The Intergovernmental Panel on Climate Change (IPCC) has effectively delivered a final call on world leaders to take urgent action to stop the planet from overheating.
India could face an annual threat of deadly heatwaves, similar to the one in 2015 that had left around 2,500 people dead, if the world gets warmer by 2 degree Celsius over pre-industrial levels, a United Nations report stated.
Another recent report from the consulting firm PwC makes it clear that even limiting warming to 2 degrees C will be a stretch: "There seems to be nearly zero chance of limiting warming to well below two degrees (the main goal of the Paris Agreement), though widespread use of carbon capture and storage technologies, including Natural Climate Solutions, may make this possible", it says.
Is It A Big Deal?
The report shows a number of technically possible pathways to cut emissions quickly enough to stabilize Earth's climate at 1.5°C, but the margins are bloody thin.
The report's authors and representatives of 195 governments which are members of the IPCC have then met to finalise the "summary for policymakers" report, which involves agreeing it line-by-line.
If every country fulfills the pledges it made for the Paris agreement in 2015, the world may still warm 2.6 to 3.2 degrees C by the end of the century, by some estimates.
Dr Stephen Cornelius, chief adviser on climate change at WWF, said the world was already seeing the loss of natural habitats and species, shrinking ice caps and rising sea levels.
How Can Cuts Be Achieved? To hit and keep that 1.5 degrees target, net anthropogenic Carbon dioxide emissions must come down 45% from 2010 levels by 2030 and reach net zero around 2050.
If emissions can't be cut to a sufficient degree, researchers will need to devise effective methods of removing Carbon dioxide from the air, such as devoting land to growing trees and biofuel crops, Erik Solheim, executive director of the UN Environment Program, tells The Washington Post.
The report also flags up how people could take the initiative by changing their lifestyles, from what they eat to how they travel and heat their homes.
Compared to the already tall task of meeting the 2.0°C goal, this effort would require even more efficiency gains to bring down total energy demand.
Fellow author Valerie Masson-Delmotte said: "The report shows that we are at a crossroads". We are already ahead of those targets and are toughening up those targets. Global sea levels rose 17cm in the 20th century.
What Will We See Once Global Warming Is Limited To 1.5C?Nations settled on a target of limiting global warming to no more than 2°C a while back. Coastal cities like Miami or NY will have to adapt or abandon part or all of their territory.
Johnny Chan Chung-leung, director of City University's Guy Carpenter Asia-Pacific Climate Impact Centre, said laws - rather than targets - that mandated a certain ratio of renewables in the power mix by a certain date were also necessary.
What Has Been The Reaction So Far?
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. We can't find any historical analogies for it. Sadly, our local councils, in the last decade, have make little or no real progress, and instead they are locking-in future emissions to poor transport infrastructure.
Reining in the emissions of another greenhouse gas, methane, from the cultivation of cattle, rice and other agricultural products - even as farmers need to feed a growing global population.
Taking excess carbon from the atmosphere requires measures such as planting new forests or, more controversially, burning plant material for energy and capturing the carbon to store underground, which is known as "BECCS". Heat waves, heavy precipitation, and regional droughts increase steeply, along with their related human health impacts.
The Scottish government published its draft Climate Change Bill earlier this year, which upped a 2050 target for reducing greenhouse gas emissions from 80% to 90% against 1990 levels.