In this paper, we study optimal economic growth programs coupled with climate change dynamics. The study is based on models
derived from MERGE, a well established integrated assessment model (IAM). We discuss first the introduction in MERGE of a
set of “tolerable window” constraints which limit both the temperature change and the rate of temperature change. These constraints,
obtained from ensemble simulations performed with the Bern 2.5-D climate model, allow us to identity a domain intended to
preserve the Atlantic thermohaline circulation. Next, we report on experiments where a two-way coupling is realized between
the economic module of MERGE and an intermediate complexity “3-D-” climate model (C-GOLDSTEIN) which computes the changes
in climate and mean temperature. The coupling is achieved through the implementation of an advanced “oracle based optimization
technique” which permits the integration of information coming from the climate model during the search for the optimal economic
growth path. Both cost-effectiveness and cost-benefit analysis modes are explored with this combined “meta-model” which we
refer to as GOLDMERGE. Some perspectives on future implementations of these approaches in the context of “collaborative” or
“community” integrated assessment modules are derived from the comparison of the different approaches.