Dietz and Stern48 incorporate more than one growth reduction channel and also find that optimal emission reduction efforts need to be significantly increased. Since empirical studies have not yet been able to quantify the extent to which observed growth reductions can be attributed to potential channels, studies using more than one action channel should be based on generally arbitrary assumptions about the contribution of channels to growth reductions. A study published in 2018 reports a threshold where temperatures could rise to 4 or 5 degrees above the pre-industrial level (ambiguous expression, continuity would be “4-5 °C”), thanks to self-concretizing feedbacks in the climate system, indicating that this threshold is below the 2 degree target set in the Paris Climate Agreement. Study author Katherine Richardson points out, “We find that, in its history, the Earth has never had a near-stable state about 2°C warmer than pre-industrial and we suggest that there is a considerable risk that the system itself, because of all these other processes, will want,” even if we stop emissions. This doesn`t just mean reducing emissions, but much more.  On these and many other issues, we use our commitments. And I don`t want anything to get in our way. I fight every day for the great peoples of this country. In order to fulfil my solemn duty to protect America and its citizens, the United States will therefore withdraw from the Paris Climate Agreement – (Applause) – thank you, thank you – but will enter into negotiations to return either to the Paris Agreement or to a truly new transaction, on fair terms to the United States, to their companies, to their workers. its people, its taxpayers.
So we go down. But we will start negotiating, and we will see if we can reach an agreement that is fair. And if we can, that`s great. And if you can`t, it doesn`t matter. (Applause) In the same way, a global analysis like ours, of course, neglects the issues of distribution of the burden of damage and mitigation costs. Some specifications of the harmful functions we use here distinguish at least two categories of income. In this regard, we need to adopt simplistic assumptions about the shares of these classes in order to integrate them into the single-region model, which is another source of uncertainty (Figure 4). In general, a different interpretation of a cost-benefit calculation must be taken into account taking into account ethical considerations. Like other studies36, we use DICE as a parsimonious surrogate for more complex and spatially disaggated TRIMs.
Future research should pass our analysis to these EMIs in order to clarify issues of regional herogenicity and to take full account of region-specific empirical estimates. . . .