As per the agreement, nations have to take action towards preventing global temperatures from rising by 2°C by 2100. But there was also a stronger goal to aim for 1.5 C.
All countries must make rapid, far-reaching and unprecedented changes across sectors to keep the increase to within 1.5°C over pre-industrial levels (1850-1900) to stop the devastating consequences of climate change, said the UN Intergovernmental Panel on Climate Change (IPCC) report in its most dire risk assessment ever. But when you put numbers on these things, some effects are particularly notable, and the roadmap to emissions cuts becomes crystal clear.
He said: 'We know what is needed to limit global warming to 1.50C and we can do it relying mostly on proven technologies such as decisively scaling up renewable energy and halting deforestation. "The next few years are probably the most important in our history". It could breach 1.5 °C some time between 2030 and 2052 if global warming continues at its current rate.
Similarly, when it comes to heat waves, in a world that's warmed by up 1.5C, about 14% of the population are exposed to a heat wave every five years.
In 2010, global negotiators adopted a goal of limiting warming to two degrees since pre-industrial times. Of the more than 100,000 terrestrial species that have been studied, for example, the number expected to disappear from half their range doubles between 1.5 and 2.0°C.
The report also warned coral reefs will decline by 70-90 percent if global warming is limited to 1.5 degrees, whereas virtually all (more than 99 percent) would be lost if temperatures rise 2 degrees.
'We also know that bold action to address climate change offers 26 trillion United States dollars [£20 trillion] in economic benefit across the global economy through to 2030.
Ten million people on small islands, low lying coastal areas, and river deltas would be protected by shaving 10 centimetres off the rise in sea levels. The broad 1.5°C pathways proposed by the SR1.5 are mainly appropriate for developed countries with capacity for significant multi-sectoral emission reductions. "And what we don't understand is that our ecosystems, on which we survive on land and in the oceans, are experiencing this more severely".
But it contains a warning about "overshooting" the 1.5C limit and trying to remove excess carbon dioxide from the atmosphere to get temperatures back down, due to the problems of relying on largely unproved technologies such as Beccs on a large scale. The bad news is that it would still require a Herculean effort.
To ensure the planet is liveable, global Carbon dioxide emissions have to be reduced by 45% from 2010 levels by 2030 and renewables must provide up to 85% of global electricity by 2050 to meet targets.
Cutting energy demand by using less of it is a highly effective step. Australia's pledge is to cut 2005-level emissions 26-28 per cent by 2030, a target environmental groups such as the Climate Action Tracker describe as "insufficient". Coal would have to be a relic of the past. The not-so-great news? They need to accelerate.
Without aggressive action, the world could become an nearly impossible place for most people to live in, says Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland in St Lucia, Australia.
Global temperature is now rising 0.2C with each decade, and it is estimated we will reach 1.5C by 2040.
But meeting the more ambitious goal of slightly less warming would require immediate, draconian cuts in emissions of heat-trapping gases and dramatic changes in the energy field.
The larger import of the finalised report's findings was not much different from that of the drafts that had leaked out earlier, though the negotiations between government representatives and scientists did end up substantially altering how much confidence the governments placed on different findings based on the scientific evidence underlying the summarised take-aways. We can't find any historical analogies for it.