The author offers an argument for the claim that there is a prima facie reason to reduce the greenhouse gases concentration at the preindustrial level as soon as possible. The argument is based on the normative belief that it is morally despicable to harm the most disadvantaded persons consiously. Furthermore, he tries to show that this moral belief is adaquate for the justification of political recommendations. Most objections against ambitious greenhouse gases reduction targets stem from the following idea: it is not reasonable for the current generation to accept the financial burden which is required in order to realise the ambitious climate targets. The author endeavours to justify the claim that the financial burden required for the reduction of the ghg-concentrations does not provide a prima facie reason against the claim that the ghg-concentrations ought to be reduced at the pre-industrial level.