Carbon dioxide, nitrous oxide and methane are gases that accumulate in the atmosphere and prevent radiation from the Earth`s surface to space, creating what is called the greenhouse effect. According to the Intergovernmental Panel on Climate Change (IPCC), the main international panel on this issue, the concentration of these thermal gases has increased significantly since pre-industrial times and has not been observed for at least 800,000 years. Carbon dioxide (the main cause of climate change) has increased by 40 per cent, nitrous oxide by 20 per cent and methane by 150 per cent since 1750, mainly due to the burning of dirty fossil fuels. The IPCC says it is „extremely likely“ that these emissions have been primarily responsible for the rise in global temperatures since the 1950s. Meanwhile, deforestation and forest degradation have also contributed to their fair share of global carbon emissions. Indeed, research shows that the cost of climate activity far outweighs the cost of reducing carbon pollution. A recent study suggests that if the United States does not meet its climate targets in Paris, it could cost the economy up to $6 trillion in the coming decades. A lack of compliance with the NPNs currently foreseen in the agreement could reduce global GDP by more than 25% by the end of the century. Meanwhile, another study estimates that achieving – or even exceeding – the Paris targets by investing in infrastructure in clean energy and energy efficiency could have great benefits globally – about $19 trillion. The initial commitment period of the Kyoto Protocol was extended until 2012. This year, at COP18 in Doha, Qatar, delegates agreed to extend the agreement until 2020 (without some industrialized countries withdrawing). They also reaffirmed their commitment made at COP17 in Durban, South Africa, in 2011, to create a new global climate treaty by 2015 that would require all major emitters not included in the Kyoto Protocol, such as China, India and the United States, to reduce their greenhouse gas emissions.
The new treaty – which was to become the Paris Agreement – was to completely replace the Kyoto Protocol by 2020. However, the Paris agreement came into force earlier than expected in November 2016. Since November 2020, 194 states and the European Union have signed the agreement. 187 countries and the EU, which account for about 79% of global greenhouse gas emissions, have ratified the agreement or have joined the agreement, including China and India, the countries with the first and third largest CO2 emissions among UNFCCC members.    As of November 2020[update], the United States, Iran and Turkey are the only countries with more than 1% not to be contracting parties. The Paris Agreement has an „upward“ structure unlike most international environmental treaties, which are „top down“, characterized by internationally defined standards and objectives that states must implement.  Unlike its predecessor, the Kyoto Protocol, which sets legal commitment targets, the Paris Agreement, which focuses on consensual training, allows for voluntary and national objectives.  Specific climate targets are therefore politically promoted and not legally binding.