So a carbon source meaning. - It's a net carbon source.

- 所以碳源的意思。 - 这是一个净碳源。

And for the first time in the forest observed history, a large portion of it flipped from being a carbon sink to a net carbon source of greenhouse gas.

第一次在森林中观察历史，其中很大一部分从碳汇转变为温室气体的净碳源。