Climate Change, page-163

The leak in the bath is enough to remove the rain falling through the ceiling (terrible analogy, forgive me, but supposed to represent the natural carbon cycle).

Humanity's greenhouse gas emisions, even if temporarily reduced due to covid, are in addition to the natural cycle. They are an additional tap into the bath.

But natural sinks are actually shrinking. The world is gaining trees in some temperate regions (often through massive monoculture plantations in places like China and Europe), but we are losing our most effective carbon sinks (tropical rainforests in the Amazon, Borneo, Congo etc). And the vast permafrost in Siberia used to be a carbon sink, but now it is flipping and becoming a source, not a sink.