Another major concern of Carbon offset is that, it is sound in theory, but not yet in practice.
First, as what did by Catholic Church in the early 16th century, carbon offset is considered as indulgences in the first place, which purchase forgiveness of past emission but not substitute for no emission.
Offsets allow a company or an individual, rather than reducing their own emissions, to pay for others to do the same. It is a zero-sum game.
If all goes well, 1 tone is emitted by the purchaser for every tone reduced by the seller of a carbon offset, and the atmosphere does not know the difference.
For example, some companies plant trees which remove carbon from atmosphere as they grow, but this approach doesn’t change essentially, since the carbon will released again when they cut down trees.

Second, we cannot deny that carbon offset will somewhat allow business to reduce their emissions. While companies declare themselves carbon neutral is somewhat designed to get image-polishing. And its offsetting is done on a voluntary basis, there is no exact regulation. And people cannot be well-informed to figure out that how many offsets are real and how many are anyway credits. To take it in case, Haier Company is now using “modularization” to try to low carbon. Although this approach can reduce cost and optimize flow to some extent, it still faces many uncertainties to full operation of “low carbon industry chain”. Producing by demand can liquidate inventory, but it increase logistics cost, that generate higher carbon emission.