Query: If every nation agrees to limit CO2 emissions, we can achieve significant cuts on a global scale.

Relevant passages:
Climate change mitigation <=SEP=> Climate change mitigation consists of actions to limit the magnitude or rate of long-term climate change . Climate change mitigation generally involves reductions in human ( anthropogenic ) emissions of greenhouse gases ( GHGs ) . Mitigation may also be achieved by increasing the capacity of carbon sinks , e.g. , through reforestation . Mitigation policies can substantially reduce the risks associated with human-induced global warming .   According to the IPCC 's 2014 assessment report , `` Mitigation is a public good ; climate change is a case of the ` tragedy of the commons . Effective climate change mitigation will not be achieved if each agent ( individual , institution or country ) acts independently in its own selfish interest ( see international cooperation and emissions trading ) , suggesting the need for collective action . Some adaptation actions , on the other hand , have characteristics of a private good as benefits of actions may accrue more directly to the individuals , regions , or countries that undertake them , at least in the short term . Nevertheless , financing such adaptive activities remains an issue , particularly for poor individuals and countries . ''   Examples of mitigation include phasing out fossil fuels by switching to low-carbon energy sources , such as renewable and nuclear energy , and expanding forests and other `` sinks '' to remove greater amounts of carbon dioxide from the atmosphere . Energy efficiency may also play a role , for example , through improving the insulation of buildings . Another approach to climate change mitigation is climate engineering .   Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) . The ultimate objective of the UNFCCC is to stabilize atmospheric concentrations of GHGs at a level that would prevent dangerous human interference of the climate system . Scientific analysis can provide information on the impacts of climate change , but deciding which impacts are dangerous requires value judgments .   In 2010 , Parties to the UNFCCC agreed that future global warming should be limited to below 2.0 ° C ( 3.6 ° F ) relative to the pre-industrial level . With the Paris Agreement of 2015 this was confirmed , but was revised with a new target laying down `` parties will do the best '' to achieve warming below 1.5 ° C . The current trajectory of global greenhouse gas emissions does not appear to be consistent with limiting global warming to below 1.5 or 2 ° C . Other mitigation policies have been proposed , some of which are more stringent or modest than the 2 ° C limit .

2009 United Nations Climate Change Conference <=SEP=> The 2009 United Nations Climate Change Conference , commonly known as the Copenhagen Summit , was held at the Bella Center in Copenhagen , Denmark , between 7 and 18 December . The conference included the 15th Conference of the Parties ( COP 15 ) to the United Nations Framework Convention on Climate Change ( UNFCCC ) and the 5th Meeting of the Parties ( MOP 5 ) to the Kyoto Protocol . According to the Bali Road Map , a framework for climate change mitigation beyond 2012 was to be agreed there .   On Friday 18 December , the final day of the conference , international media reported that the climate talks were `` in disarray '' . Media also reported that in lieu of a summit collapse , only a `` weak political statement '' was anticipated at the conclusion of the conference . The Copenhagen Accord was drafted by the United States , China , India , Brazil and South Africa on 18 December , and judged a `` meaningful agreement '' by the United States government . It was `` taken note of '' , but not `` adopted '' , in a debate of all the participating countries the next day , and it was not passed unanimously . The document recognised that climate change is one of the greatest challenges of the present day and that actions should be taken to keep any temperature increases to below 2 ° C . The document is not legally binding and does not contain any legally binding commitments for reducing emissions .   In January 2014 , documents leaked by Edward Snowden and published by Dagbladet Information revealed that the US government negotiators were in receipt of information during the conference that was being obtained by spying against other conference delegations . The US National Security Agency provided US delegates with advance details other delegations ' positions , including the Danish plan to `` rescue '' the talks should they flounder . Members of the Danish negotiating team said that both the US and Chinese delegations were `` peculiarly well-informed '' about closed-door discussions : `` They simply sat back , just as we had feared they would if they knew about our document . ''

Paris Agreement <=SEP=> The Paris Agreement ( Accord de Paris ) is an agreement within the United Nations Framework Convention on Climate Change ( UNFCCC ) dealing with greenhouse gas emissions mitigation , adaptation and finance starting in the year 2020 . The language of the agreement was negotiated by representatives of 195 countries at the 21st Conference of the Parties of the UNFCCC in Paris and adopted by consensus on 12 December 2015 . It was opened for signature on 22 April 2016 ( Earth Day ) at a ceremony in New York . As of May 2017 , 195 UNFCCC members have signed the treaty , 147 of which have ratified it . After several European Union states ratified the agreement in October 2016 , there were enough countries that had ratified the agreement that produce enough of the world 's greenhouse gases for the agreement to enter into force . The agreement went into effect on 4 November 2016 .   The head of the Paris Conference , France 's foreign minister Laurent Fabius , said this `` ambitious and balanced '' plan is a `` historic turning point '' in the goal of reducing global warming .   One year on , the ratification of the Paris Agreement was celebrated by the Mayor of Paris Anne Hidalgo by illuminating the Eiffel Tower and the Arc de Triomphe , Paris ' most iconic monuments , in green .