The IPCC demonstrates in its most recent report of 2018 that net emissions must be reduced to zero in order to stabilize global temperatures. The report also states that any scenario that does not involve a reduction to zero will not stop climate change. This objective has been ratified by Switzerland, the EU and many other countries, under the Paris Agreement. (see: What are the Kyoto Protocol and the Paris Agreement?).
Since the Earth already reacts strongly to small changes in the amount of CO₂, methane and other greenhouse gases in the atmosphere, emissions of these gases must be reduced until the whole system is back in balance again. Net zero emission means that all man-made greenhouse gas emissions must be removed from the atmosphere through reduction measures, thus reducing the Earth’s net climate balance, after removal via natural and artificial sink, (see: What are negative emissions?), to zero. This way humankind would be carbon neutral and global temperature would stabilise.
Sources: IPCC 2018 Special Report 15