Why would reaching 1.5C by 2030 be a big deal?
What does the latest IPCC report say?

The future looks worse. “If we do not halt our emissions soon, our future climate could well become some kind of hell on Earth,” says Prof Tim Palmer at the University of Oxford.
Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. The Intergovernmental Panel on Climate Change (IPCC), has released the Climate Change 2021 Report.
The new report has delivered the starkest warning yet about the deepening climate emergency and projected the global temperatures to shoot up over the next 20 years.
This sixth assessment report is the most up-to-date physical understanding of the climate system and climate change, bringing together the latest advances in climate science, and combining multiple lines of evidence from paleoclimate, observations, process understanding, and global and regional climate simulations.
The report was prepared by 234 scientists from 66 countries, highlights that human influence has warmed the climate at a rate that is unprecedented in at least the last 2,000 years.