Eleven years to limit climate change catastrophe

As reported in the guardian one year ago, the October 2018 report by the UN Intergovernmental Panel on Climate Change (IPCC) warned that we had 12 years to limit climate change catastrophe, that is, to limit global warming to a maximum of 1.5C.
Beyond this, even half a degree will significantly worsen the risks of drought, floods, extreme heat and poverty for hundreds of millions of people.

B.5.1 … Poverty and disadvantage are expected to increase in some populations as global warming increases; limiting global warming to 1.5°C, compared with 2°C, could reduce the number of people both exposed to climate-related risks and susceptible to poverty by up to several hundred million by 2050 (medium confidence).

The IPCC report expresses itself in terms of how much better things will be with 1.5C compared to 2C, which is a counter-intuitive and confusing way of describing how much worse 2C is.