The report was signed off on by the IPCC delegates on Saturday afternoon in the South Korean city of Incheon after a marathon six days of talks - including an overnighter to end the event.
"With more than 6,000 scientific references cited and the dedicated contribution of thousands of expert and government reviewers worldwide, this important report testifies to the breadth and policyrelevance of the IPCC", said Hoesung Lee, Chair of the IPCC.
The report said regionally differentiated multi-sector risks are already apparent at 1.5°C warming, being more prevalent (where) vulnerable people live, predominantly in South Asia - mostly Pakistan, India, and China, but these spread to sub-Saharan Africa, the Middle East and East Asia as temperature rises, with the world's poorest disproportionately impacted by 2°C.
The report laid out how the changes to climate, environment and human life would be less devastating and unsafe if the global temperature rise is contained at below 1.5 degree instead of 2 degree Celsius - the existing primary goal of the Paris Agreement. It's intended as a guide for policymakers who are aiming to limit temperature rise to the target 1.5 degrees Celsius.
The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5 °C, compared with at least once per decade with 2 °C.
Coral reefs will also be drastically affected, with between 70 and 90 per cent expected to die off, including Australia's Great Barrier Reef.More news: Pakistan off to steady start in first Test against Australia
Can we limit warming to that number? However, it shows that right now the world is on track to warm up by 1.5 degrees Celsius above pre-industrial levels by 2040.
The world is going to blow past its most stringent climate goal in less than a quarter century unless the political will erupts to act faster and more directly to curb greenhouse gas emissions.
The most ambitious would see a radical drawdown in energy consumption coupled with a rapid shift away from fossil fuels and a swift decline in Carbon dioxide emissions starting in 2020.
"We have done our job, we have now passed on the message", Jim Skea, a professor at Imperial College London's Centre for Environmental Policy and an IPCC co-chair, said at a press conference.
Allowing the global temperature to temporarily exceed or "overshoot" 1.5 °C would mean a greater reliance on techniques that remove Carbon dioxide from the air to return global temperature to below 1.5 °C by 2100.
The report stresses the need for measures to take carbon out of the atmosphere, such as planting forests or using land for crops to burn for energy and capturing the carbon and storing it underground, known as bioenergy and carbon capture and storage (Beccs).
The report was commissioned by world leaders as a part of the 2015 Paris Agreement, a global pact to battle global warming.More news: Hurricane Leslie forms far out in Atlantic Ocean
The IPCC, an global consortium comprised of hundreds of climate change researchers assembled by the United Nations, said "the next few years are probably the most important in our history".
But that is a big ask, considering we released more carbon dioxide into the atmosphere past year than ever before.
The IPCC report identified a range of ecosystems that will be at risk even at 1.5 degrees. The Paris pact aims to limit the global average temperature rise to "well below" 2℃ mark (above the pre-industrial level) while aiming to limit it at 1.5℃.
So the UN's Intergovernmental Panel on Climate Change (IPCC) was tasked with providing the answers.
Global Warming of 1.5 °C is the first in a series of Special Reports to be produced in the IPCC's Sixth Assessment Cycle.
Almost a decade ago, leaders of developed countries committed at the 2009 Copenhagen climate conference to mobilizing $100 billion per year of public and private finance by 2020 for climate action in developing countries. "Limiting global warming to 1.5°C compared with 2°C would reduce challenging impacts on ecosystems, human health and well-being, making it easier to achieve the United Nations sustainable development goals".More news: Rocked by Trump's sanctions, Iranian oil exports drop further