While some impact from global climate change can already be felt, it is believed the significant impact will be for future generations. As the current generation would only face a cost to alleviate what leads to this climate change, one can make the argument that the future generations should pay us. But they are not there yet to do so. However, their parents are and these care about their offspring. So parents should be taxed to take care of reducing pollution and redistributing funds to those hurt by reducing pollution from current levels. That is a rather twisted argument to argue for future generations to pay (homework: where is the error?).
A better argument can be made for parents to pay. It is by Henning Bohn and Charles Stuart, who observe that each additional person exerts a negative externality onto the others by generating more population, taking more spaces, etc. That externality is not internalized, thus it needs to be taxed. Thus, whatever the reasons are that we subsidize having children needs to be amended by this tax. And by the calculations of Bohn and Stuart, the child subsidy could very well turn into a child tax. Indeed, the child pollution tax is 21% of life-time parent income per child, which is needed to divide the population by four in the long-run. However, that tax can be reduced to 5% if there is a cap of pollution permits set at current levels.
Of course, one can have endless arguments about the calibration used in the study. In this particular case, it is assumed that it costs 3% of output to reduce pollution by 25%. Also important is the output and time cost of children, as well as preference parameters. You may think of other parametrizations, but it remains that the child pollution tax makes sense. Only its amount it up to debate.