The authors of the agreement have set a withdrawal period that President Trump must follow – which prevents him from irreparably harming our climate. 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 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. Only the processes governing reporting and revision of these objectives are imposed by international law. This structure is particularly noteworthy for the United States – in the absence of legal mitigation or funding objectives, the agreement is seen as an „executive agreement, not a treaty.” Since the 1992 UNFCCC treaty was approved by the Senate, this new agreement does not require further legislation from Congress for it to enter into force.
 These rules of transparency and accountability are similar to those set out in other international agreements. Although the system does not include financial sanctions, the requirements are intended to easily monitor the progress of individual nations and promote a sense of overall group pressure, discouraging any towing of feet among countries that might consider it. On November 4, 2019, the United States informed the custodian of its withdrawal from the agreement, which will take effect exactly one year after that date.  On October 5, 2016, when the agreement reached enough signatures to cross the threshold, U.S. President Barack Obama said, „Even if we achieve all the goals… we will only get to part of where we need to go. He also said that „this agreement will help delay or avoid some of the worst consequences of climate change.” It will help other nations reduce their emissions over time and set bolder goals as technology progresses, all under a strong transparency system that will allow each nation to assess the progress of all other nations.  However, many experts and political analysts have found that former President Barack Obama is committed to reducing THE 2005 level of CHARBON emissions from 26 to 28% by 2025, but the United States was not limited by the way it achieved these targets. They also found that, although countries are bound by the agreement and have committed, the agreement itself has „no teeth” – that is, there have been no sanctions for the absence of their climate targets.