Looking at the whole paragraph on the link you posted (complicated stuff!), I think you're right, but you need to change one more thing: Although the total net anthropogenic would barely change in the meantime, until we REACH a point at which we could no longer reduce any more aerosols, the energy imbalance of the earth WILL not worsen. The second two phrases are linked together and form a future time clause. So one of the clauses needs to have 'will' in it and the other a time clause word (in this case "until"). If I am reading this correctly that is. Hope it helps!