The conference was scheduled to take place in Brazil in November 2019, but a year before the planned launch, newly elected President Jair Bolsonaro withdrew the offer to host the event for economic reasons.  Then Chile strengthened and became a new host, but the social unrest that preceded the meeting forced it to withdraw from registration at the end of October 2019.  By mutual agreement between the United Nations, Chile and Spain, this new host became.  According to the scientists, discussions have focused on some of the rules for implementing the 2015 Paris Agreement, but the priority issue of how quickly the world must reduce greenhouse gas emissions has received little official attention. Urgent UN talks on combating the climate emergency still do not show the true extent of the crisis, one of the world`s leading climate scientists has warned.  Negotiations on the direction of implementation of market mechanisms, which had not been agreed at COP24, have become one of the strengths of COP25. The Japanese government has called for a double counting of emissions reductions and an assurance of environmental integrity. Mr. Koizumi conducted intensive bilateral consultations with other ministers and led the ministerial negotiations with constructive proposals, supplemented by technical negotiations involving heads of delegations and experts.
On the other hand, this item on the agenda did not allow agreement to be reached on all the points of discussion because of political aspects of complex interest to each country. Based on the progress made in the COP25 discussions, the Japanese government will continue to contribute to the adoption of market mechanism guidelines at COP26. The initial accommodation agreement for COP 25 with Chile was denounced on 30 October 2019. At the time, UNFCCC Executive Secretary Patricia Espinosa announced that the Chilean government had informed the UNFCCC secretariat on 30 October of its decision not to host COP 25, with the country remaining in a difficult situation. The last part of the Paris Regulation to be resolved is Article 6, which describes the rules of a carbon market and other forms of international cooperation. Agreement on this issue could not be reached at the COP24 conference. This article must be the subject of several politically difficult decisions. Negative emissions could be negotiated under the Kyoto Protocol to offset emissions from industrialized countries, but many of these negative emission projects would have been achieved anyway without the additional incentive of the Kyoto Protocol, so this mechanism has been described as « hot air ».
International carbon trade can, on the whole, make emission reductions less costly. If negotiations fail, COP26 (pushed back to 2021) will return in 2020.  On the other hand, the European Union has reached an agreement on the European Green Agreement, which aimed to reduce its emissions to zero by 2050.  In addition, many commitments have been made by countries, cities, businesses and international coalitions.