Paris Climate Agreement: Impact of the United States Withdrawal

We provide an overview of the Nationally Determined Contributions (NDCs) of the Paris Climate Agreement using an Empirical Model of Global Climate (EM-GC) developed by our research group (Salawitch et al., Springer Climate, 2017). Two types of NDCs are in place: unconditional (i.e., firm commitments) and conditional (commitments contingent on technology transfer or financial support). Recently, President Trump announced that the U.S. would not adhere to the NDC that had been established by the Obama administration. We will examine the impact of the U.S. withdrawal from the Paris Climate Agreement, quantifying the impact on global emissions of GHGs as well as projections of global mean surface temperature. These impacts will be assessed in terms of a 4-year delay in the U.S. returning to the once-promised NDC, an 8-year delay, as well as Business as Usual for the U.S. out to 2060. Finally, these projections will be used to assess the impact on achievement of the 2°C warming upper limit of the Paris Climate Agreement.