summit, citing the formation of a new government and budget restriction. The venue was shifted to Santiago on the request of the Chile government.

The current crisis comes with Chilean President Sebastian Pinera announcing on Wednesday to pull out of hosting the Asia-Pacific Economic Cooperation (APEC) summit and COP25 in the wake of violent protests over inequality in the country. 

Around 19 people have been killed and thousands detained after protests erupted in Santiago a few weeks back. "As President of all Chileans, I always have to put the problems and interests of Chileans, their needs, their desires and their hopes, first in line," said Pinera.

Costa Rica, the host of pre-COP25, is keeping a close watch on the selection of new venues for climate talks. "We are going to support the decisions that are taken in order to find a successful alternative so that COP25 can take place soon," said Carlos Manuel Rodríguez, the country's environment minister.

The UN has reportedly prepared a list of alternate venues that include New York, Geneva, Bonn, Vienna and Nairobi for the climate summit, the Associated Press reported. Jochen Flasbarth, Germany's state environment secretary said in a tweet, "We have just been informed that President Pinera has decided to cancel the COP25 in Santiago de Chile."

"We are in contact with the UN Climate Change Secretariat and the Polish COP24 Presidency to discuss the situation." Even if the new venue is finalized, COP25 is likely to be delayed as it requires a gamut of logistical preparations like arranging accommodation and selecting negotiations venue necessary for thousands of delegates.

Delegates were keenly looking forward to the summit in Santiago to build up an ambitious consensus on curbing greenhouse gas emissions to limit global temperature rise within two degrees Celsius.

"We expect a fast response from the UNFCCC. We hope that in this time of climate crisis, they will soon announce updated plans for COP25 so that we continue with all efforts to urgently move the world to a net-zero pathway," said Manuel Pulgar-Vidal, leader of WWF's global climate and energy practice.